Using zfs with Lustre, an arc_read can trigger kernel memory allocation
that in turn leads to a memory reclaim callback and a deadlock within a
single zfs process. This change uses spl_fstrans_mark and
spl_trans_unmark to prevent the reclaim attempt and the deadlock
(https://zfsonlinux.topicbox.com/groups/zfs-devel/T4db2c705ec1804ba).
The stack trace observed is:
__schedule at ffffffff81610f2e
schedule at ffffffff81611558
schedule_preempt_disabled at ffffffff8161184a
__mutex_lock at ffffffff816131e8
arc_buf_destroy at ffffffffa0bf37d7 [zfs]
dbuf_destroy at ffffffffa0bfa6fe [zfs]
dbuf_evict_one at ffffffffa0bfaa96 [zfs]
dbuf_rele_and_unlock at ffffffffa0bfa561 [zfs]
dbuf_rele_and_unlock at ffffffffa0bfa32b [zfs]
osd_object_delete at ffffffffa0b64ecc [osd_zfs]
lu_object_free at ffffffffa06d6a74 [obdclass]
lu_site_purge_objects at ffffffffa06d7fc1 [obdclass]
lu_cache_shrink_scan at ffffffffa06d81b8 [obdclass]
shrink_slab at ffffffff811ca9d8
shrink_node at ffffffff811cfd94
do_try_to_free_pages at ffffffff811cfe63
try_to_free_pages at ffffffff811d01c4
__alloc_pages_slowpath at ffffffff811be7f2
__alloc_pages_nodemask at ffffffff811bf3ed
new_slab at ffffffff81226304
___slab_alloc at ffffffff812272ab
__slab_alloc at ffffffff8122740c
kmem_cache_alloc at ffffffff81227578
spl_kmem_cache_alloc at ffffffffa048a1fd [spl]
arc_buf_alloc_impl at ffffffffa0befba2 [zfs]
arc_read at ffffffffa0bf0924 [zfs]
dbuf_read at ffffffffa0bf9083 [zfs]
dmu_buf_hold_by_dnode at ffffffffa0c04869 [zfs]
Reviewed-by: Brian Behlendorf <behlendorf1@llnl.gov>
Signed-off-by: Mark Roper <markroper@gmail.com>
Closes#9987
When doing a zfs send on a dataset with small recordsize (e.g. 8K),
performance is dominated by the per-block overheads. This is especially
true with `zfs send --compressed`, which further reduces the amount of
data sent, for the same number of blocks. Several threads are involved,
but the limiting factor is the `send_prefetch` thread, which is 100% on
CPU.
The main job of the `send_prefetch` thread is to issue zio's for the
data that will be needed by the main thread. It does this by calling
`arc_read(ARC_FLAG_PREFETCH)`. This has an immediate cost of creating
an arc_hdr, which takes around 14% of one CPU. It also induces later
costs by other threads:
* Since the data was only prefetched, dmu_send()->dmu_dump_write() will
need to call arc_read() again to get the data. This will have to
look up the arc_hdr in the hash table and copy the data from the
scatter ABD in the arc_hdr to a linear ABD in arc_buf. This takes
27% of one CPU.
* dmu_dump_write() needs to arc_buf_destroy() This takes 11% of one
CPU.
* arc_adjust() will need to evict this arc_hdr, taking about 50% of one
CPU.
All of these costs can be avoided by bypassing the ARC if the data is
not already cached. This commit changes `zfs send` to check for the
data in the ARC, and if it is not found then we directly call
`zio_read()`, reading the data into a linear ABD which is used by
dmu_dump_write() directly.
The performance improvement is best expressed in terms of how many
blocks can be processed by `zfs send` in one second. This change
increases the metric by 50%, from ~100,000 to ~150,000. When the amount
of data per block is small (e.g. 2KB), there is a corresponding
reduction in the elapsed time of `zfs send >/dev/null` (from 86 minutes
to 58 minutes in this test case).
In addition to improving the performance of `zfs send`, this change
makes `zfs send` not pollute the ARC cache. In most cases the data will
not be reused, so this allows us to keep caching useful data in the MRU
(hit-once) part of the ARC.
Reviewed-by: Paul Dagnelie <pcd@delphix.com>
Reviewed-by: Serapheim Dimitropoulos <serapheim@delphix.com>
Reviewed-by: Brian Behlendorf <behlendorf1@llnl.gov>
Signed-off-by: Matthew Ahrens <mahrens@delphix.com>
Closes#10067
When "zfs destroy" is run, it completes quickly, and in the background
we locate the blocks to free and free them. This background activity
can be observed with `zpool get freeing` and `zpool wait -t free ...`.
This background activity is processed by a single thread (the spa_sync
thread) which calls zio_free() on each of the blocks to free. With even
modest storage performance, the CPU consumption of zio_free() can be the
performance bottleneck.
Performance of zio_free() can be improved by not actually creating a
zio_t in the common case (non-dedup, non-gang), instead calling
metaslab_free() directly. This avoids the CPU cost of allocating the
zio_t, and more importantly the cost of adding and later removing this
zio_t from the parent zio's child list.
The result is that performance of background freeing more than doubles,
from 0.6 million blocks per second to 1.3 million blocks per second.
Reviewed-by: Paul Dagnelie <pcd@delphix.com>
Reviewed-by: Serapheim Dimitropoulos <serapheim@delphix.com>
Reviewed-by: Brian Behlendorf <behlendorf1@llnl.gov>
Reviewed-by: George Wilson <gwilson@delphix.com>
Signed-off-by: Matthew Ahrens <mahrens@delphix.com>
Closes#10034
Remove the ASSERTV macro and handle suppressing unused
compiler warnings for variables only in ASSERTs using the
__attribute__((unused)) compiler annotation. The annotation
is understood by both gcc and clang.
Reviewed-by: Brian Behlendorf <behlendorf1@llnl.gov>
Reviewed-by: Jorgen Lundman <lundman@lundman.net>
Signed-off-by: Matt Macy <mmacy@FreeBSD.org>
Closes#9671
In case L2ARC read failed, l2arc_read_done() creates _different_ ZIO
to read data from the original storage device. Unfortunately pointer
to the failed ZIO remains in hdr->b_l1hdr.b_acb->acb_zio_head, and if
some other read try to bump the ZIO priority, it will crash.
