The ARC shrinker callback `arc_shrinker_count/_scan()` is invoked by the
kernel's shrinker mechanism when the system is running low on free
pages. This happens via 2 code paths:
1. "direct reclaim": The system is attempting to allocate a page, but we
are low on memory. The ARC shrinker callback is invoked from the
page-allocation code path.
2. "indirect reclaim": kswapd notices that there aren't many free pages,
so it invokes the ARC shrinker callback.
In both cases, the kernel's shrinker code requests that the ARC shrinker
callback release some of its cache, and then it measures how many pages
were released. However, it's measurement of released pages does not
include pages that are freed via `__free_pages()`, which is how the ARC
releases memory (via `abd_free_chunks()`). Rather, the kernel shrinker
code is looking for pages to be placed on the lists of reclaimable pages
(which is separate from actually-free pages).
Because the kernel shrinker code doesn't detect that the ARC has
released pages, it may call the ARC shrinker callback many times,
resulting in the ARC "collapsing" down to `arc_c_min`. This has several
negative impacts:
1. ZFS doesn't use RAM to cache data effectively.
2. In the direct reclaim case, a single page allocation may wait a long
time (e.g. more than a minute) while we evict the entire ARC.
3. Even with the improvements made in 67c0f0dedc ("ARC shrinking blocks
reads/writes"), occasionally `arc_size` may stay above `arc_c` for the
entire time of the ARC collapse, thus blocking ZFS read/write operations
in `arc_get_data_impl()`.
To address these issues, this commit limits the ways that the ARC
shrinker callback can be used by the kernel shrinker code, and mitigates
the impact of arc_is_overflowing() on ZFS read/write operations.
With this commit:
1. We limit the amount of data that can be reclaimed from the ARC via
the "direct reclaim" shrinker. This limits the amount of time it takes
to allocate a single page.
2. We do not allow the ARC to shrink via kswapd (indirect reclaim).
Instead we rely on `arc_evict_zthr` to monitor free memory and reduce
the ARC target size to keep sufficient free memory in the system. Note
that we can't simply rely on limiting the amount that we reclaim at once
(as for the direct reclaim case), because kswapd's "boosted" logic can
invoke the callback an unlimited number of times (see
`balance_pgdat()`).
3. When `arc_is_overflowing()` and we want to allocate memory,
`arc_get_data_impl()` will wait only for a multiple of the requested
amount of data to be evicted, rather than waiting for the ARC to no
longer be overflowing. This allows ZFS reads/writes to make progress
even while the ARC is overflowing, while also ensuring that the eviction
thread makes progress towards reducing the total amount of memory used
by the ARC.
4. The amount of memory that the ARC always tries to keep free for the
rest of the system, `arc_sys_free` is increased.
5. Now that the shrinker callback is able to provide feedback to the
kernel's shrinker code about our progress, we can safely enable
the kswapd hook. This will allow the arc to receive notifications
when memory pressure is first detected by the kernel. We also
re-enable the appropriate kstats to track these callbacks.
Reviewed-by: Alexander Motin <mav@FreeBSD.org>
Reviewed-by: Ryan Moeller <ryan@iXsystems.com>
Reviewed-by: Brian Behlendorf <behlendorf1@llnl.gov>
Co-authored-by: George Wilson <george.wilson@delphix.com>
Signed-off-by: Matthew Ahrens <mahrens@delphix.com>
Closes#10600
FreeBSD uses more stack space in debug configurations and can overflow
the stack while formatting the error message when the call depth limit
of 20 frames is reached. This is readily reproduced by running the
gsub recursion test with increased kstack size. I hit the panic with
16 pages per kstack, and noticed it go away when bumped to 17.
Reserve an additional 64 bytes on the stack when building for FreeBSD.
This is enough to avoid the panic with a deep stack while not wasting
too much space when the default stack size is used.
Reviewed-by: Matt Ahrens <matt@delphix.com>
Reviewed-by: Brian Behlendorf <behlendorf1@llnl.gov>
Signed-off-by: Ryan Moeller <ryan@iXsystems.com>
Closes#10634
Reviewed-by: Ryan Moeller <ryan@ixsystems.com>
Reviewed-by: Brian Behlendorf <behlendorf1@llnl.gov>
Signed-off-by: Allan Jude <allan@klarasystems.com>
Closes#10636
When a clone is promoted, its livelist is no longer accurate, so it is
discarded. If the clone's origin is also a clone (i.e. we are promoting
a clone of a clone), then the origin's livelist is also no longer
accurate, so it should be discarded, but the code doesn't actually do
that.
