Metadata-intensive workloads can cause the ARC to become permanently
filled with dnode_t objects as they're pinned by the VFS layer.
Subsequent data-intensive workloads may only benefit from about
25% of the potential ARC (arc_c_max - arc_meta_limit).
In order to help track metadata usage more precisely, the other_size
metadata arcstat has replaced with dbuf_size, dnode_size and bonus_size.
The new zfs_arc_dnode_limit tunable, which defaults to 10% of
zfs_arc_meta_limit, defines the minimum number of bytes which is desirable
to be consumed by dnodes. Attempts to evict non-metadata will trigger
async prune tasks if the space used by dnodes exceeds this limit.
The new zfs_arc_dnode_reduce_percent tunable specifies the amount by
which the excess dnode space is attempted to be pruned as a percentage of
the amount by which zfs_arc_dnode_limit is being exceeded. By default,
it tries to unpin 10% of the dnodes.
The problem of dnode metadata pinning was observed with the following
testing procedure (in this example, zfs_arc_max is set to 4GiB):
- Create a large number of small files until arc_meta_used exceeds
arc_meta_limit (3GiB with default tuning) and arc_prune
starts increasing.
- Create a 3GiB file with dd. Observe arc_mata_used. It will still
be around 3GiB.
- Repeatedly read the 3GiB file and observe arc_meta_limit as before.
It will continue to stay around 3GiB.
With this modification, space for the 3GiB file is gradually made
available as subsequent demands on the ARC are made. The previous behavior
can be restored by setting zfs_arc_dnode_limit to the same value as the
zfs_arc_meta_limit.
Signed-off-by: Tim Chase <tim@chase2k.com>
Signed-off-by: Brian Behlendorf <behlendorf1@llnl.gov>
Issue #4345
Issue #4512
Issue #4773Closes#4858
In arc_buf_info(), the arc_buf_t may have no header. If not, don't try
to fetch the arc buffer stats and instead just zero them.
The null dereferences were observed while accessing the dbuf kstat with
awk on a system in which millions of small files were being created in
order to overflow the system's metadata limit.
Signed-off-by: Tim Chase <tim@chase2k.com>
Signed-off-by: Brian Behlendorf <behlendorf1@llnl.gov>
Signed-off-by: Chunwei Chen <david.chen@osnexus.com>
Closes#4837
Reviewed by: Matthew Ahrens <mahrens@delphix.com>
Reviewed by: George Wilson <george.wilson@delphix.com>
Reviewed by: Boris Protopopov <bprotopopov@hotmail.com>
Approved by: Richard Lowe <richlowe@richlowe.net>a
Ported by: Boris Protopopov <bprotopopov@actifio.com>
Signed-off-by: Boris Protopopov <bprotopopov@actifio.com>
Signed-off-by: Brian Behlendorf <behlendorf1@llnl.gov>
OpenZFS-issue: https://www.illumos.org/issues/6513
OpenZFS-commit: https://github.com/openzfs/openzfs/commit/8df0bcf0
If a ZFS object contains a hole at level one, and then a data block is
created at level 0 underneath that l1 block, l0 holes will be created.
However, these l0 holes do not have the birth time property set; as a
result, incremental sends will not send those holes.
Fix is to modify the dbuf_read code to fill in birth time data.
arc_prune_task uses a refcount to protect arc_prune_t, but it doesn't prevent
the underlying zsb from disappearing if there's a concurrent umount. We fix
this by force the caller of arc_remove_prune_callback to wait for
arc_prune_taskq to finish.
Signed-off-by: Chunwei Chen <david.chen@osnexus.com>
Signed-off-by: Brian Behlendorf <behlendorf1@llnl.gov>
Closes#4687Closes#4690
The was originally using interruptible cv_timedwait_sig, but was changed
to uninterruptible cv_timedwait_hires in ae6d0c6. Use _sig_hires instead
to allow interruptible sleep.
Signed-off-by: Chunwei Chen <david.chen@osnexus.com>
Signed-off-by: Brian Behlendorf <behlendorf1@llnl.gov>
Closes#4633Closes#4634
Set a limit for the largest compressed block which can be written
to an L2ARC device. By default this limit is set to 16M so there
is no change in behavior.
Signed-off-by: Brian Behlendorf <behlendorf1@llnl.gov>
Signed-off-by: Richard Elling <Richard.Elling@RichardElling.com>
Signed-off-by: Tim Chase <tim@chase2k.com>
Closes#4323
Since it's set to arc_c_max / 2, it must be set after arc_c_max is set.
