a7b10a9319
6033 arc_adjust() should search MFU lists for oldest buffer when adjusting MFU size Reviewed by: Saso Kiselkov <saso.kiselkov@nexenta.com> Reviewed by: Xin Li <delphij@delphij.net> Reviewed by: Prakash Surya <me@prakashsurya.com> Approved by: Matthew Ahrens <mahrens@delphix.com> References: https://www.illumos.org/issues/6033 https://github.com/illumos/illumos-gate/commit/31c46cf Ported-by: kernelOfTruth kerneloftruth@gmail.com Signed-off-by: Brian Behlendorf <behlendorf1@llnl.gov> Closes #3545
6637 lines
193 KiB
C
6637 lines
193 KiB
C
/*
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* CDDL HEADER START
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*
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* The contents of this file are subject to the terms of the
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* Common Development and Distribution License (the "License").
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* You may not use this file except in compliance with the License.
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*
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* You can obtain a copy of the license at usr/src/OPENSOLARIS.LICENSE
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* or http://www.opensolaris.org/os/licensing.
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* See the License for the specific language governing permissions
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* and limitations under the License.
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*
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* When distributing Covered Code, include this CDDL HEADER in each
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* file and include the License file at usr/src/OPENSOLARIS.LICENSE.
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* If applicable, add the following below this CDDL HEADER, with the
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* fields enclosed by brackets "[]" replaced with your own identifying
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* information: Portions Copyright [yyyy] [name of copyright owner]
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*
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* CDDL HEADER END
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*/
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/*
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* Copyright (c) 2005, 2010, Oracle and/or its affiliates. All rights reserved.
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* Copyright (c) 2011, 2014 by Delphix. All rights reserved.
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* Copyright (c) 2013 by Saso Kiselkov. All rights reserved.
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* Copyright 2014 Nexenta Systems, Inc. All rights reserved.
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*/
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/*
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* DVA-based Adjustable Replacement Cache
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*
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* While much of the theory of operation used here is
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* based on the self-tuning, low overhead replacement cache
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* presented by Megiddo and Modha at FAST 2003, there are some
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* significant differences:
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*
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* 1. The Megiddo and Modha model assumes any page is evictable.
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* Pages in its cache cannot be "locked" into memory. This makes
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* the eviction algorithm simple: evict the last page in the list.
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* This also make the performance characteristics easy to reason
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* about. Our cache is not so simple. At any given moment, some
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* subset of the blocks in the cache are un-evictable because we
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* have handed out a reference to them. Blocks are only evictable
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* when there are no external references active. This makes
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* eviction far more problematic: we choose to evict the evictable
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* blocks that are the "lowest" in the list.
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*
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* There are times when it is not possible to evict the requested
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* space. In these circumstances we are unable to adjust the cache
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* size. To prevent the cache growing unbounded at these times we
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* implement a "cache throttle" that slows the flow of new data
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* into the cache until we can make space available.
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*
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* 2. The Megiddo and Modha model assumes a fixed cache size.
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* Pages are evicted when the cache is full and there is a cache
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* miss. Our model has a variable sized cache. It grows with
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* high use, but also tries to react to memory pressure from the
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* operating system: decreasing its size when system memory is
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* tight.
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*
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* 3. The Megiddo and Modha model assumes a fixed page size. All
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* elements of the cache are therefore exactly the same size. So
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* when adjusting the cache size following a cache miss, its simply
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* a matter of choosing a single page to evict. In our model, we
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* have variable sized cache blocks (rangeing from 512 bytes to
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* 128K bytes). We therefore choose a set of blocks to evict to make
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* space for a cache miss that approximates as closely as possible
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* the space used by the new block.
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*
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* See also: "ARC: A Self-Tuning, Low Overhead Replacement Cache"
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* by N. Megiddo & D. Modha, FAST 2003
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*/
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/*
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* The locking model:
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*
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* A new reference to a cache buffer can be obtained in two
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* ways: 1) via a hash table lookup using the DVA as a key,
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* or 2) via one of the ARC lists. The arc_read() interface
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* uses method 1, while the internal arc algorithms for
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* adjusting the cache use method 2. We therefore provide two
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* types of locks: 1) the hash table lock array, and 2) the
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* arc list locks.
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*
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* Buffers do not have their own mutexes, rather they rely on the
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* hash table mutexes for the bulk of their protection (i.e. most
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* fields in the arc_buf_hdr_t are protected by these mutexes).
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*
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* buf_hash_find() returns the appropriate mutex (held) when it
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* locates the requested buffer in the hash table. It returns
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* NULL for the mutex if the buffer was not in the table.
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*
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* buf_hash_remove() expects the appropriate hash mutex to be
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* already held before it is invoked.
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*
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* Each arc state also has a mutex which is used to protect the
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* buffer list associated with the state. When attempting to
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* obtain a hash table lock while holding an arc list lock you
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* must use: mutex_tryenter() to avoid deadlock. Also note that
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* the active state mutex must be held before the ghost state mutex.
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*
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* Arc buffers may have an associated eviction callback function.
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* This function will be invoked prior to removing the buffer (e.g.
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* in arc_do_user_evicts()). Note however that the data associated
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* with the buffer may be evicted prior to the callback. The callback
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* must be made with *no locks held* (to prevent deadlock). Additionally,
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* the users of callbacks must ensure that their private data is
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* protected from simultaneous callbacks from arc_clear_callback()
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* and arc_do_user_evicts().
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*
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* It as also possible to register a callback which is run when the
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* arc_meta_limit is reached and no buffers can be safely evicted. In
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* this case the arc user should drop a reference on some arc buffers so
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* they can be reclaimed and the arc_meta_limit honored. For example,
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* when using the ZPL each dentry holds a references on a znode. These
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* dentries must be pruned before the arc buffer holding the znode can
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* be safely evicted.
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*
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* Note that the majority of the performance stats are manipulated
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* with atomic operations.
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*
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* The L2ARC uses the l2ad_mtx on each vdev for the following:
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*
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* - L2ARC buflist creation
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* - L2ARC buflist eviction
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* - L2ARC write completion, which walks L2ARC buflists
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* - ARC header destruction, as it removes from L2ARC buflists
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* - ARC header release, as it removes from L2ARC buflists
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*/
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#include <sys/spa.h>
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#include <sys/zio.h>
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#include <sys/zio_compress.h>
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#include <sys/zfs_context.h>
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#include <sys/arc.h>
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#include <sys/vdev.h>
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#include <sys/vdev_impl.h>
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#include <sys/dsl_pool.h>
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#include <sys/multilist.h>
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#ifdef _KERNEL
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#include <sys/vmsystm.h>
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#include <vm/anon.h>
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#include <sys/fs/swapnode.h>
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#include <sys/zpl.h>
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#include <linux/mm_compat.h>
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#endif
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#include <sys/callb.h>
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#include <sys/kstat.h>
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#include <sys/dmu_tx.h>
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#include <zfs_fletcher.h>
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#include <sys/arc_impl.h>
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#include <sys/trace_arc.h>
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#ifndef _KERNEL
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/* set with ZFS_DEBUG=watch, to enable watchpoints on frozen buffers */
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boolean_t arc_watch = B_FALSE;
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#endif
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static kmutex_t arc_reclaim_lock;
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static kcondvar_t arc_reclaim_thread_cv;
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static boolean_t arc_reclaim_thread_exit;
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static kcondvar_t arc_reclaim_waiters_cv;
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static kmutex_t arc_user_evicts_lock;
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static kcondvar_t arc_user_evicts_cv;
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static boolean_t arc_user_evicts_thread_exit;
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/* number of objects to prune from caches when arc_meta_limit is reached */
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int zfs_arc_meta_prune = 10000;
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/* The preferred strategy to employ when arc_meta_limit is reached */
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int zfs_arc_meta_strategy = ARC_STRATEGY_META_BALANCED;
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typedef enum arc_reclaim_strategy {
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ARC_RECLAIM_AGGR, /* Aggressive reclaim strategy */
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ARC_RECLAIM_CONS /* Conservative reclaim strategy */
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} arc_reclaim_strategy_t;
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/*
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* The number of headers to evict in arc_evict_state_impl() before
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* dropping the sublist lock and evicting from another sublist. A lower
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* value means we're more likely to evict the "correct" header (i.e. the
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* oldest header in the arc state), but comes with higher overhead
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* (i.e. more invocations of arc_evict_state_impl()).
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*/
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int zfs_arc_evict_batch_limit = 10;
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/*
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* The number of sublists used for each of the arc state lists. If this
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* is not set to a suitable value by the user, it will be configured to
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* the number of CPUs on the system in arc_init().
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*/
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int zfs_arc_num_sublists_per_state = 0;
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/* number of seconds before growing cache again */
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int zfs_arc_grow_retry = 5;
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/* shift of arc_c for calculating overflow limit in arc_get_data_buf */
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int zfs_arc_overflow_shift = 8;
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/* disable anon data aggressively growing arc_p */
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int zfs_arc_p_aggressive_disable = 1;
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/* disable arc_p adapt dampener in arc_adapt */
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int zfs_arc_p_dampener_disable = 1;
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/* log2(fraction of arc to reclaim) */
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int zfs_arc_shrink_shift = 5;
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/*
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* minimum lifespan of a prefetch block in clock ticks
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* (initialized in arc_init())
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*/
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int zfs_arc_min_prefetch_lifespan = HZ;
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/* disable arc proactive arc throttle due to low memory */
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int zfs_arc_memory_throttle_disable = 1;
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/* disable duplicate buffer eviction */
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int zfs_disable_dup_eviction = 0;
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/* average block used to size buf_hash_table */
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int zfs_arc_average_blocksize = 8 * 1024; /* 8KB */
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/*
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* minimum lifespan of a prefetch block in clock ticks
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* (initialized in arc_init())
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*/
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static int arc_min_prefetch_lifespan;
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/*
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* If this percent of memory is free, don't throttle.
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*/
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int arc_lotsfree_percent = 10;
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static int arc_dead;
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/* expiration time for arc_no_grow */
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static clock_t arc_grow_time = 0;
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/*
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* The arc has filled available memory and has now warmed up.
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*/
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static boolean_t arc_warm;
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/*
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* These tunables are for performance analysis.
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*/
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unsigned long zfs_arc_max = 0;
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unsigned long zfs_arc_min = 0;
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unsigned long zfs_arc_meta_limit = 0;
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unsigned long zfs_arc_meta_min = 0;
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/*
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* Limit the number of restarts in arc_adjust_meta()
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*/
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unsigned long zfs_arc_meta_adjust_restarts = 4096;
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/* The 6 states: */
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static arc_state_t ARC_anon;
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static arc_state_t ARC_mru;
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static arc_state_t ARC_mru_ghost;
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static arc_state_t ARC_mfu;
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static arc_state_t ARC_mfu_ghost;
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static arc_state_t ARC_l2c_only;
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typedef struct arc_stats {
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kstat_named_t arcstat_hits;
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kstat_named_t arcstat_misses;
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kstat_named_t arcstat_demand_data_hits;
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kstat_named_t arcstat_demand_data_misses;
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kstat_named_t arcstat_demand_metadata_hits;
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kstat_named_t arcstat_demand_metadata_misses;
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kstat_named_t arcstat_prefetch_data_hits;
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kstat_named_t arcstat_prefetch_data_misses;
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kstat_named_t arcstat_prefetch_metadata_hits;
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kstat_named_t arcstat_prefetch_metadata_misses;
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kstat_named_t arcstat_mru_hits;
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kstat_named_t arcstat_mru_ghost_hits;
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kstat_named_t arcstat_mfu_hits;
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kstat_named_t arcstat_mfu_ghost_hits;
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kstat_named_t arcstat_deleted;
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/*
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* Number of buffers that could not be evicted because the hash lock
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* was held by another thread. The lock may not necessarily be held
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* by something using the same buffer, since hash locks are shared
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* by multiple buffers.
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*/
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kstat_named_t arcstat_mutex_miss;
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/*
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* Number of buffers skipped because they have I/O in progress, are
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* indrect prefetch buffers that have not lived long enough, or are
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* not from the spa we're trying to evict from.
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*/
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kstat_named_t arcstat_evict_skip;
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/*
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* Number of times arc_evict_state() was unable to evict enough
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* buffers to reach its target amount.
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*/
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kstat_named_t arcstat_evict_not_enough;
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kstat_named_t arcstat_evict_l2_cached;
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kstat_named_t arcstat_evict_l2_eligible;
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kstat_named_t arcstat_evict_l2_ineligible;
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kstat_named_t arcstat_evict_l2_skip;
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kstat_named_t arcstat_hash_elements;
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kstat_named_t arcstat_hash_elements_max;
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kstat_named_t arcstat_hash_collisions;
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kstat_named_t arcstat_hash_chains;
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kstat_named_t arcstat_hash_chain_max;
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kstat_named_t arcstat_p;
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kstat_named_t arcstat_c;
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kstat_named_t arcstat_c_min;
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kstat_named_t arcstat_c_max;
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kstat_named_t arcstat_size;
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kstat_named_t arcstat_hdr_size;
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kstat_named_t arcstat_data_size;
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kstat_named_t arcstat_meta_size;
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kstat_named_t arcstat_other_size;
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kstat_named_t arcstat_anon_size;
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kstat_named_t arcstat_anon_evict_data;
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kstat_named_t arcstat_anon_evict_metadata;
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kstat_named_t arcstat_mru_size;
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kstat_named_t arcstat_mru_evict_data;
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kstat_named_t arcstat_mru_evict_metadata;
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kstat_named_t arcstat_mru_ghost_size;
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kstat_named_t arcstat_mru_ghost_evict_data;
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kstat_named_t arcstat_mru_ghost_evict_metadata;
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kstat_named_t arcstat_mfu_size;
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kstat_named_t arcstat_mfu_evict_data;
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kstat_named_t arcstat_mfu_evict_metadata;
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kstat_named_t arcstat_mfu_ghost_size;
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kstat_named_t arcstat_mfu_ghost_evict_data;
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kstat_named_t arcstat_mfu_ghost_evict_metadata;
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kstat_named_t arcstat_l2_hits;
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kstat_named_t arcstat_l2_misses;
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kstat_named_t arcstat_l2_feeds;
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kstat_named_t arcstat_l2_rw_clash;
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kstat_named_t arcstat_l2_read_bytes;
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kstat_named_t arcstat_l2_write_bytes;
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kstat_named_t arcstat_l2_writes_sent;
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kstat_named_t arcstat_l2_writes_done;
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kstat_named_t arcstat_l2_writes_error;
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kstat_named_t arcstat_l2_writes_lock_retry;
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kstat_named_t arcstat_l2_evict_lock_retry;
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kstat_named_t arcstat_l2_evict_reading;
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kstat_named_t arcstat_l2_evict_l1cached;
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kstat_named_t arcstat_l2_free_on_write;
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kstat_named_t arcstat_l2_cdata_free_on_write;
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kstat_named_t arcstat_l2_abort_lowmem;
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kstat_named_t arcstat_l2_cksum_bad;
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kstat_named_t arcstat_l2_io_error;
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kstat_named_t arcstat_l2_size;
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kstat_named_t arcstat_l2_asize;
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kstat_named_t arcstat_l2_hdr_size;
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kstat_named_t arcstat_l2_compress_successes;
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kstat_named_t arcstat_l2_compress_zeros;
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kstat_named_t arcstat_l2_compress_failures;
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kstat_named_t arcstat_memory_throttle_count;
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kstat_named_t arcstat_duplicate_buffers;
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kstat_named_t arcstat_duplicate_buffers_size;
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kstat_named_t arcstat_duplicate_reads;
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kstat_named_t arcstat_memory_direct_count;
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kstat_named_t arcstat_memory_indirect_count;
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kstat_named_t arcstat_no_grow;
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kstat_named_t arcstat_tempreserve;
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kstat_named_t arcstat_loaned_bytes;
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kstat_named_t arcstat_prune;
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kstat_named_t arcstat_meta_used;
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kstat_named_t arcstat_meta_limit;
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kstat_named_t arcstat_meta_max;
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kstat_named_t arcstat_meta_min;
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} arc_stats_t;
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static arc_stats_t arc_stats = {
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{ "hits", KSTAT_DATA_UINT64 },
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{ "misses", KSTAT_DATA_UINT64 },
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{ "demand_data_hits", KSTAT_DATA_UINT64 },
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{ "demand_data_misses", KSTAT_DATA_UINT64 },
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{ "demand_metadata_hits", KSTAT_DATA_UINT64 },
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{ "demand_metadata_misses", KSTAT_DATA_UINT64 },
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{ "prefetch_data_hits", KSTAT_DATA_UINT64 },
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{ "prefetch_data_misses", KSTAT_DATA_UINT64 },
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{ "prefetch_metadata_hits", KSTAT_DATA_UINT64 },
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{ "prefetch_metadata_misses", KSTAT_DATA_UINT64 },
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{ "mru_hits", KSTAT_DATA_UINT64 },
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{ "mru_ghost_hits", KSTAT_DATA_UINT64 },
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{ "mfu_hits", KSTAT_DATA_UINT64 },
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{ "mfu_ghost_hits", KSTAT_DATA_UINT64 },
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{ "deleted", KSTAT_DATA_UINT64 },
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{ "mutex_miss", KSTAT_DATA_UINT64 },
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{ "evict_skip", KSTAT_DATA_UINT64 },
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{ "evict_not_enough", KSTAT_DATA_UINT64 },
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{ "evict_l2_cached", KSTAT_DATA_UINT64 },
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{ "evict_l2_eligible", KSTAT_DATA_UINT64 },
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{ "evict_l2_ineligible", KSTAT_DATA_UINT64 },
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{ "evict_l2_skip", KSTAT_DATA_UINT64 },
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{ "hash_elements", KSTAT_DATA_UINT64 },
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{ "hash_elements_max", KSTAT_DATA_UINT64 },
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{ "hash_collisions", KSTAT_DATA_UINT64 },
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{ "hash_chains", KSTAT_DATA_UINT64 },
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{ "hash_chain_max", KSTAT_DATA_UINT64 },
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{ "p", KSTAT_DATA_UINT64 },
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{ "c", KSTAT_DATA_UINT64 },
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{ "c_min", KSTAT_DATA_UINT64 },
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{ "c_max", KSTAT_DATA_UINT64 },
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{ "size", KSTAT_DATA_UINT64 },
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{ "hdr_size", KSTAT_DATA_UINT64 },
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{ "data_size", KSTAT_DATA_UINT64 },
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{ "meta_size", KSTAT_DATA_UINT64 },
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{ "other_size", KSTAT_DATA_UINT64 },
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{ "anon_size", KSTAT_DATA_UINT64 },
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{ "anon_evict_data", KSTAT_DATA_UINT64 },
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{ "anon_evict_metadata", KSTAT_DATA_UINT64 },
|
|
{ "mru_size", KSTAT_DATA_UINT64 },
|
|
{ "mru_evict_data", KSTAT_DATA_UINT64 },
|
|
{ "mru_evict_metadata", KSTAT_DATA_UINT64 },
|
|
{ "mru_ghost_size", KSTAT_DATA_UINT64 },
|
|
{ "mru_ghost_evict_data", KSTAT_DATA_UINT64 },
|
|
{ "mru_ghost_evict_metadata", KSTAT_DATA_UINT64 },
|
|
{ "mfu_size", KSTAT_DATA_UINT64 },
|
|
{ "mfu_evict_data", KSTAT_DATA_UINT64 },
|
|
{ "mfu_evict_metadata", KSTAT_DATA_UINT64 },
|
|
{ "mfu_ghost_size", KSTAT_DATA_UINT64 },
|
|
{ "mfu_ghost_evict_data", KSTAT_DATA_UINT64 },
|
|
{ "mfu_ghost_evict_metadata", KSTAT_DATA_UINT64 },
|
|
{ "l2_hits", KSTAT_DATA_UINT64 },
|
|
{ "l2_misses", KSTAT_DATA_UINT64 },
|
|
{ "l2_feeds", KSTAT_DATA_UINT64 },
|
|
{ "l2_rw_clash", KSTAT_DATA_UINT64 },
|
|
{ "l2_read_bytes", KSTAT_DATA_UINT64 },
|
|
{ "l2_write_bytes", KSTAT_DATA_UINT64 },
|
|
{ "l2_writes_sent", KSTAT_DATA_UINT64 },
|
|
{ "l2_writes_done", KSTAT_DATA_UINT64 },
|
|
{ "l2_writes_error", KSTAT_DATA_UINT64 },
|
|
{ "l2_writes_lock_retry", KSTAT_DATA_UINT64 },
|
|
{ "l2_evict_lock_retry", KSTAT_DATA_UINT64 },
|
|
{ "l2_evict_reading", KSTAT_DATA_UINT64 },
|
|
{ "l2_evict_l1cached", KSTAT_DATA_UINT64 },
|
|
{ "l2_free_on_write", KSTAT_DATA_UINT64 },
|
|
{ "l2_cdata_free_on_write", KSTAT_DATA_UINT64 },
|
|
{ "l2_abort_lowmem", KSTAT_DATA_UINT64 },
|
|
{ "l2_cksum_bad", KSTAT_DATA_UINT64 },
|
|
{ "l2_io_error", KSTAT_DATA_UINT64 },
|
|
{ "l2_size", KSTAT_DATA_UINT64 },
|
|
{ "l2_asize", KSTAT_DATA_UINT64 },
|
|
{ "l2_hdr_size", KSTAT_DATA_UINT64 },
|
|
{ "l2_compress_successes", KSTAT_DATA_UINT64 },
|
|
{ "l2_compress_zeros", KSTAT_DATA_UINT64 },
|
|
{ "l2_compress_failures", KSTAT_DATA_UINT64 },
|
|
{ "memory_throttle_count", KSTAT_DATA_UINT64 },
|
|
{ "duplicate_buffers", KSTAT_DATA_UINT64 },
|
|
{ "duplicate_buffers_size", KSTAT_DATA_UINT64 },
|
|
{ "duplicate_reads", KSTAT_DATA_UINT64 },
|
|
{ "memory_direct_count", KSTAT_DATA_UINT64 },
|
|
{ "memory_indirect_count", KSTAT_DATA_UINT64 },
|
|
{ "arc_no_grow", KSTAT_DATA_UINT64 },
|
|
{ "arc_tempreserve", KSTAT_DATA_UINT64 },
|
|
{ "arc_loaned_bytes", KSTAT_DATA_UINT64 },
|
|
{ "arc_prune", KSTAT_DATA_UINT64 },
|
|
{ "arc_meta_used", KSTAT_DATA_UINT64 },
|
|
{ "arc_meta_limit", KSTAT_DATA_UINT64 },
|
|
{ "arc_meta_max", KSTAT_DATA_UINT64 },
|
|
{ "arc_meta_min", KSTAT_DATA_UINT64 },
|
|
};
|
|
|
|
#define ARCSTAT(stat) (arc_stats.stat.value.ui64)
|
|
|
|
#define ARCSTAT_INCR(stat, val) \
|
|
atomic_add_64(&arc_stats.stat.value.ui64, (val))
|
|
|
|
#define ARCSTAT_BUMP(stat) ARCSTAT_INCR(stat, 1)
|
|
#define ARCSTAT_BUMPDOWN(stat) ARCSTAT_INCR(stat, -1)
|
|
|
|
#define ARCSTAT_MAX(stat, val) { \
|
|
uint64_t m; \
|
|
while ((val) > (m = arc_stats.stat.value.ui64) && \
|
|
(m != atomic_cas_64(&arc_stats.stat.value.ui64, m, (val)))) \
|
|
continue; \
|
|
}
|
|
|
|
#define ARCSTAT_MAXSTAT(stat) \
|
|
ARCSTAT_MAX(stat##_max, arc_stats.stat.value.ui64)
|
|
|
|
/*
|
|
* We define a macro to allow ARC hits/misses to be easily broken down by
|
|
* two separate conditions, giving a total of four different subtypes for
|
|
* each of hits and misses (so eight statistics total).
|
|
*/
|
|
#define ARCSTAT_CONDSTAT(cond1, stat1, notstat1, cond2, stat2, notstat2, stat) \
|
|
if (cond1) { \
|
|
if (cond2) { \
|
|
ARCSTAT_BUMP(arcstat_##stat1##_##stat2##_##stat); \
|
|
} else { \
|
|
ARCSTAT_BUMP(arcstat_##stat1##_##notstat2##_##stat); \
|
|
} \
|
|
} else { \
|
|
if (cond2) { \
|
|
ARCSTAT_BUMP(arcstat_##notstat1##_##stat2##_##stat); \
|
|
} else { \
|
|
ARCSTAT_BUMP(arcstat_##notstat1##_##notstat2##_##stat);\
|
|
} \
|
|
}
|
|
|
|
kstat_t *arc_ksp;
|
|
static arc_state_t *arc_anon;
|
|
static arc_state_t *arc_mru;
|
|
static arc_state_t *arc_mru_ghost;
|
|
static arc_state_t *arc_mfu;
|
|
static arc_state_t *arc_mfu_ghost;
|
|
static arc_state_t *arc_l2c_only;
|
|
|
|
/*
|
|
* There are several ARC variables that are critical to export as kstats --
|
|
* but we don't want to have to grovel around in the kstat whenever we wish to
|
|
* manipulate them. For these variables, we therefore define them to be in
|
|
* terms of the statistic variable. This assures that we are not introducing
|
|
* the possibility of inconsistency by having shadow copies of the variables,
|
|
* while still allowing the code to be readable.
|
|
*/
|
|
#define arc_size ARCSTAT(arcstat_size) /* actual total arc size */
|
|
#define arc_p ARCSTAT(arcstat_p) /* target size of MRU */
|
|
#define arc_c ARCSTAT(arcstat_c) /* target size of cache */
|
|
#define arc_c_min ARCSTAT(arcstat_c_min) /* min target cache size */
|
|
#define arc_c_max ARCSTAT(arcstat_c_max) /* max target cache size */
|
|
#define arc_no_grow ARCSTAT(arcstat_no_grow)
|
|
#define arc_tempreserve ARCSTAT(arcstat_tempreserve)
|
|
#define arc_loaned_bytes ARCSTAT(arcstat_loaned_bytes)
|
|
#define arc_meta_limit ARCSTAT(arcstat_meta_limit) /* max size for metadata */
|
|
#define arc_meta_min ARCSTAT(arcstat_meta_min) /* min size for metadata */
|
|
#define arc_meta_used ARCSTAT(arcstat_meta_used) /* size of metadata */
|
|
#define arc_meta_max ARCSTAT(arcstat_meta_max) /* max size of metadata */
|
|
|
|
#define L2ARC_IS_VALID_COMPRESS(_c_) \
|
|
((_c_) == ZIO_COMPRESS_LZ4 || (_c_) == ZIO_COMPRESS_EMPTY)
|
|
|
|
static list_t arc_prune_list;
|
|
static kmutex_t arc_prune_mtx;
|
|
static taskq_t *arc_prune_taskq;
|
|
static arc_buf_t *arc_eviction_list;
|
|
static arc_buf_hdr_t arc_eviction_hdr;
|
|
|
|
#define GHOST_STATE(state) \
|
|
((state) == arc_mru_ghost || (state) == arc_mfu_ghost || \
|
|
(state) == arc_l2c_only)
|
|
|
|
#define HDR_IN_HASH_TABLE(hdr) ((hdr)->b_flags & ARC_FLAG_IN_HASH_TABLE)
|
|
#define HDR_IO_IN_PROGRESS(hdr) ((hdr)->b_flags & ARC_FLAG_IO_IN_PROGRESS)
|
|
#define HDR_IO_ERROR(hdr) ((hdr)->b_flags & ARC_FLAG_IO_ERROR)
|
|
#define HDR_PREFETCH(hdr) ((hdr)->b_flags & ARC_FLAG_PREFETCH)
|
|
#define HDR_FREED_IN_READ(hdr) ((hdr)->b_flags & ARC_FLAG_FREED_IN_READ)
|
|
#define HDR_BUF_AVAILABLE(hdr) ((hdr)->b_flags & ARC_FLAG_BUF_AVAILABLE)
|
|
|
|
#define HDR_L2CACHE(hdr) ((hdr)->b_flags & ARC_FLAG_L2CACHE)
|
|
#define HDR_L2COMPRESS(hdr) ((hdr)->b_flags & ARC_FLAG_L2COMPRESS)
|
|
#define HDR_L2_READING(hdr) \
|
|
(((hdr)->b_flags & ARC_FLAG_IO_IN_PROGRESS) && \
|
|
((hdr)->b_flags & ARC_FLAG_HAS_L2HDR))
|
|
#define HDR_L2_WRITING(hdr) ((hdr)->b_flags & ARC_FLAG_L2_WRITING)
|
|
#define HDR_L2_EVICTED(hdr) ((hdr)->b_flags & ARC_FLAG_L2_EVICTED)
|
|
#define HDR_L2_WRITE_HEAD(hdr) ((hdr)->b_flags & ARC_FLAG_L2_WRITE_HEAD)
|
|
|
|
#define HDR_ISTYPE_METADATA(hdr) \
|
|
((hdr)->b_flags & ARC_FLAG_BUFC_METADATA)
|
|
#define HDR_ISTYPE_DATA(hdr) (!HDR_ISTYPE_METADATA(hdr))
|
|
|
|
#define HDR_HAS_L1HDR(hdr) ((hdr)->b_flags & ARC_FLAG_HAS_L1HDR)
|
|
#define HDR_HAS_L2HDR(hdr) ((hdr)->b_flags & ARC_FLAG_HAS_L2HDR)
|
|
|
|
/* For storing compression mode in b_flags */
|
|
#define HDR_COMPRESS_OFFSET 24
|
|
#define HDR_COMPRESS_NBITS 7
|
|
|
|
#define HDR_GET_COMPRESS(hdr) ((enum zio_compress)BF32_GET(hdr->b_flags, \
|
|
HDR_COMPRESS_OFFSET, HDR_COMPRESS_NBITS))
|
|
#define HDR_SET_COMPRESS(hdr, cmp) BF32_SET(hdr->b_flags, \
|
|
HDR_COMPRESS_OFFSET, HDR_COMPRESS_NBITS, (cmp))
|
|
|
|
/*
|
|
* Other sizes
|
|
*/
|
|
|
|
#define HDR_FULL_SIZE ((int64_t)sizeof (arc_buf_hdr_t))
|
|
#define HDR_L2ONLY_SIZE ((int64_t)offsetof(arc_buf_hdr_t, b_l1hdr))
|
|
|
|
/*
|
|
* Hash table routines
|
|
*/
|
|
|
|
#define HT_LOCK_ALIGN 64
|
|
#define HT_LOCK_PAD (P2NPHASE(sizeof (kmutex_t), (HT_LOCK_ALIGN)))
|
|
|
|
struct ht_lock {
|
|
kmutex_t ht_lock;
|
|
#ifdef _KERNEL
|
|
unsigned char pad[HT_LOCK_PAD];
|
|
#endif
|
|
};
|
|
|
|
#define BUF_LOCKS 8192
|
|
typedef struct buf_hash_table {
|
|
uint64_t ht_mask;
|
|
arc_buf_hdr_t **ht_table;
|
|
struct ht_lock ht_locks[BUF_LOCKS];
|
|
} buf_hash_table_t;
|
|
|
|
static buf_hash_table_t buf_hash_table;
|
|
|
|
#define BUF_HASH_INDEX(spa, dva, birth) \
|
|
(buf_hash(spa, dva, birth) & buf_hash_table.ht_mask)
|
|
#define BUF_HASH_LOCK_NTRY(idx) (buf_hash_table.ht_locks[idx & (BUF_LOCKS-1)])
|
|
#define BUF_HASH_LOCK(idx) (&(BUF_HASH_LOCK_NTRY(idx).ht_lock))
|
|
#define HDR_LOCK(hdr) \
|
|
(BUF_HASH_LOCK(BUF_HASH_INDEX(hdr->b_spa, &hdr->b_dva, hdr->b_birth)))
|
|
|
|
uint64_t zfs_crc64_table[256];
|
|
|
|
/*
|
|
* Level 2 ARC
|
|
*/
|
|
|
|
#define L2ARC_WRITE_SIZE (8 * 1024 * 1024) /* initial write max */
|
|
#define L2ARC_HEADROOM 2 /* num of writes */
|
|
/*
|
|
* If we discover during ARC scan any buffers to be compressed, we boost
|
|
* our headroom for the next scanning cycle by this percentage multiple.
|
|
*/
|
|
#define L2ARC_HEADROOM_BOOST 200
|
|
#define L2ARC_FEED_SECS 1 /* caching interval secs */
|
|
#define L2ARC_FEED_MIN_MS 200 /* min caching interval ms */
|
|
|
|
/*
|
|
* Used to distinguish headers that are being process by
|
|
* l2arc_write_buffers(), but have yet to be assigned to a l2arc disk
|
|
* address. This can happen when the header is added to the l2arc's list
|
|
* of buffers to write in the first stage of l2arc_write_buffers(), but
|
|
* has not yet been written out which happens in the second stage of
|
|
* l2arc_write_buffers().
|
|
*/
|
|
#define L2ARC_ADDR_UNSET ((uint64_t)(-1))
|
|
|
|
#define l2arc_writes_sent ARCSTAT(arcstat_l2_writes_sent)
|
|
#define l2arc_writes_done ARCSTAT(arcstat_l2_writes_done)
|
|
|
|
/* L2ARC Performance Tunables */
|
|
unsigned long l2arc_write_max = L2ARC_WRITE_SIZE; /* def max write size */
|
|
unsigned long l2arc_write_boost = L2ARC_WRITE_SIZE; /* extra warmup write */
|
|
unsigned long l2arc_headroom = L2ARC_HEADROOM; /* # of dev writes */
|
|
unsigned long l2arc_headroom_boost = L2ARC_HEADROOM_BOOST;
|
|
unsigned long l2arc_feed_secs = L2ARC_FEED_SECS; /* interval seconds */
|
|
unsigned long l2arc_feed_min_ms = L2ARC_FEED_MIN_MS; /* min interval msecs */
|
|
int l2arc_noprefetch = B_TRUE; /* don't cache prefetch bufs */
|
|
int l2arc_nocompress = B_FALSE; /* don't compress bufs */
|
|
int l2arc_feed_again = B_TRUE; /* turbo warmup */
|
|
int l2arc_norw = B_FALSE; /* no reads during writes */
|
|
|
|
/*
|
|
* L2ARC Internals
|
|
*/
|
|
static list_t L2ARC_dev_list; /* device list */
|
|
static list_t *l2arc_dev_list; /* device list pointer */
|
|
static kmutex_t l2arc_dev_mtx; /* device list mutex */
|
|
static l2arc_dev_t *l2arc_dev_last; /* last device used */
|
|
static list_t L2ARC_free_on_write; /* free after write buf list */
|
|
static list_t *l2arc_free_on_write; /* free after write list ptr */
|
|
static kmutex_t l2arc_free_on_write_mtx; /* mutex for list */
|
|
static uint64_t l2arc_ndev; /* number of devices */
|
|
|
|
typedef struct l2arc_read_callback {
|
|
arc_buf_t *l2rcb_buf; /* read buffer */
|
|
spa_t *l2rcb_spa; /* spa */
|
|
blkptr_t l2rcb_bp; /* original blkptr */
|
|
zbookmark_phys_t l2rcb_zb; /* original bookmark */
|
|
int l2rcb_flags; /* original flags */
|
|
enum zio_compress l2rcb_compress; /* applied compress */
|
|
} l2arc_read_callback_t;
|
|
|
|
typedef struct l2arc_data_free {
|
|
/* protected by l2arc_free_on_write_mtx */
|
|
void *l2df_data;
|
|
size_t l2df_size;
|
|
void (*l2df_func)(void *, size_t);
|
|
list_node_t l2df_list_node;
|
|
} l2arc_data_free_t;
|
|
|
|
static kmutex_t l2arc_feed_thr_lock;
|
|
static kcondvar_t l2arc_feed_thr_cv;
|
|
static uint8_t l2arc_thread_exit;
|
|
|
|
static void arc_get_data_buf(arc_buf_t *);
|
|
static void arc_access(arc_buf_hdr_t *, kmutex_t *);
|
|
static boolean_t arc_is_overflowing(void);
|
|
static void arc_buf_watch(arc_buf_t *);
|
|
|
|
static arc_buf_contents_t arc_buf_type(arc_buf_hdr_t *);
|
|
static uint32_t arc_bufc_to_flags(arc_buf_contents_t);
|
|
|
|
static boolean_t l2arc_write_eligible(uint64_t, arc_buf_hdr_t *);
|
|
static void l2arc_read_done(zio_t *);
|
|
|
|
static boolean_t l2arc_compress_buf(arc_buf_hdr_t *);
|
|
static void l2arc_decompress_zio(zio_t *, arc_buf_hdr_t *, enum zio_compress);
|
|
static void l2arc_release_cdata_buf(arc_buf_hdr_t *);
|
|
|
|
static uint64_t
|
|
buf_hash(uint64_t spa, const dva_t *dva, uint64_t birth)
|
|
{
|
|
uint8_t *vdva = (uint8_t *)dva;
|
|
uint64_t crc = -1ULL;
|
|
int i;
|
|
|
|
ASSERT(zfs_crc64_table[128] == ZFS_CRC64_POLY);
|
|
|
|
for (i = 0; i < sizeof (dva_t); i++)
|
|
crc = (crc >> 8) ^ zfs_crc64_table[(crc ^ vdva[i]) & 0xFF];
|
|
|
|
crc ^= (spa>>8) ^ birth;
|
|
|
|
return (crc);
|
|
}
|
|
|
|
#define BUF_EMPTY(buf) \
|
|
((buf)->b_dva.dva_word[0] == 0 && \
|
|
(buf)->b_dva.dva_word[1] == 0)
|
|
|
|
#define BUF_EQUAL(spa, dva, birth, buf) \
|
|
((buf)->b_dva.dva_word[0] == (dva)->dva_word[0]) && \
|
|
((buf)->b_dva.dva_word[1] == (dva)->dva_word[1]) && \
|
|
((buf)->b_birth == birth) && ((buf)->b_spa == spa)
|
|
|
|
static void
|
|
buf_discard_identity(arc_buf_hdr_t *hdr)
|
|
{
|
|
hdr->b_dva.dva_word[0] = 0;
|
|
hdr->b_dva.dva_word[1] = 0;
|
|
hdr->b_birth = 0;
|
|
}
|
|
|
|
static arc_buf_hdr_t *
|
|
buf_hash_find(uint64_t spa, const blkptr_t *bp, kmutex_t **lockp)
|
|
{
|
|
const dva_t *dva = BP_IDENTITY(bp);
|
|
uint64_t birth = BP_PHYSICAL_BIRTH(bp);
|
|
uint64_t idx = BUF_HASH_INDEX(spa, dva, birth);
|
|
kmutex_t *hash_lock = BUF_HASH_LOCK(idx);
|
|
arc_buf_hdr_t *hdr;
|
|
|
|
mutex_enter(hash_lock);
|
|
for (hdr = buf_hash_table.ht_table[idx]; hdr != NULL;
|
|
hdr = hdr->b_hash_next) {
|
|
if (BUF_EQUAL(spa, dva, birth, hdr)) {
|
|
*lockp = hash_lock;
|
|
return (hdr);
|
|
}
|
|
}
|
|
mutex_exit(hash_lock);
|
|
*lockp = NULL;
|
|
return (NULL);
|
|
}
|
|
|
|
/*
|
|
* Insert an entry into the hash table. If there is already an element
|
|
* equal to elem in the hash table, then the already existing element
|
|
* will be returned and the new element will not be inserted.