Consider a pool with:
* Filesystem A
* Clone B, a clone of A
* Clone C, a clone of B
If we promote C, it discards C's livelist. It should discard B's
livelist, but that is not happening. The impact is that when B is
destroyed, we use the livelist to find the blocks to free, but the
livelist is no longer correct so we end up freeing blocks that are still
in use by C. The incorrectly-freed blocks can be reallocated causing
checksum errors. And when C is destroyed it can double-free the
incorrectly-freed blocks.
The problem is that we remove the livelist of `origin_ds->ds_dir`, but
the origin snapshot has already been moved to the promoted dsl_dir. So
this is actually trying to remove the livelist of the promoted dsl_dir,
which was already removed. As explained in a comment in the beginning
of `dsl_dataset_promote_sync()`, we need to use the saved `odd` for the
origin's dsl_dir.
Reviewed-by: Pavel Zakharov <pavel.zakharov@delphix.com>
Reviewed-by: Brian Behlendorf <behlendorf1@llnl.gov>
Reviewed-by: George Wilson <gwilson@delphix.com>
Reviewed by: Sara Hartse <sara.hartse@delphix.com>
Signed-off-by: Matthew Ahrens <mahrens@delphix.com>
Closes#10652
In `vdev_load()`, we look up several entries in the `vdev_top_zap`
object. In most cases, if we encounter an i/o error, it will be
returned to the caller. However, when handling
`VDEV_TOP_ZAP_ALLOCATION_BIAS`, if we get an i/o error, we may continue
on, which in theory could cause us to not realize that a vdev should be
used only for `special` allocations.
In practice, if we encountered an i/o error while looking for
`VDEV_TOP_ZAP_ALLOCATION_BIAS` in the `vdev_top_zap`, we'd also get an
i/o error while looking for other entries in the same object, and thus
the zpool open/import would fail. Therefore the impact of this problem
is negligible.
This commit adds error handling for i/o errors while accessing the
`vdev_top_zap`, so that we aren't relying on unrelated code to fail for
us.
Reviewed-by: Don Brady <don.brady@delphix.com>
Reviewed-by: Brian Behlendorf <behlendorf1@llnl.gov>
Signed-off-by: Matthew Ahrens <mahrens@delphix.com>
Closes#10637
Renamed to avoid conflicting with refcount.h when a different
implementation is already provided by the platform.
Reviewed-by: Ryan Moeller <ryan@ixsystems.com>
Reviewed-by: Brian Behlendorf <behlendorf1@llnl.gov>
Signed-off-by: Matt Macy <mmacy@FreeBSD.org>
Closes#10620
When debugging issues or generally analyzing the runtime of
a system it would be nice to be able to tell the different
ZTHRs running by name rather than having to analyze their
stack.
Reviewed-by: Brian Behlendorf <behlendorf1@llnl.gov>
Reviewed-by: Matthew Ahrens <mahrens@delphix.com>
Co-authored-by: Ryan Moeller <ryan@iXsystems.com>
Signed-off-by: Serapheim Dimitropoulos <serapheim@delphix.com>
Closes#10630
FreeBSD defines _BIG_ENDIAN BIG_ENDIAN _LITTLE_ENDIAN
LITTLE_ENDIAN on every architecture. Trying to do
cross builds whilst hiding this from ZFS has proven
extremely cumbersome.
Reviewed-by: Ryan Moeller <ryan@ixsystems.com>
Reviewed-by: Brian Behlendorf <behlendorf1@llnl.gov>
Signed-off-by: Matt Macy <mmacy@FreeBSD.org>
Closes#10621
The `zfs program` subcommand invokes a LUA interpreter to run ZFS
"channel programs". This interpreter runs in a constrained environment,
with defined memory limits. The LUA stack (used for LUA functions that
call each other) is allocated in the kernel's heap, and is limited by
the `-m MEMORY-LIMIT` flag and the `zfs_lua_max_memlimit` module
parameter. The C stack is used by certain LUA features that are
implemented in C. The C stack is limited by `LUAI_MAXCCALLS=20`, which
limits call depth.