The problem is reproducible by corrupting L2ARC content and reading
some data with prefetch if l2arc_noprefetch tunable is changed to 0.
With the default setting the issue is probably not reproducible now.
Reviewed-by: Tom Caputi <tcaputi@datto.com>
Reviewed-by: Brian Behlendorf <behlendorf1@llnl.gov>
Signed-off-by: Alexander Motin <mav@FreeBSD.org>
Sponsored-By: iXsystems, Inc.
Closes#9648
Provide a common zfs_file_* interface which can be implemented on all
platforms to perform normal file access from either the kernel module
or the libzpool library.
This allows all non-portable vnode_t usage in the common code to be
replaced by the new portable zfs_file_t. The associated vnode and
kobj compatibility functions, types, and macros have been removed
from the SPL. Moving forward, vnodes should only be used in platform
specific code when provided by the native operating system.
Reviewed-by: Sean Eric Fagan <sef@ixsystems.com>
Reviewed-by: Brian Behlendorf <behlendorf1@llnl.gov>
Reviewed-by: Igor Kozhukhov <igor@dilos.org>
Reviewed-by: Jorgen Lundman <lundman@lundman.net>
Signed-off-by: Matt Macy <mmacy@FreeBSD.org>
Closes#9556
This change modifies some of the infrastructure for enabling the use of
the DTRACE_PROBE* macros, such that we can use tehm in the "spl" module.
Currently, when the DTRACE_PROBE* macros are used, they get expanded to
create new functions, and these dynamically generated functions become
part of the "zfs" module.
Since the "spl" module does not depend on the "zfs" module, the use of
DTRACE_PROBE* in the "spl" module would result in undefined symbols
being used in the "spl" module. Specifically, DTRACE_PROBE* would turn
into a function call, and the function being called would be a symbol
only contained in the "zfs" module; which results in a linker and/or
runtime error.
Thus, this change adds the necessary logic to the "spl" module, to
mirror the tracing functionality available to the "zfs" module. After
this change, we'll have a "trace_zfs.h" header file which defines the
probes available only to the "zfs" module, and a "trace_spl.h" header
file which defines the probes available only to the "spl" module.
Reviewed by: Brad Lewis <brad.lewis@delphix.com>
Reviewed-by: Brian Behlendorf <behlendorf1@llnl.gov>
Signed-off-by: Prakash Surya <prakash.surya@delphix.com>
Closes#9525
This change leverage module_param_call() to run arc_tuning_update()
immediately after the ARC tunable has been updated as suggested in
cffa8372 code review.
A simple test case is added to the ZFS Test Suite to prevent future
regressions in functionality.
Reviewed-by: Matt Macy <mmacy@FreeBSD.org>
Reviewed-by: Brian Behlendorf <behlendorf1@llnl.gov>
Signed-off-by: loli10K <ezomori.nozomu@gmail.com>
Closes#9487Closes#9489
Contrary to initial testing we cannot rely on these kernels to
invalidate the per-cpu FPU state and restore the FPU registers.
Nor can we guarantee that the kernel won't modify the FPU state
which we saved in the task struck.
Therefore, the kfpu_begin() and kfpu_end() functions have been
updated to save and restore the FPU state using our own dedicated
per-cpu FPU state variables.
This has the additional advantage of allowing us to use the FPU
again in user threads. So we remove the code which was added to
use task queues to ensure some functions ran in kernel threads.
Reviewed-by: Fabian Grünbichler <f.gruenbichler@proxmox.com>
Reviewed-by: Tony Hutter <hutter2@llnl.gov>
Signed-off-by: Brian Behlendorf <behlendorf1@llnl.gov>
Issue #9346Closes#9403
Factor Linux specific memory pressure handling out of ARC. Each
platform will have different available interfaces for managing memory
pressure.
Reviewed-by: Brian Behlendorf <behlendorf1@llnl.gov>
Reviewed-by: Jorgen Lundman <lundman@lundman.net>
Reviewed-by: Ryan Moeller <ryan@ixsystems.com>
Signed-off-by: Matt Macy <mmacy@FreeBSD.org>
Closes#9472
This patch implements a new tree structure for ZFS, and uses it to
store range trees more efficiently.
The new structure is approximately a B-tree, though there are some
small differences from the usual characterizations. The tree has core
nodes and leaf nodes; each contain data elements, which the elements
in the core nodes acting as separators between its children. The
difference between core and leaf nodes is that the core nodes have an
array of children, while leaf nodes don't. Every node in the tree may
be only partially full; in most cases, they are all at least 50% full
(in terms of element count) except for the root node, which can be
less full. Underfull nodes will steal from their neighbors or merge to
remain full enough, while overfull nodes will split in two. The data
elements are contained in tree-controlled buffers; they are copied
into these on insertion, and overwritten on deletion. This means that
the elements are not independently allocated, which reduces overhead,
but also means they can't be shared between trees (and also that
pointers to them are only valid until a side-effectful tree operation
occurs). The overhead varies based on how dense the tree is, but is
usually on the order of about 50% of the element size; the per-node
overheads are very small, and so don't make a significant difference.
The trees can accept arbitrary records; they accept a size and a
comparator to allow them to be used for a variety of purposes.
The new trees replace the AVL trees used in the range trees today.
Currently, the range_seg_t structure contains three 8 byte integers
of payload and two 24 byte avl_tree_node_ts to handle its storage in
both an offset-sorted tree and a size-sorted tree (total size: 64
bytes). In the new model, the range seg structures are usually two 4
byte integers, but a separate one needs to exist for the size-sorted
and offset-sorted tree. Between the raw size, the 50% overhead, and
the double storage, the new btrees are expected to use 8*1.5*2 = 24
bytes per record, or 33.3% as much memory as the AVL trees (this is
for the purposes of storing metaslab range trees; for other purposes,
like scrubs, they use ~50% as much memory).