|
|
* Otherwise returns NULL.
|
|
* If lockp == NULL, the caller is assumed to already hold the hash lock.
|
|
*/
|
|
static arc_buf_hdr_t *
|
|
buf_hash_insert(arc_buf_hdr_t *hdr, kmutex_t **lockp)
|
|
{
|
|
uint64_t idx = BUF_HASH_INDEX(hdr->b_spa, &hdr->b_dva, hdr->b_birth);
|
|
kmutex_t *hash_lock = BUF_HASH_LOCK(idx);
|
|
arc_buf_hdr_t *fhdr;
|
|
uint32_t i;
|
|
|
|
ASSERT(!DVA_IS_EMPTY(&hdr->b_dva));
|
|
ASSERT(hdr->b_birth != 0);
|
|
ASSERT(!HDR_IN_HASH_TABLE(hdr));
|
|
|
|
if (lockp != NULL) {
|
|
*lockp = hash_lock;
|
|
mutex_enter(hash_lock);
|
|
} else {
|
|
ASSERT(MUTEX_HELD(hash_lock));
|
|
}
|
|
|
|
for (fhdr = buf_hash_table.ht_table[idx], i = 0; fhdr != NULL;
|
|
fhdr = fhdr->b_hash_next, i++) {
|
|
if (BUF_EQUAL(hdr->b_spa, &hdr->b_dva, hdr->b_birth, fhdr))
|
|
return (fhdr);
|
|
}
|
|
|
|
hdr->b_hash_next = buf_hash_table.ht_table[idx];
|
|
buf_hash_table.ht_table[idx] = hdr;
|
|
hdr->b_flags |= ARC_FLAG_IN_HASH_TABLE;
|
|
|
|
/* collect some hash table performance data */
|
|
if (i > 0) {
|
|
ARCSTAT_BUMP(arcstat_hash_collisions);
|
|
if (i == 1)
|
|
ARCSTAT_BUMP(arcstat_hash_chains);
|
|
|
|
ARCSTAT_MAX(arcstat_hash_chain_max, i);
|
|
}
|
|
|
|
ARCSTAT_BUMP(arcstat_hash_elements);
|
|
ARCSTAT_MAXSTAT(arcstat_hash_elements);
|
|
|
|
return (NULL);
|
|
}
|
|
|
|
static void
|
|
buf_hash_remove(arc_buf_hdr_t *hdr)
|
|
{
|
|
arc_buf_hdr_t *fhdr, **hdrp;
|
|
uint64_t idx = BUF_HASH_INDEX(hdr->b_spa, &hdr->b_dva, hdr->b_birth);
|
|
|
|
ASSERT(MUTEX_HELD(BUF_HASH_LOCK(idx)));
|
|
ASSERT(HDR_IN_HASH_TABLE(hdr));
|
|
|
|
hdrp = &buf_hash_table.ht_table[idx];
|
|
while ((fhdr = *hdrp) != hdr) {
|
|
ASSERT(fhdr != NULL);
|
|
hdrp = &fhdr->b_hash_next;
|
|
}
|
|
*hdrp = hdr->b_hash_next;
|
|
hdr->b_hash_next = NULL;
|
|
hdr->b_flags &= ~ARC_FLAG_IN_HASH_TABLE;
|
|
|
|
/* collect some hash table performance data */
|
|
ARCSTAT_BUMPDOWN(arcstat_hash_elements);
|
|
|
|
if (buf_hash_table.ht_table[idx] &&
|
|
buf_hash_table.ht_table[idx]->b_hash_next == NULL)
|
|
ARCSTAT_BUMPDOWN(arcstat_hash_chains);
|
|
}
|
|
|
|
/*
|
|
* Global data structures and functions for the buf kmem cache.
|
|
*/
|
|
static kmem_cache_t *hdr_full_cache;
|
|
static kmem_cache_t *hdr_l2only_cache;
|
|
static kmem_cache_t *buf_cache;
|
|
|
|
static void
|
|
buf_fini(void)
|
|
{
|
|
int i;
|
|
|
|
#if defined(_KERNEL) && defined(HAVE_SPL)
|
|
/*
|
|
* Large allocations which do not require contiguous pages
|
|
* should be using vmem_free() in the linux kernel\
|
|
*/
|
|
vmem_free(buf_hash_table.ht_table,
|
|
(buf_hash_table.ht_mask + 1) * sizeof (void *));
|
|
#else
|
|
kmem_free(buf_hash_table.ht_table,
|
|
(buf_hash_table.ht_mask + 1) * sizeof (void *));
|
|
#endif
|
|
for (i = 0; i < BUF_LOCKS; i++)
|
|
mutex_destroy(&buf_hash_table.ht_locks[i].ht_lock);
|
|
kmem_cache_destroy(hdr_full_cache);
|
|
kmem_cache_destroy(hdr_l2only_cache);
|
|
kmem_cache_destroy(buf_cache);
|
|
}
|
|
|
|
/*
|
|
* Constructor callback - called when the cache is empty
|
|
* and a new buf is requested.
|
|
*/
|
|
/* ARGSUSED */
|
|
static int
|
|
hdr_full_cons(void *vbuf, void *unused, int kmflag)
|
|
{
|
|
arc_buf_hdr_t *hdr = vbuf;
|
|
|
|
bzero(hdr, HDR_FULL_SIZE);
|
|
cv_init(&hdr->b_l1hdr.b_cv, NULL, CV_DEFAULT, NULL);
|
|
refcount_create(&hdr->b_l1hdr.b_refcnt);
|
|
mutex_init(&hdr->b_l1hdr.b_freeze_lock, NULL, MUTEX_DEFAULT, NULL);
|
|
list_link_init(&hdr->b_l1hdr.b_arc_node);
|
|
list_link_init(&hdr->b_l2hdr.b_l2node);
|
|
multilist_link_init(&hdr->b_l1hdr.b_arc_node);
|
|
arc_space_consume(HDR_FULL_SIZE, ARC_SPACE_HDRS);
|
|
|
|
return (0);
|
|
}
|
|
|
|
/* ARGSUSED */
|
|
static int
|
|
hdr_l2only_cons(void *vbuf, void *unused, int kmflag)
|
|
{
|
|
arc_buf_hdr_t *hdr = vbuf;
|
|
|
|
bzero(hdr, HDR_L2ONLY_SIZE);
|
|
arc_space_consume(HDR_L2ONLY_SIZE, ARC_SPACE_L2HDRS);
|
|
|
|
return (0);
|
|
}
|
|
|
|
/* ARGSUSED */
|
|
static int
|
|
buf_cons(void *vbuf, void *unused, int kmflag)
|
|
{
|
|
arc_buf_t *buf = vbuf;
|
|
|
|
bzero(buf, sizeof (arc_buf_t));
|
|
mutex_init(&buf->b_evict_lock, NULL, MUTEX_DEFAULT, NULL);
|
|
arc_space_consume(sizeof (arc_buf_t), ARC_SPACE_HDRS);
|
|
|
|
return (0);
|
|
}
|
|
|
|
/*
|
|
* Destructor callback - called when a cached buf is
|
|
* no longer required.
|
|
*/
|
|
/* ARGSUSED */
|
|
static void
|
|
hdr_full_dest(void *vbuf, void *unused)
|
|
{
|
|
arc_buf_hdr_t *hdr = vbuf;
|
|
|
|
ASSERT(BUF_EMPTY(hdr));
|
|
cv_destroy(&hdr->b_l1hdr.b_cv);
|
|
refcount_destroy(&hdr->b_l1hdr.b_refcnt);
|
|
mutex_destroy(&hdr->b_l1hdr.b_freeze_lock);
|
|
ASSERT(!multilist_link_active(&hdr->b_l1hdr.b_arc_node));
|
|
arc_space_return(HDR_FULL_SIZE, ARC_SPACE_HDRS);
|
|
}
|
|
|
|
/* ARGSUSED */
|
|
static void
|
|
hdr_l2only_dest(void *vbuf, void *unused)
|
|
{
|
|
ASSERTV(arc_buf_hdr_t *hdr = vbuf);
|
|
|
|
ASSERT(BUF_EMPTY(hdr));
|
|
arc_space_return(HDR_L2ONLY_SIZE, ARC_SPACE_L2HDRS);
|
|
}
|
|
|
|
/* ARGSUSED */
|
|
static void
|
|
buf_dest(void *vbuf, void *unused)
|
|
{
|
|
arc_buf_t *buf = vbuf;
|
|
|
|
mutex_destroy(&buf->b_evict_lock);
|
|
arc_space_return(sizeof (arc_buf_t), ARC_SPACE_HDRS);
|
|
}
|
|
|
|
static void
|
|
buf_init(void)
|
|
{
|
|
uint64_t *ct;
|
|
uint64_t hsize = 1ULL << 12;
|
|
int i, j;
|
|
|
|
/*
|
|
* The hash table is big enough to fill all of physical memory
|
|
* with an average block size of zfs_arc_average_blocksize (default 8K).
|
|
* By default, the table will take up
|
|
* totalmem * sizeof(void*) / 8K (1MB per GB with 8-byte pointers).
|
|
*/
|
|
while (hsize * zfs_arc_average_blocksize < physmem * PAGESIZE)
|
|
hsize <<= 1;
|
|
retry:
|
|
buf_hash_table.ht_mask = hsize - 1;
|
|
#if defined(_KERNEL) && defined(HAVE_SPL)
|
|
/*
|
|
* Large allocations which do not require contiguous pages
|
|
* should be using vmem_alloc() in the linux kernel
|
|
*/
|
|
buf_hash_table.ht_table =
|
|
vmem_zalloc(hsize * sizeof (void*), KM_SLEEP);
|
|
#else
|
|
buf_hash_table.ht_table =
|
|
kmem_zalloc(hsize * sizeof (void*), KM_NOSLEEP);
|
|
#endif
|
|
if (buf_hash_table.ht_table == NULL) {
|
|
ASSERT(hsize > (1ULL << 8));
|
|
hsize >>= 1;
|
|
goto retry;
|
|
}
|
|
|
|
hdr_full_cache = kmem_cache_create("arc_buf_hdr_t_full", HDR_FULL_SIZE,
|
|
0, hdr_full_cons, hdr_full_dest, NULL, NULL, NULL, 0);
|
|
hdr_l2only_cache = kmem_cache_create("arc_buf_hdr_t_l2only",
|
|
HDR_L2ONLY_SIZE, 0, hdr_l2only_cons, hdr_l2only_dest, NULL,
|
|
NULL, NULL, 0);
|
|
buf_cache = kmem_cache_create("arc_buf_t", sizeof (arc_buf_t),
|
|
0, buf_cons, buf_dest, NULL, NULL, NULL, 0);
|
|
|
|
for (i = 0; i < 256; i++)
|
|
for (ct = zfs_crc64_table + i, *ct = i, j = 8; j > 0; j--)
|
|
*ct = (*ct >> 1) ^ (-(*ct & 1) & ZFS_CRC64_POLY);
|
|
|
|
for (i = 0; i < BUF_LOCKS; i++) {
|
|
mutex_init(&buf_hash_table.ht_locks[i].ht_lock,
|
|
NULL, MUTEX_DEFAULT, NULL);
|
|
}
|
|
}
|
|
|
|
/*
|
|
* Transition between the two allocation states for the arc_buf_hdr struct.
|
|
* The arc_buf_hdr struct can be allocated with (hdr_full_cache) or without
|
|
* (hdr_l2only_cache) the fields necessary for the L1 cache - the smaller
|
|
* version is used when a cache buffer is only in the L2ARC in order to reduce
|
|
* memory usage.
|
|
*/
|
|
static arc_buf_hdr_t *
|
|
arc_hdr_realloc(arc_buf_hdr_t *hdr, kmem_cache_t *old, kmem_cache_t *new)
|
|
{
|
|
arc_buf_hdr_t *nhdr;
|
|
l2arc_dev_t *dev;
|
|
|
|
ASSERT(HDR_HAS_L2HDR(hdr));
|
|
ASSERT((old == hdr_full_cache && new == hdr_l2only_cache) ||
|
|
(old == hdr_l2only_cache && new == hdr_full_cache));
|
|
|
|
dev = hdr->b_l2hdr.b_dev;
|
|
nhdr = kmem_cache_alloc(new, KM_PUSHPAGE);
|
|
|
|
ASSERT(MUTEX_HELD(HDR_LOCK(hdr)));
|
|
buf_hash_remove(hdr);
|
|
|
|
bcopy(hdr, nhdr, HDR_L2ONLY_SIZE);
|
|
|
|
if (new == hdr_full_cache) {
|
|
nhdr->b_flags |= ARC_FLAG_HAS_L1HDR;
|
|
/*
|
|
* arc_access and arc_change_state need to be aware that a
|
|
* header has just come out of L2ARC, so we set its state to
|
|
* l2c_only even though it's about to change.
|
|
*/
|
|
nhdr->b_l1hdr.b_state = arc_l2c_only;
|
|
|
|
/* Verify previous threads set to NULL before freeing */
|
|
ASSERT3P(nhdr->b_l1hdr.b_tmp_cdata, ==, NULL);
|
|
} else {
|
|
ASSERT(hdr->b_l1hdr.b_buf == NULL);
|
|
ASSERT0(hdr->b_l1hdr.b_datacnt);
|
|
|
|
/*
|
|
* If we've reached here, We must have been called from
|
|
* arc_evict_hdr(), as such we should have already been
|
|
* removed from any ghost list we were previously on
|
|
* (which protects us from racing with arc_evict_state),
|
|
* thus no locking is needed during this check.
|
|
*/
|
|
ASSERT(!multilist_link_active(&hdr->b_l1hdr.b_arc_node));
|
|
|
|
/*
|
|
* A buffer must not be moved into the arc_l2c_only
|
|
* state if it's not finished being written out to the
|
|
* l2arc device. Otherwise, the b_l1hdr.b_tmp_cdata field
|
|
* might try to be accessed, even though it was removed.
|
|
*/
|
|
VERIFY(!HDR_L2_WRITING(hdr));
|
|
VERIFY3P(hdr->b_l1hdr.b_tmp_cdata, ==, NULL);
|
|
|
|
nhdr->b_flags &= ~ARC_FLAG_HAS_L1HDR;
|
|
}
|
|
/*
|
|
* The header has been reallocated so we need to re-insert it into any
|
|
* lists it was on.
|
|
*/
|
|
(void) buf_hash_insert(nhdr, NULL);
|
|
|
|
ASSERT(list_link_active(&hdr->b_l2hdr.b_l2node));
|
|
|
|
mutex_enter(&dev->l2ad_mtx);
|
|
|
|
/*
|
|
* We must place the realloc'ed header back into the list at
|
|
* the same spot. Otherwise, if it's placed earlier in the list,
|
|
* l2arc_write_buffers() could find it during the function's
|
|
* write phase, and try to write it out to the l2arc.
|
|
*/
|
|
list_insert_after(&dev->l2ad_buflist, hdr, nhdr);
|
|
list_remove(&dev->l2ad_buflist, hdr);
|
|
|
|
mutex_exit(&dev->l2ad_mtx);
|
|
|
|
/*
|
|
* Since we're using the pointer address as the tag when
|
|
* incrementing and decrementing the l2ad_alloc refcount, we
|
|
* must remove the old pointer (that we're about to destroy) and
|
|
* add the new pointer to the refcount. Otherwise we'd remove
|
|
* the wrong pointer address when calling arc_hdr_destroy() later.
|
|
*/
|
|
|
|
(void) refcount_remove_many(&dev->l2ad_alloc,
|
|
hdr->b_l2hdr.b_asize, hdr);
|
|
|
|
(void) refcount_add_many(&dev->l2ad_alloc,
|
|
nhdr->b_l2hdr.b_asize, nhdr);
|
|
|
|
buf_discard_identity(hdr);
|
|
hdr->b_freeze_cksum = NULL;
|
|
kmem_cache_free(old, hdr);
|
|
|
|
return (nhdr);
|
|
}
|
|
|
|
|
|
#define ARC_MINTIME (hz>>4) /* 62 ms */
|
|
|
|
static void
|
|
arc_cksum_verify(arc_buf_t *buf)
|
|
{
|
|
zio_cksum_t zc;
|
|
|
|
if (!(zfs_flags & ZFS_DEBUG_MODIFY))
|
|
return;
|
|
|
|
mutex_enter(&buf->b_hdr->b_l1hdr.b_freeze_lock);
|
|
if (buf->b_hdr->b_freeze_cksum == NULL || HDR_IO_ERROR(buf->b_hdr)) {
|
|
mutex_exit(&buf->b_hdr->b_l1hdr.b_freeze_lock);
|
|
return;
|
|
}
|
|
fletcher_2_native(buf->b_data, buf->b_hdr->b_size, &zc);
|
|
if (!ZIO_CHECKSUM_EQUAL(*buf->b_hdr->b_freeze_cksum, zc))
|
|
panic("buffer modified while frozen!");
|
|
mutex_exit(&buf->b_hdr->b_l1hdr.b_freeze_lock);
|
|
}
|
|
|
|
static int
|
|
arc_cksum_equal(arc_buf_t *buf)
|
|
{
|
|
zio_cksum_t zc;
|
|
int equal;
|
|
|
|
mutex_enter(&buf->b_hdr->b_l1hdr.b_freeze_lock);
|
|
fletcher_2_native(buf->b_data, buf->b_hdr->b_size, &zc);
|
|
equal = ZIO_CHECKSUM_EQUAL(*buf->b_hdr->b_freeze_cksum, zc);
|
|
mutex_exit(&buf->b_hdr->b_l1hdr.b_freeze_lock);
|
|
|
|
return (equal);
|
|
}
|
|
|
|
static void
|
|
arc_cksum_compute(arc_buf_t *buf, boolean_t force)
|
|
{
|
|
if (!force && !(zfs_flags & ZFS_DEBUG_MODIFY))
|
|
return;
|
|
|
|
mutex_enter(&buf->b_hdr->b_l1hdr.b_freeze_lock);
|
|
if (buf->b_hdr->b_freeze_cksum != NULL) {
|
|
mutex_exit(&buf->b_hdr->b_l1hdr.b_freeze_lock);
|
|
return;
|
|
}
|
|
buf->b_hdr->b_freeze_cksum = kmem_alloc(sizeof (zio_cksum_t),
|
|
KM_SLEEP);
|
|
fletcher_2_native(buf->b_data, buf->b_hdr->b_size,
|
|
buf->b_hdr->b_freeze_cksum);
|
|
mutex_exit(&buf->b_hdr->b_l1hdr.b_freeze_lock);
|
|
arc_buf_watch(buf);
|
|
}
|
|
|
|
#ifndef _KERNEL
|
|
void
|
|
arc_buf_sigsegv(int sig, siginfo_t *si, void *unused)
|
|
{
|
|
panic("Got SIGSEGV at address: 0x%lx\n", (long) si->si_addr);
|
|
}
|
|
#endif
|
|
|
|
/* ARGSUSED */
|
|
static void
|
|
arc_buf_unwatch(arc_buf_t *buf)
|
|
{
|
|
#ifndef _KERNEL
|
|
if (arc_watch) {
|
|
ASSERT0(mprotect(buf->b_data, buf->b_hdr->b_size,
|
|
PROT_READ | PROT_WRITE));
|
|
}
|
|
#endif
|
|
}
|
|
|
|
/* ARGSUSED */
|
|
static void
|
|
arc_buf_watch(arc_buf_t *buf)
|
|
{
|
|
#ifndef _KERNEL
|
|
if (arc_watch)
|
|
ASSERT0(mprotect(buf->b_data, buf->b_hdr->b_size, PROT_READ));
|
|
#endif
|
|
}
|
|
|
|
static arc_buf_contents_t
|
|
arc_buf_type(arc_buf_hdr_t *hdr)
|
|
{
|
|
if (HDR_ISTYPE_METADATA(hdr)) {
|
|
return (ARC_BUFC_METADATA);
|
|
} else {
|
|
return (ARC_BUFC_DATA);
|
|
}
|
|
}
|
|
|
|
static uint32_t
|
|
arc_bufc_to_flags(arc_buf_contents_t type)
|
|
{
|
|
switch (type) {
|
|
case ARC_BUFC_DATA:
|
|
/* metadata field is 0 if buffer contains normal data */
|
|
return (0);
|
|
case ARC_BUFC_METADATA:
|
|
return (ARC_FLAG_BUFC_METADATA);
|
|
default:
|
|
break;
|
|
}
|
|
panic("undefined ARC buffer type!");
|
|
return ((uint32_t)-1);
|
|
}
|
|
|
|
void
|
|
arc_buf_thaw(arc_buf_t *buf)
|
|
{
|
|
if (zfs_flags & ZFS_DEBUG_MODIFY) {
|
|
if (buf->b_hdr->b_l1hdr.b_state != arc_anon)
|
|
panic("modifying non-anon buffer!");
|
|
if (HDR_IO_IN_PROGRESS(buf->b_hdr))
|
|
panic("modifying buffer while i/o in progress!");
|
|
arc_cksum_verify(buf);
|
|
}
|
|
|
|
mutex_enter(&buf->b_hdr->b_l1hdr.b_freeze_lock);
|
|
if (buf->b_hdr->b_freeze_cksum != NULL) {
|
|
kmem_free(buf->b_hdr->b_freeze_cksum, sizeof (zio_cksum_t));
|
|
buf->b_hdr->b_freeze_cksum = NULL;
|
|
}
|
|
|
|
mutex_exit(&buf->b_hdr->b_l1hdr.b_freeze_lock);
|
|
|
|
arc_buf_unwatch(buf);
|
|
}
|
|
|
|
void
|
|
arc_buf_freeze(arc_buf_t *buf)
|
|
{
|
|
kmutex_t *hash_lock;
|
|
|
|
if (!(zfs_flags & ZFS_DEBUG_MODIFY))
|
|
return;
|
|
|
|
hash_lock = HDR_LOCK(buf->b_hdr);
|
|
mutex_enter(hash_lock);
|
|
|
|
ASSERT(buf->b_hdr->b_freeze_cksum != NULL ||
|
|
buf->b_hdr->b_l1hdr.b_state == arc_anon);
|
|
arc_cksum_compute(buf, B_FALSE);
|
|
mutex_exit(hash_lock);
|
|
|
|
}
|
|
|
|
static void
|
|
add_reference(arc_buf_hdr_t *hdr, kmutex_t *hash_lock, void *tag)
|
|
{
|
|
arc_state_t *state;
|
|
|
|
ASSERT(HDR_HAS_L1HDR(hdr));
|
|
ASSERT(MUTEX_HELD(hash_lock));
|
|
|
|
state = hdr->b_l1hdr.b_state;
|
|
|
|
if ((refcount_add(&hdr->b_l1hdr.b_refcnt, tag) == 1) &&
|
|
(state != arc_anon)) {
|
|
/* We don't use the L2-only state list. */
|
|
if (state != arc_l2c_only) {
|
|
arc_buf_contents_t type = arc_buf_type(hdr);
|
|
uint64_t delta = hdr->b_size * hdr->b_l1hdr.b_datacnt;
|
|
multilist_t *list = &state->arcs_list[type];
|
|
uint64_t *size = &state->arcs_lsize[type];
|
|
|
|
multilist_remove(list, hdr);
|
|
|
|
if (GHOST_STATE(state)) {
|
|
ASSERT0(hdr->b_l1hdr.b_datacnt);
|
|
ASSERT3P(hdr->b_l1hdr.b_buf, ==, NULL);
|
|
delta = hdr->b_size;
|
|
}
|
|
ASSERT(delta > 0);
|
|
ASSERT3U(*size, >=, delta);
|
|
atomic_add_64(size, -delta);
|
|
}
|
|
/* remove the prefetch flag if we get a reference */
|
|
hdr->b_flags &= ~ARC_FLAG_PREFETCH;
|
|
}
|
|
}
|
|
|
|
static int
|
|
remove_reference(arc_buf_hdr_t *hdr, kmutex_t *hash_lock, void *tag)
|
|
{
|
|
int cnt;
|
|
arc_state_t *state = hdr->b_l1hdr.b_state;
|
|
|
|
ASSERT(HDR_HAS_L1HDR(hdr));
|
|
ASSERT(state == arc_anon || MUTEX_HELD(hash_lock));
|
|
ASSERT(!GHOST_STATE(state));
|
|
|
|
/*
|
|
* arc_l2c_only counts as a ghost state so we don't need to explicitly
|
|
* check to prevent usage of the arc_l2c_only list.
|
|
*/
|
|
if (((cnt = refcount_remove(&hdr->b_l1hdr.b_refcnt, tag)) == 0) &&
|
|
(state != arc_anon)) {
|
|
arc_buf_contents_t type = arc_buf_type(hdr);
|
|
multilist_t *list = &state->arcs_list[type];
|
|
uint64_t *size = &state->arcs_lsize[type];
|
|
|
|
multilist_insert(list, hdr);
|
|
|
|
ASSERT(hdr->b_l1hdr.b_datacnt > 0);
|
|
atomic_add_64(size, hdr->b_size *
|
|
hdr->b_l1hdr.b_datacnt);
|
|
}
|
|
return (cnt);
|
|
}
|
|
|
|
/*
|
|
* Returns detailed information about a specific arc buffer. When the
|
|
* state_index argument is set the function will calculate the arc header
|
|
* list position for its arc state. Since this requires a linear traversal
|
|
* callers are strongly encourage not to do this. However, it can be helpful
|
|
* for targeted analysis so the functionality is provided.
|
|
*/
|
|
void
|
|
arc_buf_info(arc_buf_t *ab, arc_buf_info_t *abi, int state_index)
|
|
{
|
|
arc_buf_hdr_t *hdr = ab->b_hdr;
|
|
l1arc_buf_hdr_t *l1hdr = NULL;
|
|
l2arc_buf_hdr_t *l2hdr = NULL;
|
|
arc_state_t *state = NULL;
|
|
|
|
if (HDR_HAS_L1HDR(hdr)) {
|
|
l1hdr = &hdr->b_l1hdr;
|
|
state = l1hdr->b_state;
|
|
}
|
|
if (HDR_HAS_L2HDR(hdr))
|
|
l2hdr = &hdr->b_l2hdr;
|
|
|
|
memset(abi, 0, sizeof (arc_buf_info_t));
|
|
abi->abi_flags = hdr->b_flags;
|
|
|
|
if (l1hdr) {
|
|
abi->abi_datacnt = l1hdr->b_datacnt;
|
|
abi->abi_access = l1hdr->b_arc_access;
|
|
abi->abi_mru_hits = l1hdr->b_mru_hits;
|
|
abi->abi_mru_ghost_hits = l1hdr->b_mru_ghost_hits;
|
|
abi->abi_mfu_hits = l1hdr->b_mfu_hits;
|
|
abi->abi_mfu_ghost_hits = l1hdr->b_mfu_ghost_hits;
|
|
abi->abi_holds = refcount_count(&l1hdr->b_refcnt);
|
|
}
|
|
|
|
if (l2hdr) {
|
|
abi->abi_l2arc_dattr = l2hdr->b_daddr;
|
|
abi->abi_l2arc_asize = l2hdr->b_asize;
|
|
abi->abi_l2arc_compress = HDR_GET_COMPRESS(hdr);
|
|
abi->abi_l2arc_hits = l2hdr->b_hits;
|
|
}
|
|
|
|
abi->abi_state_type = state ? state->arcs_state : ARC_STATE_ANON;
|
|
abi->abi_state_contents = arc_buf_type(hdr);
|
|
abi->abi_size = hdr->b_size;
|
|
}
|
|
|
|
/*
|
|
* Move the supplied buffer to the indicated state. The hash lock
|
|
* for the buffer must be held by the caller.
|
|
*/
|
|
static void
|
|
arc_change_state(arc_state_t *new_state, arc_buf_hdr_t *hdr,
|
|
kmutex_t *hash_lock)
|
|
{
|
|
arc_state_t *old_state;
|
|
int64_t refcnt;
|
|
uint32_t datacnt;
|
|
uint64_t from_delta, to_delta;
|
|
arc_buf_contents_t buftype = arc_buf_type(hdr);
|
|
|
|
/*
|
|
* We almost always have an L1 hdr here, since we call arc_hdr_realloc()
|
|
* in arc_read() when bringing a buffer out of the L2ARC. However, the
|
|
* L1 hdr doesn't always exist when we change state to arc_anon before
|
|
* destroying a header, in which case reallocating to add the L1 hdr is
|
|
* pointless.
|
|
*/
|
|
if (HDR_HAS_L1HDR(hdr)) {
|
|
old_state = hdr->b_l1hdr.b_state;
|
|
refcnt = refcount_count(&hdr->b_l1hdr.b_refcnt);
|
|
datacnt = hdr->b_l1hdr.b_datacnt;
|
|
} else {
|
|
old_state = arc_l2c_only;
|
|
refcnt = 0;
|
|
datacnt = 0;
|
|
}
|
|
|
|
ASSERT(MUTEX_HELD(hash_lock));
|
|
ASSERT3P(new_state, !=, old_state);
|
|
ASSERT(refcnt == 0 || datacnt > 0);
|
|
ASSERT(!GHOST_STATE(new_state) || datacnt == 0);
|
|
ASSERT(old_state != arc_anon || datacnt <= 1);
|
|
|
|
from_delta = to_delta = datacnt * hdr->b_size;
|
|
|
|
/*
|
|
* If this buffer is evictable, transfer it from the
|
|
* old state list to the new state list.
|
|
*/
|
|
if (refcnt == 0) {
|
|
if (old_state != arc_anon && old_state != arc_l2c_only) {
|
|
uint64_t *size = &old_state->arcs_lsize[buftype];
|
|
|
|
ASSERT(HDR_HAS_L1HDR(hdr));
|
|
multilist_remove(&old_state->arcs_list[buftype], hdr);
|
|
|
|
/*
|
|
* If prefetching out of the ghost cache,
|
|
* we will have a non-zero datacnt.
|
|
*/
|
|
if (GHOST_STATE(old_state) && datacnt == 0) {
|
|
/* ghost elements have a ghost size */
|
|
ASSERT(hdr->b_l1hdr.b_buf == NULL);
|
|
from_delta = hdr->b_size;
|
|
}
|
|
ASSERT3U(*size, >=, from_delta);
|
|
atomic_add_64(size, -from_delta);
|
|
}
|
|
if (new_state != arc_anon && new_state != arc_l2c_only) {
|
|
uint64_t *size = &new_state->arcs_lsize[buftype];
|
|
|
|
/*
|
|
* An L1 header always exists here, since if we're
|
|
* moving to some L1-cached state (i.e. not l2c_only or
|
|
* anonymous), we realloc the header to add an L1hdr
|
|
* beforehand.
|
|
*/
|
|
ASSERT(HDR_HAS_L1HDR(hdr));
|
|
multilist_insert(&new_state->arcs_list[buftype], hdr);
|
|
|
|
/* ghost elements have a ghost size */
|
|
if (GHOST_STATE(new_state)) {
|
|
ASSERT0(datacnt);
|
|
ASSERT(hdr->b_l1hdr.b_buf == NULL);
|
|
to_delta = hdr->b_size;
|
|
}
|
|
atomic_add_64(size, to_delta);
|
|
}
|
|
}
|
|
|
|
ASSERT(!BUF_EMPTY(hdr));
|
|
if (new_state == arc_anon && HDR_IN_HASH_TABLE(hdr))
|
|
buf_hash_remove(hdr);
|
|
|
|
/* adjust state sizes (ignore arc_l2c_only) */
|
|
if (to_delta && new_state != arc_l2c_only)
|
|
atomic_add_64(&new_state->arcs_size, to_delta);
|
|
if (from_delta && old_state != arc_l2c_only) {
|
|
ASSERT3U(old_state->arcs_size, >=, from_delta);
|
|
atomic_add_64(&old_state->arcs_size, -from_delta);
|
|
}
|
|
if (HDR_HAS_L1HDR(hdr))
|
|
hdr->b_l1hdr.b_state = new_state;
|
|
|
|
/*
|
|
* L2 headers should never be on the L2 state list since they don't
|
|
* have L1 headers allocated.
|
|
*/
|
|
ASSERT(multilist_is_empty(&arc_l2c_only->arcs_list[ARC_BUFC_DATA]) &&
|
|
multilist_is_empty(&arc_l2c_only->arcs_list[ARC_BUFC_METADATA]));
|
|
}
|
|
|
|
void
|
|
arc_space_consume(uint64_t space, arc_space_type_t type)
|
|
{
|
|
ASSERT(type >= 0 && type < ARC_SPACE_NUMTYPES);
|
|
|
|
switch (type) {
|
|
default:
|
|
break;
|
|
case ARC_SPACE_DATA:
|
|
ARCSTAT_INCR(arcstat_data_size, space);
|
|
break;
|
|
case ARC_SPACE_META:
|
|
ARCSTAT_INCR(arcstat_meta_size, space);
|
|
break;
|
|
case ARC_SPACE_OTHER:
|
|
ARCSTAT_INCR(arcstat_other_size, space);
|
|
break;
|
|
case ARC_SPACE_HDRS:
|
|
ARCSTAT_INCR(arcstat_hdr_size, space);
|
|
break;
|
|
case ARC_SPACE_L2HDRS:
|
|
ARCSTAT_INCR(arcstat_l2_hdr_size, space);
|
|
break;
|
|
}
|
|
|
|
if (type != ARC_SPACE_DATA) {
|
|
ARCSTAT_INCR(arcstat_meta_used, space);
|
|
if (arc_meta_max < arc_meta_used)
|
|
arc_meta_max = arc_meta_used;
|
|
}
|
|
|
|
atomic_add_64(&arc_size, space);
|
|
}
|
|
|
|
void
|
|
arc_space_return(uint64_t space, arc_space_type_t type)
|
|
{
|
|
ASSERT(type >= 0 && type < ARC_SPACE_NUMTYPES);
|
|
|
|
switch (type) {
|
|
default:
|
|
break;
|
|
case ARC_SPACE_DATA:
|
|
ARCSTAT_INCR(arcstat_data_size, -space);
|
|
break;
|
|
case ARC_SPACE_META:
|
|
ARCSTAT_INCR(arcstat_meta_size, -space);
|
|
break;
|
|
case ARC_SPACE_OTHER:
|
|
ARCSTAT_INCR(arcstat_other_size, -space);
|
|
break;
|
|
case ARC_SPACE_HDRS:
|
|
ARCSTAT_INCR(arcstat_hdr_size, -space);
|
|
break;
|
|
case ARC_SPACE_L2HDRS:
|
|
ARCSTAT_INCR(arcstat_l2_hdr_size, -space);
|
|
break;
|
|
}
|
|
|
|
if (type != ARC_SPACE_DATA) {
|
|
ASSERT(arc_meta_used >= space);
|
|
ARCSTAT_INCR(arcstat_meta_used, -space);
|
|
}
|
|
|
|
ASSERT(arc_size >= space);
|
|
atomic_add_64(&arc_size, -space);
|
|
}
|
|
|
|
arc_buf_t *
|
|
arc_buf_alloc(spa_t *spa, uint64_t size, void *tag, arc_buf_contents_t type)
|
|
{
|
|
arc_buf_hdr_t *hdr;
|
|
arc_buf_t *buf;
|
|
|
|
VERIFY3U(size, <=, spa_maxblocksize(spa));
|
|
hdr = kmem_cache_alloc(hdr_full_cache, KM_PUSHPAGE);
|
|
ASSERT(BUF_EMPTY(hdr));
|
|
ASSERT3P(hdr->b_freeze_cksum, ==, NULL);
|
|
hdr->b_size = size;
|
|
hdr->b_spa = spa_load_guid(spa);
|
|
hdr->b_l1hdr.b_mru_hits = 0;
|
|
hdr->b_l1hdr.b_mru_ghost_hits = 0;
|
|
hdr->b_l1hdr.b_mfu_hits = 0;
|
|
hdr->b_l1hdr.b_mfu_ghost_hits = 0;
|
|
hdr->b_l1hdr.b_l2_hits = 0;
|
|
|
|
buf = kmem_cache_alloc(buf_cache, KM_PUSHPAGE);
|
|
buf->b_hdr = hdr;
|
|
buf->b_data = NULL;
|
|
buf->b_efunc = NULL;
|
|
buf->b_private = NULL;
|
|
buf->b_next = NULL;
|
|
|
|
hdr->b_flags = arc_bufc_to_flags(type);
|
|
hdr->b_flags |= ARC_FLAG_HAS_L1HDR;
|
|
|
|
hdr->b_l1hdr.b_buf = buf;
|
|
hdr->b_l1hdr.b_state = arc_anon;
|
|
hdr->b_l1hdr.b_arc_access = 0;
|
|
hdr->b_l1hdr.b_datacnt = 1;
|
|
hdr->b_l1hdr.b_tmp_cdata = NULL;
|
|
|
|
arc_get_data_buf(buf);
|
|
|
|
ASSERT(refcount_is_zero(&hdr->b_l1hdr.b_refcnt));
|
|
(void) refcount_add(&hdr->b_l1hdr.b_refcnt, tag);
|
|
|
|
return (buf);
|
|
}
|
|
|
|
static char *arc_onloan_tag = "onloan";
|
|
|
|
/*
|
|
* Loan out an anonymous arc buffer. Loaned buffers are not counted as in
|
|
* flight data by arc_tempreserve_space() until they are "returned". Loaned
|
|
* buffers must be returned to the arc before they can be used by the DMU or
|
|
* freed.
