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freebsd-nq/include/sys/zio_impl.h
Brian Behlendorf 1b939560be
Add TRIM support 
UNMAP/TRIM support is a frequently-requested feature to help
prevent performance from degrading on SSDs and on various other
SAN-like storage back-ends.  By issuing UNMAP/TRIM commands for
sectors which are no longer allocated the underlying device can
often more efficiently manage itself.

This TRIM implementation is modeled on the `zpool initialize`
feature which writes a pattern to all unallocated space in the
pool.  The new `zpool trim` command uses the same vdev_xlate()
code to calculate what sectors are unallocated, the same per-
vdev TRIM thread model and locking, and the same basic CLI for
a consistent user experience.  The core difference is that
instead of writing a pattern it will issue UNMAP/TRIM commands
for those extents.

The zio pipeline was updated to accommodate this by adding a new
ZIO_TYPE_TRIM type and associated spa taskq.  This new type makes
is straight forward to add the platform specific TRIM/UNMAP calls
to vdev_disk.c and vdev_file.c.  These new ZIO_TYPE_TRIM zios are
handled largely the same way as ZIO_TYPE_READs or ZIO_TYPE_WRITEs.
This makes it possible to largely avoid changing the pipieline,
one exception is that TRIM zio's may exceed the 16M block size
limit since they contain no data.

In addition to the manual `zpool trim` command, a background
automatic TRIM was added and is controlled by the 'autotrim'
property.  It relies on the exact same infrastructure as the
manual TRIM.  However, instead of relying on the extents in a
metaslab's ms_allocatable range tree, a ms_trim tree is kept
per metaslab.  When 'autotrim=on', ranges added back to the
ms_allocatable tree are also added to the ms_free tree.  The
ms_free tree is then periodically consumed by an autotrim
thread which systematically walks a top level vdev's metaslabs.

Since the automatic TRIM will skip ranges it considers too small
there is value in occasionally running a full `zpool trim`.  This
may occur when the freed blocks are small and not enough time
was allowed to aggregate them.  An automatic TRIM and a manual
`zpool trim` may be run concurrently, in which case the automatic
TRIM will yield to the manual TRIM.

Reviewed-by: Jorgen Lundman <lundman@lundman.net>
Reviewed-by: Tim Chase <tim@chase2k.com>
Reviewed-by: Matt Ahrens <mahrens@delphix.com>
Reviewed-by: George Wilson <george.wilson@delphix.com>
Reviewed-by: Serapheim Dimitropoulos <serapheim@delphix.com>
Contributions-by: Saso Kiselkov <saso.kiselkov@nexenta.com>
Contributions-by: Tim Chase <tim@chase2k.com>
Contributions-by: Chunwei Chen <tuxoko@gmail.com>
Signed-off-by: Brian Behlendorf <behlendorf1@llnl.gov>
Closes #8419 
Closes #598
2019-03-29 09:13:20 -07:00

