With multiple L2ARC devices, headers can be destroyed asynchronously
(e.g., during zpool sync) while L2_WRITING is set. The original code
destroyed L2HDR before L1HDR, causing ABDs to lose their device
association (b_l2hdr.b_dev) when arc_hdr_free_abd() is called.
This caused ABDs to be added to the global free-on-write list without
device information. When any L2ARC device completed its write and
attempted to free these orphaned ABDs, it would panic on
ASSERT(!list_link_active(&abd->abd_gang_link)) because the ABD was
still part of another device's vdev_queue I/O aggregation gang.
Fix by extending l2ad_mtx lock scope to cover L1HDR destruction and
reordering to destroy L1HDR before L2HDR when L2_WRITING is set. This
ensures arc_hdr_free_abd() can access b_l2hdr.b_dev to properly tag
ABDs with their device for deferred cleanup.
Reviewed-by: Alexander Motin <alexander.motin@TrueNAS.com>
Reviewed-by: Brian Behlendorf <behlendorf1@llnl.gov>
Signed-off-by: Ameer Hamza <ahamza@ixsystems.com>
Closes#18093
This commit introduces per-sublist persistent markers that eliminate
redundant tail scanning between L2ARC iterations, providing significant
CPU efficiency improvements. Markers are pre-allocated during device
initialization and properly cleaned up during device removal.
The implementation uses conditional behavior based on device capacity:
small devices (capacity < arc_c) retain original HEAD/TAIL scanning
based on ARC warmup state, while large devices (capacity >= arc_c)
use the persistent marker approach for optimal CPU efficiency.
Reviewed-by: Alexander Motin <alexander.motin@TrueNAS.com>
Reviewed-by: Brian Behlendorf <behlendorf1@llnl.gov>
Signed-off-by: Ameer Hamza <ahamza@ixsystems.com>
Closes#18093
The introduction of ARC multilists made L2ARC writing quite random,
depending on whether it found something to write in a randomly selected
sublist. This created inconsistent write patterns and poor utilization
of available sublists leading to uneven cache population.
This commit replaces random selection with systematic scanning across
all sublists within each burst. Fair headroom distribution ensures
even-depth traversal across all sublists until the target write size
is reached. Round-robin processing with random starting points eliminates
sequential bias while maintaining predictable write behavior.
The systematic approach provides consistent L2ARC filling patterns
and better utilization of available ARC data across all sublists.
Reviewed-by: Alexander Motin <alexander.motin@TrueNAS.com>
Reviewed-by: Brian Behlendorf <behlendorf1@llnl.gov>
Signed-off-by: Ameer Hamza <ahamza@ixsystems.com>
Closes#18093
Before parallel eviction implementation zfs_arc_evict_batch_limit
caused loop exits after evicting 10 headers. The cost of it is not
big and well motivated. Now though taskq task exit after the same
10 headers is much more expensive. To cover the context switch
overhead of taskq introduce another level of batching, controlled
by zfs_arc_evict_batches_limit tunable, used only for parallel
eviction.
My tests including 36 parallel reads with 4KB recordsize that shown
1.4GB/s (~460K blocks/s) before with heavy arc_evict_lock contention,
now show 6.5GB/s (~1.6M blocks/s) without arc_evict_lock contention.
Reviewed-by: Tony Hutter <hutter2@llnl.gov>
Reviewed-by: Brian Behlendorf <behlendorf1@llnl.gov>
Signed-off-by: Alexander Motin <alexander.motin@TrueNAS.com>
Closes#17970
There is no need to do MSEC_TO_TICK() for each evicted ARC header.
We can do it when tunables are set, since we already have separate
internal variables for those.
Reviewed-by: Rob Norris <robn@despairlabs.com>
Reviewed-by: Brian Behlendorf <behlendorf1@llnl.gov>
Signed-off-by: Alexander Motin <alexander.motin@TrueNAS.com>
Closes#17965
This is useful as debugging support, as it lets namespace lock
operations be traced directly. It will also be useful for future work to
reduce the use of spa_namespace_lock, traditionally a source of
difficult deadlocks.
Sponsored-by: Klara, Inc.
Sponsored-by: Wasabi Technology, Inc.
Reviewed-by: Brian Behlendorf <behlendorf1@llnl.gov>
Reviewed-by: Tony Hutter <hutter2@llnl.gov>
Signed-off-by: Rob Norris <rob.norris@klarasystems.com>
Closes#17906
Otherwise the compiler warns about it on production FreeBSD builds.