|
|
*/
|
|
arc_buf_t *
|
|
arc_loan_buf(spa_t *spa, uint64_t size)
|
|
{
|
|
arc_buf_t *buf;
|
|
|
|
buf = arc_buf_alloc(spa, size, arc_onloan_tag, ARC_BUFC_DATA);
|
|
|
|
atomic_add_64(&arc_loaned_bytes, size);
|
|
return (buf);
|
|
}
|
|
|
|
/*
|
|
* Return a loaned arc buffer to the arc.
|
|
*/
|
|
void
|
|
arc_return_buf(arc_buf_t *buf, void *tag)
|
|
{
|
|
arc_buf_hdr_t *hdr = buf->b_hdr;
|
|
|
|
ASSERT(buf->b_data != NULL);
|
|
ASSERT(HDR_HAS_L1HDR(hdr));
|
|
(void) refcount_add(&hdr->b_l1hdr.b_refcnt, tag);
|
|
(void) refcount_remove(&hdr->b_l1hdr.b_refcnt, arc_onloan_tag);
|
|
|
|
atomic_add_64(&arc_loaned_bytes, -hdr->b_size);
|
|
}
|
|
|
|
/* Detach an arc_buf from a dbuf (tag) */
|
|
void
|
|
arc_loan_inuse_buf(arc_buf_t *buf, void *tag)
|
|
{
|
|
arc_buf_hdr_t *hdr = buf->b_hdr;
|
|
|
|
ASSERT(buf->b_data != NULL);
|
|
ASSERT(HDR_HAS_L1HDR(hdr));
|
|
(void) refcount_add(&hdr->b_l1hdr.b_refcnt, arc_onloan_tag);
|
|
(void) refcount_remove(&hdr->b_l1hdr.b_refcnt, tag);
|
|
buf->b_efunc = NULL;
|
|
buf->b_private = NULL;
|
|
|
|
atomic_add_64(&arc_loaned_bytes, hdr->b_size);
|
|
}
|
|
|
|
static arc_buf_t *
|
|
arc_buf_clone(arc_buf_t *from)
|
|
{
|
|
arc_buf_t *buf;
|
|
arc_buf_hdr_t *hdr = from->b_hdr;
|
|
uint64_t size = hdr->b_size;
|
|
|
|
ASSERT(HDR_HAS_L1HDR(hdr));
|
|
ASSERT(hdr->b_l1hdr.b_state != arc_anon);
|
|
|
|
buf = kmem_cache_alloc(buf_cache, KM_PUSHPAGE);
|
|
buf->b_hdr = hdr;
|
|
buf->b_data = NULL;
|
|
buf->b_efunc = NULL;
|
|
buf->b_private = NULL;
|
|
buf->b_next = hdr->b_l1hdr.b_buf;
|
|
hdr->b_l1hdr.b_buf = buf;
|
|
arc_get_data_buf(buf);
|
|
bcopy(from->b_data, buf->b_data, size);
|
|
|
|
/*
|
|
* This buffer already exists in the arc so create a duplicate
|
|
* copy for the caller. If the buffer is associated with user data
|
|
* then track the size and number of duplicates. These stats will be
|
|
* updated as duplicate buffers are created and destroyed.
|
|
*/
|
|
if (HDR_ISTYPE_DATA(hdr)) {
|
|
ARCSTAT_BUMP(arcstat_duplicate_buffers);
|
|
ARCSTAT_INCR(arcstat_duplicate_buffers_size, size);
|
|
}
|
|
hdr->b_l1hdr.b_datacnt += 1;
|
|
return (buf);
|
|
}
|
|
|
|
void
|
|
arc_buf_add_ref(arc_buf_t *buf, void* tag)
|
|
{
|
|
arc_buf_hdr_t *hdr;
|
|
kmutex_t *hash_lock;
|
|
|
|
/*
|
|
* Check to see if this buffer is evicted. Callers
|
|
* must verify b_data != NULL to know if the add_ref
|
|
* was successful.
|
|
*/
|
|
mutex_enter(&buf->b_evict_lock);
|
|
if (buf->b_data == NULL) {
|
|
mutex_exit(&buf->b_evict_lock);
|
|
return;
|
|
}
|
|
hash_lock = HDR_LOCK(buf->b_hdr);
|
|
mutex_enter(hash_lock);
|
|
hdr = buf->b_hdr;
|
|
ASSERT(HDR_HAS_L1HDR(hdr));
|
|
ASSERT3P(hash_lock, ==, HDR_LOCK(hdr));
|
|
mutex_exit(&buf->b_evict_lock);
|
|
|
|
ASSERT(hdr->b_l1hdr.b_state == arc_mru ||
|
|
hdr->b_l1hdr.b_state == arc_mfu);
|
|
|
|
add_reference(hdr, hash_lock, tag);
|
|
DTRACE_PROBE1(arc__hit, arc_buf_hdr_t *, hdr);
|
|
arc_access(hdr, hash_lock);
|
|
mutex_exit(hash_lock);
|
|
ARCSTAT_BUMP(arcstat_hits);
|
|
ARCSTAT_CONDSTAT(!HDR_PREFETCH(hdr),
|
|
demand, prefetch, !HDR_ISTYPE_METADATA(hdr),
|
|
data, metadata, hits);
|
|
}
|
|
|
|
static void
|
|
arc_buf_free_on_write(void *data, size_t size,
|
|
void (*free_func)(void *, size_t))
|
|
{
|
|
l2arc_data_free_t *df;
|
|
|
|
df = kmem_alloc(sizeof (*df), KM_SLEEP);
|
|
df->l2df_data = data;
|
|
df->l2df_size = size;
|
|
df->l2df_func = free_func;
|
|
mutex_enter(&l2arc_free_on_write_mtx);
|
|
list_insert_head(l2arc_free_on_write, df);
|
|
mutex_exit(&l2arc_free_on_write_mtx);
|
|
}
|
|
|
|
/*
|
|
* Free the arc data buffer. If it is an l2arc write in progress,
|
|
* the buffer is placed on l2arc_free_on_write to be freed later.
|
|
*/
|
|
static void
|
|
arc_buf_data_free(arc_buf_t *buf, void (*free_func)(void *, size_t))
|
|
{
|
|
arc_buf_hdr_t *hdr = buf->b_hdr;
|
|
|
|
if (HDR_L2_WRITING(hdr)) {
|
|
arc_buf_free_on_write(buf->b_data, hdr->b_size, free_func);
|
|
ARCSTAT_BUMP(arcstat_l2_free_on_write);
|
|
} else {
|
|
free_func(buf->b_data, hdr->b_size);
|
|
}
|
|
}
|
|
|
|
static void
|
|
arc_buf_l2_cdata_free(arc_buf_hdr_t *hdr)
|
|
{
|
|
ASSERT(HDR_HAS_L2HDR(hdr));
|
|
ASSERT(MUTEX_HELD(&hdr->b_l2hdr.b_dev->l2ad_mtx));
|
|
|
|
/*
|
|
* The b_tmp_cdata field is linked off of the b_l1hdr, so if
|
|
* that doesn't exist, the header is in the arc_l2c_only state,
|
|
* and there isn't anything to free (it's already been freed).
|
|
*/
|
|
if (!HDR_HAS_L1HDR(hdr))
|
|
return;
|
|
|
|
/*
|
|
* The header isn't being written to the l2arc device, thus it
|
|
* shouldn't have a b_tmp_cdata to free.
|
|
*/
|
|
if (!HDR_L2_WRITING(hdr)) {
|
|
ASSERT3P(hdr->b_l1hdr.b_tmp_cdata, ==, NULL);
|
|
return;
|
|
}
|
|
|
|
/*
|
|
* The header does not have compression enabled. This can be due
|
|
* to the buffer not being compressible, or because we're
|
|
* freeing the buffer before the second phase of
|
|
* l2arc_write_buffer() has started (which does the compression
|
|
* step). In either case, b_tmp_cdata does not point to a
|
|
* separately compressed buffer, so there's nothing to free (it
|
|
* points to the same buffer as the arc_buf_t's b_data field).
|
|
*/
|
|
if (HDR_GET_COMPRESS(hdr) == ZIO_COMPRESS_OFF) {
|
|
hdr->b_l1hdr.b_tmp_cdata = NULL;
|
|
return;
|
|
}
|
|
|
|
/*
|
|
* There's nothing to free since the buffer was all zero's and
|
|
* compressed to a zero length buffer.
|
|
*/
|
|
if (HDR_GET_COMPRESS(hdr) == ZIO_COMPRESS_EMPTY) {
|
|
ASSERT3P(hdr->b_l1hdr.b_tmp_cdata, ==, NULL);
|
|
return;
|
|
}
|
|
|
|
ASSERT(L2ARC_IS_VALID_COMPRESS(HDR_GET_COMPRESS(hdr)));
|
|
|
|
arc_buf_free_on_write(hdr->b_l1hdr.b_tmp_cdata,
|
|
hdr->b_size, zio_data_buf_free);
|
|
|
|
ARCSTAT_BUMP(arcstat_l2_cdata_free_on_write);
|
|
hdr->b_l1hdr.b_tmp_cdata = NULL;
|
|
}
|
|
|
|
/*
|
|
* Free up buf->b_data and if 'remove' is set, then pull the
|
|
* arc_buf_t off of the the arc_buf_hdr_t's list and free it.
|
|
*/
|
|
static void
|
|
arc_buf_destroy(arc_buf_t *buf, boolean_t remove)
|
|
{
|
|
arc_buf_t **bufp;
|
|
|
|
/* free up data associated with the buf */
|
|
if (buf->b_data != NULL) {
|
|
arc_state_t *state = buf->b_hdr->b_l1hdr.b_state;
|
|
uint64_t size = buf->b_hdr->b_size;
|
|
arc_buf_contents_t type = arc_buf_type(buf->b_hdr);
|
|
|
|
arc_cksum_verify(buf);
|
|
arc_buf_unwatch(buf);
|
|
|
|
if (type == ARC_BUFC_METADATA) {
|
|
arc_buf_data_free(buf, zio_buf_free);
|
|
arc_space_return(size, ARC_SPACE_META);
|
|
} else {
|
|
ASSERT(type == ARC_BUFC_DATA);
|
|
arc_buf_data_free(buf, zio_data_buf_free);
|
|
arc_space_return(size, ARC_SPACE_DATA);
|
|
}
|
|
|
|
/* protected by hash lock, if in the hash table */
|
|
if (multilist_link_active(&buf->b_hdr->b_l1hdr.b_arc_node)) {
|
|
uint64_t *cnt = &state->arcs_lsize[type];
|
|
|
|
ASSERT(refcount_is_zero(
|
|
&buf->b_hdr->b_l1hdr.b_refcnt));
|
|
ASSERT(state != arc_anon && state != arc_l2c_only);
|
|
|
|
ASSERT3U(*cnt, >=, size);
|
|
atomic_add_64(cnt, -size);
|
|
}
|
|
ASSERT3U(state->arcs_size, >=, size);
|
|
atomic_add_64(&state->arcs_size, -size);
|
|
buf->b_data = NULL;
|
|
|
|
/*
|
|
* If we're destroying a duplicate buffer make sure
|
|
* that the appropriate statistics are updated.
|
|
*/
|
|
if (buf->b_hdr->b_l1hdr.b_datacnt > 1 &&
|
|
HDR_ISTYPE_DATA(buf->b_hdr)) {
|
|
ARCSTAT_BUMPDOWN(arcstat_duplicate_buffers);
|
|
ARCSTAT_INCR(arcstat_duplicate_buffers_size, -size);
|
|
}
|
|
ASSERT(buf->b_hdr->b_l1hdr.b_datacnt > 0);
|
|
buf->b_hdr->b_l1hdr.b_datacnt -= 1;
|
|
}
|
|
|
|
/* only remove the buf if requested */
|
|
if (!remove)
|
|
return;
|
|
|
|
/* remove the buf from the hdr list */
|
|
for (bufp = &buf->b_hdr->b_l1hdr.b_buf; *bufp != buf;
|
|
bufp = &(*bufp)->b_next)
|
|
continue;
|
|
*bufp = buf->b_next;
|
|
buf->b_next = NULL;
|
|
|
|
ASSERT(buf->b_efunc == NULL);
|
|
|
|
/* clean up the buf */
|
|
buf->b_hdr = NULL;
|
|
kmem_cache_free(buf_cache, buf);
|
|
}
|
|
|
|
static void
|
|
arc_hdr_l2hdr_destroy(arc_buf_hdr_t *hdr)
|
|
{
|
|
l2arc_buf_hdr_t *l2hdr = &hdr->b_l2hdr;
|
|
l2arc_dev_t *dev = l2hdr->b_dev;
|
|
|
|
ASSERT(MUTEX_HELD(&dev->l2ad_mtx));
|
|
ASSERT(HDR_HAS_L2HDR(hdr));
|
|
|
|
list_remove(&dev->l2ad_buflist, hdr);
|
|
|
|
arc_space_return(HDR_L2ONLY_SIZE, ARC_SPACE_L2HDRS);
|
|
|
|
/*
|
|
* We don't want to leak the b_tmp_cdata buffer that was
|
|
* allocated in l2arc_write_buffers()
|
|
*/
|
|
arc_buf_l2_cdata_free(hdr);
|
|
|
|
/*
|
|
* If the l2hdr's b_daddr is equal to L2ARC_ADDR_UNSET, then
|
|
* this header is being processed by l2arc_write_buffers() (i.e.
|
|
* it's in the first stage of l2arc_write_buffers()).
|
|
* Re-affirming that truth here, just to serve as a reminder. If
|
|
* b_daddr does not equal L2ARC_ADDR_UNSET, then the header may or
|
|
* may not have its HDR_L2_WRITING flag set. (the write may have
|
|
* completed, in which case HDR_L2_WRITING will be false and the
|
|
* b_daddr field will point to the address of the buffer on disk).
|
|
*/
|
|
IMPLY(l2hdr->b_daddr == L2ARC_ADDR_UNSET, HDR_L2_WRITING(hdr));
|
|
|
|
/*
|
|
* If b_daddr is equal to L2ARC_ADDR_UNSET, we're racing with
|
|
* l2arc_write_buffers(). Since we've just removed this header
|
|
* from the l2arc buffer list, this header will never reach the
|
|
* second stage of l2arc_write_buffers(), which increments the
|
|
* accounting stats for this header. Thus, we must be careful
|
|
* not to decrement them for this header either.
|
|
*/
|
|
if (l2hdr->b_daddr != L2ARC_ADDR_UNSET) {
|
|
ARCSTAT_INCR(arcstat_l2_asize, -l2hdr->b_asize);
|
|
ARCSTAT_INCR(arcstat_l2_size, -hdr->b_size);
|
|
|
|
vdev_space_update(dev->l2ad_vdev,
|
|
-l2hdr->b_asize, 0, 0);
|
|
|
|
(void) refcount_remove_many(&dev->l2ad_alloc,
|
|
l2hdr->b_asize, hdr);
|
|
}
|
|
|
|
hdr->b_flags &= ~ARC_FLAG_HAS_L2HDR;
|
|
}
|
|
|
|
static void
|
|
arc_hdr_destroy(arc_buf_hdr_t *hdr)
|
|
{
|
|
if (HDR_HAS_L1HDR(hdr)) {
|
|
ASSERT(hdr->b_l1hdr.b_buf == NULL ||
|
|
hdr->b_l1hdr.b_datacnt > 0);
|
|
ASSERT(refcount_is_zero(&hdr->b_l1hdr.b_refcnt));
|
|
ASSERT3P(hdr->b_l1hdr.b_state, ==, arc_anon);
|
|
}
|
|
ASSERT(!HDR_IO_IN_PROGRESS(hdr));
|
|
ASSERT(!HDR_IN_HASH_TABLE(hdr));
|
|
|
|
if (HDR_HAS_L2HDR(hdr)) {
|
|
l2arc_dev_t *dev = hdr->b_l2hdr.b_dev;
|
|
boolean_t buflist_held = MUTEX_HELD(&dev->l2ad_mtx);
|
|
|
|
if (!buflist_held)
|
|
mutex_enter(&dev->l2ad_mtx);
|
|
|
|
/*
|
|
* Even though we checked this conditional above, we
|
|
* need to check this again now that we have the
|
|
* l2ad_mtx. This is because we could be racing with
|
|
* another thread calling l2arc_evict() which might have
|
|
* destroyed this header's L2 portion as we were waiting
|
|
* to acquire the l2ad_mtx. If that happens, we don't
|
|
* want to re-destroy the header's L2 portion.
|
|
*/
|
|
if (HDR_HAS_L2HDR(hdr))
|
|
arc_hdr_l2hdr_destroy(hdr);
|
|
|
|
if (!buflist_held)
|
|
mutex_exit(&dev->l2ad_mtx);
|
|
}
|
|
|
|
if (!BUF_EMPTY(hdr))
|
|
buf_discard_identity(hdr);
|
|
|
|
if (hdr->b_freeze_cksum != NULL) {
|
|
kmem_free(hdr->b_freeze_cksum, sizeof (zio_cksum_t));
|
|
hdr->b_freeze_cksum = NULL;
|
|
}
|
|
|
|
if (HDR_HAS_L1HDR(hdr)) {
|
|
while (hdr->b_l1hdr.b_buf) {
|
|
arc_buf_t *buf = hdr->b_l1hdr.b_buf;
|
|
|
|
if (buf->b_efunc != NULL) {
|
|
mutex_enter(&arc_user_evicts_lock);
|
|
mutex_enter(&buf->b_evict_lock);
|
|
ASSERT(buf->b_hdr != NULL);
|
|
arc_buf_destroy(hdr->b_l1hdr.b_buf, FALSE);
|
|
hdr->b_l1hdr.b_buf = buf->b_next;
|
|
buf->b_hdr = &arc_eviction_hdr;
|
|
buf->b_next = arc_eviction_list;
|
|
arc_eviction_list = buf;
|
|
mutex_exit(&buf->b_evict_lock);
|
|
cv_signal(&arc_user_evicts_cv);
|
|
mutex_exit(&arc_user_evicts_lock);
|
|
} else {
|
|
arc_buf_destroy(hdr->b_l1hdr.b_buf, TRUE);
|
|
}
|
|
}
|
|
}
|
|
|
|
ASSERT3P(hdr->b_hash_next, ==, NULL);
|
|
if (HDR_HAS_L1HDR(hdr)) {
|
|
ASSERT(!multilist_link_active(&hdr->b_l1hdr.b_arc_node));
|
|
ASSERT3P(hdr->b_l1hdr.b_acb, ==, NULL);
|
|
kmem_cache_free(hdr_full_cache, hdr);
|
|
} else {
|
|
kmem_cache_free(hdr_l2only_cache, hdr);
|
|
}
|
|
}
|
|
|
|
void
|
|
arc_buf_free(arc_buf_t *buf, void *tag)
|
|
{
|
|
arc_buf_hdr_t *hdr = buf->b_hdr;
|
|
int hashed = hdr->b_l1hdr.b_state != arc_anon;
|
|
|
|
ASSERT(buf->b_efunc == NULL);
|
|
ASSERT(buf->b_data != NULL);
|
|
|
|
if (hashed) {
|
|
kmutex_t *hash_lock = HDR_LOCK(hdr);
|
|
|
|
mutex_enter(hash_lock);
|
|
hdr = buf->b_hdr;
|
|
ASSERT3P(hash_lock, ==, HDR_LOCK(hdr));
|
|
|
|
(void) remove_reference(hdr, hash_lock, tag);
|
|
if (hdr->b_l1hdr.b_datacnt > 1) {
|
|
arc_buf_destroy(buf, TRUE);
|
|
} else {
|
|
ASSERT(buf == hdr->b_l1hdr.b_buf);
|
|
ASSERT(buf->b_efunc == NULL);
|
|
hdr->b_flags |= ARC_FLAG_BUF_AVAILABLE;
|
|
}
|
|
mutex_exit(hash_lock);
|
|
} else if (HDR_IO_IN_PROGRESS(hdr)) {
|
|
int destroy_hdr;
|
|
/*
|
|
* We are in the middle of an async write. Don't destroy
|
|
* this buffer unless the write completes before we finish
|
|
* decrementing the reference count.
|
|
*/
|
|
mutex_enter(&arc_user_evicts_lock);
|
|
(void) remove_reference(hdr, NULL, tag);
|
|
ASSERT(refcount_is_zero(&hdr->b_l1hdr.b_refcnt));
|
|
destroy_hdr = !HDR_IO_IN_PROGRESS(hdr);
|
|
mutex_exit(&arc_user_evicts_lock);
|
|
if (destroy_hdr)
|
|
arc_hdr_destroy(hdr);
|
|
} else {
|
|
if (remove_reference(hdr, NULL, tag) > 0)
|
|
arc_buf_destroy(buf, TRUE);
|
|
else
|
|
arc_hdr_destroy(hdr);
|
|
}
|
|
}
|
|
|
|
boolean_t
|
|
arc_buf_remove_ref(arc_buf_t *buf, void* tag)
|
|
{
|
|
arc_buf_hdr_t *hdr = buf->b_hdr;
|
|
kmutex_t *hash_lock = NULL;
|
|
boolean_t no_callback = (buf->b_efunc == NULL);
|
|
|
|
if (hdr->b_l1hdr.b_state == arc_anon) {
|
|
ASSERT(hdr->b_l1hdr.b_datacnt == 1);
|
|
arc_buf_free(buf, tag);
|
|
return (no_callback);
|
|
}
|
|
|
|
hash_lock = HDR_LOCK(hdr);
|
|
mutex_enter(hash_lock);
|
|
hdr = buf->b_hdr;
|
|
ASSERT(hdr->b_l1hdr.b_datacnt > 0);
|
|
ASSERT3P(hash_lock, ==, HDR_LOCK(hdr));
|
|
ASSERT(hdr->b_l1hdr.b_state != arc_anon);
|
|
ASSERT(buf->b_data != NULL);
|
|
|
|
(void) remove_reference(hdr, hash_lock, tag);
|
|
if (hdr->b_l1hdr.b_datacnt > 1) {
|
|
if (no_callback)
|
|
arc_buf_destroy(buf, TRUE);
|
|
} else if (no_callback) {
|
|
ASSERT(hdr->b_l1hdr.b_buf == buf && buf->b_next == NULL);
|
|
ASSERT(buf->b_efunc == NULL);
|
|
hdr->b_flags |= ARC_FLAG_BUF_AVAILABLE;
|
|
}
|
|
ASSERT(no_callback || hdr->b_l1hdr.b_datacnt > 1 ||
|
|
refcount_is_zero(&hdr->b_l1hdr.b_refcnt));
|
|
mutex_exit(hash_lock);
|
|
return (no_callback);
|
|
}
|
|
|
|
uint64_t
|
|
arc_buf_size(arc_buf_t *buf)
|
|
{
|
|
return (buf->b_hdr->b_size);
|
|
}
|
|
|
|
/*
|
|
* Called from the DMU to determine if the current buffer should be
|
|
* evicted. In order to ensure proper locking, the eviction must be initiated
|
|
* from the DMU. Return true if the buffer is associated with user data and
|
|
* duplicate buffers still exist.
|
|
*/
|
|
boolean_t
|
|
arc_buf_eviction_needed(arc_buf_t *buf)
|
|
{
|
|
arc_buf_hdr_t *hdr;
|
|
boolean_t evict_needed = B_FALSE;
|
|
|
|
if (zfs_disable_dup_eviction)
|
|
return (B_FALSE);
|
|
|
|
mutex_enter(&buf->b_evict_lock);
|
|
hdr = buf->b_hdr;
|
|
if (hdr == NULL) {
|
|
/*
|
|
* We are in arc_do_user_evicts(); let that function
|
|
* perform the eviction.
|
|
*/
|
|
ASSERT(buf->b_data == NULL);
|
|
mutex_exit(&buf->b_evict_lock);
|
|
return (B_FALSE);
|
|
} else if (buf->b_data == NULL) {
|
|
/*
|
|
* We have already been added to the arc eviction list;
|
|
* recommend eviction.
|
|
*/
|
|
ASSERT3P(hdr, ==, &arc_eviction_hdr);
|
|
mutex_exit(&buf->b_evict_lock);
|
|
return (B_TRUE);
|
|
}
|
|
|
|
if (hdr->b_l1hdr.b_datacnt > 1 && HDR_ISTYPE_DATA(hdr))
|
|
evict_needed = B_TRUE;
|
|
|
|
mutex_exit(&buf->b_evict_lock);
|
|
return (evict_needed);
|
|
}
|
|
|
|
/*
|
|
* Evict the arc_buf_hdr that is provided as a parameter. The resultant
|
|
* state of the header is dependent on its state prior to entering this
|
|
* function. The following transitions are possible:
|
|
*
|
|
* - arc_mru -> arc_mru_ghost
|
|
* - arc_mfu -> arc_mfu_ghost
|
|
* - arc_mru_ghost -> arc_l2c_only
|
|
* - arc_mru_ghost -> deleted
|
|
* - arc_mfu_ghost -> arc_l2c_only
|
|
* - arc_mfu_ghost -> deleted
|
|
*/
|
|
static int64_t
|
|
arc_evict_hdr(arc_buf_hdr_t *hdr, kmutex_t *hash_lock)
|
|
{
|
|
arc_state_t *evicted_state, *state;
|
|
int64_t bytes_evicted = 0;
|
|
|
|
ASSERT(MUTEX_HELD(hash_lock));
|
|
ASSERT(HDR_HAS_L1HDR(hdr));
|
|
|
|
state = hdr->b_l1hdr.b_state;
|
|
if (GHOST_STATE(state)) {
|
|
ASSERT(!HDR_IO_IN_PROGRESS(hdr));
|
|
ASSERT(hdr->b_l1hdr.b_buf == NULL);
|
|
|
|
/*
|
|
* l2arc_write_buffers() relies on a header's L1 portion
|
|
* (i.e. its b_tmp_cdata field) during its write phase.
|
|
* Thus, we cannot push a header onto the arc_l2c_only
|
|
* state (removing its L1 piece) until the header is
|
|
* done being written to the l2arc.
|
|
*/
|
|
if (HDR_HAS_L2HDR(hdr) && HDR_L2_WRITING(hdr)) {
|
|
ARCSTAT_BUMP(arcstat_evict_l2_skip);
|
|
return (bytes_evicted);
|
|
}
|
|
|
|
ARCSTAT_BUMP(arcstat_deleted);
|
|
bytes_evicted += hdr->b_size;
|
|
|
|
DTRACE_PROBE1(arc__delete, arc_buf_hdr_t *, hdr);
|
|
|
|
if (HDR_HAS_L2HDR(hdr)) {
|
|
/*
|
|
* This buffer is cached on the 2nd Level ARC;
|
|
* don't destroy the header.
|
|
*/
|
|
arc_change_state(arc_l2c_only, hdr, hash_lock);
|
|
/*
|
|
* dropping from L1+L2 cached to L2-only,
|
|
* realloc to remove the L1 header.
|
|
*/
|
|
hdr = arc_hdr_realloc(hdr, hdr_full_cache,
|
|
hdr_l2only_cache);
|
|
} else {
|
|
arc_change_state(arc_anon, hdr, hash_lock);
|
|
arc_hdr_destroy(hdr);
|
|
}
|
|
return (bytes_evicted);
|
|
}
|
|
|
|
ASSERT(state == arc_mru || state == arc_mfu);
|
|
evicted_state = (state == arc_mru) ? arc_mru_ghost : arc_mfu_ghost;
|
|
|
|
/* prefetch buffers have a minimum lifespan */
|
|
if (HDR_IO_IN_PROGRESS(hdr) ||
|
|
((hdr->b_flags & (ARC_FLAG_PREFETCH | ARC_FLAG_INDIRECT)) &&
|
|
ddi_get_lbolt() - hdr->b_l1hdr.b_arc_access <
|
|
arc_min_prefetch_lifespan)) {
|
|
ARCSTAT_BUMP(arcstat_evict_skip);
|
|
return (bytes_evicted);
|
|
}
|
|
|
|
ASSERT0(refcount_count(&hdr->b_l1hdr.b_refcnt));
|
|
ASSERT3U(hdr->b_l1hdr.b_datacnt, >, 0);
|
|
while (hdr->b_l1hdr.b_buf) {
|
|
arc_buf_t *buf = hdr->b_l1hdr.b_buf;
|
|
if (!mutex_tryenter(&buf->b_evict_lock)) {
|
|
ARCSTAT_BUMP(arcstat_mutex_miss);
|
|
break;
|
|
}
|
|
if (buf->b_data != NULL)
|
|
bytes_evicted += hdr->b_size;
|
|
if (buf->b_efunc != NULL) {
|
|
mutex_enter(&arc_user_evicts_lock);
|
|
arc_buf_destroy(buf, FALSE);
|
|
hdr->b_l1hdr.b_buf = buf->b_next;
|
|
buf->b_hdr = &arc_eviction_hdr;
|
|
buf->b_next = arc_eviction_list;
|
|
arc_eviction_list = buf;
|
|
cv_signal(&arc_user_evicts_cv);
|
|
mutex_exit(&arc_user_evicts_lock);
|
|
mutex_exit(&buf->b_evict_lock);
|
|
} else {
|
|
mutex_exit(&buf->b_evict_lock);
|
|
arc_buf_destroy(buf, TRUE);
|
|
}
|
|
}
|
|
|
|
if (HDR_HAS_L2HDR(hdr)) {
|
|
ARCSTAT_INCR(arcstat_evict_l2_cached, hdr->b_size);
|
|
} else {
|
|
if (l2arc_write_eligible(hdr->b_spa, hdr))
|
|
ARCSTAT_INCR(arcstat_evict_l2_eligible, hdr->b_size);
|
|
else
|
|
ARCSTAT_INCR(arcstat_evict_l2_ineligible, hdr->b_size);
|
|
}
|
|
|
|
if (hdr->b_l1hdr.b_datacnt == 0) {
|
|
arc_change_state(evicted_state, hdr, hash_lock);
|
|
ASSERT(HDR_IN_HASH_TABLE(hdr));
|
|
hdr->b_flags |= ARC_FLAG_IN_HASH_TABLE;
|
|
hdr->b_flags &= ~ARC_FLAG_BUF_AVAILABLE;
|
|
DTRACE_PROBE1(arc__evict, arc_buf_hdr_t *, hdr);
|
|
}
|
|
|
|
return (bytes_evicted);
|
|
}
|
|
|
|
static uint64_t
|
|
arc_evict_state_impl(multilist_t *ml, int idx, arc_buf_hdr_t *marker,
|
|
uint64_t spa, int64_t bytes)
|
|
{
|
|
multilist_sublist_t *mls;
|
|
uint64_t bytes_evicted = 0;
|
|
arc_buf_hdr_t *hdr;
|
|
kmutex_t *hash_lock;
|
|
int evict_count = 0;
|
|
|
|
ASSERT3P(marker, !=, NULL);
|
|
ASSERTV(if (bytes < 0) ASSERT(bytes == ARC_EVICT_ALL));
|
|
|
|
mls = multilist_sublist_lock(ml, idx);
|
|
|
|
for (hdr = multilist_sublist_prev(mls, marker); hdr != NULL;
|
|
hdr = multilist_sublist_prev(mls, marker)) {
|
|
if ((bytes != ARC_EVICT_ALL && bytes_evicted >= bytes) ||
|
|
(evict_count >= zfs_arc_evict_batch_limit))
|
|
break;
|
|
|
|
/*
|
|
* To keep our iteration location, move the marker
|
|
* forward. Since we're not holding hdr's hash lock, we
|
|
* must be very careful and not remove 'hdr' from the
|
|
* sublist. Otherwise, other consumers might mistake the
|
|
* 'hdr' as not being on a sublist when they call the
|
|
* multilist_link_active() function (they all rely on
|
|
* the hash lock protecting concurrent insertions and
|
|
* removals). multilist_sublist_move_forward() was
|
|
* specifically implemented to ensure this is the case
|
|
* (only 'marker' will be removed and re-inserted).
|
|
*/
|
|
multilist_sublist_move_forward(mls, marker);
|
|
|
|
/*
|
|
* The only case where the b_spa field should ever be
|
|
* zero, is the marker headers inserted by
|
|
* arc_evict_state(). It's possible for multiple threads
|
|
* to be calling arc_evict_state() concurrently (e.g.
|
|
* dsl_pool_close() and zio_inject_fault()), so we must
|
|
* skip any markers we see from these other threads.
|
|
*/
|
|
if (hdr->b_spa == 0)
|
|
continue;
|
|
|
|
/* we're only interested in evicting buffers of a certain spa */
|
|
if (spa != 0 && hdr->b_spa != spa) {
|
|
ARCSTAT_BUMP(arcstat_evict_skip);
|
|
continue;
|
|
}
|
|
|
|
hash_lock = HDR_LOCK(hdr);
|
|
|
|
/*
|
|
* We aren't calling this function from any code path
|
|
* that would already be holding a hash lock, so we're
|
|
* asserting on this assumption to be defensive in case
|
|
* this ever changes. Without this check, it would be
|
|
* possible to incorrectly increment arcstat_mutex_miss
|
|
* below (e.g. if the code changed such that we called
|
|
* this function with a hash lock held).
|
|
*/
|
|
ASSERT(!MUTEX_HELD(hash_lock));
|
|
|
|
if (mutex_tryenter(hash_lock)) {
|
|
uint64_t evicted = arc_evict_hdr(hdr, hash_lock);
|
|
mutex_exit(hash_lock);
|
|
|
|
bytes_evicted += evicted;
|
|
|
|
/*
|
|
* If evicted is zero, arc_evict_hdr() must have
|
|
* decided to skip this header, don't increment
|
|
* evict_count in this case.
|
|
*/
|
|
if (evicted != 0)
|
|
evict_count++;
|
|
|
|
/*
|
|
* If arc_size isn't overflowing, signal any
|
|
* threads that might happen to be waiting.
|
|
*
|
|
* For each header evicted, we wake up a single
|
|
* thread. If we used cv_broadcast, we could
|
|
* wake up "too many" threads causing arc_size
|
|
* to significantly overflow arc_c; since
|
|
* arc_get_data_buf() doesn't check for overflow
|
|
* when it's woken up (it doesn't because it's
|
|
* possible for the ARC to be overflowing while
|
|
* full of un-evictable buffers, and the
|
|
* function should proceed in this case).
|
|
*
|
|
* If threads are left sleeping, due to not
|
|
* using cv_broadcast, they will be woken up
|
|
* just before arc_reclaim_thread() sleeps.
|
|
*/
|
|
mutex_enter(&arc_reclaim_lock);
|
|
if (!arc_is_overflowing())
|
|
cv_signal(&arc_reclaim_waiters_cv);
|
|
mutex_exit(&arc_reclaim_lock);
|
|
} else {
|
|
ARCSTAT_BUMP(arcstat_mutex_miss);
|
|
}
|
|
}
|
|
|
|
multilist_sublist_unlock(mls);
|
|
|
|
return (bytes_evicted);
|
|
}
|
|
|
|
/*
|
|
* Evict buffers from the given arc state, until we've removed the
|
|
* specified number of bytes. Move the removed buffers to the
|
|
* appropriate evict state.
|
|
*
|
|
* This function makes a "best effort". It skips over any buffers
|
|
* it can't get a hash_lock on, and so, may not catch all candidates.
|
|
* It may also return without evicting as much space as requested.
|
|
*
|
|
* If bytes is specified using the special value ARC_EVICT_ALL, this
|
|
* will evict all available (i.e. unlocked and evictable) buffers from
|
|
* the given arc state; which is used by arc_flush().
|
|
*/
|
|
static uint64_t
|
|
arc_evict_state(arc_state_t *state, uint64_t spa, int64_t bytes,
|
|
arc_buf_contents_t type)
|
|
{
|
|
uint64_t total_evicted = 0;
|
|
multilist_t *ml = &state->arcs_list[type];
|
|
int num_sublists;
|
|
arc_buf_hdr_t **markers;
|
|
int i;
|
|
|
|
ASSERTV(if (bytes < 0) ASSERT(bytes == ARC_EVICT_ALL));
|
|
|
|
num_sublists = multilist_get_num_sublists(ml);
|
|
|
|
/*
|
|
* If we've tried to evict from each sublist, made some
|
|
* progress, but still have not hit the target number of bytes
|
|
* to evict, we want to keep trying. The markers allow us to
|
|
* pick up where we left off for each individual sublist, rather
|
|
* than starting from the tail each time.
|
|
*/
|
|
markers = kmem_zalloc(sizeof (*markers) * num_sublists, KM_SLEEP);
|
|
for (i = 0; i < num_sublists; i++) {
|
|
multilist_sublist_t *mls;
|
|
|
|
markers[i] = kmem_cache_alloc(hdr_full_cache, KM_SLEEP);
|
|
|
|
/*
|
|
* A b_spa of 0 is used to indicate that this header is
|
|
* a marker. This fact is used in arc_adjust_type() and
|
|
* arc_evict_state_impl().
|
|
*/
|
|
markers[i]->b_spa = 0;
|
|
|
|
mls = multilist_sublist_lock(ml, i);
|
|
multilist_sublist_insert_tail(mls, markers[i]);
|
|
multilist_sublist_unlock(mls);
|
|
}
|
|
|
|
/*
|
|
* While we haven't hit our target number of bytes to evict, or
|
|
* we're evicting all available buffers.