Also added protection against it falling below 2 * maxblocksize in
userland builds.
Signed-off-by: Tim Chase <tim@chase2k.com>
Signed-off-by: Brian Behlendorf <behlendorf1@llnl.gov>
Closes#4268
Adjusting arc_c directly is racy because it can happen in the context
of multiple threads. It should always be >= 2 * maxblocksize. Set it
to a known valid value rather than adjusting it directly.
In addition refactor arc_shrink() to a simpler structure, protect against
underflow in the calculation of the new arc_c value.
Signed-off-by: Tim Chase <tim@chase2k.com>
Signed-off-by: Brian Behlendorf <behlendorf1@llnl.gov>
Reverts: 935434efCloses: #3904Closes: #4161
Commit 5f6d0b6 was originally added to gracefully handle block
pointers with a damaged logical size. However, it incorrectly
assumed that all passed arc_done_func_t could handle a NULL
arc_buf_t.
Signed-off-by: Brian Behlendorf <behlendorf1@llnl.gov>
Closes#4069Closes#4080
On 32 bit, the calculation of zfs_dirty_data_max from phymem will overflow,
causing it to be smaller than zfs_dirty_data_sync, and will cause txg being
delayed while no one write to disk. The end result is horrendous write speed.
On 4G ram 32-bit VM, before this patch, simple dd results in ~7MB/s. Now it
can reach speed on par with 64-bit VM.
Signed-off-by: Chunwei Chen <tuxoko@gmail.com>
Signed-off-by: Brian Behlendorf <behlendorf1@llnl.gov>
Closes#3973
On 32 bit system, zio_buf_cache is limit to 1M. Larger than that is all NULL.
So we need to avoid reaping them.
Signed-off-by: Chunwei Chen <tuxoko@gmail.com>
Signed-off-by: Brian Behlendorf <behlendorf1@llnl.gov>
Issue #3973
When decreasing the maximum ARC size preserve the 3/4 default
ratio for the arc_meta_limit. Otherwise, the arc_meta_limit
may be set the same as arc_max.
Signed-off-by: AndCycle <andcycle@andcycle.idv.tw>
Signed-off-by: Brian Behlendorf <behlendorf1@llnl.gov>
Closes#4001
Strictly enforce keeping 'arc_c >= arc_c_min'. The ASSERTs are
left in place to catch this in a debug build but logic has been
added to gracefully handle in a production build.
Signed-off-by: Brian Behlendorf <behlendorf1@llnl.gov>
Issue #3904
As described in the comment above arc_reclaim_thread() it's critical
that the reclaim thread be careful about blocking. Just like it must
never wait on a hash lock, it must never wait on a task which can in
turn wait on the CV in arc_get_data_buf(). This will deadlock, see
issue #3822 for full backtraces showing the problem.
To resolve this issue arc_kmem_reap_now() has been updated to use the
asynchronous arc prune function. This means that arc_prune_async()
may now be called while there are still outstanding arc_prune_tasks.
However, this isn't a problem because arc_prune_async() already
keeps a reference count preventing multiple outstanding tasks per
registered consumer. Functionally, this behavior is the same as
the counterpart illumos function dnlc_reduce_cache().
Signed-off-by: Brian Behlendorf <behlendorf1@llnl.gov>
Signed-off-by: Tim Chase <tim@chase2k.com>
Issue #3808
Issue #3834
Issue #3822
6214 zpools going south
Reviewed by: Igor Kozhukhov <ikozhukhov@gmail.com>
Reviewed by: George Wilson <george.wilson@delphix.com>
Reviewed by: Dan McDonald <danmcd@omniti.com>
Reviewed by: Saso Kiselkov <skiselkov.ml@gmail.com>
References:
https://www.illumos.org/issues/6214http://cr.illumos.org/~webrev/sensille/6214_zpools_going_south/
Porting Notes:
Reintroduce b_compress to the l2arc_buf_hdr_t. In commit b9541d6
the compression flags were moved to the generic b_flags in the
arc_buf_hdr_t. This is a problem because l2arc_compress_buf()
may manipulate the compression flags and this can only be done
safely under the hash lock which is not held. See Illumos 6214
for a detailed analysis of the race.
HDR_GET_COMPRESS() macro was removed from arc_buf_info().