We reduced the size of the payload in the range segments by teaching
range trees about starting offsets and shifts; since metaslabs have a
fixed starting offset, and they all operate in terms of disk sectors,
we can store the ranges using 4-byte integers as long as the size of
the metaslab divided by the sector size is less than 2^32. For 512-byte
sectors, this is a 2^41 (or 2TB) metaslab, which with the default
settings corresponds to a 256PB disk. 4k sector disks can handle
metaslabs up to 2^46 bytes, or 2^63 byte disks. Since we do not
anticipate disks of this size in the near future, there should be
almost no cases where metaslabs need 64-byte integers to store their
ranges. We do still have the capability to store 64-byte integer ranges
to account for cases where we are storing per-vdev (or per-dnode) trees,
which could reasonably go above the limits discussed. We also do not
store fill information in the compact version of the node, since it
is only used for sorted scrub.
We also optimized the metaslab loading process in various other ways
to offset some inefficiencies in the btree model. While individual
operations (find, insert, remove_from) are faster for the btree than
they are for the avl tree, remove usually requires a find operation,
while in the AVL tree model the element itself suffices. Some clever
changes actually caused an overall speedup in metaslab loading; we use
approximately 40% less cpu to load metaslabs in our tests on Illumos.
Another memory and performance optimization was achieved by changing
what is stored in the size-sorted trees. When a disk is heavily
fragmented, the df algorithm used by default in ZFS will almost always
find a number of small regions in its initial cursor-based search; it
will usually only fall back to the size-sorted tree to find larger
regions. If we increase the size of the cursor-based search slightly,
and don't store segments that are smaller than a tunable size floor
in the size-sorted tree, we can further cut memory usage down to
below 20% of what the AVL trees store. This also results in further
reductions in CPU time spent loading metaslabs.
The 16KiB size floor was chosen because it results in substantial memory
usage reduction while not usually resulting in situations where we can't
find an appropriate chunk with the cursor and are forced to use an
oversized chunk from the size-sorted tree. In addition, even if we do
have to use an oversized chunk from the size-sorted tree, the chunk
would be too small to use for ZIL allocations, so it isn't as big of a
loss as it might otherwise be. And often, more small allocations will
follow the initial one, and the cursor search will now find the
remainder of the chunk we didn't use all of and use it for subsequent
allocations. Practical testing has shown little or no change in
fragmentation as a result of this change.
If the size-sorted tree becomes empty while the offset sorted one still
has entries, it will load all the entries from the offset sorted tree
and disregard the size floor until it is unloaded again. This operation
occurs rarely with the default setting, only on incredibly thoroughly
fragmented pools.
There are some other small changes to zdb to teach it to handle btrees,
but nothing major.
Reviewed-by: George Wilson <gwilson@delphix.com>
Reviewed-by: Matt Ahrens <matt@delphix.com>
Reviewed by: Sebastien Roy seb@delphix.com
Reviewed-by: Igor Kozhukhov <igor@dilos.org>
Reviewed-by: Brian Behlendorf <behlendorf1@llnl.gov>
Signed-off-by: Paul Dagnelie <pcd@delphix.com>
Closes#9181
Make arc_stats visible to platform code.
Reviewed-by: Brian Behlendorf <behlendorf1@llnl.gov>
Reviewed-by: Igor Kozhukhov <igor@dilos.org>
Signed-off-by: Matt Macy <mmacy@FreeBSD.org>
Closes#9386
Move Linux specific tracing headers and source to platform directories
and update the build system.
Reviewed-by: Allan Jude <allanjude@freebsd.org>
Reviewed-by: Ryan Moeller <ryan@ixsystems.com>
Reviewed by: Brad Lewis <brad.lewis@delphix.com>
Reviewed-by: Brian Behlendorf <behlendorf1@llnl.gov>
Signed-off-by: Matt Macy <mmacy@FreeBSD.org>
Closes#9290
When adding the SIMD compatibility code in e5db313 the decryption of a
dataset wrapping key was left in a user thread context. This was done
intentionally since it's a relatively infrequent operation. However,
this also meant that the encryption context templates were initialized
using the generic operations. Therefore, subsequent encryption and
decryption operations would use the generic implementation even when
executed by an I/O pipeline thread.
Resolve the issue by initializing the context templates in an I/O
pipeline thread. And by updating zio_do_crypt_uio() to dispatch any
encryption operations to a pipeline thread when called from the user
context. For example, when performing a read from the ARC.
Tested-by: Attila Fülöp <attila@fueloep.org>
Reviewed-by: Tom Caputi <tcaputi@datto.com>
Signed-off-by: Brian Behlendorf <behlendorf1@llnl.gov>
Closes#9215Closes#9296
Adds ZFS_MODULE_PARAM to abstract module parameter
setting to operating systems other than Linux.
Reviewed-by: Jorgen Lundman <lundman@lundman.net>
Reviewed-by: Igor Kozhukhov <igor@dilos.org>
Reviewed-by: Brian Behlendorf <behlendorf1@llnl.gov>
Signed-off-by: Matt Macy <mmacy@FreeBSD.org>
Signed-off-by: Ryan Moeller <ryan@ixsystems.com>
Closes#9230
Reviewed-by: Matt Ahrens <matt@delphix.com>
Reviewed-by: Ryan Moeller <ryan@ixsystems.com>
Reviewed-by: Richard Laager <rlaager@wiktel.com>
Reviewed-by: Brian Behlendorf <behlendorf1@llnl.gov>
Signed-off-by: Andrea Gelmini <andrea.gelmini@gelma.net>
Closes#9240
On systems with large amounts of storage and high fragmentation, a huge
amount of space can be used by storing metaslab range trees. Since
metaslabs are only unloaded during a txg sync, and only if they have
been inactive for 8 txgs, it is possible to get into a state where all
of the system's memory is consumed by range trees and metaslabs, and
txgs cannot sync. While ZFS knows how to evict ARC data when needed,
it has no such mechanism for range tree data. This can result in boot
hangs for some system configurations.
First, we add the ability to unload metaslabs outside of syncing
context. Second, we store a multilist of all loaded metaslabs, sorted
by their selection txg, so we can quickly identify the oldest
metaslabs. We use a multilist to reduce lock contention during heavy
write workloads. Finally, we add logic that will unload a metaslab
when we're loading a new metaslab, if we're using more than a certain
fraction of the available memory on range trees.