The routine proved resilient to attempts to ifdef on debug.
Sponsored by: Rubicon Communications, LLC ("Netgate")
Reviewed-by: Brian Behlendorf <behlendorf1@llnl.gov>
Reviewed-by: Alexander Motin <alexander.motin@TrueNAS.com>
Signed-off-by: Mateusz Guzik <mjguzik@gmail.com>
Closes#17818
These are old pre-OpenZFS tunable names that have long been
available via either conventional ZFS_MODULE_PARAM tunables or through
kstats. There's no point doubling up anymore, so delete them.
Sponsored-by: https://despairlabs.com/sponsor/
Reviewed-by: Brian Behlendorf <behlendorf1@llnl.gov>
Reviewed-by: Alexander Motin <alexander.motin@TrueNAS.com>
Signed-off-by: Rob Norris <robn@despairlabs.com>
Closes#17375
Reviewed-by: Brian Behlendorf <behlendorf1@llnl.gov>
Reviewed-by: Alexander Motin <alexander.motin@TrueNAS.com>
Signed-off-by: Rob Norris <robn@despairlabs.com>
Sponsored-by: https://despairlabs.com/sponsor/Closes#17591
Reviewed-by: Brian Behlendorf <behlendorf1@llnl.gov>
Reviewed-by: Alexander Motin <alexander.motin@TrueNAS.com>
Signed-off-by: Rob Norris <robn@despairlabs.com>
Sponsored-by: https://despairlabs.com/sponsor/Closes#17591
Reviewed-by: Brian Behlendorf <behlendorf1@llnl.gov>
Reviewed-by: Alexander Motin <alexander.motin@TrueNAS.com>
Signed-off-by: Rob Norris <robn@despairlabs.com>
Sponsored-by: https://despairlabs.com/sponsor/Closes#17591
Reviewed-by: Brian Behlendorf <behlendorf1@llnl.gov>
Reviewed-by: Alexander Motin <alexander.motin@TrueNAS.com>
Signed-off-by: Rob Norris <robn@despairlabs.com>
Sponsored-by: https://despairlabs.com/sponsor/Closes#17591
During regular block writes ZFS sets both logical and physical
birth times equal to the current TXG. During dedup and block
cloning logical birth time is still set to the current TXG, but
physical may be copied from the original block that was used.
This represents the fact that logically user data has changed,
but the physically it is the same old block.
But block rewrite introduces a new situation, when block is not
changed logically, but stored in a different place of the pool.
From ARC, scrub and some other perspectives this is a new block,
but for example for user applications or incremental replication
it is not. Somewhat similar thing happen during remap phase of
device removal, but in that case space blocks are still acounted
as allocated at their logical birth times.
This patch introduces a new "rewrite" flag in the block pointer
structure, allowing to differentiate physical rewrite (when the
block is actually reallocated at the physical birth time) from
the device reval case (when the logical birth time is used).
The new functionality is not used at this point, and the only
expected change is that error log is now kept in terms of physical
physical birth times, rather than logical, since if a block with
logged error was somehow rewritten, then the previous error does
not matter any more.
This change also introduces a new TRAVERSE_LOGICAL flag to the
traverse code, allowing zfs send, redact and diff to work in
context of logical birth times, ignoring physical-only rewrites.
It also changes nothing at this point due to lack of those writes,
but they will come in a following patch.
Reviewed-by: Rob Norris <robn@despairlabs.com>
Reviewed-by: Brian Behlendorf <behlendorf1@llnl.gov>
Signed-off-by: Alexander Motin <alexander.motin@TrueNAS.com>
Closes#17565
Linux kernel shrinker in the context of null/root memcg does not scan
dentry and inode caches added by a task running in non-root memcg. For
ZFS this means that dnode cache routinely overflows, evicting valuable
meta/data and putting additional memory pressure on the system.
This patch restores zfs_prune_aliases as fallback when the kernel
shrinker does nothing, enabling zfs to actually free dnodes. Moreover,
it (indirectly) calls arc_evict when dnode_size > dnode_limit.
Reviewed-by: Rob Norris <robn@despairlabs.com>
Reviewed-by: Alexander Motin <mav@FreeBSD.org>
Reviewed-by: Brian Behlendorf <behlendorf1@llnl.gov>
Signed-off-by: Gionatan Danti <g.danti@assyoma.it>
Closes#17487Closes#17542
If a variable is only available in the kernel, then the tunable should
also only be available there.