Ported-by: Brian Behlendorf <behlendorf1@llnl.gov>
Closes#3757
This brings the behavior of arc_memory_throttle() back in sync with
illumos. The updated memory throttling policy roughly goes like this:
* Never throttle if more than 10% of memory is free. This threshold
is configurable with the zfs_arc_lotsfree_percent module option.
* Minimize any throttling of kswapd even when free memory is below
the set threshold. Allow it to write out pages as quickly as
possible to help alleviate the memory pressure.
* Delay all other threads when free memory is below the set threshold
in order to avoid compounding the memory pressure. Buffers will be
evicted from the ARC to reduce the issue.
The Linux specific zfs_arc_memory_throttle_disable module option has
been removed in favor of the existing zfs_arc_lotsfree_percent tuning.
Setting zfs_arc_lotsfree_percent=0 will have the same effect as
zfs_arc_memory_throttle_disable and it was therefore redundant.
Signed-off-by: Brian Behlendorf <behlendorf1@llnl.gov>
Closes#3637
While Linux doesn't provide detailed information about the state of
the VM it does provide us total free pages. This information should
be incorporated in to the arc_available_memory() calculation rather
than solely relying on a signal from direct reclaim. Conceptually
this brings arc_available_memory() back in sync with illumos.
It is also desirable that the target amount of free memory be tunable
on a system. While the default values are expected to work well
for most workloads there may be cases where custom values are needed.
The zfs_arc_sys_free module option was added for this purpose.
zfs_arc_sys_free - The target number of bytes the ARC should leave
as free memory on the system. This value can
checked in /proc/spl/kstat/zfs/arcstats and
setting this module option will override the
default value.
Signed-off-by: Brian Behlendorf <behlendorf1@llnl.gov>
Closes#3637
Under Linux filesystem threads responsible for handling I/O are
normally created with the maximum priority. Non-I/O filesystem
processes run with the default priority. ZFS should adopt the
same priority scheme under Linux to maintain good performance
and so that it will complete fairly when other Linux filesystems
are active. The priorities have been updated to the following:
$ ps -eLo rtprio,cls,pid,pri,nice,cmd | egrep 'z_|spl_|zvol|arc|dbu|meta'
- TS 10743 19 -20 [spl_kmem_cache]
- TS 10744 19 -20 [spl_system_task]
- TS 10745 19 -20 [spl_dynamic_tas]
- TS 10764 19 0 [dbu_evict]
- TS 10765 19 0 [arc_prune]
- TS 10766 19 0 [arc_reclaim]
- TS 10767 19 0 [arc_user_evicts]
- TS 10768 19 0 [l2arc_feed]
- TS 10769 39 0 [z_unmount]
- TS 10770 39 -20 [zvol]
- TS 11011 39 -20 [z_null_iss]
- TS 11012 39 -20 [z_null_int]
- TS 11013 39 -20 [z_rd_iss]
- TS 11014 39 -20 [z_rd_int_0]
- TS 11022 38 -19 [z_wr_iss]
- TS 11023 39 -20 [z_wr_iss_h]
- TS 11024 39 -20 [z_wr_int_0]
- TS 11032 39 -20 [z_wr_int_h]
- TS 11033 39 -20 [z_fr_iss_0]
- TS 11041 39 -20 [z_fr_int]
- TS 11042 39 -20 [z_cl_iss]
- TS 11043 39 -20 [z_cl_int]
- TS 11044 39 -20 [z_ioctl_iss]
- TS 11045 39 -20 [z_ioctl_int]
- TS 11046 39 -20 [metaslab_group_]
- TS 11050 19 0 [z_iput]
- TS 11121 38 -19 [z_wr_iss]
Note that under Linux the meaning of a processes priority is inverted
with respect to illumos. High values on Linux indicate a _low_ priority
while high value on illumos indicate a _high_ priority.
In order to preserve the logical meaning of the minclsyspri and
maxclsyspri macros when they are used by the illumos wrapper functions
their values have been inverted. This way when changes are merged
from upstream illumos we won't need to remember to invert the macro.
It could also lead to confusion.
This patch depends on https://github.com/zfsonlinux/spl/pull/466.
Signed-off-by: Brian Behlendorf <behlendorf1@llnl.gov>
Signed-off-by: Ned Bass <bass6@llnl.gov>
Closes#3607
Address minor differences in style between upstream and ZoL. This
patch contains no functional differences and is solely designed to
minimize the delta from upstream.