Some LUA C calls use more stack space than others, and `gsub()` uses an
unusually large amount. With a programming trick, it can be invoked
recursively using the C stack (rather than the LUA stack). This
overflows the 16KB Linux kernel stack after about 11 iterations, less
than the limit of 20.
One solution would be to decrease `LUAI_MAXCCALLS`. This could be made
to work, but it has a few drawbacks:
1. The existing test suite does not pass with `LUAI_MAXCCALLS=10`.
2. There may be other LUA functions that use a lot of stack space, and
the stack space may change depending on compiler version and options.
This commit addresses the problem by adding a new limit on the amount of
free space (in bytes) remaining on the C stack while running the LUA
interpreter: `LUAI_MINCSTACK=4096`. If there is less than this amount
of stack space remaining, a LUA runtime error is generated.
Reviewed-by: George Wilson <gwilson@delphix.com>
Reviewed-by: Brian Behlendorf <behlendorf1@llnl.gov>
Reviewed-by: Ryan Moeller <ryan@ixsystems.com>
Reviewed-by: Allan Jude <allanjude@freebsd.org>
Reviewed-by: Serapheim Dimitropoulos <serapheim@delphix.com>
Signed-off-by: Matthew Ahrens <mahrens@delphix.com>
Closes#10611Closes#10613
This is a step toward being able to vendor the OpenZFS code in FreeBSD.
Reviewed-by: Brian Behlendorf <behlendorf1@llnl.gov>
Reviewed-by: Ryan Moeller <ryan@iXsystems.com>
Signed-off-by: Matt Macy <mmacy@FreeBSD.org>
Closes#10625
Reviewed-by: Brian Behlendorf <behlendorf1@llnl.gov>
Reviewed-by: Ryan Moeller <ryan@iXsystems.com>
Signed-off-by: Matt Macy <mmacy@FreeBSD.org>
Closes#10623
i386 has some additional memory reservation logic that limits the size
of the reported available memory. This was accidentally being used on
all arches due to a missing header.
Include machine/vmparam.h in freebsd/zfs/arc_os.c to pull in the
missing UMA_MD_SMALL_ALLOC definition.
Reviewed-by: Brian Behlendorf <behlendorf1@llnl.gov>
Reviewed-by: Alexander Motin <mav@FreeBSD.org>
Signed-off-by: Ryan Moeller <ryan@iXsystems.com>
Closes#10616
This is only used for the kstat, but something other than 0 is nice.
Reviewed-by: Brian Behlendorf <behlendorf1@llnl.gov>
Reviewed-by: Alexander Motin <mav@FreeBSD.org>
Signed-off-by: Ryan Moeller <ryan@iXsystems.com>
Closes#10626
By design a gang ABD can not have another gang ABD as a child. This is
to make sure the logical offset in a gang ABD is consistent with the
individual ABDS it contains as children. If a gang ABD is added as a
child of a gang ABD we will add the individual children of the gang ABD
to the parent gang ABD. This allows for a consistent view of offsets
within the parent gang ABD.
Reviewed-by: Mark Maybee <mmaybee@cray.com>
Reviewed-by: Brian Behlendorf <behlendorf1@llnl.gov>
Signed-off-by: Brian Atkinson <batkinson@lanl.gov>
Closes#10430
Set the initial max sizes to ULONG_MAX to allow the caches to grow
with the ARC.
Recalculate the metadata cache size on demand so it can adapt, too.
Update descriptions in zfs-module-parameters(5).
Reviewed-by: Alexander Motin <mav@FreeBSD.org>
Reviewed-by: Brian Behlendorf <behlendorf1@llnl.gov>
Reviewed-by: Matt Ahrens <matt@delphix.com>
Signed-off-by: Ryan Moeller <ryan@iXsystems.com>
Closes#10563Closes#10610
By default, `spl_kmem_cache_expire` is `KMC_EXPIRE_MEM`, meaning that
objects will be removed from kmem cache magazines by
`spl_kmem_cache_reap_now()`.
There is also a module parameter to change this to `KMC_EXPIRE_AGE`,
which establishes a maximum lifetime for objects to stay in the
magazine. This setting has rarely, if ever, been used, and is not
regularly tested.
This commit removes the code for `KMC_EXPIRE_AGE`, and associated module
parameters.
Additionally, the unused module parameter
`spl_kmem_cache_obj_per_slab_min` is removed.