Reviewed-by: Matt Ahrens <mahrens@delphix.com>
Reviewed-by: George Wilson <gwilson@delphix.com>
Reviewed-by: Sebastien Roy <sebastien.roy@delphix.com>
Reviewed-by: Serapheim Dimitropoulos <serapheim@delphix.com>
Reviewed-by: Brian Behlendorf <behlendorf1@llnl.gov>
Signed-off-by: Paul Dagnelie <pcd@delphix.com>
Closes#9128
There exists a race condition were hdr_recl() calls
zthr_wakeup() on a destroyed zthr. The timeline is the
following:
[1] hdr_recl() runs first and goes intro zthr_wakeup()
because arc_initialized is set.
[2] arc_fini() is called by another thread, zeroes
that flag, destroying the zthr, and goes into
buf_init().
[3] hdr_recl() tries to enter the destroyed mutex
and we blow up.
This patch ensures that the ARC's zthrs are not offloaded
any new work once arc_initialized is set and then destroys
them after all of the ARC state has been deleted.
Reviewed by: Matt Ahrens <matt@delphix.com>
Reviewed by: Brian Behlendorf <behlendorf1@llnl.gov>
Signed-off-by: Serapheim Dimitropoulos <serapheim@delphix.com>
Closes#9047
The b_freeze_cksum field can only have data when ZFS_DEBUG_MODIFY
is set. Therefore, the EQUIV check must be wrapped accordingly.
For the same reason the ASSERT in arc_buf_fill() in unsafe.
However, since it's largely redundant it has simply been removed.
Reviewed-by: George Wilson <gwilson@delphix.com>
Reviewed-by: Allan Jude <allanjude@freebsd.org>
Reviewed-by: Igor Kozhukhov <igor@dilos.org>
Signed-off-by: Brian Behlendorf <behlendorf1@llnl.gov>
Closes#8979
Redacted send/receive allows users to send subsets of their data to
a target system. One possible use case for this feature is to not
transmit sensitive information to a data warehousing, test/dev, or
analytics environment. Another is to save space by not replicating
unimportant data within a given dataset, for example in backup tools
like zrepl.
Redacted send/receive is a three-stage process. First, a clone (or
clones) is made of the snapshot to be sent to the target. In this
clone (or clones), all unnecessary or unwanted data is removed or
modified. This clone is then snapshotted to create the "redaction
snapshot" (or snapshots). Second, the new zfs redact command is used
to create a redaction bookmark. The redaction bookmark stores the
list of blocks in a snapshot that were modified by the redaction
snapshot(s). Finally, the redaction bookmark is passed as a parameter
to zfs send. When sending to the snapshot that was redacted, the
redaction bookmark is used to filter out blocks that contain sensitive
or unwanted information, and those blocks are not included in the send
stream. When sending from the redaction bookmark, the blocks it
contains are considered as candidate blocks in addition to those
blocks in the destination snapshot that were modified since the
creation_txg of the redaction bookmark. This step is necessary to
allow the target to rehydrate data in the case where some blocks are
accidentally or unnecessarily modified in the redaction snapshot.
The changes to bookmarks to enable fast space estimation involve
adding deadlists to bookmarks. There is also logic to manage the
life cycles of these deadlists.
The new size estimation process operates in cases where previously
an accurate estimate could not be provided. In those cases, a send
is performed where no data blocks are read, reducing the runtime
significantly and providing a byte-accurate size estimate.
Reviewed-by: Dan Kimmel <dan.kimmel@delphix.com>
Reviewed-by: Matt Ahrens <mahrens@delphix.com>
Reviewed-by: Prashanth Sreenivasa <pks@delphix.com>
Reviewed-by: John Kennedy <john.kennedy@delphix.com>
Reviewed-by: George Wilson <george.wilson@delphix.com>
Reviewed-by: Chris Williamson <chris.williamson@delphix.com>
Reviewed-by: Pavel Zhakarov <pavel.zakharov@delphix.com>
Reviewed-by: Sebastien Roy <sebastien.roy@delphix.com>
Reviewed-by: Prakash Surya <prakash.surya@delphix.com>
Reviewed-by: Brian Behlendorf <behlendorf1@llnl.gov>
Signed-off-by: Paul Dagnelie <pcd@delphix.com>
Closes#7958
For busy ARC situation when arc_size close to arc_c is desired. But
then it is quite likely that aggsum_compare(&arc_size, arc_c) will need
to flush per-CPU buckets to find exact comparison result. Doing that
often in a hot path penalizes whole idea of aggsum usage there, since it
replaces few simple atomic additions with dozens of lock acquisitions.
Replacing aggsum_compare() with aggsum_upper_bound() in code increasing
arc_p when ARC is growing (arc_size < arc_c) according to PMC profiles
allows to save ~5% of CPU time in aggsum code during sequential write
to 12 ZVOLs with 16KB block size on large dual-socket system.
I suppose there some minor arc_p behavior change due to lower precision
of the new code, but I don't think it is a big deal, since it should
affect only very small window in time (aggsum buckets are flushed every
second) and in ARC size (buckets are limited to 10 average ARC blocks
per CPU).
Reviewed-by: Chris Dunlop <chris@onthe.net.au>
Reviewed-by: Richard Elling <Richard.Elling@RichardElling.com>
Reviewed-by: George Melikov <mail@gmelikov.ru>
Reviewed-by: Allan Jude <allanjude@freebsd.org>
Reviewed-by: Brian Behlendorf <behlendorf1@llnl.gov>
Signed-off-by: Alexander Motin <mav@FreeBSD.org>
Closes#8901
Sometimes the target ARC size is reduced to arc_c_min, which impacts
performance. We've seen this happen as part of the random_reads
performance regression test, where the ARC size is reduced before the
reads test starts which impacts how long it takes for system to reach
good IOPS performance.
We call arc_reduce_target_size when arc_reap_cb_check() returns TRUE,
and arc_available_memory() is less than arc_c>>arc_shrink_shift.