Signed-off-by: Brian Behlendorf <behlendorf1@llnl.gov>
Issue #3533
Commit d962d5d didn't quite properly resolve the HDR_L2ONLY_SIZE
accounting. Accounting is now performed only in the constructor
and destructor which is a nice simplification. It should have
been removed the from create and destroy functions. This brings
up back in sync with upstream.
Signed-off-by: Brian Behlendorf <behlendorf1@llnl.gov>
Issue #3533
Originally removed because it wasn't required under Linux. However,
there may still be some utility in signaling the arc reclaim thread
under Linux via reclaim. This should already have happened by other
means but it's not harmless and reduces another point of divergence
with upstream.
Signed-off-by: Brian Behlendorf <behlendorf1@llnl.gov>
Issue #3533
Commit f521ce1 removed the minimum value for "arc_p" allowing it to
drop to zero or grow to "arc_c". This was done to improve specific
workload which constantly dirties new "metadata" but also frequently
touches a "small" amount of mfu data (e.g. mkdir's).
This change may still be desirable but it needs to be re-investigated.
in the context of the recent ARC changes from upstream. Therefore
this code is being restored to facilitate benchmarking. By setting
"zfs_arc_p_min_shift=64" we easily compare the performance.
Signed-off-by: Brian Behlendorf <behlendorf1@llnl.gov>
Issue #3533
5817 change type of arcs_size from uint64_t to refcount_t
Reviewed by: Matthew Ahrens <mahrens@delphix.com>
Reviewed by: Paul Dagnelie <paul.dagnelie@delphix.com>
Reviewed by: Adam Leventhal <ahl@delphix.com>
Reviewed by: Alex Reece <alex@delphix.com>
Reviewed by: Richard Elling <richard.elling@richardelling.com>
Approved by: Garrett D'Amore <garrett@damore.org>
References:
https://www.illumos.org/issues/5817https://github.com/illumos/illumos-gate/commit/2fd872a
Ported-by: Brian Behlendorf <behlendorf1@llnl.gov>
Issue #3533
5445 Add more visibility via arcstats; specifically arc_state_t
stats and differentiate between "data" and "metadata"
Reviewed by: Basil Crow <basil.crow@delphix.com>
Reviewed by: George Wilson <george.wilson@delphix.com>
Reviewed by: Matthew Ahrens <mahrens@delphix.com>
Reviewed by: Bayard Bell <bayard.bell@nexenta.com>
Approved by: Robert Mustacchi <rm@joyent.com>
References:
https://www.illumos.org/issues/5445https://github.com/illumos/illumos-gate/commit/4076b1b
Porting Notes:
This patch is an improved version of cc7f677 which was previously
merged in ZoL. This patch incorporates the additional improvements
which were made upstream.
Ported-by: Brian Behlendorf <behlendorf1@llnl.gov>
Issue #3533
5376 arc_kmem_reap_now() should not result in clearing arc_no_grow
Reviewed by: Christopher Siden <christopher.siden@delphix.com>
Reviewed by: George Wilson <george.wilson@delphix.com>
Reviewed by: Steven Hartland <killing@multiplay.co.uk>
Reviewed by: Richard Elling <richard.elling@richardelling.com>
Approved by: Dan McDonald <danmcd@omniti.com>
References:
https://www.illumos.org/issues/5376https://github.com/illumos/illumos-gate/commit/2ec99e3
Porting Notes:
The good news is that many of the recent changes made upstream to the
ARC tackled issues previously observed by ZoL with similar solutions.
The bad news is those solution weren't identical to the ones we applied.
This patch is designed to split the difference and apply as much of the
upstream work as possible.
* The arc_available_memory() function was removed previous in ZoL but
due to the upstream changes it makes sense to add it back. This function
has been customized for Linux so that it can be used to determine a low
memory. This provides the same basic functionality as the illumos version
allowing us to minimize changes through the rest of the code base. The
exact mechanism used to detect a low memory state remains unchanged so
this change isn't a significant as it might first appear.
* This patch includes the long standing fix for arc_shrink() which was
originally proposed in #2167. Since there were related changes to this
function it made sense to include that work.
* The arc_init() function has been re-factored. As before it sets sane
default values for the ARC but then calls arc_tuning_update() to apply
user specific tuning made via module options. The arc_tuning_update()
function is then called periodically by the arc_reclaim_thread() to
apply changes to the tunings made during normal operation.