This matters very little so long as we don't have userspace tunables,
but its still good hygeine.
Sponsored-by: https://despairlabs.com/sponsor/
Reviewed-by: Brian Behlendorf <behlendorf1@llnl.gov>
Reviewed-by: Alexander Motin <mav@FreeBSD.org>
Reviewed-by: Pavel Snajdr <snajpa@snajpa.net>
Signed-off-by: Rob Norris <robn@despairlabs.com>
Closes#17377
On systems with enormous amounts of memory, the single arc_evict thread
can become a bottleneck if reads and writes are stuck behind it, waiting
for old data to be evicted before new data can take its place.
This commit adds support for evicting from multiple ARC lists in
parallel, by farming the evict work out to some number of threads and
then accumulating their results.
A new tuneable, zfs_arc_evict_threads, sets the number of threads. By
default, it will scale based on the number of CPUs.
Sponsored-by: Expensify, Inc.
Sponsored-by: Klara, Inc.
Reviewed-by: Alexander Motin <mav@FreeBSD.org>
Reviewed-by: Youzhong Yang <youzhong@gmail.com>
Signed-off-by: Allan Jude <allan@klarasystems.com>
Signed-off-by: Mateusz Piotrowski <mateusz.piotrowski@klarasystems.com>
Signed-off-by: Alexander Stetsenko <alex.stetsenko@klarasystems.com>
Signed-off-by: Rob Norris <rob.norris@klarasystems.com>
Co-authored-by: Rob Norris <rob.norris@klarasystems.com>
Co-authored-by: Mateusz Piotrowski <mateusz.piotrowski@klarasystems.com>
Co-authored-by: Alexander Stetsenko <alex.stetsenko@klarasystems.com>
Closes#16486
ARC target size might drop significantly under memory pressure,
especially if current ARC size was much smaller than the target.
Since dbuf cache size is a fraction of the target ARC size, it
might need eviction too. Aside of memory from the dbuf eviction
itself, it might help ARC by making more buffers evictable.
Reviewed-by: Tony Hutter <hutter2@llnl.gov>
Reviewed-by: Ameer Hamza <ahamza@ixsystems.com>
Signed-off-by: Alexander Motin <mav@FreeBSD.org>
Sponsored by: iXsystems, Inc.
Closes#17314
Before Direct I/O was implemented, I've implemented lighter version
I called Uncached I/O. It uses normal DMU/ARC data path with some
optimizations, but evicts data from caches as soon as possible and
reasonable. Originally I wired it only to a primarycache property,
but now completing the integration all the way up to the VFS.
While Direct I/O has the lowest possible memory bandwidth usage,
it also has a significant number of limitations. It require I/Os
to be page aligned, does not allow speculative prefetch, etc. The
Uncached I/O does not have those limitations, but instead require
additional memory copy, though still one less than regular cached
I/O. As such it should fill the gap in between. Considering this
I've disabled annoying EINVAL errors on misaligned requests, adding
a tunable for those who wants to test their applications.
To pass the information between the layers I had to change a number
of APIs. But as side effect upper layers can now control not only
the caching, but also speculative prefetch. I haven't wired it to
VFS yet, since it require looking on some OS specifics. But while
there I've implemented speculative prefetch of indirect blocks for
Direct I/O, controllable via all the same mechanisms.
Signed-off-by: Alexander Motin <mav@FreeBSD.org>
Sponsored by: iXsystems, Inc.
Fixes#17027
Reviewed-by: Rob Norris <robn@despairlabs.com>
Reviewed-by: Brian Behlendorf <behlendorf1@llnl.gov>
With certain combinations of target ARC states balance and ghost
hit rates it was possible to get the fractions outside of allowed
range. This patch limits maximum balance adjustment speed, which
should make it impossible, and also asserts it.
Fixes#17210
Signed-off-by: Alexander Motin <mav@FreeBSD.org>
Sponsored by: iXsystems, Inc.
Reviewed-by: Rob Norris <robn@despairlabs.com>
Reviewed-by: Tony Hutter <hutter2@llnl.gov>
The redundant_metadata setting in ZFS allows users to trade resilience
for performance and space savings. This applies to all data and metadata
blocks in zfs, with one exception: gang blocks. Gang blocks currently
just take the copies property of the IO being ganged and, if it's 1,
sets it to 2. This means that we always make at least two copies of a
gang header, which is good for resilience. However, if the users care
more about performance than resilience, their gang blocks will be even
more of a penalty than usual.