|
|
*/
|
|
while (total_evicted < bytes || bytes == ARC_EVICT_ALL) {
|
|
/*
|
|
* Start eviction using a randomly selected sublist,
|
|
* this is to try and evenly balance eviction across all
|
|
* sublists. Always starting at the same sublist
|
|
* (e.g. index 0) would cause evictions to favor certain
|
|
* sublists over others.
|
|
*/
|
|
int sublist_idx = multilist_get_random_index(ml);
|
|
uint64_t scan_evicted = 0;
|
|
|
|
for (i = 0; i < num_sublists; i++) {
|
|
uint64_t bytes_remaining;
|
|
uint64_t bytes_evicted;
|
|
|
|
if (bytes == ARC_EVICT_ALL)
|
|
bytes_remaining = ARC_EVICT_ALL;
|
|
else if (total_evicted < bytes)
|
|
bytes_remaining = bytes - total_evicted;
|
|
else
|
|
break;
|
|
|
|
bytes_evicted = arc_evict_state_impl(ml, sublist_idx,
|
|
markers[sublist_idx], spa, bytes_remaining);
|
|
|
|
scan_evicted += bytes_evicted;
|
|
total_evicted += bytes_evicted;
|
|
|
|
/* we've reached the end, wrap to the beginning */
|
|
if (++sublist_idx >= num_sublists)
|
|
sublist_idx = 0;
|
|
}
|
|
|
|
/*
|
|
* If we didn't evict anything during this scan, we have
|
|
* no reason to believe we'll evict more during another
|
|
* scan, so break the loop.
|
|
*/
|
|
if (scan_evicted == 0) {
|
|
/* This isn't possible, let's make that obvious */
|
|
ASSERT3S(bytes, !=, 0);
|
|
|
|
/*
|
|
* When bytes is ARC_EVICT_ALL, the only way to
|
|
* break the loop is when scan_evicted is zero.
|
|
* In that case, we actually have evicted enough,
|
|
* so we don't want to increment the kstat.
|
|
*/
|
|
if (bytes != ARC_EVICT_ALL) {
|
|
ASSERT3S(total_evicted, <, bytes);
|
|
ARCSTAT_BUMP(arcstat_evict_not_enough);
|
|
}
|
|
|
|
break;
|
|
}
|
|
}
|
|
|
|
for (i = 0; i < num_sublists; i++) {
|
|
multilist_sublist_t *mls = multilist_sublist_lock(ml, i);
|
|
multilist_sublist_remove(mls, markers[i]);
|
|
multilist_sublist_unlock(mls);
|
|
|
|
kmem_cache_free(hdr_full_cache, markers[i]);
|
|
}
|
|
kmem_free(markers, sizeof (*markers) * num_sublists);
|
|
|
|
return (total_evicted);
|
|
}
|
|
|
|
/*
|
|
* Flush all "evictable" data of the given type from the arc state
|
|
* specified. This will not evict any "active" buffers (i.e. referenced).
|
|
*
|
|
* When 'retry' is set to FALSE, the function will make a single pass
|
|
* over the state and evict any buffers that it can. Since it doesn't
|
|
* continually retry the eviction, it might end up leaving some buffers
|
|
* in the ARC due to lock misses.
|
|
*
|
|
* When 'retry' is set to TRUE, the function will continually retry the
|
|
* eviction until *all* evictable buffers have been removed from the
|
|
* state. As a result, if concurrent insertions into the state are
|
|
* allowed (e.g. if the ARC isn't shutting down), this function might
|
|
* wind up in an infinite loop, continually trying to evict buffers.
|
|
*/
|
|
static uint64_t
|
|
arc_flush_state(arc_state_t *state, uint64_t spa, arc_buf_contents_t type,
|
|
boolean_t retry)
|
|
{
|
|
uint64_t evicted = 0;
|
|
|
|
while (state->arcs_lsize[type] != 0) {
|
|
evicted += arc_evict_state(state, spa, ARC_EVICT_ALL, type);
|
|
|
|
if (!retry)
|
|
break;
|
|
}
|
|
|
|
return (evicted);
|
|
}
|
|
|
|
/*
|
|
* Helper function for arc_prune() it is responsible for safely handling
|
|
* the execution of a registered arc_prune_func_t.
|
|
*/
|
|
static void
|
|
arc_prune_task(void *ptr)
|
|
{
|
|
arc_prune_t *ap = (arc_prune_t *)ptr;
|
|
arc_prune_func_t *func = ap->p_pfunc;
|
|
|
|
if (func != NULL)
|
|
func(ap->p_adjust, ap->p_private);
|
|
|
|
/* Callback unregistered concurrently with execution */
|
|
if (refcount_remove(&ap->p_refcnt, func) == 0) {
|
|
ASSERT(!list_link_active(&ap->p_node));
|
|
refcount_destroy(&ap->p_refcnt);
|
|
kmem_free(ap, sizeof (*ap));
|
|
}
|
|
}
|
|
|
|
/*
|
|
* Notify registered consumers they must drop holds on a portion of the ARC
|
|
* buffered they reference. This provides a mechanism to ensure the ARC can
|
|
* honor the arc_meta_limit and reclaim otherwise pinned ARC buffers. This
|
|
* is analogous to dnlc_reduce_cache() but more generic.
|
|
*
|
|
* This operation is performed asyncronously so it may be safely called
|
|
* in the context of the arc_adapt_thread(). A reference is taken here
|
|
* for each registered arc_prune_t and the arc_prune_task() is responsible
|
|
* for releasing it once the registered arc_prune_func_t has completed.
|
|
*/
|
|
static void
|
|
arc_prune_async(int64_t adjust)
|
|
{
|
|
arc_prune_t *ap;
|
|
|
|
mutex_enter(&arc_prune_mtx);
|
|
for (ap = list_head(&arc_prune_list); ap != NULL;
|
|
ap = list_next(&arc_prune_list, ap)) {
|
|
|
|
if (refcount_count(&ap->p_refcnt) >= 2)
|
|
continue;
|
|
|
|
refcount_add(&ap->p_refcnt, ap->p_pfunc);
|
|
ap->p_adjust = adjust;
|
|
taskq_dispatch(arc_prune_taskq, arc_prune_task, ap, TQ_SLEEP);
|
|
ARCSTAT_BUMP(arcstat_prune);
|
|
}
|
|
mutex_exit(&arc_prune_mtx);
|
|
}
|
|
|
|
static void
|
|
arc_prune(int64_t adjust)
|
|
{
|
|
arc_prune_async(adjust);
|
|
taskq_wait_outstanding(arc_prune_taskq, 0);
|
|
}
|
|
|
|
/*
|
|
* Evict the specified number of bytes from the state specified,
|
|
* restricting eviction to the spa and type given. This function
|
|
* prevents us from trying to evict more from a state's list than
|
|
* is "evictable", and to skip evicting altogether when passed a
|
|
* negative value for "bytes". In contrast, arc_evict_state() will
|
|
* evict everything it can, when passed a negative value for "bytes".
|
|
*/
|
|
static uint64_t
|
|
arc_adjust_impl(arc_state_t *state, uint64_t spa, int64_t bytes,
|
|
arc_buf_contents_t type)
|
|
{
|
|
int64_t delta;
|
|
|
|
if (bytes > 0 && state->arcs_lsize[type] > 0) {
|
|
delta = MIN(state->arcs_lsize[type], bytes);
|
|
return (arc_evict_state(state, spa, delta, type));
|
|
}
|
|
|
|
return (0);
|
|
}
|
|
|
|
/*
|
|
* The goal of this function is to evict enough meta data buffers from the
|
|
* ARC in order to enforce the arc_meta_limit. Achieving this is slightly
|
|
* more complicated than it appears because it is common for data buffers
|
|
* to have holds on meta data buffers. In addition, dnode meta data buffers
|
|
* will be held by the dnodes in the block preventing them from being freed.
|
|
* This means we can't simply traverse the ARC and expect to always find
|
|
* enough unheld meta data buffer to release.
|
|
*
|
|
* Therefore, this function has been updated to make alternating passes
|
|
* over the ARC releasing data buffers and then newly unheld meta data
|
|
* buffers. This ensures forward progress is maintained and arc_meta_used
|
|
* will decrease. Normally this is sufficient, but if required the ARC
|
|
* will call the registered prune callbacks causing dentry and inodes to
|
|
* be dropped from the VFS cache. This will make dnode meta data buffers
|
|
* available for reclaim.
|
|
*/
|
|
static uint64_t
|
|
arc_adjust_meta_balanced(void)
|
|
{
|
|
int64_t adjustmnt, delta, prune = 0;
|
|
uint64_t total_evicted = 0;
|
|
arc_buf_contents_t type = ARC_BUFC_DATA;
|
|
unsigned long restarts = zfs_arc_meta_adjust_restarts;
|
|
|
|
restart:
|
|
/*
|
|
* This slightly differs than the way we evict from the mru in
|
|
* arc_adjust because we don't have a "target" value (i.e. no
|
|
* "meta" arc_p). As a result, I think we can completely
|
|
* cannibalize the metadata in the MRU before we evict the
|
|
* metadata from the MFU. I think we probably need to implement a
|
|
* "metadata arc_p" value to do this properly.
|
|
*/
|
|
adjustmnt = arc_meta_used - arc_meta_limit;
|
|
|
|
if (adjustmnt > 0 && arc_mru->arcs_lsize[type] > 0) {
|
|
delta = MIN(arc_mru->arcs_lsize[type], adjustmnt);
|
|
total_evicted += arc_adjust_impl(arc_mru, 0, delta, type);
|
|
adjustmnt -= delta;
|
|
}
|
|
|
|
/*
|
|
* We can't afford to recalculate adjustmnt here. If we do,
|
|
* new metadata buffers can sneak into the MRU or ANON lists,
|
|
* thus penalize the MFU metadata. Although the fudge factor is
|
|
* small, it has been empirically shown to be significant for
|
|
* certain workloads (e.g. creating many empty directories). As
|
|
* such, we use the original calculation for adjustmnt, and
|
|
* simply decrement the amount of data evicted from the MRU.
|
|
*/
|
|
|
|
if (adjustmnt > 0 && arc_mfu->arcs_lsize[type] > 0) {
|
|
delta = MIN(arc_mfu->arcs_lsize[type], adjustmnt);
|
|
total_evicted += arc_adjust_impl(arc_mfu, 0, delta, type);
|
|
}
|
|
|
|
adjustmnt = arc_meta_used - arc_meta_limit;
|
|
|
|
if (adjustmnt > 0 && arc_mru_ghost->arcs_lsize[type] > 0) {
|
|
delta = MIN(adjustmnt,
|
|
arc_mru_ghost->arcs_lsize[type]);
|
|
total_evicted += arc_adjust_impl(arc_mru_ghost, 0, delta, type);
|
|
adjustmnt -= delta;
|
|
}
|
|
|
|
if (adjustmnt > 0 && arc_mfu_ghost->arcs_lsize[type] > 0) {
|
|
delta = MIN(adjustmnt,
|
|
arc_mfu_ghost->arcs_lsize[type]);
|
|
total_evicted += arc_adjust_impl(arc_mfu_ghost, 0, delta, type);
|
|
}
|
|
|
|
/*
|
|
* If after attempting to make the requested adjustment to the ARC
|
|
* the meta limit is still being exceeded then request that the
|
|
* higher layers drop some cached objects which have holds on ARC
|
|
* meta buffers. Requests to the upper layers will be made with
|
|
* increasingly large scan sizes until the ARC is below the limit.
|
|
*/
|
|
if (arc_meta_used > arc_meta_limit) {
|
|
if (type == ARC_BUFC_DATA) {
|
|
type = ARC_BUFC_METADATA;
|
|
} else {
|
|
type = ARC_BUFC_DATA;
|
|
|
|
if (zfs_arc_meta_prune) {
|
|
prune += zfs_arc_meta_prune;
|
|
arc_prune_async(prune);
|
|
}
|
|
}
|
|
|
|
if (restarts > 0) {
|
|
restarts--;
|
|
goto restart;
|
|
}
|
|
}
|
|
return (total_evicted);
|
|
}
|
|
|
|
/*
|
|
* Evict metadata buffers from the cache, such that arc_meta_used is
|
|
* capped by the arc_meta_limit tunable.
|
|
*/
|
|
static uint64_t
|
|
arc_adjust_meta_only(void)
|
|
{
|
|
uint64_t total_evicted = 0;
|
|
int64_t target;
|
|
|
|
/*
|
|
* If we're over the meta limit, we want to evict enough
|
|
* metadata to get back under the meta limit. We don't want to
|
|
* evict so much that we drop the MRU below arc_p, though. If
|
|
* we're over the meta limit more than we're over arc_p, we
|
|
* evict some from the MRU here, and some from the MFU below.
|
|
*/
|
|
target = MIN((int64_t)(arc_meta_used - arc_meta_limit),
|
|
(int64_t)(arc_anon->arcs_size + arc_mru->arcs_size - arc_p));
|
|
|
|
total_evicted += arc_adjust_impl(arc_mru, 0, target, ARC_BUFC_METADATA);
|
|
|
|
/*
|
|
* Similar to the above, we want to evict enough bytes to get us
|
|
* below the meta limit, but not so much as to drop us below the
|
|
* space alloted to the MFU (which is defined as arc_c - arc_p).
|
|
*/
|
|
target = MIN((int64_t)(arc_meta_used - arc_meta_limit),
|
|
(int64_t)(arc_mfu->arcs_size - (arc_c - arc_p)));
|
|
|
|
total_evicted += arc_adjust_impl(arc_mfu, 0, target, ARC_BUFC_METADATA);
|
|
|
|
return (total_evicted);
|
|
}
|
|
|
|
static uint64_t
|
|
arc_adjust_meta(void)
|
|
{
|
|
if (zfs_arc_meta_strategy == ARC_STRATEGY_META_ONLY)
|
|
return (arc_adjust_meta_only());
|
|
else
|
|
return (arc_adjust_meta_balanced());
|
|
}
|
|
|
|
/*
|
|
* Return the type of the oldest buffer in the given arc state
|
|
*
|
|
* This function will select a random sublist of type ARC_BUFC_DATA and
|
|
* a random sublist of type ARC_BUFC_METADATA. The tail of each sublist
|
|
* is compared, and the type which contains the "older" buffer will be
|
|
* returned.
|
|
*/
|
|
static arc_buf_contents_t
|
|
arc_adjust_type(arc_state_t *state)
|
|
{
|
|
multilist_t *data_ml = &state->arcs_list[ARC_BUFC_DATA];
|
|
multilist_t *meta_ml = &state->arcs_list[ARC_BUFC_METADATA];
|
|
int data_idx = multilist_get_random_index(data_ml);
|
|
int meta_idx = multilist_get_random_index(meta_ml);
|
|
multilist_sublist_t *data_mls;
|
|
multilist_sublist_t *meta_mls;
|
|
arc_buf_contents_t type;
|
|
arc_buf_hdr_t *data_hdr;
|
|
arc_buf_hdr_t *meta_hdr;
|
|
|
|
/*
|
|
* We keep the sublist lock until we're finished, to prevent
|
|
* the headers from being destroyed via arc_evict_state().
|
|
*/
|
|
data_mls = multilist_sublist_lock(data_ml, data_idx);
|
|
meta_mls = multilist_sublist_lock(meta_ml, meta_idx);
|
|
|
|
/*
|
|
* These two loops are to ensure we skip any markers that
|
|
* might be at the tail of the lists due to arc_evict_state().
|
|
*/
|
|
|
|
for (data_hdr = multilist_sublist_tail(data_mls); data_hdr != NULL;
|
|
data_hdr = multilist_sublist_prev(data_mls, data_hdr)) {
|
|
if (data_hdr->b_spa != 0)
|
|
break;
|
|
}
|
|
|
|
for (meta_hdr = multilist_sublist_tail(meta_mls); meta_hdr != NULL;
|
|
meta_hdr = multilist_sublist_prev(meta_mls, meta_hdr)) {
|
|
if (meta_hdr->b_spa != 0)
|
|
break;
|
|
}
|
|
|
|
if (data_hdr == NULL && meta_hdr == NULL) {
|
|
type = ARC_BUFC_DATA;
|
|
} else if (data_hdr == NULL) {
|
|
ASSERT3P(meta_hdr, !=, NULL);
|
|
type = ARC_BUFC_METADATA;
|
|
} else if (meta_hdr == NULL) {
|
|
ASSERT3P(data_hdr, !=, NULL);
|
|
type = ARC_BUFC_DATA;
|
|
} else {
|
|
ASSERT3P(data_hdr, !=, NULL);
|
|
ASSERT3P(meta_hdr, !=, NULL);
|
|
|
|
/* The headers can't be on the sublist without an L1 header */
|
|
ASSERT(HDR_HAS_L1HDR(data_hdr));
|
|
ASSERT(HDR_HAS_L1HDR(meta_hdr));
|
|
|
|
if (data_hdr->b_l1hdr.b_arc_access <
|
|
meta_hdr->b_l1hdr.b_arc_access) {
|
|
type = ARC_BUFC_DATA;
|
|
} else {
|
|
type = ARC_BUFC_METADATA;
|
|
}
|
|
}
|
|
|
|
multilist_sublist_unlock(meta_mls);
|
|
multilist_sublist_unlock(data_mls);
|
|
|
|
return (type);
|
|
}
|
|
|
|
/*
|
|
* Evict buffers from the cache, such that arc_size is capped by arc_c.
|
|
*/
|
|
static uint64_t
|
|
arc_adjust(void)
|
|
{
|
|
uint64_t total_evicted = 0;
|
|
uint64_t bytes;
|
|
int64_t target;
|
|
|
|
/*
|
|
* If we're over arc_meta_limit, we want to correct that before
|
|
* potentially evicting data buffers below.
|
|
*/
|
|
total_evicted += arc_adjust_meta();
|
|
|
|
/*
|
|
* Adjust MRU size
|
|
*
|
|
* If we're over the target cache size, we want to evict enough
|
|
* from the list to get back to our target size. We don't want
|
|
* to evict too much from the MRU, such that it drops below
|
|
* arc_p. So, if we're over our target cache size more than
|
|
* the MRU is over arc_p, we'll evict enough to get back to
|
|
* arc_p here, and then evict more from the MFU below.
|
|
*/
|
|
target = MIN((int64_t)(arc_size - arc_c),
|
|
(int64_t)(arc_anon->arcs_size + arc_mru->arcs_size + arc_meta_used -
|
|
arc_p));
|
|
|
|
/*
|
|
* If we're below arc_meta_min, always prefer to evict data.
|
|
* Otherwise, try to satisfy the requested number of bytes to
|
|
* evict from the type which contains older buffers; in an
|
|
* effort to keep newer buffers in the cache regardless of their
|
|
* type. If we cannot satisfy the number of bytes from this
|
|
* type, spill over into the next type.
|
|
*/
|
|
if (arc_adjust_type(arc_mru) == ARC_BUFC_METADATA &&
|
|
arc_meta_used > arc_meta_min) {
|
|
bytes = arc_adjust_impl(arc_mru, 0, target, ARC_BUFC_METADATA);
|
|
total_evicted += bytes;
|
|
|
|
/*
|
|
* If we couldn't evict our target number of bytes from
|
|
* metadata, we try to get the rest from data.
|
|
*/
|
|
target -= bytes;
|
|
|
|
total_evicted +=
|
|
arc_adjust_impl(arc_mru, 0, target, ARC_BUFC_DATA);
|
|
} else {
|
|
bytes = arc_adjust_impl(arc_mru, 0, target, ARC_BUFC_DATA);
|
|
total_evicted += bytes;
|
|
|
|
/*
|
|
* If we couldn't evict our target number of bytes from
|
|
* data, we try to get the rest from metadata.
|
|
*/
|
|
target -= bytes;
|
|
|
|
total_evicted +=
|
|
arc_adjust_impl(arc_mru, 0, target, ARC_BUFC_METADATA);
|
|
}
|
|
|
|
/*
|
|
* Adjust MFU size
|
|
*
|
|
* Now that we've tried to evict enough from the MRU to get its
|
|
* size back to arc_p, if we're still above the target cache
|
|
* size, we evict the rest from the MFU.
|
|
*/
|
|
target = arc_size - arc_c;
|
|
|
|
if (arc_adjust_type(arc_mfu) == ARC_BUFC_METADATA &&
|
|
arc_meta_used > arc_meta_min) {
|
|
bytes = arc_adjust_impl(arc_mfu, 0, target, ARC_BUFC_METADATA);
|
|
total_evicted += bytes;
|
|
|
|
/*
|
|
* If we couldn't evict our target number of bytes from
|
|
* metadata, we try to get the rest from data.
|
|
*/
|
|
target -= bytes;
|
|
|
|
total_evicted +=
|
|
arc_adjust_impl(arc_mfu, 0, target, ARC_BUFC_DATA);
|
|
} else {
|
|
bytes = arc_adjust_impl(arc_mfu, 0, target, ARC_BUFC_DATA);
|
|
total_evicted += bytes;
|
|
|
|
/*
|
|
* If we couldn't evict our target number of bytes from
|
|
* data, we try to get the rest from data.
|
|
*/
|
|
target -= bytes;
|
|
|
|
total_evicted +=
|
|
arc_adjust_impl(arc_mfu, 0, target, ARC_BUFC_METADATA);
|
|
}
|
|
|
|
/*
|
|
* Adjust ghost lists
|
|
*
|
|
* In addition to the above, the ARC also defines target values
|
|
* for the ghost lists. The sum of the mru list and mru ghost
|
|
* list should never exceed the target size of the cache, and
|
|
* the sum of the mru list, mfu list, mru ghost list, and mfu
|
|
* ghost list should never exceed twice the target size of the
|
|
* cache. The following logic enforces these limits on the ghost
|
|
* caches, and evicts from them as needed.
|
|
*/
|
|
target = arc_mru->arcs_size + arc_mru_ghost->arcs_size - arc_c;
|
|
|
|
bytes = arc_adjust_impl(arc_mru_ghost, 0, target, ARC_BUFC_DATA);
|
|
total_evicted += bytes;
|
|
|
|
target -= bytes;
|
|
|
|
total_evicted +=
|
|
arc_adjust_impl(arc_mru_ghost, 0, target, ARC_BUFC_METADATA);
|
|
|
|
/*
|
|
* We assume the sum of the mru list and mfu list is less than
|
|
* or equal to arc_c (we enforced this above), which means we
|
|
* can use the simpler of the two equations below:
|
|
*
|
|
* mru + mfu + mru ghost + mfu ghost <= 2 * arc_c
|
|
* mru ghost + mfu ghost <= arc_c
|
|
*/
|
|
target = arc_mru_ghost->arcs_size + arc_mfu_ghost->arcs_size - arc_c;
|
|
|
|
bytes = arc_adjust_impl(arc_mfu_ghost, 0, target, ARC_BUFC_DATA);
|
|
total_evicted += bytes;
|
|
|
|
target -= bytes;
|
|
|
|
total_evicted +=
|
|
arc_adjust_impl(arc_mfu_ghost, 0, target, ARC_BUFC_METADATA);
|
|
|
|
return (total_evicted);
|
|
}
|
|
|
|
static void
|
|
arc_do_user_evicts(void)
|
|
{
|
|
mutex_enter(&arc_user_evicts_lock);
|
|
while (arc_eviction_list != NULL) {
|
|
arc_buf_t *buf = arc_eviction_list;
|
|
arc_eviction_list = buf->b_next;
|
|
mutex_enter(&buf->b_evict_lock);
|
|
buf->b_hdr = NULL;
|
|
mutex_exit(&buf->b_evict_lock);
|
|
mutex_exit(&arc_user_evicts_lock);
|
|
|
|
if (buf->b_efunc != NULL)
|
|
VERIFY0(buf->b_efunc(buf->b_private));
|
|
|
|
buf->b_efunc = NULL;
|
|
buf->b_private = NULL;
|
|
kmem_cache_free(buf_cache, buf);
|
|
mutex_enter(&arc_user_evicts_lock);
|
|
}
|
|
mutex_exit(&arc_user_evicts_lock);
|
|
}
|
|
|
|
void
|
|
arc_flush(spa_t *spa, boolean_t retry)
|
|
{
|
|
uint64_t guid = 0;
|
|
|
|
/*
|
|
* If retry is TRUE, a spa must not be specified since we have
|
|
* no good way to determine if all of a spa's buffers have been
|
|
* evicted from an arc state.
|
|
*/
|
|
ASSERT(!retry || spa == 0);
|
|
|
|
if (spa != NULL)
|
|
guid = spa_load_guid(spa);
|
|
|
|
(void) arc_flush_state(arc_mru, guid, ARC_BUFC_DATA, retry);
|
|
(void) arc_flush_state(arc_mru, guid, ARC_BUFC_METADATA, retry);
|
|
|
|
(void) arc_flush_state(arc_mfu, guid, ARC_BUFC_DATA, retry);
|
|
(void) arc_flush_state(arc_mfu, guid, ARC_BUFC_METADATA, retry);
|
|
|
|
(void) arc_flush_state(arc_mru_ghost, guid, ARC_BUFC_DATA, retry);
|
|
(void) arc_flush_state(arc_mru_ghost, guid, ARC_BUFC_METADATA, retry);
|
|
|
|
(void) arc_flush_state(arc_mfu_ghost, guid, ARC_BUFC_DATA, retry);
|
|
(void) arc_flush_state(arc_mfu_ghost, guid, ARC_BUFC_METADATA, retry);
|
|
|
|
arc_do_user_evicts();
|
|
ASSERT(spa || arc_eviction_list == NULL);
|
|
}
|
|
|
|
void
|
|
arc_shrink(uint64_t bytes)
|
|
{
|
|
if (arc_c > arc_c_min) {
|
|
uint64_t to_free;
|
|
|
|
to_free = bytes ? bytes : arc_c >> zfs_arc_shrink_shift;
|
|
|
|
if (arc_c > arc_c_min + to_free)
|
|
atomic_add_64(&arc_c, -to_free);
|
|
else
|
|
arc_c = arc_c_min;
|
|
|
|
to_free = bytes ? bytes : arc_p >> zfs_arc_shrink_shift;
|
|
|
|
if (arc_p > to_free)
|
|
atomic_add_64(&arc_p, -to_free);
|
|
else
|
|
arc_p = 0;
|
|
|
|
if (arc_c > arc_size)
|
|
arc_c = MAX(arc_size, arc_c_min);
|
|
if (arc_p > arc_c)
|
|
arc_p = (arc_c >> 1);
|
|
ASSERT(arc_c >= arc_c_min);
|
|
ASSERT((int64_t)arc_p >= 0);
|
|
}
|
|
|
|
if (arc_size > arc_c)
|
|
(void) arc_adjust();
|
|
}
|
|
|
|
static void
|
|
arc_kmem_reap_now(arc_reclaim_strategy_t strat, uint64_t bytes)
|
|
{
|
|
size_t i;
|
|
kmem_cache_t *prev_cache = NULL;
|
|
kmem_cache_t *prev_data_cache = NULL;
|
|
extern kmem_cache_t *zio_buf_cache[];
|
|
extern kmem_cache_t *zio_data_buf_cache[];
|
|
extern kmem_cache_t *range_seg_cache;
|
|
|
|
if ((arc_meta_used >= arc_meta_limit) && zfs_arc_meta_prune) {
|
|
/*
|
|
* We are exceeding our meta-data cache limit.
|
|
* Prune some entries to release holds on meta-data.
|
|
*/
|
|
arc_prune(zfs_arc_meta_prune);
|
|
}
|
|
|
|
/*
|
|
* An aggressive reclamation will shrink the cache size as well as
|
|
* reap free buffers from the arc kmem caches.
|
|
*/
|
|
if (strat == ARC_RECLAIM_AGGR)
|
|
arc_shrink(bytes);
|
|
|
|
for (i = 0; i < SPA_MAXBLOCKSIZE >> SPA_MINBLOCKSHIFT; i++) {
|
|
if (zio_buf_cache[i] != prev_cache) {
|
|
prev_cache = zio_buf_cache[i];
|
|
kmem_cache_reap_now(zio_buf_cache[i]);
|
|
}
|
|
if (zio_data_buf_cache[i] != prev_data_cache) {
|
|
prev_data_cache = zio_data_buf_cache[i];
|
|
kmem_cache_reap_now(zio_data_buf_cache[i]);
|
|
}
|
|
}
|
|
|
|
kmem_cache_reap_now(buf_cache);
|
|
kmem_cache_reap_now(hdr_full_cache);
|
|
kmem_cache_reap_now(hdr_l2only_cache);
|
|
kmem_cache_reap_now(range_seg_cache);
|
|
}
|
|
|
|
/*
|
|
* Threads can block in arc_get_data_buf() waiting for this thread to evict
|
|
* enough data and signal them to proceed. When this happens, the threads in
|
|
* arc_get_data_buf() are sleeping while holding the hash lock for their
|
|
* particular arc header. Thus, we must be careful to never sleep on a
|
|
* hash lock in this thread. This is to prevent the following deadlock:
|
|
*
|
|
* - Thread A sleeps on CV in arc_get_data_buf() holding hash lock "L",
|
|
* waiting for the reclaim thread to signal it.
|
|
*
|
|
* - arc_reclaim_thread() tries to acquire hash lock "L" using mutex_enter,
|
|
* fails, and goes to sleep forever.
|
|
*
|
|
* This possible deadlock is avoided by always acquiring a hash lock
|
|
* using mutex_tryenter() from arc_reclaim_thread().
|
|
*/
|
|
static void
|
|
arc_adapt_thread(void)
|
|
{
|
|
callb_cpr_t cpr;
|
|
fstrans_cookie_t cookie;
|
|
uint64_t arc_evicted;
|
|
|
|
CALLB_CPR_INIT(&cpr, &arc_reclaim_lock, callb_generic_cpr, FTAG);
|
|
|
|
cookie = spl_fstrans_mark();
|
|
mutex_enter(&arc_reclaim_lock);
|
|
while (arc_reclaim_thread_exit == 0) {
|
|
#ifndef _KERNEL
|
|
arc_reclaim_strategy_t last_reclaim = ARC_RECLAIM_CONS;
|
|
|
|
mutex_exit(&arc_reclaim_lock);
|
|
if (spa_get_random(100) == 0) {
|
|
|
|
if (arc_no_grow) {
|
|
if (last_reclaim == ARC_RECLAIM_CONS) {
|
|
last_reclaim = ARC_RECLAIM_AGGR;
|
|
} else {
|
|
last_reclaim = ARC_RECLAIM_CONS;
|
|
}
|
|
} else {
|
|
arc_no_grow = TRUE;
|
|
last_reclaim = ARC_RECLAIM_AGGR;
|
|
membar_producer();
|
|
}
|
|
|
|
/* reset the growth delay for every reclaim */
|
|
arc_grow_time = ddi_get_lbolt() +
|
|
(zfs_arc_grow_retry * hz);
|
|
|
|
arc_kmem_reap_now(last_reclaim, 0);
|
|
arc_warm = B_TRUE;
|
|
}
|
|
#else /* _KERNEL */
|
|
mutex_exit(&arc_reclaim_lock);
|
|
#endif /* !_KERNEL */
|
|
|
|
/* No recent memory pressure allow the ARC to grow. */
|
|
if (arc_no_grow &&
|
|
ddi_time_after_eq(ddi_get_lbolt(), arc_grow_time))
|
|
arc_no_grow = FALSE;
|
|
|
|
arc_evicted = arc_adjust();
|
|
|
|
/*
|
|
* We're either no longer overflowing, or we
|
|
* can't evict anything more, so we should wake
|
|
* up any threads before we go to sleep.
|
|
*/
|
|
if (arc_size <= arc_c || arc_evicted == 0)
|
|
cv_broadcast(&arc_reclaim_waiters_cv);
|
|
|
|
mutex_enter(&arc_reclaim_lock);
|
|
|
|
/* block until needed, or one second, whichever is shorter */
|
|
CALLB_CPR_SAFE_BEGIN(&cpr);
|
|
(void) cv_timedwait_sig(&arc_reclaim_thread_cv,
|
|
&arc_reclaim_lock, (ddi_get_lbolt() + hz));
|
|
CALLB_CPR_SAFE_END(&cpr, &arc_reclaim_lock);
|
|
|
|
|
|
/* Allow the module options to be changed */
|
|
if (zfs_arc_max > 64 << 20 &&
|
|
zfs_arc_max < physmem * PAGESIZE &&
|
|
zfs_arc_max != arc_c_max)
|
|
arc_c_max = zfs_arc_max;
|
|
|
|
if (zfs_arc_min >= 2ULL << SPA_MAXBLOCKSHIFT &&
|
|
zfs_arc_min <= arc_c_max &&
|
|
zfs_arc_min != arc_c_min)
|
|
arc_c_min = zfs_arc_min;
|
|
|
|
if (zfs_arc_meta_limit > 0 &&
|
|
zfs_arc_meta_limit <= arc_c_max &&
|
|
zfs_arc_meta_limit != arc_meta_limit)
|
|
arc_meta_limit = zfs_arc_meta_limit;
|
|
}
|
|
|
|
arc_reclaim_thread_exit = 0;
|
|
cv_broadcast(&arc_reclaim_thread_cv);
|
|
CALLB_CPR_EXIT(&cpr); /* drops arc_reclaim_lock */
|
|
spl_fstrans_unmark(cookie);
|
|
thread_exit();
|
|
}
|
|
|
|
static void
|
|
arc_user_evicts_thread(void)
|
|
{
|
|
callb_cpr_t cpr;
|
|
fstrans_cookie_t cookie;
|
|
|
|
CALLB_CPR_INIT(&cpr, &arc_user_evicts_lock, callb_generic_cpr, FTAG);
|
|
|
|
cookie = spl_fstrans_mark();
|
|
mutex_enter(&arc_user_evicts_lock);
|
|
while (!arc_user_evicts_thread_exit) {
|
|
mutex_exit(&arc_user_evicts_lock);
|
|
|
|
arc_do_user_evicts();
|
|
|
|
/*
|
|
* This is necessary in order for the mdb ::arc dcmd to
|
|
* show up to date information. Since the ::arc command
|
|
* does not call the kstat's update function, without
|
|
* this call, the command may show stale stats for the
|
|
* anon, mru, mru_ghost, mfu, and mfu_ghost lists. Even
|
|
* with this change, the data might be up to 1 second
|
|
* out of date; but that should suffice. The arc_state_t
|
|
* structures can be queried directly if more accurate
|
|
* information is needed.
|
|
*/
|
|
if (arc_ksp != NULL)
|
|
arc_ksp->ks_update(arc_ksp, KSTAT_READ);
|
|
|
|
mutex_enter(&arc_user_evicts_lock);
|
|
|
|
/*
|
|
* Block until signaled, or after one second (we need to
|
|
* call the arc's kstat update function regularly).
|
|
*/
|
|
CALLB_CPR_SAFE_BEGIN(&cpr);
|
|
(void) cv_timedwait_sig(&arc_user_evicts_cv,
|
|
&arc_user_evicts_lock, ddi_get_lbolt() + hz);
|
|
CALLB_CPR_SAFE_END(&cpr, &arc_user_evicts_lock);
|
|
}
|
|
|
|
arc_user_evicts_thread_exit = FALSE;
|
|
cv_broadcast(&arc_user_evicts_cv);
|
|
CALLB_CPR_EXIT(&cpr); /* drops arc_user_evicts_lock */
|
|
spl_fstrans_unmark(cookie);
|
|
thread_exit();
|
|
}
|
|
|
|
#ifdef _KERNEL
|
|
/*
|
|
* Determine the amount of memory eligible for eviction contained in the
|
|
* ARC. All clean data reported by the ghost lists can always be safely
|
|
* evicted. Due to arc_c_min, the same does not hold for all clean data
|
|
* contained by the regular mru and mfu lists.
|
|
*
|
|
* In the case of the regular mru and mfu lists, we need to report as
|
|
* much clean data as possible, such that evicting that same reported
|
|
* data will not bring arc_size below arc_c_min. Thus, in certain
|
|
* circumstances, the total amount of clean data in the mru and mfu
|
|
* lists might not actually be evictable.
|
|
*
|
|
* The following two distinct cases are accounted for:
|
|
*
|
|
* 1. The sum of the amount of dirty data contained by both the mru and
|
|
* mfu lists, plus the ARC's other accounting (e.g. the anon list),
|
|
* is greater than or equal to arc_c_min.
|
|
* (i.e. amount of dirty data >= arc_c_min)
|
|
*
|
|
* This is the easy case; all clean data contained by the mru and mfu
|
|
* lists is evictable. Evicting all clean data can only drop arc_size
|
|
* to the amount of dirty data, which is greater than arc_c_min.
|
|
*
|
|
* 2. The sum of the amount of dirty data contained by both the mru and
|
|
* mfu lists, plus the ARC's other accounting (e.g. the anon list),
|
|
* is less than arc_c_min.
|
|
* (i.e. arc_c_min > amount of dirty data)
|
|
*
|
|
* 2.1. arc_size is greater than or equal arc_c_min.
|
|
* (i.e. arc_size >= arc_c_min > amount of dirty data)
|
|
*
|
|
* In this case, not all clean data from the regular mru and mfu
|
|
* lists is actually evictable; we must leave enough clean data
|
|
* to keep arc_size above arc_c_min. Thus, the maximum amount of
|
|
* evictable data from the two lists combined, is exactly the
|
|
* difference between arc_size and arc_c_min.
|
|
*
|
|
* 2.2. arc_size is less than arc_c_min
|
|
* (i.e. arc_c_min > arc_size > amount of dirty data)
|
|
*
|
|
* In this case, none of the data contained in the mru and mfu
|
|
* lists is evictable, even if it's clean. Since arc_size is
|
|
* already below arc_c_min, evicting any more would only
|
|
* increase this negative difference.