Ported-by: Brian Behlendorf <behlendorf1@llnl.gov>
Closes#3616Closes#2167
5368 ARC should cache more metadata
Reviewed by: Alex Reece <alex.reece@delphix.com>
Reviewed by: Christopher Siden <christopher.siden@delphix.com>
Reviewed by: George Wilson <george.wilson@delphix.com>
Reviewed by: Richard Elling <richard.elling@richardelling.com>
Approved by: Dan McDonald <danmcd@omniti.com>
References:
https://www.illumos.org/issues/5368https://github.com/illumos/illumos-gate/commit/3a5286a
Porting Notes:
The vast majority of this patch was already merged in the context
of the 06358ea changes. This is just a small hunk which was missed.
Ported-by: Brian Behlendorf <behlendorf1@llnl.gov>
5163 arc should reap range_seg_cache
Reviewed by: Christopher Siden <christopher.siden@delphix.com>
Reviewed by: Matthew Ahrens <mahrens@delphix.com>
Reviewed by: Richard Elling <richard.elling@gmail.com>
Reviewed by: Saso Kiselkov <skiselkov.ml@gmail.com>
Approved by: Dan McDonald <danmcd@omniti.com>
References:
https://www.illumos.org/issues/5163https://github.com/illumos/illumos-gate/commit/83803b5
Porting Notes:
Added umem_cache_reap_now() wrapped to suppress unused variable
warning for user space build in arc_kmem_reap_now().
Ported-by: Brian Behlendorf <behlendorf1@llnl.gov>
Over the years the default values for the taskqs used on Linux have
differed slightly from illumos. In the vast majority of cases this
was done to avoid creating an obnoxious number of idle threads which
would pollute the process listing.
With the addition of support for dynamic taskqs all multi-threaded
queues should be created as dynamic taskqs. This allows us to get
the best of both worlds.
* The illumos default values for the I/O pipeline can be restored.
These values are known to work well for most workloads. The only
exception is the zio write interrupt taskq which is changed to
ZTI_P(12, 8). At least under Linux more threads has been shown
to improve performance, see commit 7e55f4e.
* Reduces the number of idle threads on the system when it's not
under heavy load. The maximum number of threads will only be
created when they are required.
* Remove the vdev_file_taskq and rely on the system_taskq instead
which is now dynamic and may have up to 64-threads. Again this
brings us back inline with upstream.
* Tasks dispatched with taskq_dispatch_ent() are allowed to use
dynamic taskqs. The Linux taskq implementation supports this.
Signed-off-by: Brian Behlendorf <behlendorf1@llnl.gov>
Signed-off-by: Tim Chase <tim@chase2k.com>
Closes#3507
If we don't account for that, then we might end up overwriting disk
area of buffers that have not been evicted yet, because l2arc_evict
operates in terms of disk addresses.
The discrepancy between the write size calculation and the actual
increment to l2ad_hand was introduced in commit 3a17a7a9.
The change that introduced l2ad_hand alignment was almost correct
as the write size was accumulated as a sum of rounded buffer sizes.
See commit illumos/illumos-gate@e14bb32.
Also, we now consistently use asize / a_sz for the allocated size and
psize / p_sz for the physical size. The latter accounts for a
possible size reduction because of the compression, whereas the
former accounts for a possible subsequent size expansion because of
the alignment requirements.
The code still assumes that either underlying storage subsystems or
hardware is able to do read-modify-write when an L2ARC buffer size is
not a multiple of a disk's block size. This is true for 4KB sector disks
that provide 512B sector emulation, but may not be true in general.
In other words, we currently do not have any code to make sure that
an L2ARC buffer, whether compressed or not, which is used for physical
I/O has a suitable size.
Note that currently the cache device utilization is calculated based
on the physical size, not the allocated size. The same applies to
l2_asize kstat. That is wrong, but this commit does not fix that.
The accounting problem was introduced partially in commit 3a17a7a9
and partially in 3038a2b (accounting became consistent but in favour
of the wrong size).
Porting Notes:
Reworked to be C90 compatible and the 'write_psize' variable was
removed because it is now unused.
References:
https://reviews.csiden.org/r/229/https://reviews.freebsd.org/D2764
Ported-by: kernelOfTruth <kerneloftruth@gmail.com>
Signed-off-by: Brian Behlendorf <behlendorf1@llnl.gov>
Closes#3400Closes#3433Closes#3451
This is the counterpart to zfsonlinux/spl@2345368 which replaces the
cv_wait_interruptible() function with cv_wait_sig(). There is no
functional change to patch merely brings the function names in to
sync to maximize portability.