However, arc_available_memory() could easily be low, even when arc_c is
low, because we can have tons of unused bufs in the abd kmem cache. This
would be especially true just after the DMU requests a bunch of stuff be
evicted from the ARC (e.g. due to "zpool export").
To fix this, the ARC should reduce arc_c by the requested amount, not
all the way down to arc_size (or arc_c_min), which can be very small.
Reviewed-by: Tim Chase <tim@chase2k.com>
Reviewed by: Brian Behlendorf <behlendorf1@llnl.gov>
Reviewed-by: George Melikov <mail@gmelikov.ru>
Signed-off-by: Matthew Ahrens <mahrens@delphix.com>
External-issue: DLPX-59431
Closes#8864
Scatter ABD's are allocated from a number of pages. In contrast to
linear ABD's, these pages are disjoint in the kernel's virtual address
space, so they can't be accessed as a contiguous buffer. Therefore
routines that need a linear buffer (e.g. abd_borrow_buf() and friends)
must allocate a separate linear buffer (with zio_buf_alloc()), and copy
the contents of the pages to/from the linear buffer. This can have a
measurable performance overhead on some workloads.
https://github.com/zfsonlinux/zfs/commit/87c25d567fb7969b44c7d8af63990e
("abd_alloc should use scatter for >1K allocations") increased the use
of scatter ABD's, specifically switching 1.5K through 4K (inclusive)
buffers from linear to scatter. For workloads that access blocks whose
compressed sizes are in this range, that commit introduced an additional
copy into the read code path. For example, the
sequential_reads_arc_cached tests in the test suite were reduced by
around 5% (this is doing reads of 8K-logical blocks, compressed to 3K,
which are cached in the ARC).
This commit treats single-chunk scattered buffers as linear buffers,
because they are contiguous in the kernel's virtual address space.
All single-page (4K) ABD's can be represented this way. Some multi-page
ABD's can also be represented this way, if we were able to allocate a
single "chunk" (higher-order "page" which represents a power-of-2 series
of physically-contiguous pages). This is often the case for 2-page (8K)
ABD's.
Representing a single-entry scatter ABD as a linear ABD has the
performance advantage of avoiding the copy (and allocation) in
abd_borrow_buf_copy / abd_return_buf_copy. A performance increase of
around 5% has been observed for ARC-cached reads (of small blocks which
can take advantage of this), fixing the regression introduced by
87c25d567.
Note that this optimization is only possible because all physical memory
is always mapped into the kernel's address space. This is not the case
for HIGHMEM pages, so the optimization can not be made on 32-bit
systems.
Reviewed-by: Chunwei Chen <tuxoko@gmail.com>
Reviewed-by: Brian Behlendorf <behlendorf1@llnl.gov>
Signed-off-by: Matthew Ahrens <mahrens@delphix.com>
Closes#8580
When ARC size is very small, aggsum_lower_bound(&arc_size) may return
negative values, that due to unsigned comparison caused delays, waiting
for arc_adjust() to "fix" it by calling aggsum_value(&arc_size). Use
of signed comparison there fixes the problem.
Reviewed-by: Matt Ahrens <mahrens@delphix.com>
Reviewed-by: Brian Behlendorf <behlendorf1@llnl.gov>
Reviewed-by: George Melikov <mail@gmelikov.ru>
Signed-off-by: Alexander Motin <mav@FreeBSD.org>
Closes#8873
Reviewed-by: Chris Dunlop <chris@onthe.net.au>
Reviewed-by: Matt Ahrens <mahrens@delphix.com>
Reviewed-by: Brian Behlendorf <behlendorf1@llnl.gov>
Reviewed-by: George Melikov <mail@gmelikov.ru>
Reviewed-by: Richard Laager <rlaager@wiktel.com>
Signed-off-by: Allan Jude <allanjude@freebsd.org>
Closes#8822
Linux kernel commit ca79b0c211af63fa3276f0e3fd7dd9ada2439839
"mm: convert totalram_pages and totalhigh_pages variables to atomic"
replaced `totalhigh_pages` with an inline function `totalhigh_pages()`.
This broke compilation on IA32, etc, as ZoL uses `totalhigh_pages`
on archs with highmem. Confirmed on Fedora 30 (5.0.9-301.fc30.i686).
Reviewed-by: Brian Behlendorf <behlendorf1@llnl.gov>
Signed-off-by: Tomohiro Kusumi <kusumi.tomohiro@gmail.com>
Closes#8677Closes#8701
There are several places where we use zfs_dbgmsg and %p to
print pointers. In the Linux kernel, these values obfuscated
to prevent information leaks which means the pointers aren't
very useful for debugging crash dumps. We decided to restrict
the permissions of dbgmsg (and some other kstats while we were
at it) and print pointers with %px in zfs_dbgmsg as well as
spl_dumpstack
Reviewed-by: Brian Behlendorf <behlendorf1@llnl.gov>
Reviewed-by: John Gallagher <john.gallagher@delphix.com>
Signed-off-by: sara hartse <sara.hartse@delphix.com>
Closes#8467Closes#8476
When destroying an arc_buf_hdr_t its identity cannot be discarded
until it is entirely undiscoverable. This not only includes being
unhashed, but also being removed from the l2arc header list.
Discarding the header's identify prematurely renders the hash
lock useless because it will always hash to bucket zero.
This change resolves a race with l2arc_evict() by discarding the
identity after it has been removed from the l2arc header list.
This ensures either the header is not on the list or contains
the correct identify.
Reviewed-by: Tom Caputi <tcaputi@datto.com>
Signed-off-by: Brian Behlendorf <behlendorf1@llnl.gov>
Closes#7688Closes#8144
Most of the zfs_arc_* module parameters do not have their values used by
the ARC code directly. Instead, there is a function, arc_tuning_update,
which is called during module initialization and periodically
thereafter, whose job is to fetch the module parameter values, clamp/
limit them appropriately, and then assign those values to a separate set
of internal variables that are actually referenced by the ARC code.