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/*
* CDDL HEADER START
*
* The contents of this file are subject to the terms of the
* Common Development and Distribution License (the "License").
* You may not use this file except in compliance with the License.
*
* You can obtain a copy of the license at usr/src/OPENSOLARIS.LICENSE
* or http://www.opensolaris.org/os/licensing.
* See the License for the specific language governing permissions
* and limitations under the License.
*
* When distributing Covered Code, include this CDDL HEADER in each
* file and include the License file at usr/src/OPENSOLARIS.LICENSE.
* If applicable, add the following below this CDDL HEADER, with the
* fields enclosed by brackets "[]" replaced with your own identifying
* information: Portions Copyright [yyyy] [name of copyright owner]
*
* CDDL HEADER END
*/
/*
* Copyright 2009 Sun Microsystems, Inc. All rights reserved.
* Use is subject to license terms.
*/
/*
* Copyright (c) 2012, 2015 by Delphix. All rights reserved.
*/
#ifndef _ZIO_IMPL_H
#define _ZIO_IMPL_H
#ifdef __cplusplus
extern "C" {
#endif
/*
* XXX -- Describe ZFS I/O pipeline here. Fill in as needed.
*
* The ZFS I/O pipeline is comprised of various stages which are defined
* in the zio_stage enum below. The individual stages are used to construct
* these basic I/O operations: Read, Write, Free, Claim, and Ioctl.
*
* I/O operations: (XXX - provide detail for each of the operations)
*
* Read:
* Write:
* Free:
* Claim:
* Ioctl:
*
* Although the most common pipeline are used by the basic I/O operations
* above, there are some helper pipelines (one could consider them
* sub-pipelines) which are used internally by the ZIO module and are
* explained below:
*
* Interlock Pipeline:
* The interlock pipeline is the most basic pipeline and is used by all
* of the I/O operations. The interlock pipeline does not perform any I/O
* and is used to coordinate the dependencies between I/Os that are being
* issued (i.e. the parent/child relationship).
*
* Vdev child Pipeline:
* The vdev child pipeline is responsible for performing the physical I/O.
* It is in this pipeline where the I/O are queued and possibly cached.
*
* In addition to performing I/O, the pipeline is also responsible for
* data transformations. The transformations performed are based on the
* specific properties that user may have selected and modify the
* behavior of the pipeline. Examples of supported transformations are
* compression, dedup, and nop writes. Transformations will either modify
* the data or the pipeline. This list below further describes each of
* the supported transformations:
*
* Compression:
* ZFS supports three different flavors of compression -- gzip, lzjb, and
* zle. Compression occurs as part of the write pipeline and is performed
* in the ZIO_STAGE_WRITE_BP_INIT stage.
*
* Dedup:
* Dedup reads are handled by the ZIO_STAGE_DDT_READ_START and
* ZIO_STAGE_DDT_READ_DONE stages. These stages are added to an existing
* read pipeline if the dedup bit is set on the block pointer.
* Writing a dedup block is performed by the ZIO_STAGE_DDT_WRITE stage
* and added to a write pipeline if a user has enabled dedup on that
* particular dataset.
*
* NOP Write:
* The NOP write feature is performed by the ZIO_STAGE_NOP_WRITE stage
* and is added to an existing write pipeline if a crypographically
* secure checksum (i.e. SHA256) is enabled and compression is turned on.
* The NOP write stage will compare the checksums of the current data
* on-disk (level-0 blocks only) and the data that is currently being written.
* If the checksum values are identical then the pipeline is converted to
* an interlock pipeline skipping block allocation and bypassing the
* physical I/O. The nop write feature can handle writes in either
* syncing or open context (i.e. zil writes) and as a result is mutually
* exclusive with dedup.
*
* Encryption:
* Encryption and authentication is handled by the ZIO_STAGE_ENCRYPT stage.
* This stage determines how the encryption metadata is stored in the bp.
* Decryption and MAC verification is performed during zio_decrypt() as a