Signed-off-by: Brian Behlendorf <behlendorf1@llnl.gov>
Issue #3450
Issue #3402
ZoL had lowered the minimum ARC size to 4MiB to better accommodate tiny
systems such as the raspberry pi, however, as of addition of large block
support, the arc_adapt() function depends on arc_c being >= 32MiB (2 *
SPA_MAXBLOCKSIZE).
This patch raises the minimum ARC size to 32MiB and adds a VERIFY test
to arc_adapt() for future-proofing.
Signed-off-by: Tim Chase <tim@chase2k.com>
Signed-off-by: Brian Behlendorf <behlendorf1@llnl.gov>
As described in the comment above arc_adapt_thread() it is critical
that the arc_adapt_thread() function never sleep while holding a hash
lock. This behavior was possible in the Linux implementation because
the arc_prune() logic was implemented to be synchronous. Under
illumos the analogous dnlc_reduce_cache() function is asynchronous.
To address this the arc_do_user_prune() function is has been reworked
in to two new functions as follows:
* arc_prune_async() is an asynchronous implementation which dispatches
the prune callback to be run by the system taskq. This makes it
suitable to use in the context of the arc_adapt_thread().
* arc_prune() is a synchronous implementation which depends on the
arc_prune_async() implementation but blocks until the outstanding
callbacks complete. This is used in arc_kmem_reap_now() where it
is safe, and expected, that memory will be freed.
This patch additionally adds the zfs_arc_meta_strategy module option
while allows the meta reclaim strategy to be configured. It defaults
to a balanced strategy which has been proved to work well under Linux
but the illumos meta-only strategy can be enabled.
Signed-off-by: Tim Chase <tim@chase2k.com>
Signed-off-by: Brian Behlendorf <behlendorf1@llnl.gov>
Reviewed by: George Wilson <george.wilson@delphix.com>
Reviewed by: Matthew Ahrens <mahrens@delphix.com>
Reviewed by: Richard Elling <richard.elling@richardelling.com>
Approved by: Dan McDonald <danmcd@omniti.com>
Porting notes and other significant code changes:
The illumos 5368 patch (ARC should cache more metadata), which
was never picked up by ZoL, is mostly reverted by this patch.
Since ZoL relies on the kernel asynchronously calling the shrinker to
actually reap memory, the shrinker wakes up arc_reclaim_waiters_cv every
time it runs.
The arc_adapt_thread() function no longer calls arc_do_user_evicts()
since the newly-added arc_user_evicts_thread() calls it periodically.
Notable conflicting ZoL commits which conflicted with this patch or
whose effects are either duplicated or un-done by this patch:
302f753 - Integrate ARC more tightly with Linux
39e055c - Adjust arc_p based on "bytes" in arc_shrink
f521ce1 - Allow "arc_p" to drop to zero or grow to "arc_c"
77765b5 - Remove "arc_meta_used" from arc_adjust calculation
94520ca - Prune metadata from ghost lists in arc_adjust_meta
Trace support for multilist_insert() and multilist_remove() has been
added and produces the following output:
fio-12498 [077] .... 112936.448324: zfs_multilist__insert: ml { offset 240 numsublists 80 sublistidx 63 }
fio-12498 [077] .... 112936.448347: zfs_multilist__remove: ml { offset 240 numsublists 80 sublistidx 29 }
The following arcstats have been removed:
recycle_miss - Used by arcstat.py and arc_summary.py, both of which
have been updated appropriately.
l2_writes_hdr_miss
The following arcstats have been added:
evict_not_enough - Number of times arc_evict_state() was unable to
evict enough buffers to reach its target amount.
evict_l2_skip - Number of times arc_evict_hdr() skipped eviction
because it was being written to the l2arc.
l2_writes_lock_retry - Replaces l2_writes_hdr_miss. Number of times
l2arc_write_done() failed to acquire hash_lock (and re-tries).
arc_meta_min - Shows the value of the zfs_arc_meta_min module
parameter (see below).
The "index" column of the "dbuf" kstat has been removed since it doesn't
have a direct analog in the new multilist scheme. Additional multilist-
related stats could be added in the future but would likely require
extensions to the mulilist API.