Reviewed-by: Brian Behlendorf <behlendorf1@llnl.gov>
Signed-off-by: Matthew Ahrens <mahrens@delphix.com>
Closes#10608
Drop unnecessary redefinition's of several arcstat values.
Put missing extern declaration of arc_no_grow_shift in arc_impl.h.
Reviewed-by: Brian Behlendorf <behlendorf1@llnl.gov>
Signed-off-by: Ryan Moeller <ryan@iXsystems.com>
Closes#10609
The process of evicting data from the ARC is referred to as
`arc_adjust`.
This commit changes the term to `arc_evict`, which is more specific.
Reviewed-by: George Wilson <gwilson@delphix.com>
Reviewed-by: Brian Behlendorf <behlendorf1@llnl.gov>
Reviewed-by: George Melikov <mail@gmelikov.ru>
Signed-off-by: Matthew Ahrens <mahrens@delphix.com>
Closes#10592
These tunables were renamed from vfs.zfs.arc_min and
vfs.zfs.arc_max to vfs.zfs.arc.min and vfs.zfs.arc.max.
Add legacy compat tunables for the old names.
Reviewed-by: Brian Behlendorf <behlendorf1@llnl.gov>
Signed-off-by: Ryan Moeller <ryan@iXsystems.com>
Closes#10579
The SPL kmem_cache implementation provides a mechanism, `skc_reclaim`,
whereby individual caches can register a callback to be invoked when
there is memory pressure. This mechanism is used in only one place: the
ARC registers the `hdr_recl()` reclaim function. This function wakes up
the `arc_reap_zthr`, whose job is to call `kmem_cache_reap()` and
`arc_reduce_target_size()`.
The `skc_reclaim` callbacks are invoked only by shrinker callbacks and
`arc_reap_zthr`, and only callback only wakes up `arc_reap_zthr`. When
called from `arc_reap_zthr`, waking `arc_reap_zthr` is a no-op. When
called from shrinker callbacks, we are already aware of memory pressure
and responding to it. Therefore there is little benefit to ever calling
the `hdr_recl()` `skc_reclaim` callback.
The `arc_reap_zthr` also wakes once a second, and if memory is low when
allocating an ARC buffer. Therefore, additionally waking it from the
shrinker calbacks has little benefit.
The shrinker callbacks can be invoked very frequently, e.g. 10,000 times
per second. Additionally, for invocation of the shrinker callback,
skc_reclaim is invoked many times. Therefore, this mechanism consumes
significant amounts of CPU time.
The kmem_cache shrinker calls `spl_kmem_cache_reap_now()`, which,
in addition to invoking `skc_reclaim()`, does two things to attempt to
free pages for use by the system:
1. Return free objects from the magazine layer to the slab layer
2. Return entirely-free slabs to the page layer (i.e. free pages)
These actions apply only to caches implemented by the SPL, not those
that use the underlying kernel SLAB/SLUB caches. The SPL caches are
used for objects >=32KB, which are primarily linear ABD's cached in the
DBUF cache.
These actions (freeing objects from the magazine layer and returning
entirely-free slabs) are also taken whenever a `kmem_cache_free()` call
finds a full magazine. So there would typically be zero entirely-free
slabs, and the number of objects in magazines is limited (typically no
more than 64 objects per magazine, and there's one magazine per CPU).
Therefore the benefit of `spl_kmem_cache_reap_now()`, while nonzero, is
modest.
We also call `spl_kmem_cache_reap_now()` from the `arc_reap_zthr`, when
memory pressure is detected. Therefore, calling
`spl_kmem_cache_reap_now()` from the kmem_cache shrinker is not needed.
This commit removes the `skc_reclaim` mechanism, its only callback
`hdr_recl()`, and the kmem_cache shrinker callback.
Reviewed-By: Brian Behlendorf <behlendorf1@llnl.gov>
Reviewed-by: George Wilson <gwilson@delphix.com>
Reviewed-by: Pavel Zakharov <pavel.zakharov@delphix.com>
Signed-off-by: Matthew Ahrens <mahrens@delphix.com>
Closes#10576
Stock kernels older than 4.10 do not export the has_capability()
function which is required by commit e59a377. To avoid breaking
the build on older kernels revert to the safe legacy behavior and
return EACCES when privileges cannot be checked.