|
|
*/
|
|
static uint64_t
|
|
arc_evictable_memory(void) {
|
|
uint64_t arc_clean =
|
|
arc_mru->arcs_lsize[ARC_BUFC_DATA] +
|
|
arc_mru->arcs_lsize[ARC_BUFC_METADATA] +
|
|
arc_mfu->arcs_lsize[ARC_BUFC_DATA] +
|
|
arc_mfu->arcs_lsize[ARC_BUFC_METADATA];
|
|
uint64_t ghost_clean =
|
|
arc_mru_ghost->arcs_lsize[ARC_BUFC_DATA] +
|
|
arc_mru_ghost->arcs_lsize[ARC_BUFC_METADATA] +
|
|
arc_mfu_ghost->arcs_lsize[ARC_BUFC_DATA] +
|
|
arc_mfu_ghost->arcs_lsize[ARC_BUFC_METADATA];
|
|
uint64_t arc_dirty = MAX((int64_t)arc_size - (int64_t)arc_clean, 0);
|
|
|
|
if (arc_dirty >= arc_c_min)
|
|
return (ghost_clean + arc_clean);
|
|
|
|
return (ghost_clean + MAX((int64_t)arc_size - (int64_t)arc_c_min, 0));
|
|
}
|
|
|
|
/*
|
|
* If sc->nr_to_scan is zero, the caller is requesting a query of the
|
|
* number of objects which can potentially be freed. If it is nonzero,
|
|
* the request is to free that many objects.
|
|
*
|
|
* Linux kernels >= 3.12 have the count_objects and scan_objects callbacks
|
|
* in struct shrinker and also require the shrinker to return the number
|
|
* of objects freed.
|
|
*
|
|
* Older kernels require the shrinker to return the number of freeable
|
|
* objects following the freeing of nr_to_free.
|
|
*/
|
|
static spl_shrinker_t
|
|
__arc_shrinker_func(struct shrinker *shrink, struct shrink_control *sc)
|
|
{
|
|
int64_t pages;
|
|
|
|
/* The arc is considered warm once reclaim has occurred */
|
|
if (unlikely(arc_warm == B_FALSE))
|
|
arc_warm = B_TRUE;
|
|
|
|
/* Return the potential number of reclaimable pages */
|
|
pages = btop((int64_t)arc_evictable_memory());
|
|
if (sc->nr_to_scan == 0)
|
|
return (pages);
|
|
|
|
/* Not allowed to perform filesystem reclaim */
|
|
if (!(sc->gfp_mask & __GFP_FS))
|
|
return (SHRINK_STOP);
|
|
|
|
/* Reclaim in progress */
|
|
if (mutex_tryenter(&arc_reclaim_lock) == 0)
|
|
return (SHRINK_STOP);
|
|
|
|
mutex_exit(&arc_reclaim_lock);
|
|
|
|
/*
|
|
* Evict the requested number of pages by shrinking arc_c the
|
|
* requested amount. If there is nothing left to evict just
|
|
* reap whatever we can from the various arc slabs.
|
|
*/
|
|
if (pages > 0) {
|
|
arc_kmem_reap_now(ARC_RECLAIM_AGGR, ptob(sc->nr_to_scan));
|
|
|
|
#ifdef HAVE_SPLIT_SHRINKER_CALLBACK
|
|
pages = MAX(pages - btop(arc_evictable_memory()), 0);
|
|
#else
|
|
pages = btop(arc_evictable_memory());
|
|
#endif
|
|
} else {
|
|
arc_kmem_reap_now(ARC_RECLAIM_CONS, ptob(sc->nr_to_scan));
|
|
pages = SHRINK_STOP;
|
|
}
|
|
|
|
/*
|
|
* We've reaped what we can, wake up threads.
|
|
*/
|
|
cv_broadcast(&arc_reclaim_waiters_cv);
|
|
|
|
/*
|
|
* When direct reclaim is observed it usually indicates a rapid
|
|
* increase in memory pressure. This occurs because the kswapd
|
|
* threads were unable to asynchronously keep enough free memory
|
|
* available. In this case set arc_no_grow to briefly pause arc
|
|
* growth to avoid compounding the memory pressure.
|
|
*/
|
|
if (current_is_kswapd()) {
|
|
ARCSTAT_BUMP(arcstat_memory_indirect_count);
|
|
} else {
|
|
arc_no_grow = B_TRUE;
|
|
arc_grow_time = ddi_get_lbolt() + (zfs_arc_grow_retry * hz);
|
|
ARCSTAT_BUMP(arcstat_memory_direct_count);
|
|
}
|
|
|
|
return (pages);
|
|
}
|
|
SPL_SHRINKER_CALLBACK_WRAPPER(arc_shrinker_func);
|
|
|
|
SPL_SHRINKER_DECLARE(arc_shrinker, arc_shrinker_func, DEFAULT_SEEKS);
|
|
#endif /* _KERNEL */
|
|
|
|
/*
|
|
* Adapt arc info given the number of bytes we are trying to add and
|
|
* the state that we are comming from. This function is only called
|
|
* when we are adding new content to the cache.
|
|
*/
|
|
static void
|
|
arc_adapt(int bytes, arc_state_t *state)
|
|
{
|
|
int mult;
|
|
|
|
if (state == arc_l2c_only)
|
|
return;
|
|
|
|
ASSERT(bytes > 0);
|
|
/*
|
|
* Adapt the target size of the MRU list:
|
|
* - if we just hit in the MRU ghost list, then increase
|
|
* the target size of the MRU list.
|
|
* - if we just hit in the MFU ghost list, then increase
|
|
* the target size of the MFU list by decreasing the
|
|
* target size of the MRU list.
|
|
*/
|
|
if (state == arc_mru_ghost) {
|
|
mult = ((arc_mru_ghost->arcs_size >= arc_mfu_ghost->arcs_size) ?
|
|
1 : (arc_mfu_ghost->arcs_size/arc_mru_ghost->arcs_size));
|
|
|
|
if (!zfs_arc_p_dampener_disable)
|
|
mult = MIN(mult, 10); /* avoid wild arc_p adjustment */
|
|
|
|
arc_p = MIN(arc_c, arc_p + bytes * mult);
|
|
} else if (state == arc_mfu_ghost) {
|
|
uint64_t delta;
|
|
|
|
mult = ((arc_mfu_ghost->arcs_size >= arc_mru_ghost->arcs_size) ?
|
|
1 : (arc_mru_ghost->arcs_size/arc_mfu_ghost->arcs_size));
|
|
|
|
if (!zfs_arc_p_dampener_disable)
|
|
mult = MIN(mult, 10);
|
|
|
|
delta = MIN(bytes * mult, arc_p);
|
|
arc_p = MAX(0, arc_p - delta);
|
|
}
|
|
ASSERT((int64_t)arc_p >= 0);
|
|
|
|
if (arc_no_grow)
|
|
return;
|
|
|
|
if (arc_c >= arc_c_max)
|
|
return;
|
|
|
|
/*
|
|
* If we're within (2 * maxblocksize) bytes of the target
|
|
* cache size, increment the target cache size
|
|
*/
|
|
VERIFY3U(arc_c, >=, 2ULL << SPA_MAXBLOCKSHIFT);
|
|
if (arc_size >= arc_c - (2ULL << SPA_MAXBLOCKSHIFT)) {
|
|
atomic_add_64(&arc_c, (int64_t)bytes);
|
|
if (arc_c > arc_c_max)
|
|
arc_c = arc_c_max;
|
|
else if (state == arc_anon)
|
|
atomic_add_64(&arc_p, (int64_t)bytes);
|
|
if (arc_p > arc_c)
|
|
arc_p = arc_c;
|
|
}
|
|
ASSERT((int64_t)arc_p >= 0);
|
|
}
|
|
|
|
/*
|
|
* Check if arc_size has grown past our upper threshold, determined by
|
|
* zfs_arc_overflow_shift.
|
|
*/
|
|
static boolean_t
|
|
arc_is_overflowing(void)
|
|
{
|
|
/* Always allow at least one block of overflow */
|
|
uint64_t overflow = MAX(SPA_MAXBLOCKSIZE,
|
|
arc_c >> zfs_arc_overflow_shift);
|
|
|
|
return (arc_size >= arc_c + overflow);
|
|
}
|
|
|
|
/*
|
|
* The buffer, supplied as the first argument, needs a data block. If we
|
|
* are hitting the hard limit for the cache size, we must sleep, waiting
|
|
* for the eviction thread to catch up. If we're past the target size
|
|
* but below the hard limit, we'll only signal the reclaim thread and
|
|
* continue on.
|
|
*/
|
|
static void
|
|
arc_get_data_buf(arc_buf_t *buf)
|
|
{
|
|
arc_state_t *state = buf->b_hdr->b_l1hdr.b_state;
|
|
uint64_t size = buf->b_hdr->b_size;
|
|
arc_buf_contents_t type = arc_buf_type(buf->b_hdr);
|
|
|
|
arc_adapt(size, state);
|
|
|
|
/*
|
|
* If arc_size is currently overflowing, and has grown past our
|
|
* upper limit, we must be adding data faster than the evict
|
|
* thread can evict. Thus, to ensure we don't compound the
|
|
* problem by adding more data and forcing arc_size to grow even
|
|
* further past it's target size, we halt and wait for the
|
|
* eviction thread to catch up.
|
|
*
|
|
* It's also possible that the reclaim thread is unable to evict
|
|
* enough buffers to get arc_size below the overflow limit (e.g.
|
|
* due to buffers being un-evictable, or hash lock collisions).
|
|
* In this case, we want to proceed regardless if we're
|
|
* overflowing; thus we don't use a while loop here.
|
|
*/
|
|
if (arc_is_overflowing()) {
|
|
mutex_enter(&arc_reclaim_lock);
|
|
|
|
/*
|
|
* Now that we've acquired the lock, we may no longer be
|
|
* over the overflow limit, lets check.
|
|
*
|
|
* We're ignoring the case of spurious wake ups. If that
|
|
* were to happen, it'd let this thread consume an ARC
|
|
* buffer before it should have (i.e. before we're under
|
|
* the overflow limit and were signalled by the reclaim
|
|
* thread). As long as that is a rare occurrence, it
|
|
* shouldn't cause any harm.
|
|
*/
|
|
if (arc_is_overflowing()) {
|
|
cv_signal(&arc_reclaim_thread_cv);
|
|
cv_wait(&arc_reclaim_waiters_cv, &arc_reclaim_lock);
|
|
}
|
|
|
|
mutex_exit(&arc_reclaim_lock);
|
|
}
|
|
|
|
if (type == ARC_BUFC_METADATA) {
|
|
buf->b_data = zio_buf_alloc(size);
|
|
arc_space_consume(size, ARC_SPACE_META);
|
|
} else {
|
|
ASSERT(type == ARC_BUFC_DATA);
|
|
buf->b_data = zio_data_buf_alloc(size);
|
|
arc_space_consume(size, ARC_SPACE_DATA);
|
|
}
|
|
|
|
/*
|
|
* Update the state size. Note that ghost states have a
|
|
* "ghost size" and so don't need to be updated.
|
|
*/
|
|
if (!GHOST_STATE(buf->b_hdr->b_l1hdr.b_state)) {
|
|
arc_buf_hdr_t *hdr = buf->b_hdr;
|
|
|
|
atomic_add_64(&hdr->b_l1hdr.b_state->arcs_size, size);
|
|
|
|
/*
|
|
* If this is reached via arc_read, the link is
|
|
* protected by the hash lock. If reached via
|
|
* arc_buf_alloc, the header should not be accessed by
|
|
* any other thread. And, if reached via arc_read_done,
|
|
* the hash lock will protect it if it's found in the
|
|
* hash table; otherwise no other thread should be
|
|
* trying to [add|remove]_reference it.
|
|
*/
|
|
if (multilist_link_active(&hdr->b_l1hdr.b_arc_node)) {
|
|
ASSERT(refcount_is_zero(&hdr->b_l1hdr.b_refcnt));
|
|
atomic_add_64(&hdr->b_l1hdr.b_state->arcs_lsize[type],
|
|
size);
|
|
}
|
|
/*
|
|
* If we are growing the cache, and we are adding anonymous
|
|
* data, and we have outgrown arc_p, update arc_p
|
|
*/
|
|
if (arc_size < arc_c && hdr->b_l1hdr.b_state == arc_anon &&
|
|
arc_anon->arcs_size + arc_mru->arcs_size > arc_p)
|
|
arc_p = MIN(arc_c, arc_p + size);
|
|
}
|
|
}
|
|
|
|
/*
|
|
* This routine is called whenever a buffer is accessed.
|
|
* NOTE: the hash lock is dropped in this function.
|
|
*/
|
|
static void
|
|
arc_access(arc_buf_hdr_t *hdr, kmutex_t *hash_lock)
|
|
{
|
|
clock_t now;
|
|
|
|
ASSERT(MUTEX_HELD(hash_lock));
|
|
ASSERT(HDR_HAS_L1HDR(hdr));
|
|
|
|
if (hdr->b_l1hdr.b_state == arc_anon) {
|
|
/*
|
|
* This buffer is not in the cache, and does not
|
|
* appear in our "ghost" list. Add the new buffer
|
|
* to the MRU state.
|
|
*/
|
|
|
|
ASSERT0(hdr->b_l1hdr.b_arc_access);
|
|
hdr->b_l1hdr.b_arc_access = ddi_get_lbolt();
|
|
DTRACE_PROBE1(new_state__mru, arc_buf_hdr_t *, hdr);
|
|
arc_change_state(arc_mru, hdr, hash_lock);
|
|
|
|
} else if (hdr->b_l1hdr.b_state == arc_mru) {
|
|
now = ddi_get_lbolt();
|
|
|
|
/*
|
|
* If this buffer is here because of a prefetch, then either:
|
|
* - clear the flag if this is a "referencing" read
|
|
* (any subsequent access will bump this into the MFU state).
|
|
* or
|
|
* - move the buffer to the head of the list if this is
|
|
* another prefetch (to make it less likely to be evicted).
|
|
*/
|
|
if (HDR_PREFETCH(hdr)) {
|
|
if (refcount_count(&hdr->b_l1hdr.b_refcnt) == 0) {
|
|
/* link protected by hash lock */
|
|
ASSERT(multilist_link_active(
|
|
&hdr->b_l1hdr.b_arc_node));
|
|
} else {
|
|
hdr->b_flags &= ~ARC_FLAG_PREFETCH;
|
|
atomic_inc_32(&hdr->b_l1hdr.b_mru_hits);
|
|
ARCSTAT_BUMP(arcstat_mru_hits);
|
|
}
|
|
hdr->b_l1hdr.b_arc_access = now;
|
|
return;
|
|
}
|
|
|
|
/*
|
|
* This buffer has been "accessed" only once so far,
|
|
* but it is still in the cache. Move it to the MFU
|
|
* state.
|
|
*/
|
|
if (ddi_time_after(now, hdr->b_l1hdr.b_arc_access +
|
|
ARC_MINTIME)) {
|
|
/*
|
|
* More than 125ms have passed since we
|
|
* instantiated this buffer. Move it to the
|
|
* most frequently used state.
|
|
*/
|
|
hdr->b_l1hdr.b_arc_access = now;
|
|
DTRACE_PROBE1(new_state__mfu, arc_buf_hdr_t *, hdr);
|
|
arc_change_state(arc_mfu, hdr, hash_lock);
|
|
}
|
|
atomic_inc_32(&hdr->b_l1hdr.b_mru_hits);
|
|
ARCSTAT_BUMP(arcstat_mru_hits);
|
|
} else if (hdr->b_l1hdr.b_state == arc_mru_ghost) {
|
|
arc_state_t *new_state;
|
|
/*
|
|
* This buffer has been "accessed" recently, but
|
|
* was evicted from the cache. Move it to the
|
|
* MFU state.
|
|
*/
|
|
|
|
if (HDR_PREFETCH(hdr)) {
|
|
new_state = arc_mru;
|
|
if (refcount_count(&hdr->b_l1hdr.b_refcnt) > 0)
|
|
hdr->b_flags &= ~ARC_FLAG_PREFETCH;
|
|
DTRACE_PROBE1(new_state__mru, arc_buf_hdr_t *, hdr);
|
|
} else {
|
|
new_state = arc_mfu;
|
|
DTRACE_PROBE1(new_state__mfu, arc_buf_hdr_t *, hdr);
|
|
}
|
|
|
|
hdr->b_l1hdr.b_arc_access = ddi_get_lbolt();
|
|
arc_change_state(new_state, hdr, hash_lock);
|
|
|
|
atomic_inc_32(&hdr->b_l1hdr.b_mru_ghost_hits);
|
|
ARCSTAT_BUMP(arcstat_mru_ghost_hits);
|
|
} else if (hdr->b_l1hdr.b_state == arc_mfu) {
|
|
/*
|
|
* This buffer has been accessed more than once and is
|
|
* still in the cache. Keep it in the MFU state.
|
|
*
|
|
* NOTE: an add_reference() that occurred when we did
|
|
* the arc_read() will have kicked this off the list.
|
|
* If it was a prefetch, we will explicitly move it to
|
|
* the head of the list now.
|
|
*/
|
|
if ((HDR_PREFETCH(hdr)) != 0) {
|
|
ASSERT(refcount_is_zero(&hdr->b_l1hdr.b_refcnt));
|
|
/* link protected by hash_lock */
|
|
ASSERT(multilist_link_active(&hdr->b_l1hdr.b_arc_node));
|
|
}
|
|
atomic_inc_32(&hdr->b_l1hdr.b_mfu_hits);
|
|
ARCSTAT_BUMP(arcstat_mfu_hits);
|
|
hdr->b_l1hdr.b_arc_access = ddi_get_lbolt();
|
|
} else if (hdr->b_l1hdr.b_state == arc_mfu_ghost) {
|
|
arc_state_t *new_state = arc_mfu;
|
|
/*
|
|
* This buffer has been accessed more than once but has
|
|
* been evicted from the cache. Move it back to the
|
|
* MFU state.
|
|
*/
|
|
|
|
if (HDR_PREFETCH(hdr)) {
|
|
/*
|
|
* This is a prefetch access...
|
|
* move this block back to the MRU state.
|
|
*/
|
|
ASSERT0(refcount_count(&hdr->b_l1hdr.b_refcnt));
|
|
new_state = arc_mru;
|
|
}
|
|
|
|
hdr->b_l1hdr.b_arc_access = ddi_get_lbolt();
|
|
DTRACE_PROBE1(new_state__mfu, arc_buf_hdr_t *, hdr);
|
|
arc_change_state(new_state, hdr, hash_lock);
|
|
|
|
atomic_inc_32(&hdr->b_l1hdr.b_mfu_ghost_hits);
|
|
ARCSTAT_BUMP(arcstat_mfu_ghost_hits);
|
|
} else if (hdr->b_l1hdr.b_state == arc_l2c_only) {
|
|
/*
|
|
* This buffer is on the 2nd Level ARC.
|
|
*/
|
|
|
|
hdr->b_l1hdr.b_arc_access = ddi_get_lbolt();
|
|
DTRACE_PROBE1(new_state__mfu, arc_buf_hdr_t *, hdr);
|
|
arc_change_state(arc_mfu, hdr, hash_lock);
|
|
} else {
|
|
cmn_err(CE_PANIC, "invalid arc state 0x%p",
|
|
hdr->b_l1hdr.b_state);
|
|
}
|
|
}
|
|
|
|
/* a generic arc_done_func_t which you can use */
|
|
/* ARGSUSED */
|
|
void
|
|
arc_bcopy_func(zio_t *zio, arc_buf_t *buf, void *arg)
|
|
{
|
|
if (zio == NULL || zio->io_error == 0)
|
|
bcopy(buf->b_data, arg, buf->b_hdr->b_size);
|
|
VERIFY(arc_buf_remove_ref(buf, arg));
|
|
}
|
|
|
|
/* a generic arc_done_func_t */
|
|
void
|
|
arc_getbuf_func(zio_t *zio, arc_buf_t *buf, void *arg)
|
|
{
|
|
arc_buf_t **bufp = arg;
|
|
if (zio && zio->io_error) {
|
|
VERIFY(arc_buf_remove_ref(buf, arg));
|
|
*bufp = NULL;
|
|
} else {
|
|
*bufp = buf;
|
|
ASSERT(buf->b_data);
|
|
}
|
|
}
|
|
|
|
static void
|
|
arc_read_done(zio_t *zio)
|
|
{
|
|
arc_buf_hdr_t *hdr;
|
|
arc_buf_t *buf;
|
|
arc_buf_t *abuf; /* buffer we're assigning to callback */
|
|
kmutex_t *hash_lock = NULL;
|
|
arc_callback_t *callback_list, *acb;
|
|
int freeable = FALSE;
|
|
|
|
buf = zio->io_private;
|
|
hdr = buf->b_hdr;
|
|
|
|
/*
|
|
* The hdr was inserted into hash-table and removed from lists
|
|
* prior to starting I/O. We should find this header, since
|
|
* it's in the hash table, and it should be legit since it's
|
|
* not possible to evict it during the I/O. The only possible
|
|
* reason for it not to be found is if we were freed during the
|
|
* read.
|
|
*/
|
|
if (HDR_IN_HASH_TABLE(hdr)) {
|
|
arc_buf_hdr_t *found;
|
|
|
|
ASSERT3U(hdr->b_birth, ==, BP_PHYSICAL_BIRTH(zio->io_bp));
|
|
ASSERT3U(hdr->b_dva.dva_word[0], ==,
|
|
BP_IDENTITY(zio->io_bp)->dva_word[0]);
|
|
ASSERT3U(hdr->b_dva.dva_word[1], ==,
|
|
BP_IDENTITY(zio->io_bp)->dva_word[1]);
|
|
|
|
found = buf_hash_find(hdr->b_spa, zio->io_bp,
|
|
&hash_lock);
|
|
|
|
ASSERT((found == NULL && HDR_FREED_IN_READ(hdr) &&
|
|
hash_lock == NULL) ||
|
|
(found == hdr &&
|
|
DVA_EQUAL(&hdr->b_dva, BP_IDENTITY(zio->io_bp))) ||
|
|
(found == hdr && HDR_L2_READING(hdr)));
|
|
}
|
|
|
|
hdr->b_flags &= ~ARC_FLAG_L2_EVICTED;
|
|
if (l2arc_noprefetch && HDR_PREFETCH(hdr))
|
|
hdr->b_flags &= ~ARC_FLAG_L2CACHE;
|
|
|
|
/* byteswap if necessary */
|
|
callback_list = hdr->b_l1hdr.b_acb;
|
|
ASSERT(callback_list != NULL);
|
|
if (BP_SHOULD_BYTESWAP(zio->io_bp) && zio->io_error == 0) {
|
|
dmu_object_byteswap_t bswap =
|
|
DMU_OT_BYTESWAP(BP_GET_TYPE(zio->io_bp));
|
|
if (BP_GET_LEVEL(zio->io_bp) > 0)
|
|
byteswap_uint64_array(buf->b_data, hdr->b_size);
|
|
else
|
|
dmu_ot_byteswap[bswap].ob_func(buf->b_data, hdr->b_size);
|
|
}
|
|
|
|
arc_cksum_compute(buf, B_FALSE);
|
|
arc_buf_watch(buf);
|
|
|
|
if (hash_lock && zio->io_error == 0 &&
|
|
hdr->b_l1hdr.b_state == arc_anon) {
|
|
/*
|
|
* Only call arc_access on anonymous buffers. This is because
|
|
* if we've issued an I/O for an evicted buffer, we've already
|
|
* called arc_access (to prevent any simultaneous readers from
|
|
* getting confused).
|
|
*/
|
|
arc_access(hdr, hash_lock);
|
|
}
|
|
|
|
/* create copies of the data buffer for the callers */
|
|
abuf = buf;
|
|
for (acb = callback_list; acb; acb = acb->acb_next) {
|
|
if (acb->acb_done) {
|
|
if (abuf == NULL) {
|
|
ARCSTAT_BUMP(arcstat_duplicate_reads);
|
|
abuf = arc_buf_clone(buf);
|
|
}
|
|
acb->acb_buf = abuf;
|
|
abuf = NULL;
|
|
}
|
|
}
|
|
hdr->b_l1hdr.b_acb = NULL;
|
|
hdr->b_flags &= ~ARC_FLAG_IO_IN_PROGRESS;
|
|
ASSERT(!HDR_BUF_AVAILABLE(hdr));
|
|
if (abuf == buf) {
|
|
ASSERT(buf->b_efunc == NULL);
|
|
ASSERT(hdr->b_l1hdr.b_datacnt == 1);
|
|
hdr->b_flags |= ARC_FLAG_BUF_AVAILABLE;
|
|
}
|
|
|
|
ASSERT(refcount_is_zero(&hdr->b_l1hdr.b_refcnt) ||
|
|
callback_list != NULL);
|
|
|
|
if (zio->io_error != 0) {
|
|
hdr->b_flags |= ARC_FLAG_IO_ERROR;
|
|
if (hdr->b_l1hdr.b_state != arc_anon)
|
|
arc_change_state(arc_anon, hdr, hash_lock);
|
|
if (HDR_IN_HASH_TABLE(hdr))
|
|
buf_hash_remove(hdr);
|
|
freeable = refcount_is_zero(&hdr->b_l1hdr.b_refcnt);
|
|
}
|
|
|
|
/*
|
|
* Broadcast before we drop the hash_lock to avoid the possibility
|
|
* that the hdr (and hence the cv) might be freed before we get to
|
|
* the cv_broadcast().
|
|
*/
|
|
cv_broadcast(&hdr->b_l1hdr.b_cv);
|
|
|
|
if (hash_lock != NULL) {
|
|
mutex_exit(hash_lock);
|
|
} else {
|
|
/*
|
|
* This block was freed while we waited for the read to
|
|
* complete. It has been removed from the hash table and
|
|
* moved to the anonymous state (so that it won't show up
|
|
* in the cache).
|
|
*/
|
|
ASSERT3P(hdr->b_l1hdr.b_state, ==, arc_anon);
|
|
freeable = refcount_is_zero(&hdr->b_l1hdr.b_refcnt);
|
|
}
|
|
|
|
/* execute each callback and free its structure */
|
|
while ((acb = callback_list) != NULL) {
|
|
if (acb->acb_done)
|
|
acb->acb_done(zio, acb->acb_buf, acb->acb_private);
|
|
|
|
if (acb->acb_zio_dummy != NULL) {
|
|
acb->acb_zio_dummy->io_error = zio->io_error;
|
|
zio_nowait(acb->acb_zio_dummy);
|
|
}
|
|
|
|
callback_list = acb->acb_next;
|
|
kmem_free(acb, sizeof (arc_callback_t));
|
|
}
|
|
|
|
if (freeable)
|
|
arc_hdr_destroy(hdr);
|
|
}
|
|
|
|
/*
|
|
* "Read" the block at the specified DVA (in bp) via the
|
|
* cache. If the block is found in the cache, invoke the provided
|
|
* callback immediately and return. Note that the `zio' parameter
|
|
* in the callback will be NULL in this case, since no IO was
|
|
* required. If the block is not in the cache pass the read request
|
|
* on to the spa with a substitute callback function, so that the
|
|
* requested block will be added to the cache.
|
|
*
|
|
* If a read request arrives for a block that has a read in-progress,
|
|
* either wait for the in-progress read to complete (and return the
|
|
* results); or, if this is a read with a "done" func, add a record
|
|
* to the read to invoke the "done" func when the read completes,
|
|
* and return; or just return.
|
|
*
|
|
* arc_read_done() will invoke all the requested "done" functions
|
|
* for readers of this block.
|
|
*/
|
|
int
|
|
arc_read(zio_t *pio, spa_t *spa, const blkptr_t *bp, arc_done_func_t *done,
|
|
void *private, zio_priority_t priority, int zio_flags,
|
|
arc_flags_t *arc_flags, const zbookmark_phys_t *zb)
|
|
{
|
|
arc_buf_hdr_t *hdr = NULL;
|
|
arc_buf_t *buf = NULL;
|
|
kmutex_t *hash_lock = NULL;
|
|
zio_t *rzio;
|
|
uint64_t guid = spa_load_guid(spa);
|
|
int rc = 0;
|
|
|
|
ASSERT(!BP_IS_EMBEDDED(bp) ||
|
|
BPE_GET_ETYPE(bp) == BP_EMBEDDED_TYPE_DATA);
|
|
|
|
top:
|
|
if (!BP_IS_EMBEDDED(bp)) {
|
|
/*
|
|
* Embedded BP's have no DVA and require no I/O to "read".
|
|
* Create an anonymous arc buf to back it.
|
|
*/
|
|
hdr = buf_hash_find(guid, bp, &hash_lock);
|
|
}
|
|
|
|
if (hdr != NULL && HDR_HAS_L1HDR(hdr) && hdr->b_l1hdr.b_datacnt > 0) {
|
|
|
|
*arc_flags |= ARC_FLAG_CACHED;
|
|
|
|
if (HDR_IO_IN_PROGRESS(hdr)) {
|
|
|
|
if (*arc_flags & ARC_FLAG_WAIT) {
|
|
cv_wait(&hdr->b_l1hdr.b_cv, hash_lock);
|
|
mutex_exit(hash_lock);
|
|
goto top;
|
|
}
|
|
ASSERT(*arc_flags & ARC_FLAG_NOWAIT);
|
|
|
|
if (done) {
|
|
arc_callback_t *acb = NULL;
|
|
|
|
acb = kmem_zalloc(sizeof (arc_callback_t),
|
|
KM_SLEEP);
|
|
acb->acb_done = done;
|
|
acb->acb_private = private;
|
|
if (pio != NULL)
|
|
acb->acb_zio_dummy = zio_null(pio,
|
|
spa, NULL, NULL, NULL, zio_flags);
|
|
|
|
ASSERT(acb->acb_done != NULL);
|
|
acb->acb_next = hdr->b_l1hdr.b_acb;
|
|
hdr->b_l1hdr.b_acb = acb;
|
|
add_reference(hdr, hash_lock, private);
|
|
mutex_exit(hash_lock);
|
|
goto out;
|
|
}
|
|
mutex_exit(hash_lock);
|
|
goto out;
|
|
}
|
|
|
|
ASSERT(hdr->b_l1hdr.b_state == arc_mru ||
|
|
hdr->b_l1hdr.b_state == arc_mfu);
|
|
|
|
if (done) {
|
|
add_reference(hdr, hash_lock, private);
|
|
/*
|
|
* If this block is already in use, create a new
|
|
* copy of the data so that we will be guaranteed
|
|
* that arc_release() will always succeed.
|
|
*/
|
|
buf = hdr->b_l1hdr.b_buf;
|
|
ASSERT(buf);
|
|
ASSERT(buf->b_data);
|
|
if (HDR_BUF_AVAILABLE(hdr)) {
|
|
ASSERT(buf->b_efunc == NULL);
|
|
hdr->b_flags &= ~ARC_FLAG_BUF_AVAILABLE;
|
|
} else {
|
|
buf = arc_buf_clone(buf);
|
|
}
|
|
|
|
} else if (*arc_flags & ARC_FLAG_PREFETCH &&
|
|
refcount_count(&hdr->b_l1hdr.b_refcnt) == 0) {
|
|
hdr->b_flags |= ARC_FLAG_PREFETCH;
|
|
}
|
|
DTRACE_PROBE1(arc__hit, arc_buf_hdr_t *, hdr);
|
|
arc_access(hdr, hash_lock);
|
|
if (*arc_flags & ARC_FLAG_L2CACHE)
|
|
hdr->b_flags |= ARC_FLAG_L2CACHE;
|
|
if (*arc_flags & ARC_FLAG_L2COMPRESS)
|
|
hdr->b_flags |= ARC_FLAG_L2COMPRESS;
|
|
mutex_exit(hash_lock);
|
|
ARCSTAT_BUMP(arcstat_hits);
|
|
ARCSTAT_CONDSTAT(!HDR_PREFETCH(hdr),
|
|
demand, prefetch, !HDR_ISTYPE_METADATA(hdr),
|
|
data, metadata, hits);
|
|
|
|
if (done)
|
|
done(NULL, buf, private);
|
|
} else {
|
|
uint64_t size = BP_GET_LSIZE(bp);
|
|
arc_callback_t *acb;
|
|
vdev_t *vd = NULL;
|
|
uint64_t addr = 0;
|
|
boolean_t devw = B_FALSE;
|
|
enum zio_compress b_compress = ZIO_COMPRESS_OFF;
|
|
int32_t b_asize = 0;
|
|
|
|
/*
|
|
* Gracefully handle a damaged logical block size as a
|
|
* checksum error by passing a dummy zio to the done callback.
|
|
*/
|
|
if (size > spa_maxblocksize(spa)) {
|
|
if (done) {
|
|
rzio = zio_null(pio, spa, NULL,
|
|
NULL, NULL, zio_flags);
|
|
rzio->io_error = ECKSUM;
|
|
done(rzio, buf, private);
|
|
zio_nowait(rzio);
|
|
}
|
|
rc = ECKSUM;
|
|
goto out;
|
|
}
|
|
|
|
if (hdr == NULL) {
|
|
/* this block is not in the cache */
|
|
arc_buf_hdr_t *exists = NULL;
|
|
arc_buf_contents_t type = BP_GET_BUFC_TYPE(bp);
|
|
buf = arc_buf_alloc(spa, size, private, type);
|
|
hdr = buf->b_hdr;
|
|
if (!BP_IS_EMBEDDED(bp)) {
|
|
hdr->b_dva = *BP_IDENTITY(bp);
|
|
hdr->b_birth = BP_PHYSICAL_BIRTH(bp);
|
|
exists = buf_hash_insert(hdr, &hash_lock);
|
|
}
|
|
if (exists != NULL) {
|
|
/* somebody beat us to the hash insert */
|
|
mutex_exit(hash_lock);
|
|
buf_discard_identity(hdr);
|
|
(void) arc_buf_remove_ref(buf, private);
|
|
goto top; /* restart the IO request */
|
|
}
|
|
|
|
/* if this is a prefetch, we don't have a reference */
|
|
if (*arc_flags & ARC_FLAG_PREFETCH) {
|
|
(void) remove_reference(hdr, hash_lock,
|
|
private);
|
|
hdr->b_flags |= ARC_FLAG_PREFETCH;
|
|
}
|
|
if (*arc_flags & ARC_FLAG_L2CACHE)
|
|
hdr->b_flags |= ARC_FLAG_L2CACHE;
|
|
if (*arc_flags & ARC_FLAG_L2COMPRESS)
|
|
hdr->b_flags |= ARC_FLAG_L2COMPRESS;
|
|
if (BP_GET_LEVEL(bp) > 0)
|
|
hdr->b_flags |= ARC_FLAG_INDIRECT;
|
|
} else {
|
|
/*
|
|
* This block is in the ghost cache. If it was L2-only
|
|
* (and thus didn't have an L1 hdr), we realloc the
|
|
* header to add an L1 hdr.
|
|
*/
|
|
if (!HDR_HAS_L1HDR(hdr)) {
|
|
hdr = arc_hdr_realloc(hdr, hdr_l2only_cache,
|
|
hdr_full_cache);
|
|
}
|
|
|
|
ASSERT(GHOST_STATE(hdr->b_l1hdr.b_state));
|
|
ASSERT(!HDR_IO_IN_PROGRESS(hdr));
|
|
ASSERT(refcount_is_zero(&hdr->b_l1hdr.b_refcnt));
|
|
ASSERT3P(hdr->b_l1hdr.b_buf, ==, NULL);
|
|
|
|
/* if this is a prefetch, we don't have a reference */
|
|
if (*arc_flags & ARC_FLAG_PREFETCH)
|
|
hdr->b_flags |= ARC_FLAG_PREFETCH;
|
|
else
|
|
add_reference(hdr, hash_lock, private);
|
|
if (*arc_flags & ARC_FLAG_L2CACHE)
|
|
hdr->b_flags |= ARC_FLAG_L2CACHE;
|
|
if (*arc_flags & ARC_FLAG_L2COMPRESS)
|
|
hdr->b_flags |= ARC_FLAG_L2COMPRESS;
|
|
buf = kmem_cache_alloc(buf_cache, KM_PUSHPAGE);
|
|
buf->b_hdr = hdr;
|
|
buf->b_data = NULL;
|
|
buf->b_efunc = NULL;
|
|
buf->b_private = NULL;
|
|
buf->b_next = NULL;
|
|
hdr->b_l1hdr.b_buf = buf;
|
|
ASSERT0(hdr->b_l1hdr.b_datacnt);
|
|
hdr->b_l1hdr.b_datacnt = 1;
|
|
arc_get_data_buf(buf);
|
|
arc_access(hdr, hash_lock);
|
|
}
|
|
|
|
ASSERT(!GHOST_STATE(hdr->b_l1hdr.b_state));
|
|
|
|
acb = kmem_zalloc(sizeof (arc_callback_t), KM_SLEEP);
|
|
acb->acb_done = done;
|
|
acb->acb_private = private;
|
|
|
|
ASSERT(hdr->b_l1hdr.b_acb == NULL);
|
|
hdr->b_l1hdr.b_acb = acb;
|
|
hdr->b_flags |= ARC_FLAG_IO_IN_PROGRESS;
|
|
|
|
if (HDR_HAS_L2HDR(hdr) &&
|
|
(vd = hdr->b_l2hdr.b_dev->l2ad_vdev) != NULL) {
|
|
devw = hdr->b_l2hdr.b_dev->l2ad_writing;
|
|
addr = hdr->b_l2hdr.b_daddr;
|
|
b_compress = HDR_GET_COMPRESS(hdr);
|
|
b_asize = hdr->b_l2hdr.b_asize;
|
|
/*
|
|
* Lock out device removal.
|
|
*/
|
|
if (vdev_is_dead(vd) ||
|
|
!spa_config_tryenter(spa, SCL_L2ARC, vd, RW_READER))
|
|
vd = NULL;
|
|
}
|
|
|
|
if (hash_lock != NULL)
|
|
mutex_exit(hash_lock);
|
|
|
|
/*
|
|
* At this point, we have a level 1 cache miss. Try again in
|
|
* L2ARC if possible.
|
|
*/
|
|
ASSERT3U(hdr->b_size, ==, size);
|
|
DTRACE_PROBE4(arc__miss, arc_buf_hdr_t *, hdr, blkptr_t *, bp,
|
|
uint64_t, size, zbookmark_phys_t *, zb);
|
|
ARCSTAT_BUMP(arcstat_misses);
|
|
ARCSTAT_CONDSTAT(!HDR_PREFETCH(hdr),
|
|
demand, prefetch, !HDR_ISTYPE_METADATA(hdr),
|
|
data, metadata, misses);
|
|
|
|
if (vd != NULL && l2arc_ndev != 0 && !(l2arc_norw && devw)) {
|
|
/*
|
|
* Read from the L2ARC if the following are true:
|
|
* 1. The L2ARC vdev was previously cached.