The following module parameters have been added:
zfs_arc_evict_batch_limit - Number of ARC headers to free per sub-list
before moving on to the next sub-list.
zfs_arc_meta_min - Enforce a floor on the amount of metadata in
the ARC.
zfs_arc_num_sublists_per_state - Number of multilist sub-lists per
ARC state.
zfs_arc_overflow_shift - Controls amount by which the ARC must exceed
the target size to be considered "overflowing".
Ported-by: Tim Chase <tim@chase2k.com>
Signed-off-by: Brian Behlendorf <behlendorf1@llnl.gov
5408 managing ZFS cache devices requires lots of RAM
Reviewed by: Christopher Siden <christopher.siden@delphix.com>
Reviewed by: George Wilson <george.wilson@delphix.com>
Reviewed by: Matthew Ahrens <mahrens@delphix.com>
Reviewed by: Don Brady <dev.fs.zfs@gmail.com>
Reviewed by: Josef 'Jeff' Sipek <josef.sipek@nexenta.com>
Approved by: Garrett D'Amore <garrett@damore.org>
Porting notes:
Due to the restructuring of the ARC-related structures, this
patch conflicts with at least the following existing ZoL commits:
6e1d7276c9
Fix inaccurate arcstat_l2_hdr_size calculations
The ARC_SPACE_HDRS constant no longer exists and has been
somewhat equivalently replaced by HDR_L2ONLY_SIZE.
e0b0ca983d
Add visibility in to cached dbufs
The new layering of l{1,2}arc_buf_hdr_t within the arc_buf_hdr
struct requires additional structure member names to be used
when referencing the inner items. Also, the presence of L1 or L2
inner member is indicated by flags using the new HDR_HAS_L{1,2}HDR
macros.
Ported by: Tim Chase <tim@chase2k.com>
Signed-off-by: Brian Behlendorf <behlendorf1@llnl.gov>
5369 arc flags should be an enum
5370 consistent arc_buf_hdr_t naming scheme
Reviewed by: Matthew Ahrens <mahrens@delphix.com>
Reviewed by: Alex Reece <alex.reece@delphix.com>
Reviewed by: Sebastien Roy <sebastien.roy@delphix.com>
Reviewed by: Richard Elling <richard.elling@richardelling.com>
Approved by: Richard Lowe <richlowe@richlowe.net>
Porting notes:
ZoL has moved some ARC definitions into arc_impl.h.
Signed-off-by: Brian Behlendorf <behlendorf1@llnl.gov>
Ported by: Tim Chase <tim@chase2k.com>
This reverts only the l2arc_hdr part of commit
ecf3d9b8e6 in preparation for the illumos
5497 "lock contention on arcs_mtx" patch which does the same thing
but uses the newer two-level ARC structure following the Illumos 5408
"managing ZFS cache devices requires lots of RAM" patch.
Signed-off-by: Tim Chase <tim@chase2k.com>
Signed-off-by: Brian Behlendorf <behlendorf1@llnl.gov>
Illumos 5497 "lock contention on arcs_mtx" reworks eviction and obviates
the need for this.
Signed-off-by: Tim Chase <tim@chase2k.com>
Signed-off-by: Brian Behlendorf <behlendorf1@llnl.gov>
This reverts commit 037763e44e in
preparation for the illumos 5497 "lock contention on arcs_mtx" patch
which includes a fix for this very problem.
ZoL had picked up a subset of the illumos 5497 patch to deal with the
l2arc compression buffer leak.
Signed-off-by: Tim Chase <tim@chase2k.com>
Signed-off-by: Brian Behlendorf <behlendorf1@llnl.gov>
This reverts commit 16fcdea363 in preparation
for the illumos 5497 "lock contention on arcs_mtx" patch which eliminates
"marker" within the ARC code.
Signed-off-by: Tim Chase <tim@chase2k.com>
Signed-off-by: Brian Behlendorf <behlendorf1@llnl.gov>
5027 zfs large block support
Reviewed by: Alek Pinchuk <pinchuk.alek@gmail.com>
Reviewed by: George Wilson <george.wilson@delphix.com>
Reviewed by: Josef 'Jeff' Sipek <josef.sipek@nexenta.com>
Reviewed by: Richard Elling <richard.elling@richardelling.com>
Reviewed by: Saso Kiselkov <skiselkov.ml@gmail.com>
Reviewed by: Brian Behlendorf <behlendorf1@llnl.gov>
Approved by: Dan McDonald <danmcd@omniti.com>
References:
https://www.illumos.org/issues/5027https://github.com/illumos/illumos-gate/commit/b515258
Porting Notes:
* Included in this patch is a tiny ISP2() cleanup in zio_init() from
Illumos 5255.