We add logic to calculate the number of gang headers copies directly,
and store it as a separate IO property. This is stored in the IO
properties and not calculated when we decide to gang because by that
point we may not have easy access to the relevant information about what
kind of block is being stored. We also check the redundant_metadata
property when doing so, and use that to decide whether to store an extra
copy of the gang headers, compared to the underlying blocks.
Sponsored-by: Klara, Inc.
Sponsored-by: Wasabi Technology, Inc.
Signed-off-by: Paul Dagnelie <paul.dagnelie@klarasystems.com>
Co-authored-by: Paul Dagnelie <paul.dagnelie@klarasystems.com>
Reviewed-by: Alexander Motin <mav@FreeBSD.org>
Reviewed-by: Tony Hutter <hutter2@llnl.gov>
- Don't drop L2ARC header if we have more buffers in this header.
Since we leave them the header, leave them the L2ARC header also.
Honestly we are not required to drop it even if there are no other
buffers, but then we'd need to allocate it a separate header, which
we might drop soon if the old block is really deleted. Multiple
buffers in a header likely mean active snapshots or dedup, so we
know that the block in L2ARC will remain valid. It might be rare,
but why not?
- Remove some impossible assertions and conditions.
Reviewed-by: Tony Hutter <hutter2@llnl.gov>
Signed-off-by: Alexander Motin <mav@FreeBSD.org>
Sponsored by: iXsystems, Inc.
Closes#17126
Sponsored-by: https://despairlabs.com/sponsor/
Signed-off-by: Rob Norris <robn@despairlabs.com>
Reviewed-by: Tony Hutter <hutter2@llnl.gov>
Reviewed-by: Brian Behlendorf <behlendorf1@llnl.gov>
In l2arc_evict(), the config lock may be acquired in reverse order
(e.g., first the config lock (writer), then a hash lock) unlike in
arc_read() during scenarios like L2ARC device removal. To avoid
deadlocks, if the attempt to acquire the config lock (reader) fails
in arc_read(), release the hash lock, wait for the config lock, and
retry from the beginning.
Reviewed-by: Alexander Motin <mav@FreeBSD.org>
Signed-off-by: Ameer Hamza <ahamza@ixsystems.com>
Closes#17071
Need to use arc_free_data_abd to free abd type buffer.
Reviewed-by: Alexander Motin <mav@FreeBSD.org>
Signed-off-by: Chunwei Chen <tuxoko@gmail.com>
Closes#17079
This change will prevent prefetch to perform unnecessary ARC buffer
fill when reading from disk.
Reviewed-by: Alexander Motin <mav@FreeBSD.org>
Signed-off-by: Jaydeep Kshirsagar <jkshirsagar@maxlinear.com>
Co-authored-by: Alexander Motin <mav@FreeBSD.org>
Closes#17013
This also includes removing L2 vdevs asynchronously.
This commit also guarantees that spa_load_guid is unique.
The zpool reguid feature introduced the spa_load_guid, which is a
transient value used for runtime identification purposes in the ARC.
This value is not the same as the spa's persistent pool guid.
However, the value is seeded from spa_generate_load_guid() which
does not check for uniqueness against the spa_load_guid from other
pools. Although extremely rare, you can end up with two different
pools sharing the same spa_load_guid value! So we guarantee that
the value is always unique and additionally not still in use by an
async arc flush task.
Sponsored-by: Klara, Inc.
Sponsored-by: Wasabi Technology, Inc.
Reviewed-by: Brian Behlendorf <behlendorf1@llnl.gov>
Reviewed-by: Alexander Motin <mav@FreeBSD.org>
Reviewed-by: Allan Jude <allan@klarasystems.com>
Signed-off-by: Don Brady <don.brady@klarasystems.com>
Closes#16215
Without doing that there is a race window on export when history
log write by completed rebuild dirties transaction beyond final,
triggering assertion.
Reviewed-by: Brian Behlendorf <behlendorf1@llnl.gov>
Reviewed-by: George Amanakis <gamanakis@gmail.com>
Signed-off-by: Alexander Motin <mav@FreeBSD.org>
Sponsored by: iXsystems, Inc.
Closes#16714Closes#16782
Those values require global atomics to get current hash_elements
values in few of the hottest code paths, while in all the years I
never cared about it. If somebody wants, it should be easy to
get it by periodic sampling, since neither ARC header nor DBUF
counts change so fast that it would be difficult to catch.