Reviewed-by: Ryan Moeller <ryan@ixsystems.com>
Reviewed-by: Matt Ahrens <matt@delphix.com>
Signed-off-by: Brian Behlendorf <behlendorf1@llnl.gov>
Closes#10565Closes#10573
`arc_free_memory()` returns the amount of memory that the ARC considers
to be free. This includes pages that are not actually free, but can be
evicted with essentially zero cost (without doing any i/o), for example
the page cache. The ARC can "squeeze out" any pages included in this
calculation, leaving only `arc_sys_free` (1/64th of RAM) for these
free/evictable pages.
Included in the count of free/evictable pages is
`nr_inactive_anon_pages()`, which is described as "Anonymous memory that
has not been used recently and can be swapped out". These pages would
have to be written out to disk (swap) in order to evict them, and they
are not included in `/proc/meminfo`'s `MemAvailable`.
Therefore it is not appropriate for `nr_inactive_anon_pages()` to be
included in the free/evictable memory returned by `arc_free_memory()`,
because the ARC shouldn't (intentionally) make the system swap.
This commit removes `nr_inactive_anon_pages()` from the memory returned
by `arc_free_memory()`. This is a step towards enabling the ARC to
manage free memory by monitoring it and reducing the ARC size as we
notice that there is insufficient free memory (in the `arc_reap_zthr`),
rather than the current method of relying on the `arc_shrinker`
callback.
Reviewed-by: Tony Nguyen <tony.nguyen@delphix.com>
Reviewed-by: Pavel Zakharov <pavel.zakharov@delphix.com>
Reviewed-by: George Wilson <gwilson@delphix.com>
Reviewed-by: Brian Behlendorf <behlendorf1@llnl.gov>
Signed-off-by: Matthew Ahrens <mahrens@delphix.com>
Closes#10575
Update the zfs commands such that they're backwards compatible with
the version of ZFS is the base FreeBSD.
Reviewed-by: Brian Behlendorf <behlendorf1@llnl.gov>
Reviewed-by: Ryan Moeller <ryan@ixsystems.com>
Signed-off-by: Matt Macy <mmacy@FreeBSD.org>
Closes#10542
Move/add include of <linux/percpu_compat.h> to satisfy missing
requirements.
Reviewed-by: Brian Behlendorf <behlendorf1@llnl.gov>
Signed-off-by: Romain Dolbeau <romain@dolbeau.org>
Closes#10568Closes#10569
Livelists and spacemaps are data structures that are logs of allocations
and frees. Livelists entries are block pointers (blkptr_t). Spacemaps
entries are ranges of numbers, most often used as to track
allocated/freed regions of metaslabs/vdevs.
These data structures can become self-inconsistent, for example if a
block or range can be "double allocated" (two allocation records without
an intervening free) or "double freed" (two free records without an
intervening allocation).
ZDB (as well as zfs running in the kernel) can detect these
inconsistencies when loading livelists and metaslab. However, it
generally halts processing when the error is detected.
When analyzing an on-disk problem, we often want to know the entire set
of inconsistencies, which is not possible with the current behavior.
This commit adds a new flag, `zdb -y`, which analyzes the livelist and
metaslab data structures and displays all of their inconsistencies.
Note that this is different from the leak detection performed by
`zdb -b`, which checks for inconsistencies between the spacemaps and the
tree of block pointers, but assumes the spacemaps are self-consistent.
The specific checks added are:
Verify livelists by iterating through each sublivelists and:
- report leftover FREEs
- report double ALLOCs and double FREEs
- record leftover ALLOCs together with their TXG [see Cross Check]
Verify spacemaps by iterating over each metaslab and:
- iterate over spacemap and then the metaslab's entries in the
spacemap log, then report any double FREEs and double ALLOCs
Verify that livelists are consistenet with spacemaps. The space
referenced by livelists (after using the FREE's to cancel out
corresponding ALLOCs) should be allocated, according to the spacemaps.
Reviewed-by: Serapheim Dimitropoulos <serapheim@delphix.com>
Reviewed-by: Brian Behlendorf <behlendorf1@llnl.gov>
Co-authored-by: Sara Hartse <sara.hartse@delphix.com>
Signed-off-by: Matthew Ahrens <mahrens@delphix.com>
External-issue: DLPX-66031
Closes#10515
Our QE team during automated API testing hit deadlock in ZFS, caused
by lock order reversal. From one side dsl_sync_task_sync() locks
dp_config_rwlock as writer and calls spa_sync_props(), which waits
for spa_props_lock. From another spa_prop_get() locks spa_props_lock
and then calls dsl_pool_config_enter(), trying to lock dp_config_rwlock
as reader.