|
|
* 2. This buffer still has L2ARC metadata.
|
|
* 3. This buffer isn't currently writing to the L2ARC.
|
|
* 4. The L2ARC entry wasn't evicted, which may
|
|
* also have invalidated the vdev.
|
|
* 5. This isn't prefetch and l2arc_noprefetch is set.
|
|
*/
|
|
if (HDR_HAS_L2HDR(hdr) &&
|
|
!HDR_L2_WRITING(hdr) && !HDR_L2_EVICTED(hdr) &&
|
|
!(l2arc_noprefetch && HDR_PREFETCH(hdr))) {
|
|
l2arc_read_callback_t *cb;
|
|
|
|
DTRACE_PROBE1(l2arc__hit, arc_buf_hdr_t *, hdr);
|
|
ARCSTAT_BUMP(arcstat_l2_hits);
|
|
atomic_inc_32(&hdr->b_l2hdr.b_hits);
|
|
|
|
cb = kmem_zalloc(sizeof (l2arc_read_callback_t),
|
|
KM_SLEEP);
|
|
cb->l2rcb_buf = buf;
|
|
cb->l2rcb_spa = spa;
|
|
cb->l2rcb_bp = *bp;
|
|
cb->l2rcb_zb = *zb;
|
|
cb->l2rcb_flags = zio_flags;
|
|
cb->l2rcb_compress = b_compress;
|
|
|
|
ASSERT(addr >= VDEV_LABEL_START_SIZE &&
|
|
addr + size < vd->vdev_psize -
|
|
VDEV_LABEL_END_SIZE);
|
|
|
|
/*
|
|
* l2arc read. The SCL_L2ARC lock will be
|
|
* released by l2arc_read_done().
|
|
* Issue a null zio if the underlying buffer
|
|
* was squashed to zero size by compression.
|
|
*/
|
|
if (b_compress == ZIO_COMPRESS_EMPTY) {
|
|
rzio = zio_null(pio, spa, vd,
|
|
l2arc_read_done, cb,
|
|
zio_flags | ZIO_FLAG_DONT_CACHE |
|
|
ZIO_FLAG_CANFAIL |
|
|
ZIO_FLAG_DONT_PROPAGATE |
|
|
ZIO_FLAG_DONT_RETRY);
|
|
} else {
|
|
rzio = zio_read_phys(pio, vd, addr,
|
|
b_asize, buf->b_data,
|
|
ZIO_CHECKSUM_OFF,
|
|
l2arc_read_done, cb, priority,
|
|
zio_flags | ZIO_FLAG_DONT_CACHE |
|
|
ZIO_FLAG_CANFAIL |
|
|
ZIO_FLAG_DONT_PROPAGATE |
|
|
ZIO_FLAG_DONT_RETRY, B_FALSE);
|
|
}
|
|
DTRACE_PROBE2(l2arc__read, vdev_t *, vd,
|
|
zio_t *, rzio);
|
|
ARCSTAT_INCR(arcstat_l2_read_bytes, b_asize);
|
|
|
|
if (*arc_flags & ARC_FLAG_NOWAIT) {
|
|
zio_nowait(rzio);
|
|
goto out;
|
|
}
|
|
|
|
ASSERT(*arc_flags & ARC_FLAG_WAIT);
|
|
if (zio_wait(rzio) == 0)
|
|
goto out;
|
|
|
|
/* l2arc read error; goto zio_read() */
|
|
} else {
|
|
DTRACE_PROBE1(l2arc__miss,
|
|
arc_buf_hdr_t *, hdr);
|
|
ARCSTAT_BUMP(arcstat_l2_misses);
|
|
if (HDR_L2_WRITING(hdr))
|
|
ARCSTAT_BUMP(arcstat_l2_rw_clash);
|
|
spa_config_exit(spa, SCL_L2ARC, vd);
|
|
}
|
|
} else {
|
|
if (vd != NULL)
|
|
spa_config_exit(spa, SCL_L2ARC, vd);
|
|
if (l2arc_ndev != 0) {
|
|
DTRACE_PROBE1(l2arc__miss,
|
|
arc_buf_hdr_t *, hdr);
|
|
ARCSTAT_BUMP(arcstat_l2_misses);
|
|
}
|
|
}
|
|
|
|
rzio = zio_read(pio, spa, bp, buf->b_data, size,
|
|
arc_read_done, buf, priority, zio_flags, zb);
|
|
|
|
if (*arc_flags & ARC_FLAG_WAIT) {
|
|
rc = zio_wait(rzio);
|
|
goto out;
|
|
}
|
|
|
|
ASSERT(*arc_flags & ARC_FLAG_NOWAIT);
|
|
zio_nowait(rzio);
|
|
}
|
|
|
|
out:
|
|
spa_read_history_add(spa, zb, *arc_flags);
|
|
return (rc);
|
|
}
|
|
|
|
arc_prune_t *
|
|
arc_add_prune_callback(arc_prune_func_t *func, void *private)
|
|
{
|
|
arc_prune_t *p;
|
|
|
|
p = kmem_alloc(sizeof (*p), KM_SLEEP);
|
|
p->p_pfunc = func;
|
|
p->p_private = private;
|
|
list_link_init(&p->p_node);
|
|
refcount_create(&p->p_refcnt);
|
|
|
|
mutex_enter(&arc_prune_mtx);
|
|
refcount_add(&p->p_refcnt, &arc_prune_list);
|
|
list_insert_head(&arc_prune_list, p);
|
|
mutex_exit(&arc_prune_mtx);
|
|
|
|
return (p);
|
|
}
|
|
|
|
void
|
|
arc_remove_prune_callback(arc_prune_t *p)
|
|
{
|
|
mutex_enter(&arc_prune_mtx);
|
|
list_remove(&arc_prune_list, p);
|
|
if (refcount_remove(&p->p_refcnt, &arc_prune_list) == 0) {
|
|
refcount_destroy(&p->p_refcnt);
|
|
kmem_free(p, sizeof (*p));
|
|
}
|
|
mutex_exit(&arc_prune_mtx);
|
|
}
|
|
|
|
void
|
|
arc_set_callback(arc_buf_t *buf, arc_evict_func_t *func, void *private)
|
|
{
|
|
ASSERT(buf->b_hdr != NULL);
|
|
ASSERT(buf->b_hdr->b_l1hdr.b_state != arc_anon);
|
|
ASSERT(!refcount_is_zero(&buf->b_hdr->b_l1hdr.b_refcnt) ||
|
|
func == NULL);
|
|
ASSERT(buf->b_efunc == NULL);
|
|
ASSERT(!HDR_BUF_AVAILABLE(buf->b_hdr));
|
|
|
|
buf->b_efunc = func;
|
|
buf->b_private = private;
|
|
}
|
|
|
|
/*
|
|
* Notify the arc that a block was freed, and thus will never be used again.
|
|
*/
|
|
void
|
|
arc_freed(spa_t *spa, const blkptr_t *bp)
|
|
{
|
|
arc_buf_hdr_t *hdr;
|
|
kmutex_t *hash_lock;
|
|
uint64_t guid = spa_load_guid(spa);
|
|
|
|
ASSERT(!BP_IS_EMBEDDED(bp));
|
|
|
|
hdr = buf_hash_find(guid, bp, &hash_lock);
|
|
if (hdr == NULL)
|
|
return;
|
|
if (HDR_BUF_AVAILABLE(hdr)) {
|
|
arc_buf_t *buf = hdr->b_l1hdr.b_buf;
|
|
add_reference(hdr, hash_lock, FTAG);
|
|
hdr->b_flags &= ~ARC_FLAG_BUF_AVAILABLE;
|
|
mutex_exit(hash_lock);
|
|
|
|
arc_release(buf, FTAG);
|
|
(void) arc_buf_remove_ref(buf, FTAG);
|
|
} else {
|
|
mutex_exit(hash_lock);
|
|
}
|
|
|
|
}
|
|
|
|
/*
|
|
* Clear the user eviction callback set by arc_set_callback(), first calling
|
|
* it if it exists. Because the presence of a callback keeps an arc_buf cached
|
|
* clearing the callback may result in the arc_buf being destroyed. However,
|
|
* it will not result in the *last* arc_buf being destroyed, hence the data
|
|
* will remain cached in the ARC. We make a copy of the arc buffer here so
|
|
* that we can process the callback without holding any locks.
|
|
*
|
|
* It's possible that the callback is already in the process of being cleared
|
|
* by another thread. In this case we can not clear the callback.
|
|
*
|
|
* Returns B_TRUE if the callback was successfully called and cleared.
|
|
*/
|
|
boolean_t
|
|
arc_clear_callback(arc_buf_t *buf)
|
|
{
|
|
arc_buf_hdr_t *hdr;
|
|
kmutex_t *hash_lock;
|
|
arc_evict_func_t *efunc = buf->b_efunc;
|
|
void *private = buf->b_private;
|
|
|
|
mutex_enter(&buf->b_evict_lock);
|
|
hdr = buf->b_hdr;
|
|
if (hdr == NULL) {
|
|
/*
|
|
* We are in arc_do_user_evicts().
|
|
*/
|
|
ASSERT(buf->b_data == NULL);
|
|
mutex_exit(&buf->b_evict_lock);
|
|
return (B_FALSE);
|
|
} else if (buf->b_data == NULL) {
|
|
/*
|
|
* We are on the eviction list; process this buffer now
|
|
* but let arc_do_user_evicts() do the reaping.
|
|
*/
|
|
buf->b_efunc = NULL;
|
|
mutex_exit(&buf->b_evict_lock);
|
|
VERIFY0(efunc(private));
|
|
return (B_TRUE);
|
|
}
|
|
hash_lock = HDR_LOCK(hdr);
|
|
mutex_enter(hash_lock);
|
|
hdr = buf->b_hdr;
|
|
ASSERT3P(hash_lock, ==, HDR_LOCK(hdr));
|
|
|
|
ASSERT3U(refcount_count(&hdr->b_l1hdr.b_refcnt), <,
|
|
hdr->b_l1hdr.b_datacnt);
|
|
ASSERT(hdr->b_l1hdr.b_state == arc_mru ||
|
|
hdr->b_l1hdr.b_state == arc_mfu);
|
|
|
|
buf->b_efunc = NULL;
|
|
buf->b_private = NULL;
|
|
|
|
if (hdr->b_l1hdr.b_datacnt > 1) {
|
|
mutex_exit(&buf->b_evict_lock);
|
|
arc_buf_destroy(buf, TRUE);
|
|
} else {
|
|
ASSERT(buf == hdr->b_l1hdr.b_buf);
|
|
hdr->b_flags |= ARC_FLAG_BUF_AVAILABLE;
|
|
mutex_exit(&buf->b_evict_lock);
|
|
}
|
|
|
|
mutex_exit(hash_lock);
|
|
VERIFY0(efunc(private));
|
|
return (B_TRUE);
|
|
}
|
|
|
|
/*
|
|
* Release this buffer from the cache, making it an anonymous buffer. This
|
|
* must be done after a read and prior to modifying the buffer contents.
|
|
* If the buffer has more than one reference, we must make
|
|
* a new hdr for the buffer.
|
|
*/
|
|
void
|
|
arc_release(arc_buf_t *buf, void *tag)
|
|
{
|
|
kmutex_t *hash_lock;
|
|
arc_state_t *state;
|
|
arc_buf_hdr_t *hdr = buf->b_hdr;
|
|
|
|
/*
|
|
* It would be nice to assert that if its DMU metadata (level >
|
|
* 0 || it's the dnode file), then it must be syncing context.
|
|
* But we don't know that information at this level.
|
|
*/
|
|
|
|
mutex_enter(&buf->b_evict_lock);
|
|
|
|
ASSERT(HDR_HAS_L1HDR(hdr));
|
|
|
|
/*
|
|
* We don't grab the hash lock prior to this check, because if
|
|
* the buffer's header is in the arc_anon state, it won't be
|
|
* linked into the hash table.
|
|
*/
|
|
if (hdr->b_l1hdr.b_state == arc_anon) {
|
|
mutex_exit(&buf->b_evict_lock);
|
|
ASSERT(!HDR_IO_IN_PROGRESS(hdr));
|
|
ASSERT(!HDR_IN_HASH_TABLE(hdr));
|
|
ASSERT(!HDR_HAS_L2HDR(hdr));
|
|
ASSERT(BUF_EMPTY(hdr));
|
|
|
|
ASSERT3U(hdr->b_l1hdr.b_datacnt, ==, 1);
|
|
ASSERT3S(refcount_count(&hdr->b_l1hdr.b_refcnt), ==, 1);
|
|
ASSERT(!list_link_active(&hdr->b_l1hdr.b_arc_node));
|
|
|
|
ASSERT3P(buf->b_efunc, ==, NULL);
|
|
ASSERT3P(buf->b_private, ==, NULL);
|
|
|
|
hdr->b_l1hdr.b_arc_access = 0;
|
|
arc_buf_thaw(buf);
|
|
|
|
return;
|
|
}
|
|
|
|
hash_lock = HDR_LOCK(hdr);
|
|
mutex_enter(hash_lock);
|
|
|
|
/*
|
|
* This assignment is only valid as long as the hash_lock is
|
|
* held, we must be careful not to reference state or the
|
|
* b_state field after dropping the lock.
|
|
*/
|
|
state = hdr->b_l1hdr.b_state;
|
|
ASSERT3P(hash_lock, ==, HDR_LOCK(hdr));
|
|
ASSERT3P(state, !=, arc_anon);
|
|
|
|
/* this buffer is not on any list */
|
|
ASSERT(refcount_count(&hdr->b_l1hdr.b_refcnt) > 0);
|
|
|
|
if (HDR_HAS_L2HDR(hdr)) {
|
|
mutex_enter(&hdr->b_l2hdr.b_dev->l2ad_mtx);
|
|
|
|
/*
|
|
* We have to recheck this conditional again now that
|
|
* we're holding the l2ad_mtx to prevent a race with
|
|
* another thread which might be concurrently calling
|
|
* l2arc_evict(). In that case, l2arc_evict() might have
|
|
* destroyed the header's L2 portion as we were waiting
|
|
* to acquire the l2ad_mtx.
|
|
*/
|
|
if (HDR_HAS_L2HDR(hdr))
|
|
arc_hdr_l2hdr_destroy(hdr);
|
|
|
|
mutex_exit(&hdr->b_l2hdr.b_dev->l2ad_mtx);
|
|
}
|
|
|
|
/*
|
|
* Do we have more than one buf?
|
|
*/
|
|
if (hdr->b_l1hdr.b_datacnt > 1) {
|
|
arc_buf_hdr_t *nhdr;
|
|
arc_buf_t **bufp;
|
|
uint64_t blksz = hdr->b_size;
|
|
uint64_t spa = hdr->b_spa;
|
|
arc_buf_contents_t type = arc_buf_type(hdr);
|
|
uint32_t flags = hdr->b_flags;
|
|
|
|
ASSERT(hdr->b_l1hdr.b_buf != buf || buf->b_next != NULL);
|
|
/*
|
|
* Pull the data off of this hdr and attach it to
|
|
* a new anonymous hdr.
|
|
*/
|
|
(void) remove_reference(hdr, hash_lock, tag);
|
|
bufp = &hdr->b_l1hdr.b_buf;
|
|
while (*bufp != buf)
|
|
bufp = &(*bufp)->b_next;
|
|
*bufp = buf->b_next;
|
|
buf->b_next = NULL;
|
|
|
|
ASSERT3P(state, !=, arc_l2c_only);
|
|
ASSERT3U(state->arcs_size, >=, hdr->b_size);
|
|
atomic_add_64(&state->arcs_size, -hdr->b_size);
|
|
if (refcount_is_zero(&hdr->b_l1hdr.b_refcnt)) {
|
|
uint64_t *size;
|
|
|
|
ASSERT3P(state, !=, arc_l2c_only);
|
|
size = &state->arcs_lsize[type];
|
|
ASSERT3U(*size, >=, hdr->b_size);
|
|
atomic_add_64(size, -hdr->b_size);
|
|
}
|
|
|
|
/*
|
|
* We're releasing a duplicate user data buffer, update
|
|
* our statistics accordingly.
|
|
*/
|
|
if (HDR_ISTYPE_DATA(hdr)) {
|
|
ARCSTAT_BUMPDOWN(arcstat_duplicate_buffers);
|
|
ARCSTAT_INCR(arcstat_duplicate_buffers_size,
|
|
-hdr->b_size);
|
|
}
|
|
hdr->b_l1hdr.b_datacnt -= 1;
|
|
arc_cksum_verify(buf);
|
|
arc_buf_unwatch(buf);
|
|
|
|
mutex_exit(hash_lock);
|
|
|
|
nhdr = kmem_cache_alloc(hdr_full_cache, KM_PUSHPAGE);
|
|
nhdr->b_size = blksz;
|
|
nhdr->b_spa = spa;
|
|
|
|
nhdr->b_l1hdr.b_mru_hits = 0;
|
|
nhdr->b_l1hdr.b_mru_ghost_hits = 0;
|
|
nhdr->b_l1hdr.b_mfu_hits = 0;
|
|
nhdr->b_l1hdr.b_mfu_ghost_hits = 0;
|
|
nhdr->b_l1hdr.b_l2_hits = 0;
|
|
nhdr->b_flags = flags & ARC_FLAG_L2_WRITING;
|
|
nhdr->b_flags |= arc_bufc_to_flags(type);
|
|
nhdr->b_flags |= ARC_FLAG_HAS_L1HDR;
|
|
|
|
nhdr->b_l1hdr.b_buf = buf;
|
|
nhdr->b_l1hdr.b_datacnt = 1;
|
|
nhdr->b_l1hdr.b_state = arc_anon;
|
|
nhdr->b_l1hdr.b_arc_access = 0;
|
|
nhdr->b_l1hdr.b_tmp_cdata = NULL;
|
|
nhdr->b_freeze_cksum = NULL;
|
|
|
|
(void) refcount_add(&nhdr->b_l1hdr.b_refcnt, tag);
|
|
buf->b_hdr = nhdr;
|
|
mutex_exit(&buf->b_evict_lock);
|
|
atomic_add_64(&arc_anon->arcs_size, blksz);
|
|
} else {
|
|
mutex_exit(&buf->b_evict_lock);
|
|
ASSERT(refcount_count(&hdr->b_l1hdr.b_refcnt) == 1);
|
|
/* protected by hash lock, or hdr is on arc_anon */
|
|
ASSERT(!multilist_link_active(&hdr->b_l1hdr.b_arc_node));
|
|
ASSERT(!HDR_IO_IN_PROGRESS(hdr));
|
|
hdr->b_l1hdr.b_mru_hits = 0;
|
|
hdr->b_l1hdr.b_mru_ghost_hits = 0;
|
|
hdr->b_l1hdr.b_mfu_hits = 0;
|
|
hdr->b_l1hdr.b_mfu_ghost_hits = 0;
|
|
hdr->b_l1hdr.b_l2_hits = 0;
|
|
arc_change_state(arc_anon, hdr, hash_lock);
|
|
hdr->b_l1hdr.b_arc_access = 0;
|
|
mutex_exit(hash_lock);
|
|
|
|
buf_discard_identity(hdr);
|
|
arc_buf_thaw(buf);
|
|
}
|
|
buf->b_efunc = NULL;
|
|
buf->b_private = NULL;
|
|
}
|
|
|
|
int
|
|
arc_released(arc_buf_t *buf)
|
|
{
|
|
int released;
|
|
|
|
mutex_enter(&buf->b_evict_lock);
|
|
released = (buf->b_data != NULL &&
|
|
buf->b_hdr->b_l1hdr.b_state == arc_anon);
|
|
mutex_exit(&buf->b_evict_lock);
|
|
return (released);
|
|
}
|
|
|
|
#ifdef ZFS_DEBUG
|
|
int
|
|
arc_referenced(arc_buf_t *buf)
|
|
{
|
|
int referenced;
|
|
|
|
mutex_enter(&buf->b_evict_lock);
|
|
referenced = (refcount_count(&buf->b_hdr->b_l1hdr.b_refcnt));
|
|
mutex_exit(&buf->b_evict_lock);
|
|
return (referenced);
|
|
}
|
|
#endif
|
|
|
|
static void
|
|
arc_write_ready(zio_t *zio)
|
|
{
|
|
arc_write_callback_t *callback = zio->io_private;
|
|
arc_buf_t *buf = callback->awcb_buf;
|
|
arc_buf_hdr_t *hdr = buf->b_hdr;
|
|
|
|
ASSERT(HDR_HAS_L1HDR(hdr));
|
|
ASSERT(!refcount_is_zero(&buf->b_hdr->b_l1hdr.b_refcnt));
|
|
ASSERT(hdr->b_l1hdr.b_datacnt > 0);
|
|
callback->awcb_ready(zio, buf, callback->awcb_private);
|
|
|
|
/*
|
|
* If the IO is already in progress, then this is a re-write
|
|
* attempt, so we need to thaw and re-compute the cksum.
|
|
* It is the responsibility of the callback to handle the
|
|
* accounting for any re-write attempt.
|
|
*/
|
|
if (HDR_IO_IN_PROGRESS(hdr)) {
|
|
mutex_enter(&hdr->b_l1hdr.b_freeze_lock);
|
|
if (hdr->b_freeze_cksum != NULL) {
|
|
kmem_free(hdr->b_freeze_cksum, sizeof (zio_cksum_t));
|
|
hdr->b_freeze_cksum = NULL;
|
|
}
|
|
mutex_exit(&hdr->b_l1hdr.b_freeze_lock);
|
|
}
|
|
arc_cksum_compute(buf, B_FALSE);
|
|
hdr->b_flags |= ARC_FLAG_IO_IN_PROGRESS;
|
|
}
|
|
|
|
/*
|
|
* The SPA calls this callback for each physical write that happens on behalf
|
|
* of a logical write. See the comment in dbuf_write_physdone() for details.
|
|
*/
|
|
static void
|
|
arc_write_physdone(zio_t *zio)
|
|
{
|
|
arc_write_callback_t *cb = zio->io_private;
|
|
if (cb->awcb_physdone != NULL)
|
|
cb->awcb_physdone(zio, cb->awcb_buf, cb->awcb_private);
|
|
}
|
|
|
|
static void
|
|
arc_write_done(zio_t *zio)
|
|
{
|
|
arc_write_callback_t *callback = zio->io_private;
|
|
arc_buf_t *buf = callback->awcb_buf;
|
|
arc_buf_hdr_t *hdr = buf->b_hdr;
|
|
|
|
ASSERT(hdr->b_l1hdr.b_acb == NULL);
|
|
|
|
if (zio->io_error == 0) {
|
|
if (BP_IS_HOLE(zio->io_bp) || BP_IS_EMBEDDED(zio->io_bp)) {
|
|
buf_discard_identity(hdr);
|
|
} else {
|
|
hdr->b_dva = *BP_IDENTITY(zio->io_bp);
|
|
hdr->b_birth = BP_PHYSICAL_BIRTH(zio->io_bp);
|
|
}
|
|
} else {
|
|
ASSERT(BUF_EMPTY(hdr));
|
|
}
|
|
|
|
/*
|
|
* If the block to be written was all-zero or compressed enough to be
|
|
* embedded in the BP, no write was performed so there will be no
|
|
* dva/birth/checksum. The buffer must therefore remain anonymous
|
|
* (and uncached).
|
|
*/
|
|
if (!BUF_EMPTY(hdr)) {
|
|
arc_buf_hdr_t *exists;
|
|
kmutex_t *hash_lock;
|
|
|
|
ASSERT(zio->io_error == 0);
|
|
|
|
arc_cksum_verify(buf);
|
|
|
|
exists = buf_hash_insert(hdr, &hash_lock);
|
|
if (exists != NULL) {
|
|
/*
|
|
* This can only happen if we overwrite for
|
|
* sync-to-convergence, because we remove
|
|
* buffers from the hash table when we arc_free().
|
|
*/
|
|
if (zio->io_flags & ZIO_FLAG_IO_REWRITE) {
|
|
if (!BP_EQUAL(&zio->io_bp_orig, zio->io_bp))
|
|
panic("bad overwrite, hdr=%p exists=%p",
|
|
(void *)hdr, (void *)exists);
|
|
ASSERT(refcount_is_zero(
|
|
&exists->b_l1hdr.b_refcnt));
|
|
arc_change_state(arc_anon, exists, hash_lock);
|
|
mutex_exit(hash_lock);
|
|
arc_hdr_destroy(exists);
|
|
exists = buf_hash_insert(hdr, &hash_lock);
|
|
ASSERT3P(exists, ==, NULL);
|
|
} else if (zio->io_flags & ZIO_FLAG_NOPWRITE) {
|
|
/* nopwrite */
|
|
ASSERT(zio->io_prop.zp_nopwrite);
|
|
if (!BP_EQUAL(&zio->io_bp_orig, zio->io_bp))
|
|
panic("bad nopwrite, hdr=%p exists=%p",
|
|
(void *)hdr, (void *)exists);
|
|
} else {
|
|
/* Dedup */
|
|
ASSERT(hdr->b_l1hdr.b_datacnt == 1);
|
|
ASSERT(hdr->b_l1hdr.b_state == arc_anon);
|
|
ASSERT(BP_GET_DEDUP(zio->io_bp));
|
|
ASSERT(BP_GET_LEVEL(zio->io_bp) == 0);
|
|
}
|
|
}
|
|
hdr->b_flags &= ~ARC_FLAG_IO_IN_PROGRESS;
|
|
/* if it's not anon, we are doing a scrub */
|
|
if (exists == NULL && hdr->b_l1hdr.b_state == arc_anon)
|
|
arc_access(hdr, hash_lock);
|
|
mutex_exit(hash_lock);
|
|
} else {
|
|
hdr->b_flags &= ~ARC_FLAG_IO_IN_PROGRESS;
|
|
}
|
|
|
|
ASSERT(!refcount_is_zero(&hdr->b_l1hdr.b_refcnt));
|
|
callback->awcb_done(zio, buf, callback->awcb_private);
|
|
|
|
kmem_free(callback, sizeof (arc_write_callback_t));
|
|
}
|
|
|
|
zio_t *
|
|
arc_write(zio_t *pio, spa_t *spa, uint64_t txg,
|
|
blkptr_t *bp, arc_buf_t *buf, boolean_t l2arc, boolean_t l2arc_compress,
|
|
const zio_prop_t *zp, arc_done_func_t *ready, arc_done_func_t *physdone,
|
|
arc_done_func_t *done, void *private, zio_priority_t priority,
|
|
int zio_flags, const zbookmark_phys_t *zb)
|
|
{
|
|
arc_buf_hdr_t *hdr = buf->b_hdr;
|
|
arc_write_callback_t *callback;
|
|
zio_t *zio;
|
|
|
|
ASSERT(ready != NULL);
|
|
ASSERT(done != NULL);
|
|
ASSERT(!HDR_IO_ERROR(hdr));
|
|
ASSERT(!HDR_IO_IN_PROGRESS(hdr));
|
|
ASSERT(hdr->b_l1hdr.b_acb == NULL);
|
|
ASSERT(hdr->b_l1hdr.b_datacnt > 0);
|
|
if (l2arc)
|
|
hdr->b_flags |= ARC_FLAG_L2CACHE;
|
|
if (l2arc_compress)
|
|
hdr->b_flags |= ARC_FLAG_L2COMPRESS;
|
|
callback = kmem_zalloc(sizeof (arc_write_callback_t), KM_SLEEP);
|
|
callback->awcb_ready = ready;
|
|
callback->awcb_physdone = physdone;
|
|
callback->awcb_done = done;
|
|
callback->awcb_private = private;
|
|
callback->awcb_buf = buf;
|
|
|
|
zio = zio_write(pio, spa, txg, bp, buf->b_data, hdr->b_size, zp,
|
|
arc_write_ready, arc_write_physdone, arc_write_done, callback,
|
|
priority, zio_flags, zb);
|
|
|
|
return (zio);
|
|
}
|
|
|
|
static int
|
|
arc_memory_throttle(uint64_t reserve, uint64_t txg)
|
|
{
|
|
#ifdef _KERNEL
|
|
if (zfs_arc_memory_throttle_disable)
|
|
return (0);
|
|
|
|
if (freemem <= physmem * arc_lotsfree_percent / 100) {
|
|
ARCSTAT_INCR(arcstat_memory_throttle_count, 1);
|
|
DMU_TX_STAT_BUMP(dmu_tx_memory_reclaim);
|
|
return (SET_ERROR(EAGAIN));
|
|
}
|
|
#endif
|
|
return (0);
|
|
}
|
|
|
|
void
|
|
arc_tempreserve_clear(uint64_t reserve)
|
|
{
|
|
atomic_add_64(&arc_tempreserve, -reserve);
|
|
ASSERT((int64_t)arc_tempreserve >= 0);
|
|
}
|
|
|
|
int
|
|
arc_tempreserve_space(uint64_t reserve, uint64_t txg)
|
|
{
|
|
int error;
|
|
uint64_t anon_size;
|
|
|
|
if (reserve > arc_c/4 && !arc_no_grow)
|
|
arc_c = MIN(arc_c_max, reserve * 4);
|
|
|
|
/*
|
|
* Throttle when the calculated memory footprint for the TXG
|
|
* exceeds the target ARC size.
|
|
*/
|
|
if (reserve > arc_c) {
|
|
DMU_TX_STAT_BUMP(dmu_tx_memory_reserve);
|
|
return (SET_ERROR(ERESTART));
|
|
}
|
|
|
|
/*
|
|
* Don't count loaned bufs as in flight dirty data to prevent long
|
|
* network delays from blocking transactions that are ready to be
|
|
* assigned to a txg.
|
|
*/
|
|
anon_size = MAX((int64_t)(arc_anon->arcs_size - arc_loaned_bytes), 0);
|
|
|
|
/*
|
|
* Writes will, almost always, require additional memory allocations
|
|
* in order to compress/encrypt/etc the data. We therefore need to
|
|
* make sure that there is sufficient available memory for this.
|
|
*/
|
|
error = arc_memory_throttle(reserve, txg);
|
|
if (error != 0)
|
|
return (error);
|
|
|
|
/*
|
|
* Throttle writes when the amount of dirty data in the cache
|
|
* gets too large. We try to keep the cache less than half full
|
|
* of dirty blocks so that our sync times don't grow too large.
|
|
* Note: if two requests come in concurrently, we might let them
|
|
* both succeed, when one of them should fail. Not a huge deal.
|
|
*/
|
|
|
|
if (reserve + arc_tempreserve + anon_size > arc_c / 2 &&
|
|
anon_size > arc_c / 4) {
|
|
dprintf("failing, arc_tempreserve=%lluK anon_meta=%lluK "
|
|
"anon_data=%lluK tempreserve=%lluK arc_c=%lluK\n",
|
|
arc_tempreserve>>10,
|
|
arc_anon->arcs_lsize[ARC_BUFC_METADATA]>>10,
|
|
arc_anon->arcs_lsize[ARC_BUFC_DATA]>>10,
|
|
reserve>>10, arc_c>>10);
|
|
DMU_TX_STAT_BUMP(dmu_tx_dirty_throttle);
|
|
return (SET_ERROR(ERESTART));
|
|
}
|
|
atomic_add_64(&arc_tempreserve, reserve);
|
|
return (0);
|
|
}
|
|
|
|
static void
|
|
arc_kstat_update_state(arc_state_t *state, kstat_named_t *size,
|
|
kstat_named_t *evict_data, kstat_named_t *evict_metadata)
|
|
{
|
|
size->value.ui64 = state->arcs_size;
|
|
evict_data->value.ui64 = state->arcs_lsize[ARC_BUFC_DATA];
|
|
evict_metadata->value.ui64 = state->arcs_lsize[ARC_BUFC_METADATA];
|
|
}
|
|
|
|
static int
|
|
arc_kstat_update(kstat_t *ksp, int rw)
|
|
{
|
|
arc_stats_t *as = ksp->ks_data;
|
|
|
|
if (rw == KSTAT_WRITE) {
|
|
return (SET_ERROR(EACCES));
|
|
} else {
|
|
arc_kstat_update_state(arc_anon,
|
|
&as->arcstat_anon_size,
|
|
&as->arcstat_anon_evict_data,
|
|
&as->arcstat_anon_evict_metadata);
|
|
arc_kstat_update_state(arc_mru,
|
|
&as->arcstat_mru_size,
|
|
&as->arcstat_mru_evict_data,
|
|
&as->arcstat_mru_evict_metadata);
|
|
arc_kstat_update_state(arc_mru_ghost,
|
|
&as->arcstat_mru_ghost_size,
|
|
&as->arcstat_mru_ghost_evict_data,
|
|
&as->arcstat_mru_ghost_evict_metadata);
|
|
arc_kstat_update_state(arc_mfu,
|
|
&as->arcstat_mfu_size,
|
|
&as->arcstat_mfu_evict_data,
|
|
&as->arcstat_mfu_evict_metadata);
|
|
arc_kstat_update_state(arc_mfu_ghost,
|
|
&as->arcstat_mfu_ghost_size,
|
|
&as->arcstat_mfu_ghost_evict_data,
|
|
&as->arcstat_mfu_ghost_evict_metadata);
|
|
}
|
|
|
|
return (0);
|
|
}
|
|
|
|
/*
|
|
* This function *must* return indices evenly distributed between all
|
|
* sublists of the multilist. This is needed due to how the ARC eviction
|
|
* code is laid out; arc_evict_state() assumes ARC buffers are evenly
|
|
* distributed between all sublists and uses this assumption when
|
|
* deciding which sublist to evict from and how much to evict from it.
|
|
*/
|
|
unsigned int
|
|
arc_state_multilist_index_func(multilist_t *ml, void *obj)
|
|
{
|
|
arc_buf_hdr_t *hdr = obj;
|
|
|
|
/*
|
|
* We rely on b_dva to generate evenly distributed index
|
|
* numbers using buf_hash below. So, as an added precaution,
|
|
* let's make sure we never add empty buffers to the arc lists.
|
|
*/
|
|
ASSERT(!BUF_EMPTY(hdr));
|
|
|
|
/*
|
|
* The assumption here, is the hash value for a given
|
|
* arc_buf_hdr_t will remain constant throughout its lifetime
|
|
* (i.e. its b_spa, b_dva, and b_birth fields don't change).
|
|
* Thus, we don't need to store the header's sublist index
|
|
* on insertion, as this index can be recalculated on removal.
|
|
*
|
|
* Also, the low order bits of the hash value are thought to be
|
|
* distributed evenly. Otherwise, in the case that the multilist
|
|
* has a power of two number of sublists, each sublists' usage
|
|
* would not be evenly distributed.
|
|
*/
|
|
return (buf_hash(hdr->b_spa, &hdr->b_dva, hdr->b_birth) %
|
|
multilist_get_num_sublists(ml));
|
|
}
|
|
|
|
void
|
|
arc_init(void)
|
|
{
|
|
mutex_init(&arc_reclaim_lock, NULL, MUTEX_DEFAULT, NULL);
|
|
cv_init(&arc_reclaim_thread_cv, NULL, CV_DEFAULT, NULL);
|
|
cv_init(&arc_reclaim_waiters_cv, NULL, CV_DEFAULT, NULL);
|
|
|
|
mutex_init(&arc_user_evicts_lock, NULL, MUTEX_DEFAULT, NULL);
|
|
cv_init(&arc_user_evicts_cv, NULL, CV_DEFAULT, NULL);
|
|
|
|
/* Convert seconds to clock ticks */
|
|
zfs_arc_min_prefetch_lifespan = 1 * hz;
|
|
|
|
/* Start out with 1/8 of all memory */
|
|
arc_c = physmem * PAGESIZE / 8;
|
|
|
|
#ifdef _KERNEL
|
|
/*
|
|
* On architectures where the physical memory can be larger
|
|
* than the addressable space (intel in 32-bit mode), we may
|
|
* need to limit the cache to 1/8 of VM size.
|
|
*/
|
|
arc_c = MIN(arc_c, vmem_size(heap_arena, VMEM_ALLOC | VMEM_FREE) / 8);
|
|
/*
|
|
* Register a shrinker to support synchronous (direct) memory
|
|
* reclaim from the arc. This is done to prevent kswapd from
|
|
* swapping out pages when it is preferable to shrink the arc.