For now I've left hash_elements_max kstat for ARC, since it was
used/reported by arc_summary and it would break older versions,
but now it just reports the current value.
Reviewed-by: Brian Behlendorf <behlendorf1@llnl.gov>
Signed-off-by: Alexander Motin <mav@FreeBSD.org>
Sponsored by: iXsystems, Inc.
Closes#16759
..., before we make the header or the log block visible to others.
It should fix assertion on allocated space going negative if the
header is freed once the lock is dropped, while the write is still
going.
Reviewed-by: Brian Behlendorf <behlendorf1@llnl.gov>
Reviewed-by: Rob Norris <robn@despairlabs.com>
Signed-off-by: Alexander Motin <mav@FreeBSD.org>
Sponsored by: iXsystems, Inc.
Closes#16040Closes#16743
Since arc_evict() run can take some time, arc_c change during it
may result in undesired shift in ARC states balance. Primarily in
case of arc_c reduction it may cause eviction from MFU data state
despite its being below the target already. Instead we should
evict as originally planned and if needed do another round after.
Reviewed-by: Theera K. <tkittich@hotmail.com>
Reviewed-by: George Melikov <mail@gmelikov.ru>
Reviewed-by: Brian Behlendorf <behlendorf1@llnl.gov>
Signed-off-by: Alexander Motin <mav@FreeBSD.org>
Sponsored by: iXsystems, Inc.
Closes#16576Closes#16605
Without updating 'm' we evict from MFU metadata all that we wanted
to evict from all metadata, including already evicted MRU metadata
('m' is the total amount of metadata we had at the beginning,
and 'w' is the total amount of metadata we want to have).
Reviewed-by: Brian Behlendorf <behlendorf1@llnl.gov>
Reviewed-by: Alexander Motin <mav@FreeBSD.org>
Signed-off-by: Theera K. <tkittich@hotmail.com>
Closes#16521Closes#16546
On compression we could be more explicit here for cases
where we can not recompress the data.
Reviewed-by: Brian Behlendorf <behlendorf1@llnl.gov>
Reviewed-by: Tony Hutter <hutter2@llnl.gov>
Co-authored-by: Alexander Motin <mav@FreeBSD.org>
Signed-off-by: George Melikov <mail@gmelikov.ru>
Closes#9416
ZLE compressor needs additional bytes to process
d_len argument efficiently.
Don't use BPE_PAYLOAD_SIZE as d_len with it
before we rework zle compressor somehow.
Reviewed-by: Brian Behlendorf <behlendorf1@llnl.gov>
Reviewed-by: Tony Hutter <hutter2@llnl.gov>
Reviewed-by: Alexander Motin <mav@FreeBSD.org>
Signed-off-by: George Melikov <mail@gmelikov.ru>
Closes#9416
Now default compression is lz4, which can stop
compression process by itself on incompressible data.
If there are additional size checks -
we will only make our compressratio worse.
New usable compression thresholds are:
- less than BPE_PAYLOAD_SIZE (embedded_data feature);
- at least one saved sector.
Old 12.5% threshold is left to minimize affect
on existing user expectations of CPU utilization.
If data wasn't compressed - it will be saved as
ZIO_COMPRESS_OFF, so if we really need to recompress
data without ashift info and check anything -
we can just compress it with zero threshold.
So, we don't need a new feature flag here!
Reviewed-by: Brian Behlendorf <behlendorf1@llnl.gov>
Reviewed-by: Tony Hutter <hutter2@llnl.gov>
Reviewed-by: Alexander Motin <mav@FreeBSD.org>
Signed-off-by: George Melikov <mail@gmelikov.ru>
Closes#9416
Adding O_DIRECT support to ZFS to bypass the ARC for writes/reads.
O_DIRECT support in ZFS will always ensure there is coherency between
buffered and O_DIRECT IO requests. This ensures that all IO requests,
whether buffered or direct, will see the same file contents at all
times. Just as in other FS's , O_DIRECT does not imply O_SYNC. While
data is written directly to VDEV disks, metadata will not be synced
until the associated TXG is synced.
For both O_DIRECT read and write request the offset and request sizes,
at a minimum, must be PAGE_SIZE aligned. In the event they are not,
then EINVAL is returned unless the direct property is set to always (see
below).
For O_DIRECT writes:
The request also must be block aligned (recordsize) or the write
request will take the normal (buffered) write path. In the event that
request is block aligned and a cached copy of the buffer in the ARC,
then it will be discarded from the ARC forcing all further reads to
retrieve the data from disk.