This patch makes spa_prop_get() lock dp_config_rwlock before
spa_props_lock, making the order consistent.
Reviewed-by: Brian Behlendorf <behlendorf1@llnl.gov>
Reviewed-by: Ryan Moeller <ryan@ixsystems.com>
Signed-off-by: Alexander Motin <mav@FreeBSD.org>
Closes#10553
On linux the list debug code has been setting off a failure when
checking that the node->next->prev value is pointing back at the node.
At times this check evaluates to 0xdead. When removing a child from a
gang ABD we must acquire the child's abd_mtx to make sure that the
same ABD is not being added to another gang ABD while it is being
removed from a gang ABD. This fixes a race condition when checking
if an ABDs link is already active and part of another gang ABD before
adding it to a gang.
Added additional debug code for the gang ABD in abd_verify() to make
sure each child ABD has active links. Also check to make sure another
gang ABD is not added to a gang ABD.
Reviewed-by: Serapheim Dimitropoulos <serapheim@delphix.com>
Reviewed-by: Brian Behlendorf <behlendorf1@llnl.gov>
Reviewed-by: Matt Ahrens <matt@delphix.com>
Signed-off-by: Brian Atkinson <batkinson@lanl.gov>
Closes#10511
The filesystem_limit and snapshot_limit properties limit the number of
filesystems or snapshots that can be created below this dataset.
According to the manpage, "The limit is not enforced if the user is
allowed to change the limit." Two types of users are allowed to change
the limit:
1. Those that have been delegated the `filesystem_limit` or
`snapshot_limit` permission, e.g. with
`zfs allow USER filesystem_limit DATASET`. This works properly.
2. A user with elevated system privileges (e.g. root). This does not
work - the root user will incorrectly get an error when trying to create
a snapshot/filesystem, if it exceeds the `_limit` property.
The problem is that `priv_policy_ns()` does not work if the `cred_t` is
not that of the current process. This happens when
`dsl_enforce_ds_ss_limits()` is called in syncing context (as part of a
sync task's check func) to determine the permissions of the
corresponding user process.
This commit fixes the issue by passing the `task_struct` (typedef'ed as
a `proc_t`) to syncing context, and then using `has_capability()` to
determine if that process is privileged. Note that we still need to
pass the `cred_t` to syncing context so that we can check if the user
was delegated this permission with `zfs allow`.
This problem only impacts Linux. Wrappers are added to FreeBSD but it
continues to use `priv_check_cred()`, which works on arbitrary `cred_t`.
Reviewed-by: Brian Behlendorf <behlendorf1@llnl.gov>
Reviewed-by: Ryan Moeller <ryan@ixsystems.com>
Signed-off-by: Matthew Ahrens <mahrens@delphix.com>
Closes#8226Closes#10545
Previously a tqent could be recycled prematurely, update the
code to use a hash table for lookups to resolve this.
Reviewed-by: Brian Behlendorf <behlendorf1@llnl.gov>
Reviewed-by: Ryan Moeller <ryan@ixsystems.com>
Signed-off-by: Matt Macy <mmacy@FreeBSD.org>
Closes#10529
In case l2arc_write_done() handles a zio that was not successful check
that the list of log block pointers is not empty when restoring them
in the device header. Otherwise zero them out. In any case perform the
actual write updating the device header after the zio of
l2arc_write_buffers() completes as l2arc_write_done() may have touched
the memory holding the log block pointers in the device header.
Reviewed-by: Serapheim Dimitropoulos <serapheim@delphix.com>
Reviewed-by: Brian Behlendorf <behlendorf1@llnl.gov>
Signed-off-by: George Amanakis <gamanakis@gmail.com>
Closes#10540Closes#10543
FreeBSD has a per-page "busy" lock which is held when handling a page
fault on a mapped file. This lock is also acquired when copying data
from the DMU to the page cache in zfs_write(). File range locks are
also acquired in both of these paths, in the opposite order with respect
to the busy lock.