|
|
*/
|
|
spl_register_shrinker(&arc_shrinker);
|
|
#endif
|
|
|
|
/* set min cache to allow safe operation of arc_adapt() */
|
|
arc_c_min = 2ULL << SPA_MAXBLOCKSHIFT;
|
|
/* set max to 1/2 of all memory */
|
|
arc_c_max = arc_c * 4;
|
|
|
|
/*
|
|
* Allow the tunables to override our calculations if they are
|
|
* reasonable (ie. over 64MB)
|
|
*/
|
|
if (zfs_arc_max > 64<<20 && zfs_arc_max < physmem * PAGESIZE)
|
|
arc_c_max = zfs_arc_max;
|
|
if (zfs_arc_min >= 2ULL << SPA_MAXBLOCKSHIFT &&
|
|
zfs_arc_min <= arc_c_max)
|
|
arc_c_min = zfs_arc_min;
|
|
|
|
arc_c = arc_c_max;
|
|
arc_p = (arc_c >> 1);
|
|
|
|
/* limit meta-data to 3/4 of the arc capacity */
|
|
arc_meta_limit = (3 * arc_c_max) / 4;
|
|
arc_meta_max = 0;
|
|
|
|
/* Allow the tunable to override if it is reasonable */
|
|
if (zfs_arc_meta_limit > 0 && zfs_arc_meta_limit <= arc_c_max)
|
|
arc_meta_limit = zfs_arc_meta_limit;
|
|
|
|
if (zfs_arc_meta_min > 0) {
|
|
arc_meta_min = zfs_arc_meta_min;
|
|
} else {
|
|
arc_meta_min = arc_c_min / 2;
|
|
}
|
|
|
|
if (zfs_arc_num_sublists_per_state < 1)
|
|
zfs_arc_num_sublists_per_state = num_online_cpus();
|
|
|
|
/* if kmem_flags are set, lets try to use less memory */
|
|
if (kmem_debugging())
|
|
arc_c = arc_c / 2;
|
|
if (arc_c < arc_c_min)
|
|
arc_c = arc_c_min;
|
|
|
|
arc_anon = &ARC_anon;
|
|
arc_mru = &ARC_mru;
|
|
arc_mru_ghost = &ARC_mru_ghost;
|
|
arc_mfu = &ARC_mfu;
|
|
arc_mfu_ghost = &ARC_mfu_ghost;
|
|
arc_l2c_only = &ARC_l2c_only;
|
|
arc_size = 0;
|
|
|
|
multilist_create(&arc_mru->arcs_list[ARC_BUFC_METADATA],
|
|
sizeof (arc_buf_hdr_t),
|
|
offsetof(arc_buf_hdr_t, b_l1hdr.b_arc_node),
|
|
zfs_arc_num_sublists_per_state, arc_state_multilist_index_func);
|
|
multilist_create(&arc_mru->arcs_list[ARC_BUFC_DATA],
|
|
sizeof (arc_buf_hdr_t),
|
|
offsetof(arc_buf_hdr_t, b_l1hdr.b_arc_node),
|
|
zfs_arc_num_sublists_per_state, arc_state_multilist_index_func);
|
|
multilist_create(&arc_mru_ghost->arcs_list[ARC_BUFC_METADATA],
|
|
sizeof (arc_buf_hdr_t),
|
|
offsetof(arc_buf_hdr_t, b_l1hdr.b_arc_node),
|
|
zfs_arc_num_sublists_per_state, arc_state_multilist_index_func);
|
|
multilist_create(&arc_mru_ghost->arcs_list[ARC_BUFC_DATA],
|
|
sizeof (arc_buf_hdr_t),
|
|
offsetof(arc_buf_hdr_t, b_l1hdr.b_arc_node),
|
|
zfs_arc_num_sublists_per_state, arc_state_multilist_index_func);
|
|
multilist_create(&arc_mfu->arcs_list[ARC_BUFC_METADATA],
|
|
sizeof (arc_buf_hdr_t),
|
|
offsetof(arc_buf_hdr_t, b_l1hdr.b_arc_node),
|
|
zfs_arc_num_sublists_per_state, arc_state_multilist_index_func);
|
|
multilist_create(&arc_mfu->arcs_list[ARC_BUFC_DATA],
|
|
sizeof (arc_buf_hdr_t),
|
|
offsetof(arc_buf_hdr_t, b_l1hdr.b_arc_node),
|
|
zfs_arc_num_sublists_per_state, arc_state_multilist_index_func);
|
|
multilist_create(&arc_mfu_ghost->arcs_list[ARC_BUFC_METADATA],
|
|
sizeof (arc_buf_hdr_t),
|
|
offsetof(arc_buf_hdr_t, b_l1hdr.b_arc_node),
|
|
zfs_arc_num_sublists_per_state, arc_state_multilist_index_func);
|
|
multilist_create(&arc_mfu_ghost->arcs_list[ARC_BUFC_DATA],
|
|
sizeof (arc_buf_hdr_t),
|
|
offsetof(arc_buf_hdr_t, b_l1hdr.b_arc_node),
|
|
zfs_arc_num_sublists_per_state, arc_state_multilist_index_func);
|
|
multilist_create(&arc_l2c_only->arcs_list[ARC_BUFC_METADATA],
|
|
sizeof (arc_buf_hdr_t),
|
|
offsetof(arc_buf_hdr_t, b_l1hdr.b_arc_node),
|
|
zfs_arc_num_sublists_per_state, arc_state_multilist_index_func);
|
|
multilist_create(&arc_l2c_only->arcs_list[ARC_BUFC_DATA],
|
|
sizeof (arc_buf_hdr_t),
|
|
offsetof(arc_buf_hdr_t, b_l1hdr.b_arc_node),
|
|
zfs_arc_num_sublists_per_state, arc_state_multilist_index_func);
|
|
|
|
arc_anon->arcs_state = ARC_STATE_ANON;
|
|
arc_mru->arcs_state = ARC_STATE_MRU;
|
|
arc_mru_ghost->arcs_state = ARC_STATE_MRU_GHOST;
|
|
arc_mfu->arcs_state = ARC_STATE_MFU;
|
|
arc_mfu_ghost->arcs_state = ARC_STATE_MFU_GHOST;
|
|
arc_l2c_only->arcs_state = ARC_STATE_L2C_ONLY;
|
|
|
|
buf_init();
|
|
|
|
arc_reclaim_thread_exit = FALSE;
|
|
arc_user_evicts_thread_exit = FALSE;
|
|
list_create(&arc_prune_list, sizeof (arc_prune_t),
|
|
offsetof(arc_prune_t, p_node));
|
|
arc_eviction_list = NULL;
|
|
mutex_init(&arc_prune_mtx, NULL, MUTEX_DEFAULT, NULL);
|
|
bzero(&arc_eviction_hdr, sizeof (arc_buf_hdr_t));
|
|
|
|
arc_prune_taskq = taskq_create("arc_prune", max_ncpus, minclsyspri,
|
|
max_ncpus, INT_MAX, TASKQ_PREPOPULATE | TASKQ_DYNAMIC);
|
|
|
|
arc_ksp = kstat_create("zfs", 0, "arcstats", "misc", KSTAT_TYPE_NAMED,
|
|
sizeof (arc_stats) / sizeof (kstat_named_t), KSTAT_FLAG_VIRTUAL);
|
|
|
|
if (arc_ksp != NULL) {
|
|
arc_ksp->ks_data = &arc_stats;
|
|
arc_ksp->ks_update = arc_kstat_update;
|
|
kstat_install(arc_ksp);
|
|
}
|
|
|
|
(void) thread_create(NULL, 0, arc_adapt_thread, NULL, 0, &p0,
|
|
TS_RUN, minclsyspri);
|
|
|
|
(void) thread_create(NULL, 0, arc_user_evicts_thread, NULL, 0, &p0,
|
|
TS_RUN, minclsyspri);
|
|
|
|
arc_dead = FALSE;
|
|
arc_warm = B_FALSE;
|
|
|
|
/*
|
|
* Calculate maximum amount of dirty data per pool.
|
|
*
|
|
* If it has been set by a module parameter, take that.
|
|
* Otherwise, use a percentage of physical memory defined by
|
|
* zfs_dirty_data_max_percent (default 10%) with a cap at
|
|
* zfs_dirty_data_max_max (default 25% of physical memory).
|
|
*/
|
|
if (zfs_dirty_data_max_max == 0)
|
|
zfs_dirty_data_max_max = physmem * PAGESIZE *
|
|
zfs_dirty_data_max_max_percent / 100;
|
|
|
|
if (zfs_dirty_data_max == 0) {
|
|
zfs_dirty_data_max = physmem * PAGESIZE *
|
|
zfs_dirty_data_max_percent / 100;
|
|
zfs_dirty_data_max = MIN(zfs_dirty_data_max,
|
|
zfs_dirty_data_max_max);
|
|
}
|
|
}
|
|
|
|
void
|
|
arc_fini(void)
|
|
{
|
|
arc_prune_t *p;
|
|
|
|
#ifdef _KERNEL
|
|
spl_unregister_shrinker(&arc_shrinker);
|
|
#endif /* _KERNEL */
|
|
|
|
mutex_enter(&arc_reclaim_lock);
|
|
arc_reclaim_thread_exit = TRUE;
|
|
/*
|
|
* The reclaim thread will set arc_reclaim_thread_exit back to
|
|
* FALSE when it is finished exiting; we're waiting for that.
|
|
*/
|
|
while (arc_reclaim_thread_exit) {
|
|
cv_signal(&arc_reclaim_thread_cv);
|
|
cv_wait(&arc_reclaim_thread_cv, &arc_reclaim_lock);
|
|
}
|
|
mutex_exit(&arc_reclaim_lock);
|
|
|
|
mutex_enter(&arc_user_evicts_lock);
|
|
arc_user_evicts_thread_exit = TRUE;
|
|
/*
|
|
* The user evicts thread will set arc_user_evicts_thread_exit
|
|
* to FALSE when it is finished exiting; we're waiting for that.
|
|
*/
|
|
while (arc_user_evicts_thread_exit) {
|
|
cv_signal(&arc_user_evicts_cv);
|
|
cv_wait(&arc_user_evicts_cv, &arc_user_evicts_lock);
|
|
}
|
|
mutex_exit(&arc_user_evicts_lock);
|
|
|
|
/* Use TRUE to ensure *all* buffers are evicted */
|
|
arc_flush(NULL, TRUE);
|
|
|
|
arc_dead = TRUE;
|
|
|
|
if (arc_ksp != NULL) {
|
|
kstat_delete(arc_ksp);
|
|
arc_ksp = NULL;
|
|
}
|
|
|
|
taskq_wait(arc_prune_taskq);
|
|
taskq_destroy(arc_prune_taskq);
|
|
|
|
mutex_enter(&arc_prune_mtx);
|
|
while ((p = list_head(&arc_prune_list)) != NULL) {
|
|
list_remove(&arc_prune_list, p);
|
|
refcount_remove(&p->p_refcnt, &arc_prune_list);
|
|
refcount_destroy(&p->p_refcnt);
|
|
kmem_free(p, sizeof (*p));
|
|
}
|
|
mutex_exit(&arc_prune_mtx);
|
|
|
|
list_destroy(&arc_prune_list);
|
|
mutex_destroy(&arc_prune_mtx);
|
|
mutex_destroy(&arc_reclaim_lock);
|
|
cv_destroy(&arc_reclaim_thread_cv);
|
|
cv_destroy(&arc_reclaim_waiters_cv);
|
|
|
|
mutex_destroy(&arc_user_evicts_lock);
|
|
cv_destroy(&arc_user_evicts_cv);
|
|
|
|
multilist_destroy(&arc_mru->arcs_list[ARC_BUFC_METADATA]);
|
|
multilist_destroy(&arc_mru_ghost->arcs_list[ARC_BUFC_METADATA]);
|
|
multilist_destroy(&arc_mfu->arcs_list[ARC_BUFC_METADATA]);
|
|
multilist_destroy(&arc_mfu_ghost->arcs_list[ARC_BUFC_METADATA]);
|
|
multilist_destroy(&arc_mru->arcs_list[ARC_BUFC_DATA]);
|
|
multilist_destroy(&arc_mru_ghost->arcs_list[ARC_BUFC_DATA]);
|
|
multilist_destroy(&arc_mfu->arcs_list[ARC_BUFC_DATA]);
|
|
multilist_destroy(&arc_mfu_ghost->arcs_list[ARC_BUFC_DATA]);
|
|
multilist_destroy(&arc_l2c_only->arcs_list[ARC_BUFC_METADATA]);
|
|
multilist_destroy(&arc_l2c_only->arcs_list[ARC_BUFC_DATA]);
|
|
|
|
buf_fini();
|
|
|
|
ASSERT0(arc_loaned_bytes);
|
|
}
|
|
|
|
/*
|
|
* Level 2 ARC
|
|
*
|
|
* The level 2 ARC (L2ARC) is a cache layer in-between main memory and disk.
|
|
* It uses dedicated storage devices to hold cached data, which are populated
|
|
* using large infrequent writes. The main role of this cache is to boost
|
|
* the performance of random read workloads. The intended L2ARC devices
|
|
* include short-stroked disks, solid state disks, and other media with
|
|
* substantially faster read latency than disk.
|
|
*
|
|
* +-----------------------+
|
|
* | ARC |
|
|
* +-----------------------+
|
|
* | ^ ^
|
|
* | | |
|
|
* l2arc_feed_thread() arc_read()
|
|
* | | |
|
|
* | l2arc read |
|
|
* V | |
|
|
* +---------------+ |
|
|
* | L2ARC | |
|
|
* +---------------+ |
|
|
* | ^ |
|
|
* l2arc_write() | |
|
|
* | | |
|
|
* V | |
|
|
* +-------+ +-------+
|
|
* | vdev | | vdev |
|
|
* | cache | | cache |
|
|
* +-------+ +-------+
|
|
* +=========+ .-----.
|
|
* : L2ARC : |-_____-|
|
|
* : devices : | Disks |
|
|
* +=========+ `-_____-'
|
|
*
|
|
* Read requests are satisfied from the following sources, in order:
|
|
*
|
|
* 1) ARC
|
|
* 2) vdev cache of L2ARC devices
|
|
* 3) L2ARC devices
|
|
* 4) vdev cache of disks
|
|
* 5) disks
|
|
*
|
|
* Some L2ARC device types exhibit extremely slow write performance.
|
|
* To accommodate for this there are some significant differences between
|
|
* the L2ARC and traditional cache design:
|
|
*
|
|
* 1. There is no eviction path from the ARC to the L2ARC. Evictions from
|
|
* the ARC behave as usual, freeing buffers and placing headers on ghost
|
|
* lists. The ARC does not send buffers to the L2ARC during eviction as
|
|
* this would add inflated write latencies for all ARC memory pressure.
|
|
*
|
|
* 2. The L2ARC attempts to cache data from the ARC before it is evicted.
|
|
* It does this by periodically scanning buffers from the eviction-end of
|
|
* the MFU and MRU ARC lists, copying them to the L2ARC devices if they are
|
|
* not already there. It scans until a headroom of buffers is satisfied,
|
|
* which itself is a buffer for ARC eviction. If a compressible buffer is
|
|
* found during scanning and selected for writing to an L2ARC device, we
|
|
* temporarily boost scanning headroom during the next scan cycle to make
|
|
* sure we adapt to compression effects (which might significantly reduce
|
|
* the data volume we write to L2ARC). The thread that does this is
|
|
* l2arc_feed_thread(), illustrated below; example sizes are included to
|
|
* provide a better sense of ratio than this diagram:
|
|
*
|
|
* head --> tail
|
|
* +---------------------+----------+
|
|
* ARC_mfu |:::::#:::::::::::::::|o#o###o###|-->. # already on L2ARC
|
|
* +---------------------+----------+ | o L2ARC eligible
|
|
* ARC_mru |:#:::::::::::::::::::|#o#ooo####|-->| : ARC buffer
|
|
* +---------------------+----------+ |
|
|
* 15.9 Gbytes ^ 32 Mbytes |
|
|
* headroom |
|
|
* l2arc_feed_thread()
|
|
* |
|
|
* l2arc write hand <--[oooo]--'
|
|
* | 8 Mbyte
|
|
* | write max
|
|
* V
|
|
* +==============================+
|
|
* L2ARC dev |####|#|###|###| |####| ... |
|
|
* +==============================+
|
|
* 32 Gbytes
|
|
*
|
|
* 3. If an ARC buffer is copied to the L2ARC but then hit instead of
|
|
* evicted, then the L2ARC has cached a buffer much sooner than it probably
|
|
* needed to, potentially wasting L2ARC device bandwidth and storage. It is
|
|
* safe to say that this is an uncommon case, since buffers at the end of
|
|
* the ARC lists have moved there due to inactivity.
|
|
*
|
|
* 4. If the ARC evicts faster than the L2ARC can maintain a headroom,
|
|
* then the L2ARC simply misses copying some buffers. This serves as a
|
|
* pressure valve to prevent heavy read workloads from both stalling the ARC
|
|
* with waits and clogging the L2ARC with writes. This also helps prevent
|
|
* the potential for the L2ARC to churn if it attempts to cache content too
|
|
* quickly, such as during backups of the entire pool.
|
|
*
|
|
* 5. After system boot and before the ARC has filled main memory, there are
|
|
* no evictions from the ARC and so the tails of the ARC_mfu and ARC_mru
|
|
* lists can remain mostly static. Instead of searching from tail of these
|
|
* lists as pictured, the l2arc_feed_thread() will search from the list heads
|
|
* for eligible buffers, greatly increasing its chance of finding them.
|
|
*
|
|
* The L2ARC device write speed is also boosted during this time so that
|
|
* the L2ARC warms up faster. Since there have been no ARC evictions yet,
|
|
* there are no L2ARC reads, and no fear of degrading read performance
|
|
* through increased writes.
|
|
*
|
|
* 6. Writes to the L2ARC devices are grouped and sent in-sequence, so that
|
|
* the vdev queue can aggregate them into larger and fewer writes. Each
|
|
* device is written to in a rotor fashion, sweeping writes through
|
|
* available space then repeating.
|
|
*
|
|
* 7. The L2ARC does not store dirty content. It never needs to flush
|
|
* write buffers back to disk based storage.
|
|
*
|
|
* 8. If an ARC buffer is written (and dirtied) which also exists in the
|
|
* L2ARC, the now stale L2ARC buffer is immediately dropped.
|
|
*
|
|
* The performance of the L2ARC can be tweaked by a number of tunables, which
|
|
* may be necessary for different workloads:
|
|
*
|
|
* l2arc_write_max max write bytes per interval
|
|
* l2arc_write_boost extra write bytes during device warmup
|
|
* l2arc_noprefetch skip caching prefetched buffers
|
|
* l2arc_nocompress skip compressing buffers
|
|
* l2arc_headroom number of max device writes to precache
|
|
* l2arc_headroom_boost when we find compressed buffers during ARC
|
|
* scanning, we multiply headroom by this
|
|
* percentage factor for the next scan cycle,
|
|
* since more compressed buffers are likely to
|
|
* be present
|
|
* l2arc_feed_secs seconds between L2ARC writing
|
|
*
|
|
* Tunables may be removed or added as future performance improvements are
|
|
* integrated, and also may become zpool properties.
|
|
*
|
|
* There are three key functions that control how the L2ARC warms up:
|
|
*
|
|
* l2arc_write_eligible() check if a buffer is eligible to cache
|
|
* l2arc_write_size() calculate how much to write
|
|
* l2arc_write_interval() calculate sleep delay between writes
|
|
*
|
|
* These three functions determine what to write, how much, and how quickly
|
|
* to send writes.
|
|
*/
|
|
|
|
static boolean_t
|
|
l2arc_write_eligible(uint64_t spa_guid, arc_buf_hdr_t *hdr)
|
|
{
|
|
/*
|
|
* A buffer is *not* eligible for the L2ARC if it:
|
|
* 1. belongs to a different spa.
|
|
* 2. is already cached on the L2ARC.
|
|
* 3. has an I/O in progress (it may be an incomplete read).
|
|
* 4. is flagged not eligible (zfs property).
|
|
*/
|
|
if (hdr->b_spa != spa_guid || HDR_HAS_L2HDR(hdr) ||
|
|
HDR_IO_IN_PROGRESS(hdr) || !HDR_L2CACHE(hdr))
|
|
return (B_FALSE);
|
|
|
|
return (B_TRUE);
|
|
}
|
|
|
|
static uint64_t
|
|
l2arc_write_size(void)
|
|
{
|
|
uint64_t size;
|
|
|
|
/*
|
|
* Make sure our globals have meaningful values in case the user
|
|
* altered them.
|
|
*/
|
|
size = l2arc_write_max;
|
|
if (size == 0) {
|
|
cmn_err(CE_NOTE, "Bad value for l2arc_write_max, value must "
|
|
"be greater than zero, resetting it to the default (%d)",
|
|
L2ARC_WRITE_SIZE);
|
|
size = l2arc_write_max = L2ARC_WRITE_SIZE;
|
|
}
|
|
|
|
if (arc_warm == B_FALSE)
|
|
size += l2arc_write_boost;
|
|
|
|
return (size);
|
|
|
|
}
|
|
|
|
static clock_t
|
|
l2arc_write_interval(clock_t began, uint64_t wanted, uint64_t wrote)
|
|
{
|
|
clock_t interval, next, now;
|
|
|
|
/*
|
|
* If the ARC lists are busy, increase our write rate; if the
|
|
* lists are stale, idle back. This is achieved by checking
|
|
* how much we previously wrote - if it was more than half of
|
|
* what we wanted, schedule the next write much sooner.
|
|
*/
|
|
if (l2arc_feed_again && wrote > (wanted / 2))
|
|
interval = (hz * l2arc_feed_min_ms) / 1000;
|
|
else
|
|
interval = hz * l2arc_feed_secs;
|
|
|
|
now = ddi_get_lbolt();
|
|
next = MAX(now, MIN(now + interval, began + interval));
|
|
|
|
return (next);
|
|
}
|
|
|
|
/*
|
|
* Cycle through L2ARC devices. This is how L2ARC load balances.
|
|
* If a device is returned, this also returns holding the spa config lock.
|
|
*/
|
|
static l2arc_dev_t *
|
|
l2arc_dev_get_next(void)
|
|
{
|
|
l2arc_dev_t *first, *next = NULL;
|
|
|
|
/*
|
|
* Lock out the removal of spas (spa_namespace_lock), then removal
|
|
* of cache devices (l2arc_dev_mtx). Once a device has been selected,
|
|
* both locks will be dropped and a spa config lock held instead.
|
|
*/
|
|
mutex_enter(&spa_namespace_lock);
|
|
mutex_enter(&l2arc_dev_mtx);
|
|
|
|
/* if there are no vdevs, there is nothing to do */
|
|
if (l2arc_ndev == 0)
|
|
goto out;
|
|
|
|
first = NULL;
|
|
next = l2arc_dev_last;
|
|
do {
|
|
/* loop around the list looking for a non-faulted vdev */
|
|
if (next == NULL) {
|
|
next = list_head(l2arc_dev_list);
|
|
} else {
|
|
next = list_next(l2arc_dev_list, next);
|
|
if (next == NULL)
|
|
next = list_head(l2arc_dev_list);
|
|
}
|
|
|
|
/* if we have come back to the start, bail out */
|
|
if (first == NULL)
|
|
first = next;
|
|
else if (next == first)
|
|
break;
|
|
|
|
} while (vdev_is_dead(next->l2ad_vdev));
|
|
|
|
/* if we were unable to find any usable vdevs, return NULL */
|
|
if (vdev_is_dead(next->l2ad_vdev))
|
|
next = NULL;
|
|
|
|
l2arc_dev_last = next;
|
|
|
|
out:
|
|
mutex_exit(&l2arc_dev_mtx);
|
|
|
|
/*
|
|
* Grab the config lock to prevent the 'next' device from being
|
|
* removed while we are writing to it.
|
|
*/
|
|
if (next != NULL)
|
|
spa_config_enter(next->l2ad_spa, SCL_L2ARC, next, RW_READER);
|
|
mutex_exit(&spa_namespace_lock);
|
|
|
|
return (next);
|
|
}
|
|
|
|
/*
|
|
* Free buffers that were tagged for destruction.
|
|
*/
|
|
static void
|
|
l2arc_do_free_on_write(void)
|
|
{
|
|
list_t *buflist;
|
|
l2arc_data_free_t *df, *df_prev;
|
|
|
|
mutex_enter(&l2arc_free_on_write_mtx);
|
|
buflist = l2arc_free_on_write;
|
|
|
|
for (df = list_tail(buflist); df; df = df_prev) {
|
|
df_prev = list_prev(buflist, df);
|
|
ASSERT(df->l2df_data != NULL);
|
|
ASSERT(df->l2df_func != NULL);
|
|
df->l2df_func(df->l2df_data, df->l2df_size);
|
|
list_remove(buflist, df);
|
|
kmem_free(df, sizeof (l2arc_data_free_t));
|
|
}
|
|
|
|
mutex_exit(&l2arc_free_on_write_mtx);
|
|
}
|
|
|
|
/*
|
|
* A write to a cache device has completed. Update all headers to allow
|
|
* reads from these buffers to begin.
|
|
*/
|
|
static void
|
|
l2arc_write_done(zio_t *zio)
|
|
{
|
|
l2arc_write_callback_t *cb;
|
|
l2arc_dev_t *dev;
|
|
list_t *buflist;
|
|
arc_buf_hdr_t *head, *hdr, *hdr_prev;
|
|
kmutex_t *hash_lock;
|
|
int64_t bytes_dropped = 0;
|
|
|
|
cb = zio->io_private;
|
|
ASSERT(cb != NULL);
|
|
dev = cb->l2wcb_dev;
|
|
ASSERT(dev != NULL);
|
|
head = cb->l2wcb_head;
|
|
ASSERT(head != NULL);
|
|
buflist = &dev->l2ad_buflist;
|
|
ASSERT(buflist != NULL);
|
|
DTRACE_PROBE2(l2arc__iodone, zio_t *, zio,
|
|
l2arc_write_callback_t *, cb);
|
|
|
|
if (zio->io_error != 0)
|
|
ARCSTAT_BUMP(arcstat_l2_writes_error);
|
|
|
|
/*
|
|
* All writes completed, or an error was hit.
|
|
*/
|
|
top:
|
|
mutex_enter(&dev->l2ad_mtx);
|
|
for (hdr = list_prev(buflist, head); hdr; hdr = hdr_prev) {
|
|
hdr_prev = list_prev(buflist, hdr);
|
|
|
|
hash_lock = HDR_LOCK(hdr);
|
|
|
|
/*
|
|
* We cannot use mutex_enter or else we can deadlock
|
|
* with l2arc_write_buffers (due to swapping the order
|
|
* the hash lock and l2ad_mtx are taken).
|
|
*/
|
|
if (!mutex_tryenter(hash_lock)) {
|
|
/*
|
|
* Missed the hash lock. We must retry so we
|
|
* don't leave the ARC_FLAG_L2_WRITING bit set.
|
|
*/
|
|
ARCSTAT_BUMP(arcstat_l2_writes_lock_retry);
|
|
|
|
/*
|
|
* We don't want to rescan the headers we've
|
|
* already marked as having been written out, so
|
|
* we reinsert the head node so we can pick up
|
|
* where we left off.
|
|
*/
|
|
list_remove(buflist, head);
|
|
list_insert_after(buflist, hdr, head);
|
|
|
|
mutex_exit(&dev->l2ad_mtx);
|
|
|
|
/*
|
|
* We wait for the hash lock to become available
|
|
* to try and prevent busy waiting, and increase
|
|
* the chance we'll be able to acquire the lock
|
|
* the next time around.
|
|
*/
|
|
mutex_enter(hash_lock);
|
|
mutex_exit(hash_lock);
|
|
goto top;
|
|
}
|
|
|
|
/*
|
|
* We could not have been moved into the arc_l2c_only
|
|
* state while in-flight due to our ARC_FLAG_L2_WRITING
|
|
* bit being set. Let's just ensure that's being enforced.
|
|
*/
|
|
ASSERT(HDR_HAS_L1HDR(hdr));
|
|
|
|
/*
|
|
* We may have allocated a buffer for L2ARC compression,
|
|
* we must release it to avoid leaking this data.
|
|
*/
|
|
l2arc_release_cdata_buf(hdr);
|
|
|
|
if (zio->io_error != 0) {
|
|
/*
|
|
* Error - drop L2ARC entry.
|
|
*/
|
|
list_remove(buflist, hdr);
|
|
hdr->b_flags &= ~ARC_FLAG_HAS_L2HDR;
|
|
|
|
ARCSTAT_INCR(arcstat_l2_asize, -hdr->b_l2hdr.b_asize);
|
|
ARCSTAT_INCR(arcstat_l2_size, -hdr->b_size);
|
|
|
|
bytes_dropped += hdr->b_l2hdr.b_asize;
|
|
(void) refcount_remove_many(&dev->l2ad_alloc,
|
|
hdr->b_l2hdr.b_asize, hdr);
|
|
}
|
|
|
|
/*
|
|
* Allow ARC to begin reads and ghost list evictions to
|
|
* this L2ARC entry.
|
|
*/
|
|
hdr->b_flags &= ~ARC_FLAG_L2_WRITING;
|
|
|
|
mutex_exit(hash_lock);
|
|
}
|
|
|
|
atomic_inc_64(&l2arc_writes_done);
|
|
list_remove(buflist, head);
|
|
ASSERT(!HDR_HAS_L1HDR(head));
|
|
kmem_cache_free(hdr_l2only_cache, head);
|
|
mutex_exit(&dev->l2ad_mtx);
|
|
|
|
vdev_space_update(dev->l2ad_vdev, -bytes_dropped, 0, 0);
|
|
|
|
l2arc_do_free_on_write();
|
|
|
|
kmem_free(cb, sizeof (l2arc_write_callback_t));
|
|
}
|
|
|
|
/*
|
|
* A read to a cache device completed. Validate buffer contents before
|
|
* handing over to the regular ARC routines.
|
|
*/
|
|
static void
|
|
l2arc_read_done(zio_t *zio)
|
|
{
|
|
l2arc_read_callback_t *cb;
|
|
arc_buf_hdr_t *hdr;
|
|
arc_buf_t *buf;
|
|
kmutex_t *hash_lock;
|
|
int equal;
|
|
|
|
ASSERT(zio->io_vd != NULL);
|
|
ASSERT(zio->io_flags & ZIO_FLAG_DONT_PROPAGATE);
|
|
|
|
spa_config_exit(zio->io_spa, SCL_L2ARC, zio->io_vd);
|
|
|
|
cb = zio->io_private;
|
|
ASSERT(cb != NULL);
|
|
buf = cb->l2rcb_buf;
|
|
ASSERT(buf != NULL);
|
|
|
|
hash_lock = HDR_LOCK(buf->b_hdr);
|
|
mutex_enter(hash_lock);
|
|
hdr = buf->b_hdr;
|
|
ASSERT3P(hash_lock, ==, HDR_LOCK(hdr));
|
|
|
|
/*
|
|
* If the buffer was compressed, decompress it first.
|
|
*/
|
|
if (cb->l2rcb_compress != ZIO_COMPRESS_OFF)
|
|
l2arc_decompress_zio(zio, hdr, cb->l2rcb_compress);
|
|
ASSERT(zio->io_data != NULL);
|
|
|
|
/*
|
|
* Check this survived the L2ARC journey.
|
|
*/
|
|
equal = arc_cksum_equal(buf);
|
|
if (equal && zio->io_error == 0 && !HDR_L2_EVICTED(hdr)) {
|
|
mutex_exit(hash_lock);
|
|
zio->io_private = buf;
|
|
zio->io_bp_copy = cb->l2rcb_bp; /* XXX fix in L2ARC 2.0 */
|
|
zio->io_bp = &zio->io_bp_copy; /* XXX fix in L2ARC 2.0 */
|
|
arc_read_done(zio);
|
|
} else {
|
|
mutex_exit(hash_lock);
|
|
/*
|
|
* Buffer didn't survive caching. Increment stats and
|
|
* reissue to the original storage device.
|
|
*/
|
|
if (zio->io_error != 0) {
|
|
ARCSTAT_BUMP(arcstat_l2_io_error);
|
|
} else {
|
|
zio->io_error = SET_ERROR(EIO);
|
|
}
|
|
if (!equal)
|
|
ARCSTAT_BUMP(arcstat_l2_cksum_bad);
|
|
|
|
/*
|
|
* If there's no waiter, issue an async i/o to the primary
|
|
* storage now. If there *is* a waiter, the caller must
|
|
* issue the i/o in a context where it's OK to block.
|
|
*/
|
|
if (zio->io_waiter == NULL) {
|
|
zio_t *pio = zio_unique_parent(zio);
|
|
|
|
ASSERT(!pio || pio->io_child_type == ZIO_CHILD_LOGICAL);
|
|
|
|
zio_nowait(zio_read(pio, cb->l2rcb_spa, &cb->l2rcb_bp,
|
|
buf->b_data, zio->io_size, arc_read_done, buf,
|
|
zio->io_priority, cb->l2rcb_flags, &cb->l2rcb_zb));
|
|
}
|
|
}
|
|
|
|
kmem_free(cb, sizeof (l2arc_read_callback_t));
|
|
}
|
|
|
|
/*
|
|
* This is the list priority from which the L2ARC will search for pages to
|
|
* cache. This is used within loops (0..3) to cycle through lists in the
|
|
* desired order. This order can have a significant effect on cache
|
|
* performance.
|
|
*
|
|
* Currently the metadata lists are hit first, MFU then MRU, followed by
|
|
* the data lists. This function returns a locked list, and also returns
|
|
* the lock pointer.
|
|
*/
|
|
static multilist_sublist_t *
|
|
l2arc_sublist_lock(int list_num)
|
|
{
|
|
multilist_t *ml = NULL;
|
|
unsigned int idx;
|
|
|
|
ASSERT(list_num >= 0 && list_num <= 3);
|
|
|
|
switch (list_num) {
|
|
case 0:
|
|
ml = &arc_mfu->arcs_list[ARC_BUFC_METADATA];
|
|
break;
|
|
case 1:
|
|
ml = &arc_mru->arcs_list[ARC_BUFC_METADATA];
|
|
break;
|
|
case 2:
|
|
ml = &arc_mfu->arcs_list[ARC_BUFC_DATA];
|
|
break;
|
|
case 3:
|
|
ml = &arc_mru->arcs_list[ARC_BUFC_DATA];
|
|
break;
|
|
}
|
|
|
|
/*
|
|
* Return a randomly-selected sublist. This is acceptable
|
|
* because the caller feeds only a little bit of data for each
|
|
* call (8MB). Subsequent calls will result in different
|
|
* sublists being selected.
|
|
*/
|
|
idx = multilist_get_random_index(ml);
|
|
return (multilist_sublist_lock(ml, idx));
|
|
}
|
|
|
|
/*
|
|
* Evict buffers from the device write hand to the distance specified in
|
|
* bytes. This distance may span populated buffers, it may span nothing.
|
|
* This is clearing a region on the L2ARC device ready for writing.
|
|
* If the 'all' boolean is set, every buffer is evicted.
|
|
*/
|
|
static void
|
|
l2arc_evict(l2arc_dev_t *dev, uint64_t distance, boolean_t all)
|
|
{
|
|
list_t *buflist;
|
|
arc_buf_hdr_t *hdr, *hdr_prev;
|
|
kmutex_t *hash_lock;
|
|
uint64_t taddr;
|
|
|
|
buflist = &dev->l2ad_buflist;
|
|
|
|
if (!all && dev->l2ad_first) {
|
|
/*
|
|
* This is the first sweep through the device. There is
|
|
* nothing to evict.
|
|
*/
|
|
return;
|
|
}
|
|
|
|
if (dev->l2ad_hand >= (dev->l2ad_end - (2 * distance))) {
|
|
/*
|
|
* When nearing the end of the device, evict to the end
|
|
* before the device write hand jumps to the start.
|
|
*/
|
|
taddr = dev->l2ad_end;
|
|
} else {
|
|
taddr = dev->l2ad_hand + distance;
|
|
}
|
|
DTRACE_PROBE4(l2arc__evict, l2arc_dev_t *, dev, list_t *, buflist,
|
|
uint64_t, taddr, boolean_t, all);
|
|
|
|
top:
|
|
mutex_enter(&dev->l2ad_mtx);
|
|
for (hdr = list_tail(buflist); hdr; hdr = hdr_prev) {
|
|
hdr_prev = list_prev(buflist, hdr);
|
|
|
|
hash_lock = HDR_LOCK(hdr);
|
|
|
|
/*
|
|
* We cannot use mutex_enter or else we can deadlock
|
|
* with l2arc_write_buffers (due to swapping the order
|
|
* the hash lock and l2ad_mtx are taken).
|
|
*/
|
|
if (!mutex_tryenter(hash_lock)) {
|
|
/*
|
|
* Missed the hash lock. Retry.
|
|
*/
|
|
ARCSTAT_BUMP(arcstat_l2_evict_lock_retry);
|
|
mutex_exit(&dev->l2ad_mtx);
|
|
mutex_enter(hash_lock);
|
|
mutex_exit(hash_lock);
|
|
goto top;
|
|
}
|
|
|
|
if (HDR_L2_WRITE_HEAD(hdr)) {
|
|
/*
|
|
* We hit a write head node. Leave it for
|
|
* l2arc_write_done().
|
|
*/
|
|
list_remove(buflist, hdr);
|
|
mutex_exit(hash_lock);
|
|
continue;
|
|
}
|
|
|
|
if (!all && HDR_HAS_L2HDR(hdr) &&
|
|
(hdr->b_l2hdr.b_daddr > taddr ||
|
|
hdr->b_l2hdr.b_daddr < dev->l2ad_hand)) {
|
|
/*
|
|
* We've evicted to the target address,
|
|
* or the end of the device.
|
|
*/
|
|
mutex_exit(hash_lock);
|
|
break;
|
|
}
|
|
|
|
ASSERT(HDR_HAS_L2HDR(hdr));
|
|
if (!HDR_HAS_L1HDR(hdr)) {
|
|
ASSERT(!HDR_L2_READING(hdr));
|
|
/*
|
|
* This doesn't exist in the ARC. Destroy.
|
|
* arc_hdr_destroy() will call list_remove()
|
|
* and decrement arcstat_l2_size.
|
|
*/
|
|
arc_change_state(arc_anon, hdr, hash_lock);
|
|
arc_hdr_destroy(hdr);
|
|
} else {
|
|
ASSERT(hdr->b_l1hdr.b_state != arc_l2c_only);
|
|
ARCSTAT_BUMP(arcstat_l2_evict_l1cached);
|
|
/*
|
|
* Invalidate issued or about to be issued
|
|
* reads, since we may be about to write
|
|
* over this location.
|
|
*/
|
|
if (HDR_L2_READING(hdr)) {
|
|
ARCSTAT_BUMP(arcstat_l2_evict_reading);
|
|
hdr->b_flags |= ARC_FLAG_L2_EVICTED;
|
|
}
|
|
|
|
/* Ensure this header has finished being written */
|
|
ASSERT(!HDR_L2_WRITING(hdr));
|
|
ASSERT3P(hdr->b_l1hdr.b_tmp_cdata, ==, NULL);
|
|
|
|
arc_hdr_l2hdr_destroy(hdr);
|
|
}
|
|
mutex_exit(hash_lock);
|
|
}
|
|
mutex_exit(&dev->l2ad_mtx);
|
|
}
|
|
|
|
/*
|
|
* Find and write ARC buffers to the L2ARC device.
|
|
*
|
|
* An ARC_FLAG_L2_WRITING flag is set so that the L2ARC buffers are not valid
|
|
* for reading until they have completed writing.
|
|
* The headroom_boost is an in-out parameter used to maintain headroom boost
|
|
* state between calls to this function.