For O_DIRECT reads:
The only alignment restrictions are PAGE_SIZE alignment. In the event
that the requested data is in buffered (in the ARC) it will just be
copied from the ARC into the user buffer.
For both O_DIRECT writes and reads the O_DIRECT flag will be ignored in
the event that file contents are mmap'ed. In this case, all requests
that are at least PAGE_SIZE aligned will just fall back to the buffered
paths. If the request however is not PAGE_SIZE aligned, EINVAL will
be returned as always regardless if the file's contents are mmap'ed.
Since O_DIRECT writes go through the normal ZIO pipeline, the
following operations are supported just as with normal buffered writes:
Checksum
Compression
Encryption
Erasure Coding
There is one caveat for the data integrity of O_DIRECT writes that is
distinct for each of the OS's supported by ZFS.
FreeBSD - FreeBSD is able to place user pages under write protection so
any data in the user buffers and written directly down to the
VDEV disks is guaranteed to not change. There is no concern
with data integrity and O_DIRECT writes.
Linux - Linux is not able to place anonymous user pages under write
protection. Because of this, if the user decides to manipulate
the page contents while the write operation is occurring, data
integrity can not be guaranteed. However, there is a module
parameter `zfs_vdev_direct_write_verify` that controls the
if a O_DIRECT writes that can occur to a top-level VDEV before
a checksum verify is run before the contents of the I/O buffer
are committed to disk. In the event of a checksum verification
failure the write will return EIO. The number of O_DIRECT write
checksum verification errors can be observed by doing
`zpool status -d`, which will list all verification errors that
have occurred on a top-level VDEV. Along with `zpool status`, a
ZED event will be issues as `dio_verify` when a checksum
verification error occurs.
ZVOLs and dedup is not currently supported with Direct I/O.
A new dataset property `direct` has been added with the following 3
allowable values:
disabled - Accepts O_DIRECT flag, but silently ignores it and treats
the request as a buffered IO request.
standard - Follows the alignment restrictions outlined above for
write/read IO requests when the O_DIRECT flag is used.
always - Treats every write/read IO request as though it passed
O_DIRECT and will do O_DIRECT if the alignment restrictions
are met otherwise will redirect through the ARC. This
property will not allow a request to fail.
There is also a module parameter zfs_dio_enabled that can be used to
force all reads and writes through the ARC. By setting this module
parameter to 0, it mimics as if the direct dataset property is set to
disabled.
Reviewed-by: Brian Behlendorf <behlendorf@llnl.gov>
Reviewed-by: Alexander Motin <mav@FreeBSD.org>
Reviewed-by: Tony Hutter <hutter2@llnl.gov>
Signed-off-by: Brian Atkinson <batkinson@lanl.gov>
Co-authored-by: Mark Maybee <mark.maybee@delphix.com>
Co-authored-by: Matt Macy <mmacy@FreeBSD.org>
Co-authored-by: Brian Behlendorf <behlendorf@llnl.gov>
Closes#10018
This commit changes the frontend zio_compress_data and
zio_decompress_data APIs to take ABD points instead of buffer pointers.
All callers are updated to match. Any that already have an appropriate
ABD nearby now use it directly, while at the rest we create an one.
Internally, the ABDs are passed through to the provider directly.
Sponsored-by: Klara, Inc.
Sponsored-by: Wasabi Technology, Inc.
Signed-off-by: Rob Norris <rob.norris@klarasystems.com>
`l2arc_mfuonly` was added to avoid wasting L2 ARC on read-once MRU
data and metadata. However it can be useful to cache as much
metadata as possible while, at the same time, restricting data
cache to MFU buffers only.
This patch allow for such behavior by setting `l2arc_mfuonly` to 2
(or higher). The list of possible values is the following:
0: cache both MRU and MFU for both data and metadata;
1: cache only MFU for both data and metadata;
2: cache both MRU and MFU for metadata, but only MFU for data.
Reviewed-by: Alexander Motin <mav@FreeBSD.org>
Reviewed-by: Brian Behlendorf <behlendorf1@llnl.gov>
Signed-off-by: Gionatan Danti <g.danti@assyoma.it>
Closes#16343Closes#16402
Previous code pruned 10% of dnodes once 3/4 of metadata appeared
unevictable. On workloads with many millions of dnodes and little
other metadata it creates significant load spikes for many seconds
straight. This change instead gradually increases pruning as
unevictable metadata grow above the 3/4, which may allow it to
stabilize at some level.