* Unlike the upstream Illumos commit this patch does not impose an
arbitrary 128K block size limit on volumes. Volumes, like filesystems,
are limited by the zfs_max_recordsize=1M module option.
* By default the maximum record size is limited to 1M by the module
option zfs_max_recordsize. This value may be safely increased up to
16M which is the largest block size supported by the on-disk format.
At the moment, 1M blocks clearly offer a significant performance
improvement but the benefits of going beyond this for the majority
of workloads are less clear.
* The illumos version of this patch increased DMU_MAX_ACCESS to 32M.
This was determined not to be large enough when using 16M blocks
because the zfs_make_xattrdir() function will fail (EFBIG) when
assigning a TX. This was immediately observed under Linux because
all newly created files must have a security xattr created and
that was failing. Therefore, we've set DMU_MAX_ACCESS to 64M.
* On 32-bit platforms a hard limit of 1M is set for blocks due
to the limited virtual address space. We should be able to relax
this one the ABD patches are merged.
Ported-by: Brian Behlendorf <behlendorf1@llnl.gov>
Closes#354
With debugging enabled and depending on your kernel config, the size of
arc_buf_hdr_t can blow out the stack of arc_evict() and arc_evict_ghost()
to greater than 1024 bytes. Let's avoid this.
Signed-off-by: Chris Dunlop <chris@onthe.net.au>
Signed-off-by: Brian Behlendorf <behlendorf1@llnl.gov>
Closes#3377
Prevent deadlocks by disabling direct reclaim during all ZPL and ioctl
calls as well as the l2arc and adapt ARC threads.
This obviates the need for MUTEX_FSTRANS so its previous uses and
definition have been eliminated.
Signed-off-by: Tim Chase <tim@chase2k.com>
Signed-off-by: Brian Behlendorf <behlendorf1@llnl.gov>
Closes#3225
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. The number of total restarts in limited by
zfs_arc_meta_adjust_restarts to prevent spinning in the rare case
where all meta data is pinned.
Signed-off-by: Brian Behlendorf <behlendorf1@llnl.gov>
Signed-off-by: Pavel Snajdr <snajpa@snajpa.net>
Issue #3160
Originally when the ARC prune callback was introduced the idea was
to register a single callback for the ZPL. The ARC could invoke this
call back if it needed the ZPL to drop dentries, inodes, or other
cache objects which might be pinning buffers in the ARC. The ZPL
would iterate over all ZFS super blocks and perform the reclaim.
For the most part this design has worked well but due to limitations
in 2.6.35 and earlier kernels there were some problems. This patch
is designed to address those issues.
1) iterate_supers_type() is not provided by all kernels which makes
it impossible to safely iterate over all zpl_fs_type filesystems in
a single callback. The most straight forward and portable way to
resolve this is to register a callback per-filesystem during mount.
The arc_*_prune_callback() functions have always supported multiple
callbacks so this is functionally a very small change.
2) Commit 050d22b removed the non-portable shrink_dcache_memory()
and shrink_icache_memory() functions and didn't replace them with
equivalent functionality. This meant that for Linux 3.1 and older
kernels the ARC had no mechanism to drop dentries and inodes from
the caches if needed. This patch adds that missing functionality
by calling shrink_dcache_parent() to release dentries which may be
pinning inodes. This will result in all unused cache entries being
dropped which is a bit heavy handed but it's the only interface
available for old kernels.
3) A zpl_drop_inode() callback is registered for kernels older than
2.6.35 which do not support the .evict_inode callback. This ensures
that when the last reference on an inode is dropped it is immediately
removed from the cache. If this isn't done than inode can end up on
the global unused LRU with no mechanism available to ZFS to drop them.
Since the ARC buffers are not dropped the hottest inodes can still
be recreated without performing disk IO.
Signed-off-by: Brian Behlendorf <behlendorf1@llnl.gov>
Signed-off-by: Pavel Snajdr <snajpa@snajpa.net>
Issue #3160
The arc_meta_max value should be increased when space it consumed not when
it is returned. This ensure's that arc_meta_max is always up to date.
Signed-off-by: Brian Behlendorf <behlendorf1@llnl.gov>
Signed-off-by: Pavel Snajdr <snajpa@snajpa.net>
Issue #3160