Commit 3ec34e55 featured an overhaul of arc_reclaim_thread, which is the
former location where the post-init-time calls to arc_tuning_update
would occur. The rework split the work previously done by the
arc_reclaim_thread into a pair of replacement threads; and
unfortunately, the call to arc_tuning_update fell through the cracks and
was lost in the reorganization.
This meant that changing almost any ARC-related zfs module parameter via
/sys/module/zfs/parameters/ would result in the module parameter value
itself appearing to change; however the modification would not actually
propagate to the ARC code and have any real effect.
This commit reinstates the post-init-time call to arc_tuning_update. It
is now called during arc_adjust_cb_check; this should be equivalent to
its former call location in arc_reclaim_thread.
Reviewed-by: Brian Behlendorf <behlendorf1@llnl.gov>
Reviewed-by: Tony Hutter <hutter2@llnl.gov>
Signed-off-by: Justin Gottula <justin@jgottula.com>
Closes#8405Closes#8463
Re-factor arc_read() to better account for embedded data blkptrs.
Previously, reading the payload from an embedded blkptr would cause
arcstats such as demand_metadata_misses to be bumped when there was
actually no cache "miss" because the data are already available in
the blkptr.
The following test procedure was used to demonstrate the problem:
zpool create tank ...
zfs create -o compression=lz4 tank/fs
echo blah > /tank/fs/blah
stat /tank/fs/blah
grep 'meta.*mis' /proc/spl/kstat/zfs/arcstats
and repeating the last two steps to watch the metadata miss counter
increment. This can also be demonstrated via the zfs_arc_miss DTRACE4
probe in arc_read().
Reviewed-by: loli10K <ezomori.nozomu@gmail.com>
Reviewed-by: George Wilson <george.wilson@delphix.com>
Reviewed-by: Matt Ahrens <mahrens@delphix.com>
Reviewed-by: Brian Behlendorf <behlendorf1@llnl.gov>
Reviewed-by: George Melikov <mail@gmelikov.ru>
Signed-off-by: Tim Chase <tim@chase2k.com>
Closes#8319
The current L2 ARC device code consistently uses psize to
increment vs_alloc but varies between psize and lsize when
decrementing it. The result of this behavior is that
vs_alloc can be decremented more that it is incremented
and underflow. This patch changes the code so asize is
used anywhere.
In addition, it ensures that vs_alloc gets incremented by
the L2 ARC device code as buffers are written and not at
the end of the l2arc_write_buffers() routine. The latter
(and old) way would temporarily underflow vs_alloc as
buffers that were just written, would be destroyed while
l2arc_write_buffers() was still looping.
Reviewed-by: Matt Ahrens <mahrens@delphix.com>
Reviewed-by: Brian Behlendorf <behlendorf1@llnl.gov>
Signed-off-by: Serapheim Dimitropoulos <serapheim@delphix.com>
Closes#8298
totalram_pages() was converted to an atomic variable in 5.0:
https://patchwork.kernel.org/patch/10652795/
Its value should now be read though the totalram_pages() helper
function.
Reviewed-by: Brian Behlendorf <behlendorf1@llnl.gov>
Signed-off-by: Tony Hutter <hutter2@llnl.gov>
Closes#8263
Adds a new lock for serializing operations on zthrs.
The commit also includes some code cleanup and
refactoring.
Reviewed by: Matt Ahrens <mahrens@delphix.com>
Reviewed by: Tom Caputi <tcaputi@datto.com>
Reviewed-by: Brian Behlendorf <behlendorf1@llnl.gov>
Signed-off-by: Serapheim Dimitropoulos <serapheim@delphix.com>
Closes#8229
Following the fix for 9018 (Replace kmem_cache_reap_now() with
kmem_cache_reap_soon), the arc_reclaim_thread() no longer blocks
while reaping. However, the code is still confusing and error-prone,
because this thread has two responsibilities. We should instead
separate this into two threads each with their own responsibility:
1. keep `arc_size` under `arc_c`, by calling `arc_adjust()`, which
improves `arc_is_overflowing()`
2. keep enough free memory in the system, by calling
`arc_kmem_reap_now()` plus `arc_shrink()`, which improves
`arc_available_memory()`.
Furthermore, we can use the zthr infrastructure to separate the
"should we do something" from "do it" parts of the logic, and
normalize the start up / shut down of the threads.
Authored by: Brad Lewis <brad.lewis@delphix.com>
Reviewed by: Matt Ahrens <mahrens@delphix.com>
Reviewed by: Serapheim Dimitropoulos <serapheim@delphix.com>
Reviewed by: Pavel Zakharov <pavel.zakharov@delphix.com>
Reviewed by: Dan Kimmel <dan.kimmel@delphix.com>
Reviewed by: Paul Dagnelie <pcd@delphix.com>
Reviewed by: Dan McDonald <danmcd@joyent.com>
Reviewed by: Tim Kordas <tim.kordas@joyent.com>
Reviewed by: Tim Chase <tim@chase2k.com>
Reviewed by: Brian Behlendorf <behlendorf1@llnl.gov>
Ported-by: Brad Lewis <brad.lewis@delphix.com>
Signed-off-by: Brad Lewis <brad.lewis@delphix.com>
OpenZFS-issue: https://www.illumos.org/issues/9284
OpenZFS-commit: https://github.com/openzfs/openzfs/commit/de753e34f9Closes#8165
Porting Notes:
- Most of these fixes were applied in the original 37fb3e43
commit when this change was ported for Linux.
Authored by: Paul Dagnelie <pcd@delphix.com>
Reviewed by: Serapheim Dimitropoulos <serapheim.dimitro@delphix.com>
Reviewed by: Matt Ahrens <matt@delphix.com>
Reviewed by: Prashanth Sreenivasa <pks@delphix.com>
Reviewed by: Jorgen Lundman <lundman@lundman.net>
Reviewed by: Igor Kozhukhov <igor@dilos.org>
Reviewed by: George Melikov <mail@gmelikov.ru>
Approved by: Robert Mustacchi <rm@joyent.com>
Ported-by: Brian Behlendorf <behlendorf1@llnl.gov>
OpenZFS-issue: https://www.illumos.org/issues/9688
OpenZFS-commit: https://github.com/openzfs/openzfs/commit/29bf2d68beCloses#8042
Update arc_release to use arc_buf_size(). This hunk was accidentally
dropped when porting compressed send/recv, 2aa34383b.