Reviewed-by: Brian Behlendorf <behlendorf1@llnl.gov>
Signed-off-by: Alexander Motin <mav@FreeBSD.org>
Sponsored by: iXsystems, Inc.
Closes#16401
- Skip config lock enter/exit for embedded blocks. They have no
DVAs, so there is nothing to check under the lock.
- Skip CHECKSUM check and properly check PSIZE for embedded blocks.
- Add static branch predictions for unlikely conditions.
- Do not verify DVAs for blocks already in ARC. ARC hit already
"verified" the first (often the only) DVA, and it does not worth to
enter/exit config lock for nothing.
Some profiles show me up to 3% of CPU saving from this change.
Reviewed-by: Brian Behlendorf <behlendorf1@llnl.gov>
Reviewed-by: Allan Jude <allan@klarasystems.com>
Signed-off-by: Alexander Motin <mav@FreeBSD.org>
Sponsored by: iXsystems, Inc.
Closes#16387
Linux provides SLAB_RECLAIM_ACCOUNT and __GFP_RECLAIMABLE flags to
mark memory allocations that can be freed via shinker calls. It
should allow kernel to tune and group such allocations for lower
memory fragmentation and better reclamation under pressure.
This patch marks as reclaimable most of ARC memory, directly
evictable via ZFS shrinker, plus also dnode/znode/sa memory,
indirectly evictable via kernel's superblock shrinker.
Signed-off-by: Alexander Motin <mav@FreeBSD.org>
Sponsored by: iXsystems, Inc.
Reviewed-by: Tony Hutter <hutter2@llnl.gov>
Reviewed-by: Allan Jude <allan@klarasystems.com>
This change adds a new `zpool prefetch -t ddt $pool` command which
causes a pool's DDT to be loaded into the ARC. The primary goal is to
remove the need to "warm" a pool's cache before deduplication stops
slowing write performance. It may also provide a way to reload portions
of a DDT if they have been flushed due to inactivity.
Sponsored-by: iXsystems, Inc.
Sponsored-by: Catalogics, Inc.
Sponsored-by: Klara, Inc.
Reviewed-by: Alexander Motin <mav@FreeBSD.org>
Reviewed-by: Tony Hutter <hutter2@llnl.gov>
Reviewed-by: Brian Behlendorf <behlendorf1@llnl.gov>
Signed-off-by: Allan Jude <allan@klarasystems.com>
Signed-off-by: Will Andrews <will.andrews@klarasystems.com>
Signed-off-by: Fred Weigel <fred.weigel@klarasystems.com>
Signed-off-by: Rob Norris <rob.norris@klarasystems.com>
Signed-off-by: Don Brady <don.brady@klarasystems.com>
Co-authored-by: Will Andrews <will.andrews@klarasystems.com>
Co-authored-by: Don Brady <don.brady@klarasystems.com>
Closes#15890
- When receiving memory pressure signal from OS be more strict
trying to free some memory. Otherwise kernel may come again and
request much more. Return as result how much arc_c was actually
reduced due to this request, that may be less than requested.
- On Linux when receiving direct reclaim from some file system
(that may be ZFS) instead of ignoring request completely, just
shrink the ARC, but do not wait for eviction. Waiting there may
cause deadlock. Ignoring it as before may put extra pressure on
other caches and/or swap, and cause OOM if nothing help. While
not waiting may result in more ARC evicted later, and may be too
late if OOM killer activate right now, but I hope it to be better
than doing nothing at all.
- On Linux set arc_no_grow before waiting for reclaim, not after,
or it may grow back while we are waiting.
- On Linux add new parameter zfs_arc_shrinker_seeks to balance
ARC eviction cost, relative to page cache and other subsystems.
- Slightly update Linux arc_set_sys_free() math for new kernels.
Signed-off-by: Alexander Motin <mav@FreeBSD.org>
Sponsored by: iXsystems, Inc.
Reviewed-by: Rob Norris <rob.norris@klarasystems.com>
Reviewed-by: Tony Hutter <hutter2@llnl.gov>
At the end of l2arc_evict() fix an assertion in the case that l2ad_hand
+ distance == l2ad_end.
Reviewed-by: Brian Behlendorf <behlendorf1@llnl.gov>
Signed-off-by: George Amanakis <gamanakis@gmail.com>
Closes#16202Closes#16207
Changed spa_export_common() such that it no longer holds the
spa_namespace_lock for the entire duration and instead sets
spa_export_thread to indicate an import is in progress on the
spa. This allows for an export to a diffent pool to proceed
in parallel while an export is still processing potentially
long operations like spa_unload_log_sm_flush_all().