* transform callback. Encryption is mutually exclusive with nopwrite, because
* blocks with the same plaintext will be encrypted with different salts and
* IV's (if dedup is off), and therefore have different ciphertexts. For dedup
* blocks we deterministically generate the IV and salt by performing an HMAC
* of the plaintext, which is computationally expensive, but allows us to keep
* support for encrypted dedup. See the block comment in zio_crypt.c for
* details.
*/
/*
* zio pipeline stage definitions
*/
enum zio_stage {
ZIO_STAGE_OPEN = 1 << 0, /* RWFCI */
ZIO_STAGE_READ_BP_INIT = 1 << 1, /* R---- */
ZIO_STAGE_WRITE_BP_INIT = 1 << 2, /* -W--- */
ZIO_STAGE_FREE_BP_INIT = 1 << 3, /* --F-- */
ZIO_STAGE_ISSUE_ASYNC = 1 << 4, /* RWF-- */
ZIO_STAGE_WRITE_COMPRESS = 1 << 5, /* -W--- */
ZIO_STAGE_ENCRYPT = 1 << 6, /* -W--- */
ZIO_STAGE_CHECKSUM_GENERATE = 1 << 7, /* -W--- */
ZIO_STAGE_NOP_WRITE = 1 << 8, /* -W--- */
ZIO_STAGE_DDT_READ_START = 1 << 9, /* R---- */
ZIO_STAGE_DDT_READ_DONE = 1 << 10, /* R---- */
ZIO_STAGE_DDT_WRITE = 1 << 11, /* -W--- */
ZIO_STAGE_DDT_FREE = 1 << 12, /* --F-- */
ZIO_STAGE_GANG_ASSEMBLE = 1 << 13, /* RWFC- */
ZIO_STAGE_GANG_ISSUE = 1 << 14, /* RWFC- */
ZIO_STAGE_DVA_THROTTLE = 1 << 15, /* -W--- */
ZIO_STAGE_DVA_ALLOCATE = 1 << 16, /* -W--- */
ZIO_STAGE_DVA_FREE = 1 << 17, /* --F-- */
ZIO_STAGE_DVA_CLAIM = 1 << 18, /* ---C- */
ZIO_STAGE_READY = 1 << 19, /* RWFCI */
ZIO_STAGE_VDEV_IO_START = 1 << 20, /* RW--I */
ZIO_STAGE_VDEV_IO_DONE = 1 << 21, /* RW--I */
ZIO_STAGE_VDEV_IO_ASSESS = 1 << 22, /* RW--I */
ZIO_STAGE_CHECKSUM_VERIFY = 1 << 23, /* R---- */
ZIO_STAGE_DONE = 1 << 24 /* RWFCI */
};
#define ZIO_INTERLOCK_STAGES \
(ZIO_STAGE_READY | \
ZIO_STAGE_DONE)
#define ZIO_INTERLOCK_PIPELINE \
ZIO_INTERLOCK_STAGES
#define ZIO_VDEV_IO_STAGES \
(ZIO_STAGE_VDEV_IO_START | \
ZIO_STAGE_VDEV_IO_DONE | \
ZIO_STAGE_VDEV_IO_ASSESS)
#define ZIO_VDEV_CHILD_PIPELINE \
(ZIO_VDEV_IO_STAGES | \
ZIO_STAGE_DONE)
#define ZIO_READ_COMMON_STAGES \
(ZIO_INTERLOCK_STAGES | \
ZIO_VDEV_IO_STAGES | \
ZIO_STAGE_CHECKSUM_VERIFY)
#define ZIO_READ_PHYS_PIPELINE \
ZIO_READ_COMMON_STAGES
#define ZIO_READ_PIPELINE \
(ZIO_READ_COMMON_STAGES | \
ZIO_STAGE_READ_BP_INIT)
#define ZIO_DDT_CHILD_READ_PIPELINE \
ZIO_READ_COMMON_STAGES
#define ZIO_DDT_READ_PIPELINE \
(ZIO_INTERLOCK_STAGES | \
ZIO_STAGE_READ_BP_INIT | \
ZIO_STAGE_DDT_READ_START | \
ZIO_STAGE_DDT_READ_DONE)
#define ZIO_WRITE_COMMON_STAGES \
(ZIO_INTERLOCK_STAGES | \
ZIO_VDEV_IO_STAGES | \
ZIO_STAGE_ISSUE_ASYNC | \
ZIO_STAGE_CHECKSUM_GENERATE)
#define ZIO_WRITE_PHYS_PIPELINE \
ZIO_WRITE_COMMON_STAGES
#define ZIO_REWRITE_PIPELINE \
(ZIO_WRITE_COMMON_STAGES | \
ZIO_STAGE_WRITE_COMPRESS | \
ZIO_STAGE_ENCRYPT | \
ZIO_STAGE_WRITE_BP_INIT)
#define ZIO_WRITE_PIPELINE \
(ZIO_WRITE_COMMON_STAGES | \
ZIO_STAGE_WRITE_BP_INIT | \
ZIO_STAGE_WRITE_COMPRESS | \
ZIO_STAGE_ENCRYPT | \
ZIO_STAGE_DVA_THROTTLE | \
ZIO_STAGE_DVA_ALLOCATE)
#define ZIO_DDT_CHILD_WRITE_PIPELINE \
(ZIO_INTERLOCK_STAGES | \
ZIO_VDEV_IO_STAGES | \
ZIO_STAGE_DVA_THROTTLE | \
ZIO_STAGE_DVA_ALLOCATE)
#define ZIO_DDT_WRITE_PIPELINE \
(ZIO_INTERLOCK_STAGES | \
ZIO_STAGE_WRITE_BP_INIT | \
ZIO_STAGE_ISSUE_ASYNC | \
ZIO_STAGE_WRITE_COMPRESS | \
ZIO_STAGE_ENCRYPT | \
ZIO_STAGE_CHECKSUM_GENERATE | \
ZIO_STAGE_DDT_WRITE)
#define ZIO_GANG_STAGES \
(ZIO_STAGE_GANG_ASSEMBLE | \
ZIO_STAGE_GANG_ISSUE)
#define ZIO_FREE_PIPELINE \
(ZIO_INTERLOCK_STAGES | \
ZIO_STAGE_FREE_BP_INIT | \
ZIO_STAGE_DVA_FREE)
#define ZIO_DDT_FREE_PIPELINE \
(ZIO_INTERLOCK_STAGES | \
ZIO_STAGE_FREE_BP_INIT | \
ZIO_STAGE_ISSUE_ASYNC | \
ZIO_STAGE_DDT_FREE)
#define ZIO_CLAIM_PIPELINE \
(ZIO_INTERLOCK_STAGES | \
ZIO_STAGE_DVA_CLAIM)
#define ZIO_IOCTL_PIPELINE \
(ZIO_INTERLOCK_STAGES | \
ZIO_STAGE_VDEV_IO_START | \
ZIO_STAGE_VDEV_IO_ASSESS)
#define ZIO_TRIM_PIPELINE \
(ZIO_INTERLOCK_STAGES | \
ZIO_STAGE_ISSUE_ASYNC | \
ZIO_VDEV_IO_STAGES)
#define ZIO_BLOCKING_STAGES \
(ZIO_STAGE_DVA_ALLOCATE | \
ZIO_STAGE_DVA_CLAIM | \
ZIO_STAGE_VDEV_IO_START)
extern void zio_inject_init(void);
extern void zio_inject_fini(void);
#ifdef __cplusplus
}
#endif
#endif /* _ZIO_IMPL_H */
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