|
|
*
|
|
* Returns the number of bytes actually written (which may be smaller than
|
|
* the delta by which the device hand has changed due to alignment).
|
|
*/
|
|
static uint64_t
|
|
l2arc_write_buffers(spa_t *spa, l2arc_dev_t *dev, uint64_t target_sz,
|
|
boolean_t *headroom_boost)
|
|
{
|
|
arc_buf_hdr_t *hdr, *hdr_prev, *head;
|
|
uint64_t write_asize, write_sz, headroom, buf_compress_minsz,
|
|
stats_size;
|
|
void *buf_data;
|
|
boolean_t full;
|
|
l2arc_write_callback_t *cb;
|
|
zio_t *pio, *wzio;
|
|
uint64_t guid = spa_load_guid(spa);
|
|
int try;
|
|
const boolean_t do_headroom_boost = *headroom_boost;
|
|
|
|
ASSERT(dev->l2ad_vdev != NULL);
|
|
|
|
/* Lower the flag now, we might want to raise it again later. */
|
|
*headroom_boost = B_FALSE;
|
|
|
|
pio = NULL;
|
|
write_sz = write_asize = 0;
|
|
full = B_FALSE;
|
|
head = kmem_cache_alloc(hdr_l2only_cache, KM_PUSHPAGE);
|
|
head->b_flags |= ARC_FLAG_L2_WRITE_HEAD;
|
|
head->b_flags |= ARC_FLAG_HAS_L2HDR;
|
|
|
|
/*
|
|
* We will want to try to compress buffers that are at least 2x the
|
|
* device sector size.
|
|
*/
|
|
buf_compress_minsz = 2 << dev->l2ad_vdev->vdev_ashift;
|
|
|
|
/*
|
|
* Copy buffers for L2ARC writing.
|
|
*/
|
|
for (try = 0; try <= 3; try++) {
|
|
multilist_sublist_t *mls = l2arc_sublist_lock(try);
|
|
uint64_t passed_sz = 0;
|
|
|
|
/*
|
|
* L2ARC fast warmup.
|
|
*
|
|
* Until the ARC is warm and starts to evict, read from the
|
|
* head of the ARC lists rather than the tail.
|
|
*/
|
|
if (arc_warm == B_FALSE)
|
|
hdr = multilist_sublist_head(mls);
|
|
else
|
|
hdr = multilist_sublist_tail(mls);
|
|
|
|
headroom = target_sz * l2arc_headroom;
|
|
if (do_headroom_boost)
|
|
headroom = (headroom * l2arc_headroom_boost) / 100;
|
|
|
|
for (; hdr; hdr = hdr_prev) {
|
|
kmutex_t *hash_lock;
|
|
uint64_t buf_sz;
|
|
uint64_t buf_a_sz;
|
|
|
|
if (arc_warm == B_FALSE)
|
|
hdr_prev = multilist_sublist_next(mls, hdr);
|
|
else
|
|
hdr_prev = multilist_sublist_prev(mls, hdr);
|
|
|
|
hash_lock = HDR_LOCK(hdr);
|
|
if (!mutex_tryenter(hash_lock)) {
|
|
/*
|
|
* Skip this buffer rather than waiting.
|
|
*/
|
|
continue;
|
|
}
|
|
|
|
passed_sz += hdr->b_size;
|
|
if (passed_sz > headroom) {
|
|
/*
|
|
* Searched too far.
|
|
*/
|
|
mutex_exit(hash_lock);
|
|
break;
|
|
}
|
|
|
|
if (!l2arc_write_eligible(guid, hdr)) {
|
|
mutex_exit(hash_lock);
|
|
continue;
|
|
}
|
|
|
|
/*
|
|
* Assume that the buffer is not going to be compressed
|
|
* and could take more space on disk because of a larger
|
|
* disk block size.
|
|
*/
|
|
buf_sz = hdr->b_size;
|
|
buf_a_sz = vdev_psize_to_asize(dev->l2ad_vdev, buf_sz);
|
|
|
|
if ((write_asize + buf_a_sz) > target_sz) {
|
|
full = B_TRUE;
|
|
mutex_exit(hash_lock);
|
|
break;
|
|
}
|
|
|
|
if (pio == NULL) {
|
|
/*
|
|
* Insert a dummy header on the buflist so
|
|
* l2arc_write_done() can find where the
|
|
* write buffers begin without searching.
|
|
*/
|
|
mutex_enter(&dev->l2ad_mtx);
|
|
list_insert_head(&dev->l2ad_buflist, head);
|
|
mutex_exit(&dev->l2ad_mtx);
|
|
|
|
cb = kmem_alloc(sizeof (l2arc_write_callback_t),
|
|
KM_SLEEP);
|
|
cb->l2wcb_dev = dev;
|
|
cb->l2wcb_head = head;
|
|
pio = zio_root(spa, l2arc_write_done, cb,
|
|
ZIO_FLAG_CANFAIL);
|
|
}
|
|
|
|
/*
|
|
* Create and add a new L2ARC header.
|
|
*/
|
|
hdr->b_l2hdr.b_dev = dev;
|
|
arc_space_consume(HDR_L2ONLY_SIZE, ARC_SPACE_L2HDRS);
|
|
hdr->b_flags |= ARC_FLAG_L2_WRITING;
|
|
/*
|
|
* Temporarily stash the data buffer in b_tmp_cdata.
|
|
* The subsequent write step will pick it up from
|
|
* there. This is because can't access b_l1hdr.b_buf
|
|
* without holding the hash_lock, which we in turn
|
|
* can't access without holding the ARC list locks
|
|
* (which we want to avoid during compression/writing)
|
|
*/
|
|
HDR_SET_COMPRESS(hdr, ZIO_COMPRESS_OFF);
|
|
hdr->b_l2hdr.b_asize = hdr->b_size;
|
|
hdr->b_l2hdr.b_hits = 0;
|
|
hdr->b_l1hdr.b_tmp_cdata = hdr->b_l1hdr.b_buf->b_data;
|
|
|
|
/*
|
|
* Explicitly set the b_daddr field to a known
|
|
* value which means "invalid address". This
|
|
* enables us to differentiate which stage of
|
|
* l2arc_write_buffers() the particular header
|
|
* is in (e.g. this loop, or the one below).
|
|
* ARC_FLAG_L2_WRITING is not enough to make
|
|
* this distinction, and we need to know in
|
|
* order to do proper l2arc vdev accounting in
|
|
* arc_release() and arc_hdr_destroy().
|
|
*
|
|
* Note, we can't use a new flag to distinguish
|
|
* the two stages because we don't hold the
|
|
* header's hash_lock below, in the second stage
|
|
* of this function. Thus, we can't simply
|
|
* change the b_flags field to denote that the
|
|
* IO has been sent. We can change the b_daddr
|
|
* field of the L2 portion, though, since we'll
|
|
* be holding the l2ad_mtx; which is why we're
|
|
* using it to denote the header's state change.
|
|
*/
|
|
hdr->b_l2hdr.b_daddr = L2ARC_ADDR_UNSET;
|
|
hdr->b_flags |= ARC_FLAG_HAS_L2HDR;
|
|
|
|
mutex_enter(&dev->l2ad_mtx);
|
|
list_insert_head(&dev->l2ad_buflist, hdr);
|
|
mutex_exit(&dev->l2ad_mtx);
|
|
|
|
/*
|
|
* Compute and store the buffer cksum before
|
|
* writing. On debug the cksum is verified first.
|
|
*/
|
|
arc_cksum_verify(hdr->b_l1hdr.b_buf);
|
|
arc_cksum_compute(hdr->b_l1hdr.b_buf, B_TRUE);
|
|
|
|
mutex_exit(hash_lock);
|
|
|
|
write_sz += buf_sz;
|
|
write_asize += buf_a_sz;
|
|
}
|
|
|
|
multilist_sublist_unlock(mls);
|
|
|
|
if (full == B_TRUE)
|
|
break;
|
|
}
|
|
|
|
/* No buffers selected for writing? */
|
|
if (pio == NULL) {
|
|
ASSERT0(write_sz);
|
|
ASSERT(!HDR_HAS_L1HDR(head));
|
|
kmem_cache_free(hdr_l2only_cache, head);
|
|
return (0);
|
|
}
|
|
|
|
mutex_enter(&dev->l2ad_mtx);
|
|
|
|
/*
|
|
* Note that elsewhere in this file arcstat_l2_asize
|
|
* and the used space on l2ad_vdev are updated using b_asize,
|
|
* which is not necessarily rounded up to the device block size.
|
|
* Too keep accounting consistent we do the same here as well:
|
|
* stats_size accumulates the sum of b_asize of the written buffers,
|
|
* while write_asize accumulates the sum of b_asize rounded up
|
|
* to the device block size.
|
|
* The latter sum is used only to validate the corectness of the code.
|
|
*/
|
|
stats_size = 0;
|
|
write_asize = 0;
|
|
|
|
/*
|
|
* Now start writing the buffers. We're starting at the write head
|
|
* and work backwards, retracing the course of the buffer selector
|
|
* loop above.
|
|
*/
|
|
for (hdr = list_prev(&dev->l2ad_buflist, head); hdr;
|
|
hdr = list_prev(&dev->l2ad_buflist, hdr)) {
|
|
uint64_t buf_sz;
|
|
|
|
/*
|
|
* We rely on the L1 portion of the header below, so
|
|
* it's invalid for this header to have been evicted out
|
|
* of the ghost cache, prior to being written out. The
|
|
* ARC_FLAG_L2_WRITING bit ensures this won't happen.
|
|
*/
|
|
ASSERT(HDR_HAS_L1HDR(hdr));
|
|
|
|
/*
|
|
* We shouldn't need to lock the buffer here, since we flagged
|
|
* it as ARC_FLAG_L2_WRITING in the previous step, but we must
|
|
* take care to only access its L2 cache parameters. In
|
|
* particular, hdr->l1hdr.b_buf may be invalid by now due to
|
|
* ARC eviction.
|
|
*/
|
|
hdr->b_l2hdr.b_daddr = dev->l2ad_hand;
|
|
|
|
if ((!l2arc_nocompress && HDR_L2COMPRESS(hdr)) &&
|
|
hdr->b_l2hdr.b_asize >= buf_compress_minsz) {
|
|
if (l2arc_compress_buf(hdr)) {
|
|
/*
|
|
* If compression succeeded, enable headroom
|
|
* boost on the next scan cycle.
|
|
*/
|
|
*headroom_boost = B_TRUE;
|
|
}
|
|
}
|
|
|
|
/*
|
|
* Pick up the buffer data we had previously stashed away
|
|
* (and now potentially also compressed).
|
|
*/
|
|
buf_data = hdr->b_l1hdr.b_tmp_cdata;
|
|
buf_sz = hdr->b_l2hdr.b_asize;
|
|
|
|
/*
|
|
* We need to do this regardless if buf_sz is zero or
|
|
* not, otherwise, when this l2hdr is evicted we'll
|
|
* remove a reference that was never added.
|
|
*/
|
|
(void) refcount_add_many(&dev->l2ad_alloc, buf_sz, hdr);
|
|
|
|
/* Compression may have squashed the buffer to zero length. */
|
|
if (buf_sz != 0) {
|
|
uint64_t buf_a_sz;
|
|
|
|
wzio = zio_write_phys(pio, dev->l2ad_vdev,
|
|
dev->l2ad_hand, buf_sz, buf_data, ZIO_CHECKSUM_OFF,
|
|
NULL, NULL, ZIO_PRIORITY_ASYNC_WRITE,
|
|
ZIO_FLAG_CANFAIL, B_FALSE);
|
|
|
|
DTRACE_PROBE2(l2arc__write, vdev_t *, dev->l2ad_vdev,
|
|
zio_t *, wzio);
|
|
(void) zio_nowait(wzio);
|
|
|
|
stats_size += buf_sz;
|
|
|
|
/*
|
|
* Keep the clock hand suitably device-aligned.
|
|
*/
|
|
buf_a_sz = vdev_psize_to_asize(dev->l2ad_vdev, buf_sz);
|
|
write_asize += buf_a_sz;
|
|
dev->l2ad_hand += buf_a_sz;
|
|
}
|
|
}
|
|
|
|
mutex_exit(&dev->l2ad_mtx);
|
|
|
|
ASSERT3U(write_asize, <=, target_sz);
|
|
ARCSTAT_BUMP(arcstat_l2_writes_sent);
|
|
ARCSTAT_INCR(arcstat_l2_write_bytes, write_asize);
|
|
ARCSTAT_INCR(arcstat_l2_size, write_sz);
|
|
ARCSTAT_INCR(arcstat_l2_asize, stats_size);
|
|
vdev_space_update(dev->l2ad_vdev, stats_size, 0, 0);
|
|
|
|
/*
|
|
* Bump device hand to the device start if it is approaching the end.
|
|
* l2arc_evict() will already have evicted ahead for this case.
|
|
*/
|
|
if (dev->l2ad_hand >= (dev->l2ad_end - target_sz)) {
|
|
dev->l2ad_hand = dev->l2ad_start;
|
|
dev->l2ad_first = B_FALSE;
|
|
}
|
|
|
|
dev->l2ad_writing = B_TRUE;
|
|
(void) zio_wait(pio);
|
|
dev->l2ad_writing = B_FALSE;
|
|
|
|
return (write_asize);
|
|
}
|
|
|
|
/*
|
|
* Compresses an L2ARC buffer.
|
|
* The data to be compressed must be prefilled in l1hdr.b_tmp_cdata and its
|
|
* size in l2hdr->b_asize. This routine tries to compress the data and
|
|
* depending on the compression result there are three possible outcomes:
|
|
* *) The buffer was incompressible. The original l2hdr contents were left
|
|
* untouched and are ready for writing to an L2 device.
|
|
* *) The buffer was all-zeros, so there is no need to write it to an L2
|
|
* device. To indicate this situation b_tmp_cdata is NULL'ed, b_asize is
|
|
* set to zero and b_compress is set to ZIO_COMPRESS_EMPTY.
|
|
* *) Compression succeeded and b_tmp_cdata was replaced with a temporary
|
|
* data buffer which holds the compressed data to be written, and b_asize
|
|
* tells us how much data there is. b_compress is set to the appropriate
|
|
* compression algorithm. Once writing is done, invoke
|
|
* l2arc_release_cdata_buf on this l2hdr to free this temporary buffer.
|
|
*
|
|
* Returns B_TRUE if compression succeeded, or B_FALSE if it didn't (the
|
|
* buffer was incompressible).
|
|
*/
|
|
static boolean_t
|
|
l2arc_compress_buf(arc_buf_hdr_t *hdr)
|
|
{
|
|
void *cdata;
|
|
size_t csize, len, rounded;
|
|
l2arc_buf_hdr_t *l2hdr;
|
|
|
|
ASSERT(HDR_HAS_L2HDR(hdr));
|
|
|
|
l2hdr = &hdr->b_l2hdr;
|
|
|
|
ASSERT(HDR_HAS_L1HDR(hdr));
|
|
ASSERT(HDR_GET_COMPRESS(hdr) == ZIO_COMPRESS_OFF);
|
|
ASSERT(hdr->b_l1hdr.b_tmp_cdata != NULL);
|
|
|
|
len = l2hdr->b_asize;
|
|
cdata = zio_data_buf_alloc(len);
|
|
ASSERT3P(cdata, !=, NULL);
|
|
csize = zio_compress_data(ZIO_COMPRESS_LZ4, hdr->b_l1hdr.b_tmp_cdata,
|
|
cdata, l2hdr->b_asize);
|
|
|
|
rounded = P2ROUNDUP(csize, (size_t)SPA_MINBLOCKSIZE);
|
|
if (rounded > csize) {
|
|
bzero((char *)cdata + csize, rounded - csize);
|
|
csize = rounded;
|
|
}
|
|
|
|
if (csize == 0) {
|
|
/* zero block, indicate that there's nothing to write */
|
|
zio_data_buf_free(cdata, len);
|
|
HDR_SET_COMPRESS(hdr, ZIO_COMPRESS_EMPTY);
|
|
l2hdr->b_asize = 0;
|
|
hdr->b_l1hdr.b_tmp_cdata = NULL;
|
|
ARCSTAT_BUMP(arcstat_l2_compress_zeros);
|
|
return (B_TRUE);
|
|
} else if (csize > 0 && csize < len) {
|
|
/*
|
|
* Compression succeeded, we'll keep the cdata around for
|
|
* writing and release it afterwards.
|
|
*/
|
|
HDR_SET_COMPRESS(hdr, ZIO_COMPRESS_LZ4);
|
|
l2hdr->b_asize = csize;
|
|
hdr->b_l1hdr.b_tmp_cdata = cdata;
|
|
ARCSTAT_BUMP(arcstat_l2_compress_successes);
|
|
return (B_TRUE);
|
|
} else {
|
|
/*
|
|
* Compression failed, release the compressed buffer.
|
|
* l2hdr will be left unmodified.
|
|
*/
|
|
zio_data_buf_free(cdata, len);
|
|
ARCSTAT_BUMP(arcstat_l2_compress_failures);
|
|
return (B_FALSE);
|
|
}
|
|
}
|
|
|
|
/*
|
|
* Decompresses a zio read back from an l2arc device. On success, the
|
|
* underlying zio's io_data buffer is overwritten by the uncompressed
|
|
* version. On decompression error (corrupt compressed stream), the
|
|
* zio->io_error value is set to signal an I/O error.
|
|
*
|
|
* Please note that the compressed data stream is not checksummed, so
|
|
* if the underlying device is experiencing data corruption, we may feed
|
|
* corrupt data to the decompressor, so the decompressor needs to be
|
|
* able to handle this situation (LZ4 does).
|
|
*/
|
|
static void
|
|
l2arc_decompress_zio(zio_t *zio, arc_buf_hdr_t *hdr, enum zio_compress c)
|
|
{
|
|
uint64_t csize;
|
|
void *cdata;
|
|
|
|
ASSERT(L2ARC_IS_VALID_COMPRESS(c));
|
|
|
|
if (zio->io_error != 0) {
|
|
/*
|
|
* An io error has occured, just restore the original io
|
|
* size in preparation for a main pool read.
|
|
*/
|
|
zio->io_orig_size = zio->io_size = hdr->b_size;
|
|
return;
|
|
}
|
|
|
|
if (c == ZIO_COMPRESS_EMPTY) {
|
|
/*
|
|
* An empty buffer results in a null zio, which means we
|
|
* need to fill its io_data after we're done restoring the
|
|
* buffer's contents.
|
|
*/
|
|
ASSERT(hdr->b_l1hdr.b_buf != NULL);
|
|
bzero(hdr->b_l1hdr.b_buf->b_data, hdr->b_size);
|
|
zio->io_data = zio->io_orig_data = hdr->b_l1hdr.b_buf->b_data;
|
|
} else {
|
|
ASSERT(zio->io_data != NULL);
|
|
/*
|
|
* We copy the compressed data from the start of the arc buffer
|
|
* (the zio_read will have pulled in only what we need, the
|
|
* rest is garbage which we will overwrite at decompression)
|
|
* and then decompress back to the ARC data buffer. This way we
|
|
* can minimize copying by simply decompressing back over the
|
|
* original compressed data (rather than decompressing to an
|
|
* aux buffer and then copying back the uncompressed buffer,
|
|
* which is likely to be much larger).
|
|
*/
|
|
csize = zio->io_size;
|
|
cdata = zio_data_buf_alloc(csize);
|
|
bcopy(zio->io_data, cdata, csize);
|
|
if (zio_decompress_data(c, cdata, zio->io_data, csize,
|
|
hdr->b_size) != 0)
|
|
zio->io_error = SET_ERROR(EIO);
|
|
zio_data_buf_free(cdata, csize);
|
|
}
|
|
|
|
/* Restore the expected uncompressed IO size. */
|
|
zio->io_orig_size = zio->io_size = hdr->b_size;
|
|
}
|
|
|
|
/*
|
|
* Releases the temporary b_tmp_cdata buffer in an l2arc header structure.
|
|
* This buffer serves as a temporary holder of compressed data while
|
|
* the buffer entry is being written to an l2arc device. Once that is
|
|
* done, we can dispose of it.
|
|
*/
|
|
static void
|
|
l2arc_release_cdata_buf(arc_buf_hdr_t *hdr)
|
|
{
|
|
enum zio_compress comp = HDR_GET_COMPRESS(hdr);
|
|
|
|
ASSERT(HDR_HAS_L1HDR(hdr));
|
|
ASSERT(comp == ZIO_COMPRESS_OFF || L2ARC_IS_VALID_COMPRESS(comp));
|
|
|
|
if (comp == ZIO_COMPRESS_OFF) {
|
|
/*
|
|
* In this case, b_tmp_cdata points to the same buffer
|
|
* as the arc_buf_t's b_data field. We don't want to
|
|
* free it, since the arc_buf_t will handle that.
|
|
*/
|
|
hdr->b_l1hdr.b_tmp_cdata = NULL;
|
|
} else if (comp == ZIO_COMPRESS_EMPTY) {
|
|
/*
|
|
* In this case, b_tmp_cdata was compressed to an empty
|
|
* buffer, thus there's nothing to free and b_tmp_cdata
|
|
* should have been set to NULL in l2arc_write_buffers().
|
|
*/
|
|
ASSERT3P(hdr->b_l1hdr.b_tmp_cdata, ==, NULL);
|
|
} else {
|
|
/*
|
|
* If the data was compressed, then we've allocated a
|
|
* temporary buffer for it, so now we need to release it.
|
|
*/
|
|
ASSERT(hdr->b_l1hdr.b_tmp_cdata != NULL);
|
|
zio_data_buf_free(hdr->b_l1hdr.b_tmp_cdata,
|
|
hdr->b_size);
|
|
hdr->b_l1hdr.b_tmp_cdata = NULL;
|
|
}
|
|
|
|
}
|
|
|
|
/*
|
|
* This thread feeds the L2ARC at regular intervals. This is the beating
|
|
* heart of the L2ARC.
|
|
*/
|
|
static void
|
|
l2arc_feed_thread(void)
|
|
{
|
|
callb_cpr_t cpr;
|
|
l2arc_dev_t *dev;
|
|
spa_t *spa;
|
|
uint64_t size, wrote;
|
|
clock_t begin, next = ddi_get_lbolt();
|
|
boolean_t headroom_boost = B_FALSE;
|
|
fstrans_cookie_t cookie;
|
|
|
|
CALLB_CPR_INIT(&cpr, &l2arc_feed_thr_lock, callb_generic_cpr, FTAG);
|
|
|
|
mutex_enter(&l2arc_feed_thr_lock);
|
|
|
|
cookie = spl_fstrans_mark();
|
|
while (l2arc_thread_exit == 0) {
|
|
CALLB_CPR_SAFE_BEGIN(&cpr);
|
|
(void) cv_timedwait_sig(&l2arc_feed_thr_cv,
|
|
&l2arc_feed_thr_lock, next);
|
|
CALLB_CPR_SAFE_END(&cpr, &l2arc_feed_thr_lock);
|
|
next = ddi_get_lbolt() + hz;
|
|
|
|
/*
|
|
* Quick check for L2ARC devices.
|
|
*/
|
|
mutex_enter(&l2arc_dev_mtx);
|
|
if (l2arc_ndev == 0) {
|
|
mutex_exit(&l2arc_dev_mtx);
|
|
continue;
|
|
}
|
|
mutex_exit(&l2arc_dev_mtx);
|
|
begin = ddi_get_lbolt();
|
|
|
|
/*
|
|
* This selects the next l2arc device to write to, and in
|
|
* doing so the next spa to feed from: dev->l2ad_spa. This
|
|
* will return NULL if there are now no l2arc devices or if
|
|
* they are all faulted.
|
|
*
|
|
* If a device is returned, its spa's config lock is also
|
|
* held to prevent device removal. l2arc_dev_get_next()
|
|
* will grab and release l2arc_dev_mtx.
|
|
*/
|
|
if ((dev = l2arc_dev_get_next()) == NULL)
|
|
continue;
|
|
|
|
spa = dev->l2ad_spa;
|
|
ASSERT(spa != NULL);
|
|
|
|
/*
|
|
* If the pool is read-only then force the feed thread to
|
|
* sleep a little longer.
|
|
*/
|
|
if (!spa_writeable(spa)) {
|
|
next = ddi_get_lbolt() + 5 * l2arc_feed_secs * hz;
|
|
spa_config_exit(spa, SCL_L2ARC, dev);
|
|
continue;
|
|
}
|
|
|
|
/*
|
|
* Avoid contributing to memory pressure.
|
|
*/
|
|
if (arc_no_grow) {
|
|
ARCSTAT_BUMP(arcstat_l2_abort_lowmem);
|
|
spa_config_exit(spa, SCL_L2ARC, dev);
|
|
continue;
|
|
}
|
|
|
|
ARCSTAT_BUMP(arcstat_l2_feeds);
|
|
|
|
size = l2arc_write_size();
|
|
|
|
/*
|
|
* Evict L2ARC buffers that will be overwritten.
|
|
*/
|
|
l2arc_evict(dev, size, B_FALSE);
|
|
|
|
/*
|
|
* Write ARC buffers.
|
|
*/
|
|
wrote = l2arc_write_buffers(spa, dev, size, &headroom_boost);
|
|
|
|
/*
|
|
* Calculate interval between writes.
|
|
*/
|
|
next = l2arc_write_interval(begin, size, wrote);
|
|
spa_config_exit(spa, SCL_L2ARC, dev);
|
|
}
|
|
spl_fstrans_unmark(cookie);
|
|
|
|
l2arc_thread_exit = 0;
|
|
cv_broadcast(&l2arc_feed_thr_cv);
|
|
CALLB_CPR_EXIT(&cpr); /* drops l2arc_feed_thr_lock */
|
|
thread_exit();
|
|
}
|
|
|
|
boolean_t
|
|
l2arc_vdev_present(vdev_t *vd)
|
|
{
|
|
l2arc_dev_t *dev;
|
|
|
|
mutex_enter(&l2arc_dev_mtx);
|
|
for (dev = list_head(l2arc_dev_list); dev != NULL;
|
|
dev = list_next(l2arc_dev_list, dev)) {
|
|
if (dev->l2ad_vdev == vd)
|
|
break;
|
|
}
|
|
mutex_exit(&l2arc_dev_mtx);
|
|
|
|
return (dev != NULL);
|
|
}
|
|
|
|
/*
|
|
* Add a vdev for use by the L2ARC. By this point the spa has already
|
|
* validated the vdev and opened it.
|
|
*/
|
|
void
|
|
l2arc_add_vdev(spa_t *spa, vdev_t *vd)
|
|
{
|
|
l2arc_dev_t *adddev;
|
|
|
|
ASSERT(!l2arc_vdev_present(vd));
|
|
|
|
/*
|
|
* Create a new l2arc device entry.
|
|
*/
|
|
adddev = kmem_zalloc(sizeof (l2arc_dev_t), KM_SLEEP);
|
|
adddev->l2ad_spa = spa;
|
|
adddev->l2ad_vdev = vd;
|
|
adddev->l2ad_start = VDEV_LABEL_START_SIZE;
|
|
adddev->l2ad_end = VDEV_LABEL_START_SIZE + vdev_get_min_asize(vd);
|
|
adddev->l2ad_hand = adddev->l2ad_start;
|
|
adddev->l2ad_first = B_TRUE;
|
|
adddev->l2ad_writing = B_FALSE;
|
|
list_link_init(&adddev->l2ad_node);
|
|
|
|
mutex_init(&adddev->l2ad_mtx, NULL, MUTEX_DEFAULT, NULL);
|
|
/*
|
|
* This is a list of all ARC buffers that are still valid on the
|
|
* device.
|
|
*/
|
|
list_create(&adddev->l2ad_buflist, sizeof (arc_buf_hdr_t),
|
|
offsetof(arc_buf_hdr_t, b_l2hdr.b_l2node));
|
|
|
|
vdev_space_update(vd, 0, 0, adddev->l2ad_end - adddev->l2ad_hand);
|
|
refcount_create(&adddev->l2ad_alloc);
|
|
|
|
/*
|
|
* Add device to global list
|
|
*/
|
|
mutex_enter(&l2arc_dev_mtx);
|
|
list_insert_head(l2arc_dev_list, adddev);
|
|
atomic_inc_64(&l2arc_ndev);
|
|
mutex_exit(&l2arc_dev_mtx);
|
|
}
|
|
|
|
/*
|
|
* Remove a vdev from the L2ARC.
|
|
*/
|
|
void
|
|
l2arc_remove_vdev(vdev_t *vd)
|
|
{
|
|
l2arc_dev_t *dev, *nextdev, *remdev = NULL;
|
|
|
|
/*
|
|
* Find the device by vdev
|
|
*/
|
|
mutex_enter(&l2arc_dev_mtx);
|
|
for (dev = list_head(l2arc_dev_list); dev; dev = nextdev) {
|
|
nextdev = list_next(l2arc_dev_list, dev);
|
|
if (vd == dev->l2ad_vdev) {
|
|
remdev = dev;
|
|
break;
|
|
}
|
|
}
|
|
ASSERT(remdev != NULL);
|
|
|
|
/*
|
|
* Remove device from global list
|
|
*/
|
|
list_remove(l2arc_dev_list, remdev);
|
|
l2arc_dev_last = NULL; /* may have been invalidated */
|
|
atomic_dec_64(&l2arc_ndev);
|
|
mutex_exit(&l2arc_dev_mtx);
|
|
|
|
/*
|
|
* Clear all buflists and ARC references. L2ARC device flush.
|
|
*/
|
|
l2arc_evict(remdev, 0, B_TRUE);
|
|
list_destroy(&remdev->l2ad_buflist);
|
|
mutex_destroy(&remdev->l2ad_mtx);
|
|
refcount_destroy(&remdev->l2ad_alloc);
|
|
kmem_free(remdev, sizeof (l2arc_dev_t));
|
|
}
|
|
|
|
void
|
|
l2arc_init(void)
|
|
{
|
|
l2arc_thread_exit = 0;
|
|
l2arc_ndev = 0;
|
|
l2arc_writes_sent = 0;
|
|
l2arc_writes_done = 0;
|
|
|
|
mutex_init(&l2arc_feed_thr_lock, NULL, MUTEX_DEFAULT, NULL);
|
|
cv_init(&l2arc_feed_thr_cv, NULL, CV_DEFAULT, NULL);
|
|
mutex_init(&l2arc_dev_mtx, NULL, MUTEX_DEFAULT, NULL);
|
|
mutex_init(&l2arc_free_on_write_mtx, NULL, MUTEX_DEFAULT, NULL);
|
|
|
|
l2arc_dev_list = &L2ARC_dev_list;
|
|
l2arc_free_on_write = &L2ARC_free_on_write;
|
|
list_create(l2arc_dev_list, sizeof (l2arc_dev_t),
|
|
offsetof(l2arc_dev_t, l2ad_node));
|
|
list_create(l2arc_free_on_write, sizeof (l2arc_data_free_t),
|
|
offsetof(l2arc_data_free_t, l2df_list_node));
|
|
}
|
|
|
|
void
|
|
l2arc_fini(void)
|
|
{
|
|
/*
|
|
* This is called from dmu_fini(), which is called from spa_fini();
|
|
* Because of this, we can assume that all l2arc devices have
|
|
* already been removed when the pools themselves were removed.
|
|
*/
|
|
|
|
l2arc_do_free_on_write();
|
|
|
|
mutex_destroy(&l2arc_feed_thr_lock);
|
|
cv_destroy(&l2arc_feed_thr_cv);
|
|
mutex_destroy(&l2arc_dev_mtx);
|
|
mutex_destroy(&l2arc_free_on_write_mtx);
|
|
|
|
list_destroy(l2arc_dev_list);
|
|
list_destroy(l2arc_free_on_write);
|
|
}
|
|
|
|
void
|
|
l2arc_start(void)
|
|
{
|
|
if (!(spa_mode_global & FWRITE))
|
|
return;
|
|
|
|
(void) thread_create(NULL, 0, l2arc_feed_thread, NULL, 0, &p0,
|
|
TS_RUN, minclsyspri);
|
|
}
|
|
|
|
void
|
|
l2arc_stop(void)
|
|
{
|
|
if (!(spa_mode_global & FWRITE))
|
|
return;
|
|
|
|
mutex_enter(&l2arc_feed_thr_lock);
|
|
cv_signal(&l2arc_feed_thr_cv); /* kick thread out of startup */
|
|
l2arc_thread_exit = 1;
|
|
while (l2arc_thread_exit != 0)
|
|
cv_wait(&l2arc_feed_thr_cv, &l2arc_feed_thr_lock);
|
|
mutex_exit(&l2arc_feed_thr_lock);
|
|
}
|
|
|
|
#if defined(_KERNEL) && defined(HAVE_SPL)
|
|
EXPORT_SYMBOL(arc_buf_size);
|
|
EXPORT_SYMBOL(arc_write);
|
|
EXPORT_SYMBOL(arc_read);
|
|
EXPORT_SYMBOL(arc_buf_remove_ref);
|
|
EXPORT_SYMBOL(arc_buf_info);
|
|
EXPORT_SYMBOL(arc_getbuf_func);
|
|
EXPORT_SYMBOL(arc_add_prune_callback);
|
|
EXPORT_SYMBOL(arc_remove_prune_callback);
|
|
|
|
module_param(zfs_arc_min, ulong, 0644);
|
|
MODULE_PARM_DESC(zfs_arc_min, "Min arc size");
|
|
|
|
module_param(zfs_arc_max, ulong, 0644);
|
|
MODULE_PARM_DESC(zfs_arc_max, "Max arc size");
|
|
|
|
module_param(zfs_arc_meta_limit, ulong, 0644);
|
|
MODULE_PARM_DESC(zfs_arc_meta_limit, "Meta limit for arc size");
|
|
|
|
module_param(zfs_arc_meta_min, ulong, 0644);
|
|
MODULE_PARM_DESC(zfs_arc_meta_min, "Min arc metadata");
|
|
|
|
module_param(zfs_arc_meta_prune, int, 0644);
|
|
MODULE_PARM_DESC(zfs_arc_meta_prune, "Meta objects to scan for prune");
|
|
|
|
module_param(zfs_arc_meta_adjust_restarts, ulong, 0644);
|
|
MODULE_PARM_DESC(zfs_arc_meta_adjust_restarts,
|
|
"Limit number of restarts in arc_adjust_meta");
|
|
|
|
module_param(zfs_arc_meta_strategy, int, 0644);
|
|
MODULE_PARM_DESC(zfs_arc_meta_strategy, "Meta reclaim strategy");
|
|
|
|
module_param(zfs_arc_grow_retry, int, 0644);
|
|
MODULE_PARM_DESC(zfs_arc_grow_retry, "Seconds before growing arc size");
|
|
|
|
module_param(zfs_arc_p_aggressive_disable, int, 0644);
|
|
MODULE_PARM_DESC(zfs_arc_p_aggressive_disable, "disable aggressive arc_p grow");
|
|
|
|
module_param(zfs_arc_p_dampener_disable, int, 0644);
|
|
MODULE_PARM_DESC(zfs_arc_p_dampener_disable, "disable arc_p adapt dampener");
|
|
|
|
module_param(zfs_arc_shrink_shift, int, 0644);
|
|
MODULE_PARM_DESC(zfs_arc_shrink_shift, "log2(fraction of arc to reclaim)");
|
|
|
|
module_param(zfs_disable_dup_eviction, int, 0644);
|
|
MODULE_PARM_DESC(zfs_disable_dup_eviction, "disable duplicate buffer eviction");
|
|
|
|
module_param(zfs_arc_average_blocksize, int, 0444);
|
|
MODULE_PARM_DESC(zfs_arc_average_blocksize, "Target average block size");
|
|
|
|
module_param(zfs_arc_memory_throttle_disable, int, 0644);
|
|
MODULE_PARM_DESC(zfs_arc_memory_throttle_disable, "disable memory throttle");
|
|
|
|
module_param(zfs_arc_min_prefetch_lifespan, int, 0644);
|
|
MODULE_PARM_DESC(zfs_arc_min_prefetch_lifespan, "Min life of prefetch block");
|
|
|
|
module_param(zfs_arc_num_sublists_per_state, int, 0644);
|
|
MODULE_PARM_DESC(zfs_arc_num_sublists_per_state,
|
|
"Number of sublists used in each of the ARC state lists");
|
|
|
|
module_param(l2arc_write_max, ulong, 0644);
|
|
MODULE_PARM_DESC(l2arc_write_max, "Max write bytes per interval");
|
|
|
|
module_param(l2arc_write_boost, ulong, 0644);
|
|
MODULE_PARM_DESC(l2arc_write_boost, "Extra write bytes during device warmup");
|
|
|
|
module_param(l2arc_headroom, ulong, 0644);
|
|
MODULE_PARM_DESC(l2arc_headroom, "Number of max device writes to precache");
|
|
|
|
module_param(l2arc_headroom_boost, ulong, 0644);
|
|
MODULE_PARM_DESC(l2arc_headroom_boost, "Compressed l2arc_headroom multiplier");
|
|
|
|
module_param(l2arc_feed_secs, ulong, 0644);
|
|
MODULE_PARM_DESC(l2arc_feed_secs, "Seconds between L2ARC writing");
|
|
|
|
module_param(l2arc_feed_min_ms, ulong, 0644);
|
|
MODULE_PARM_DESC(l2arc_feed_min_ms, "Min feed interval in milliseconds");
|
|
|
|
module_param(l2arc_noprefetch, int, 0644);
|
|
MODULE_PARM_DESC(l2arc_noprefetch, "Skip caching prefetched buffers");
|
|
|
|
module_param(l2arc_nocompress, int, 0644);
|
|
MODULE_PARM_DESC(l2arc_nocompress, "Skip compressing L2ARC buffers");
|
|
|
|
module_param(l2arc_feed_again, int, 0644);
|
|
MODULE_PARM_DESC(l2arc_feed_again, "Turbo L2ARC warmup");
|
|
|
|
module_param(l2arc_norw, int, 0644);
|
|
MODULE_PARM_DESC(l2arc_norw, "No reads during writes");
|
|
|
|
#endif
|