Calls like spa_lookup() and spa_vdev_enter() that rely on
the spa_namespace_lock to serialize them against a concurrent
export, now wait for any in-progress export thread to complete
before proceeding.
The 'zpool import -a' sub-command also provides multi-threaded
support, using a thread pool to submit the exports in parallel.
Sponsored-By: Klara Inc.
Sponsored-by: Wasabi Technology, Inc.
Reviewed-by: Brian Behlendorf <behlendorf1@llnl.gov>
Reviewed-by: George Wilson <gwilson@delphix.com>
Signed-off-by: Don Brady <don.brady@klarasystems.com>
Closes#16153
When compressed ARC is disabled, we may have to re-compress when
writing into L2ARC. If doing so we can't fit it into the original
physical size, we should just fail immediately, since even if it
may still fit into allocation size, its checksum will never match.
While there, refactor the code similar to other compression places
without using abd_return_buf_copy().
Reviewed-by: Brian Behlendorf <behlendorf1@llnl.gov>
Signed-off-by: Alexander Motin <mav@FreeBSD.org>
Sponsored by: iXsystems, Inc.
Closes#16038
Being able to print custom debug information on assert trip
seems useful.
Reviewed-by: Brian Behlendorf <behlendorf1@llnl.gov>
Reviewed-by: Paul Dagnelie <pcd@delphix.com>
Signed-off-by: Rich Ercolani <rincebrain@gmail.com>
Closes#15792
Previous code held ARC state sublist lock throughout all L2ARC
write process, which included number of allocations and even ZIO
issues. Being blocked in any of those places the code could also
block ARC eviction, that could cause OOM activation or even dead-
lock if system is low on memory or one is too fragmented.
Fix it by dropping the lock as soon as we see a block eligible
for L2ARC writing and pick it up later using earlier inserted
marker. While there, also reduce scope of hash lock, moving
ZIO allocation and other operations not requiring header access
out of it. All operations requiring header access move under
hash lock, since L2_WRITING flag does not prevent header eviction
only transition to arc_l2c_only state with L1 header.
To be able to manipulate sublist lock and marker as needed add few
more multilist functions and modify one.
Reviewed-by: Brian Behlendorf <behlendorf1@llnl.gov>
Signed-off-by: Alexander Motin <mav@FreeBSD.org>
Sponsored by: iXsystems, Inc.
Closes#16040
There exist a couple of macros that are used to update the blkptr birth
times but they can often be confusing. For example, the
BP_PHYSICAL_BIRTH() macro will provide either the physical birth time
if it is set or else return back the logical birth time. The
complement to this macro is BP_SET_BIRTH() which will set the logical
birth time and set the physical birth time if they are not the same.
Consumers may get confused when they are trying to get the physical
birth time and use the BP_PHYSICAL_BIRTH() macro only to find out that
the logical birth time is what is actually returned.
This change cleans up these macros and makes them symmetrical. The same
functionally is preserved but the name is changed. Instead of calling
BP_PHYSICAL_BIRTH(), consumer can now call BP_GET_BIRTH(). In
additional to cleaning up this naming conventions, two new sets of
macros are introduced -- BP_[SET|GET]_LOGICAL_BIRTH() and
BP_[SET|GET]_PHYSICAL_BIRTH. These new macros allow the consumer to
get and set the specific birth time.
As part of the cleanup, the unused GRID macros have been removed and
that portion of the blkptr are currently unused.
Reviewed-by: Matthew Ahrens <mahrens@delphix.com>
Reviewed-by: Alexander Motin <mav@FreeBSD.org>
Reviewed-by: Mark Maybee <mark.maybee@delphix.com>
Signed-off-by: George Wilson <gwilson@delphix.com>
Closes#15962
Coverity noticed that sometimes we ignore the return, and sometimes we
don't. Its not wrong, and I like consistent style, so here we are.
Reported-by: Coverity (CID-1564584)
Reported-by: Coverity (CID-1564585)
Reported-by: Coverity (CID-1564586)
Reported-by: Coverity (CID-1564587)
Reported-by: Coverity (CID-1564588)
Reviewed-by: Alexander Motin <mav@FreeBSD.org>
Reviewed-by: Brian Behlendorf <behlendorf1@llnl.gov>
Signed-off-by: Rob Norris <robn@despairlabs.com>
Closes#15647