Reviewed-by: Matthew Ahrens <mahrens@delphix.com>
Signed-off-by: Tom Caputi <tcaputi@datto.com>
Signed-off-by: Brian Behlendorf <behlendorf1@llnl.gov>
Closes#8000
When debugging is enabled and a zfs_refcount_t contains multiple holders
using the same key, but different ref_counts, the wrong reference_t may
be transferred. Add a zfs_refcount_transfer_ownership_many() function,
like the existing zfs_refcount_*_many() functions, to match and transfer
the correct refcount_t;
This issue may occur when using encryption with refcount debugging
enabled. An arc_buf_hdr_t can have references for both the
hdr->b_l1hdr.b_pabd and hdr->b_crypt_hdr.b_rabd both of which use
the hdr as the reference holder. When unsharing the buffer the
p_abd should be transferred.
This issue does not impact production builds because refcount holders
are not tracked.
Reviewed-by: Matthew Ahrens <mahrens@delphix.com>
Signed-off-by: Tom Caputi <tcaputi@datto.com>
Signed-off-by: Brian Behlendorf <behlendorf1@llnl.gov>
Closes#7219Closes#8000
Recent changes in the Linux kernel made it necessary to prefix
the refcount_add() function with zfs_ due to a name collision.
To bring the other functions in line with that and to avoid future
collisions, prefix the other refcount functions as well.
Reviewed by: Matthew Ahrens <mahrens@delphix.com>
Reviewed-by: Brian Behlendorf <behlendorf1@llnl.gov>
Signed-off-by: Tim Schumacher <timschumi@gmx.de>
Closes#7963
torvalds/linux@59b57717f ("blkcg: delay blkg destruction until
after writeback has finished") added a refcount_t to the blkcg
structure. Due to the refcount_t compatibility code, zfs_refcount_t
was used by mistake.
Resolve this by removing the compatibility code and replacing the
occurrences of refcount_t with zfs_refcount_t.
Reviewed-by: Franz Pletz <fpletz@fnordicwalking.de>
Reviewed-by: Brian Behlendorf <behlendorf1@llnl.gov>
Signed-off-by: Tim Schumacher <timschumi@gmx.de>
Closes#7885Closes#7932
Re-adds a recalculation step for the ARC stats after the MRU
eviction so that we don't pathologically attempt to evict the MFU.
Reviewed-by: Richard Elling <Richard.Elling@RichardElling.com>
Reviewed-by: George Melikov <mail@gmelikov.ru>
Reviewed-by: Brian Behlendorf <behlendorf1@llnl.gov>
Authored-by: Mark Johnston <markj@freebsd.org>
Signed-off-by: Rich Ercolani <rincebrain@gmail.com>
Closes#7855
Assertion failed in arc_buf_destroy() when concurrently reading
block with checksum error.
Porting notes:
* The ability to zinject decompression errors has been added, but
this only works at the zio_decompress() level, where we have all
of the info we need to match against the user's zinject options.
* The decompress_fault test has been added to test the new zinject
functionality
* We attempted to set zio_decompress_fail_fraction to (1 << 18) in
ztest for further test coverage. Although this did uncover a few
low priority issues, this unfortuantely also causes ztest to
ASSERT in many locations where the code is working correctly since
it is designed to fail on IO errors. Developers can manually set
this variable with the '-o' option to find and debug issues.
Authored by: Matt Ahrens <mahrens@delphix.com>
Reviewed by: George Wilson <george.wilson@delphix.com>
Reviewed by: Paul Dagnelie <pcd@delphix.com>
Reviewed by: Pavel Zakharov <pavel.zakharov@delphix.com>
Reviewed by: Brian Behlendorf <behlendorf1@llnl.gov>
Approved by: Matt Ahrens <mahrens@delphix.com>
Ported-by: Tom Caputi <tcaputi@datto.com>
OpenZFS-issue: https://illumos.org/issues/9403
OpenZFS-commit: https://github.com/openzfs/openzfs/commit/fa98e487a9Closes#7822
This patch fixes 2 issues with raw, deduplicated send streams. The
first is that datasets who had been completely received earlier in
the stream were not still marked as raw receives. This caused
problems when newly received datasets attempted to fetch raw data
from these datasets without this flag set.
The second problem was that the arc freeze checksum code was not
consistent about which locks needed to be held while performing
its asserts. The proper locking needed to run these asserts is
actually fairly nuanced, since the asserts touch the linked list
of buffers (requiring the header lock), the arc_state (requiring
the b_evict_lock), and the b_freeze_cksum (requiring the
b_freeze_lock). This seems like a large performance sacrifice and
a lot of unneeded complexity to verify that this relatively small
debug feature is working as intended, so this patch simply removes
these asserts instead.
Reviewed by: Matthew Ahrens <mahrens@delphix.com>
Reviewed-by: Brian Behlendorf <behlendorf1@llnl.gov>
Signed-off-by: Tom Caputi <tcaputi@datto.com>
Closes#7701
In the case of one pool being built on another pool, we want
to make sure we don't end up throttling the lower (backing)
pool when the upper pool is the majority contributor to dirty
data. To insure we make forward progress during throttling, we
also check the current pool's net dirty data and only throttle
if it exceeds zfs_arc_pool_dirty_percent of the anonymous dirty
data in the cache.
Authored by: Don Brady <don.brady@delphix.com>
Reviewed by: Sebastien Roy <sebastien.roy@delphix.com>
Reviewed by: Matt Ahrens <matt@delphix.com>
Reviewed by: Prashanth Sreenivasa <pks@delphix.com>
Approved by: Robert Mustacchi <rm@joyent.com>
Ported-by: Brian Behlendorf <behlendorf1@llnl.gov>
Porting Notes:
* The new global variables zfs_arc_dirty_limit_percent,
zfs_arc_anon_limit_percent, and zfs_arc_pool_dirty_percent
were intentially not added as tunable module parameters.
OpenZFS-issue: https://illumos.org/issues/9465
OpenZFS-commit: https://github.com/openzfs/openzfs/commit/d6a4c3efCloses#7749
The arc_hdr_realloc_crypt() function is responsible for converting
a "full" arc header to an extended "crypt" header and visa versa.
This code was originally written with a bcopy() so that any new
members added to arc headers would automatically be included
without requiring a code change. However, in practice this (along
with small differences in kmem_cache implementations between
various platforms) has caused a number of hard-to-find problems in
ports to other operating systems. This patch solves this problem
by making all member copies explicit and adding ASSERTs for fields
that cannot be set during the transfer. It also manually resets the
old header after the reallocation is finished so it can be properly
reallocated and reused.
Reviewed-by: Jorgen Lundman <lundman@lundman.net>
Reviewed-by: Brian Behlendorf <behlendorf1@llnl.gov>
Reviewed by: Matthew Ahrens <mahrens@delphix.com>
Signed-off-by: Tom Caputi <tcaputi@datto.com>
Closes#7711
This patch fixes two problems with the encryption code. First, the
current code does not correctly prohibit the DMU from updating
dn_maxblkid during object truncation within a raw receive. This
usually only causes issues when the truncating DRR_FREE record is
aggregated with DRR_FREE records later in the receive, so it is
relatively hard to hit.
Second, this patch fixes a security issue where reading blocks
within an encrypted object did not guarantee that the dnode block
itself had ever been verified against its MAC. Usually the
verification happened anyway when the bonus buffer was read, but
some use cases (notably zvols) might never perform the check.
Reviewed-by: Brian Behlendorf <behlendorf1@llnl.gov>
Reviewed by: Matthew Ahrens <mahrens@delphix.com>
Signed-off-by: Tom Caputi <tcaputi@datto.com>
Closes#7632
This patch fixes an issue where l2arc_read_done() would always
write data to b_pabd, even if raw encrypted data was requested.
This only occured in cases where the L2ARC device had a different
ashift than the main pool.
Reviewed-by: Brian Behlendorf <behlendorf1@llnl.gov>
Reviewed by: Matthew Ahrens <mahrens@delphix.com>
Signed-off-by: Tom Caputi <tcaputi@datto.com>
Closes#7586Closes#7593
This patch fixes a small bug found where receive_spill() sometimes
attempted to decrypt spill blocks when doing a raw receive. In
addition, this patch fixes another small issue in arc_buf_fill()'s
error handling where a decryption failure (which could be caused by
the first bug) would attempt to set the arc header's IO_ERROR flag
without holding the header's lock.
Reviewed-by: Matthew Thode <prometheanfire@gentoo.org>
Reviewed-by: Brian Behlendorf <behlendorf1@llnl.gov>
Reviewed by: Matthew Ahrens <mahrens@delphix.com>
Signed-off-by: Tom Caputi <tcaputi@datto.com>
Closes#7564Closes#7584Closes#7592
In pursuit of improving performance on multi-core systems, we should
implements fanned out counters and use them to improve the performance of
some of the arc statistics. These stats are updated extremely frequently,
and can consume a significant amount of CPU time.
Authored by: Paul Dagnelie <pcd@delphix.com>
Reviewed by: Pavel Zakharov <pavel.zakharov@delphix.com>
Reviewed by: Matthew Ahrens <mahrens@delphix.com>
Approved by: Dan McDonald <danmcd@joyent.com>
Reviewed-by: Brian Behlendorf <behlendorf1@llnl.gov>
Ported-by: Paul Dagnelie <pcd@delphix.com>
OpenZFS-issue: https://www.illumos.org/issues/8484
OpenZFS-commit: https://github.com/openzfs/openzfs/commit/7028a8b92b7
Issue #3752Closes#7462
Minimal changes required to integrate the SPL sources in to the
ZFS repository build infrastructure and packaging.
Build system and packaging:
* Renamed SPL_* autoconf m4 macros to ZFS_*.
* Removed redundant SPL_* autoconf m4 macros.
* Updated the RPM spec files to remove SPL package dependency.
* The zfs package obsoletes the spl package, and the zfs-kmod
package obsoletes the spl-kmod package.
* The zfs-kmod-devel* packages were updated to add compatibility
symlinks under /usr/src/spl-x.y.z until all dependent packages
can be updated. They will be removed in a future release.
* Updated copy-builtin script for in-kernel builds.
* Updated DKMS package to include the spl.ko.
* Updated stale AUTHORS file to include all contributors.
* Updated stale COPYRIGHT and included the SPL as an exception.
* Renamed README.markdown to README.md
* Renamed OPENSOLARIS.LICENSE to LICENSE.
* Renamed DISCLAIMER to NOTICE.
Required code changes:
* Removed redundant HAVE_SPL macro.
* Removed _BOOT from nvpairs since it doesn't apply for Linux.
* Initial header cleanup (removal of empty headers, refactoring).
* Remove SPL repository clone/build from zimport.sh.
* Use of DEFINE_RATELIMIT_STATE and DEFINE_SPINLOCK removed due
to build issues when forcing C99 compilation.
* Replaced legacy ACCESS_ONCE with READ_ONCE.
* Include needed headers for `current` and `EXPORT_SYMBOL`.
Reviewed-by: Tony Hutter <hutter2@llnl.gov>
Reviewed-by: Olaf Faaland <faaland1@llnl.gov>
Reviewed-by: Matthew Ahrens <mahrens@delphix.com>
Reviewed-by: Pavel Zakharov <pavel.zakharov@delphix.com>
Signed-off-by: Brian Behlendorf <behlendorf1@llnl.gov>
TEST_ZIMPORT_SKIP="yes"
Closes#7556
This patch adds the ability for zinject to trigger decryption
and authentication faults in the ZIO and ARC layers. This
functionality is exposed via the new "decrypt" error type, which
may be provided for "data" object types.
This patch also refactors some of the core encryption / decryption
functions so that they have consistent prototypes, handle errors
consistently, and do not have unused arguments.
Reviewed-by: Brian Behlendorf <behlendorf1@llnl.gov>
Signed-off-by: Tom Caputi <tcaputi@datto.com>
Closes#7474