In the getpages VOP, the range lock is only used to determine the extent
of optional read-ahead and read-behind operations. To resolve the lock
order reversal, modify the getpages VOP to avoid blocking on the range
lock.
Reviewed-by: Brian Behlendorf <behlendorf1@llnl.gov>
Reviewed-by: Ryan Moeller <ryan@ixsystems.com>
Signed-off-by: Mark Johnston <markj@FreeBSD.org>
Closes#10519
zfs_rangelock_tryenter() bails immediately instead of waiting for the
lock to become available. This will be used to resolve a deadlock in
the FreeBSD page-in code. No functional change intended.
Reviewed-by: Brian Behlendorf <behlendorf1@llnl.gov>
Reviewed-by: Ryan Moeller <ryan@ixsystems.com>
Signed-off-by: Mark Johnston <markj@FreeBSD.org>
Closes#10519
`zfs_freebsd_need_inactive` appears to been based on an unfinished
version of https://reviews.freebsd.org/D22130 which had a bug where
files written via mmap wouldn't actually persist.
Update the function to match the final version committed to FreeBSD.
Authored-by: Mateusz Guzik <mjg@FreeBSD.org>
Reviewed-by: Brian Behlendorf <behlendorf1@llnl.gov>
Signed-off-by: Ryan Moeller <ryan@iXsystems.com>
Closes#10527Closes#10528
The device_rebuild feature enables sequential reconstruction when
resilvering. Mirror vdevs can be rebuilt in LBA order which may
more quickly restore redundancy depending on the pools average block
size, overall fragmentation and the performance characteristics
of the devices. However, block checksums cannot be verified
as part of the rebuild thus a scrub is automatically started after
the sequential resilver completes.
The new '-s' option has been added to the `zpool attach` and
`zpool replace` command to request sequential reconstruction
instead of healing reconstruction when resilvering.
zpool attach -s <pool> <existing vdev> <new vdev>
zpool replace -s <pool> <old vdev> <new vdev>
The `zpool status` output has been updated to report the progress
of sequential resilvering in the same way as healing resilvering.
The one notable difference is that multiple sequential resilvers
may be in progress as long as they're operating on different
top-level vdevs.
The `zpool wait -t resilver` command was extended to wait on
sequential resilvers. From this perspective they are no different
than healing resilvers.
Sequential resilvers cannot be supported for RAIDZ, but are
compatible with the dRAID feature being developed.
As part of this change the resilver_restart_* tests were moved
in to the functional/replacement directory. Additionally, the
replacement tests were renamed and extended to verify both
resilvering and rebuilding.
Original-patch-by: Isaac Huang <he.huang@intel.com>
Reviewed-by: Tony Hutter <hutter2@llnl.gov>
Reviewed-by: John Poduska <jpoduska@datto.com>
Co-authored-by: Mark Maybee <mmaybee@cray.com>
Signed-off-by: Brian Behlendorf <behlendorf1@llnl.gov>
Closes#10349
Fix header conflicts when building zfs with openzfs as a vendor import.
Reviewed-by: Brian Behlendorf <behlendorf1@llnl.gov>
Reviewed-by: Ryan Moeller <ryan@ixsystems.com>
Signed-off-by: Matt Macy <mmacy@FreeBSD.org>
Closes#10497
OS-specific code (e.g. under `module/os/linux`) does not need to share
its code structure with any other operating systems. In particular, the
ARC and kmem code need not be similar to the code in illumos, because we
won't be syncing this OS-specific code between operating systems. For
example, if/when illumos support is added to the common repo, we would
add a file `module/os/illumos/zfs/arc_os.c` for the illumos versions of
this code.
Therefore, we can simplify the code in the OS-specific ARC and kmem
routines.
These changes do not impact system behavior, they are purely code
cleanup. The changes are:
Arenas are not used on Linux or FreeBSD (they are always `NULL`), so
`heap_arena`, `zio_arena`, and `zio_alloc_arena` can be removed, along
with code that uses them.
In `arc_available_memory()`:
* `desfree` is unused, remove it
* rename `freemem` to avoid conflict with pre-existing `#define`
* remove checks related to arenas
* use units of bytes, rather than converting from bytes to pages and
then back to bytes
`SPL_KMEM_CACHE_REAP` is unused, remove it.
`skc_reap` is unused, remove it.
The `count` argument to `spl_kmem_cache_reap_now()` is unused, remove
it.
`vmem_size()` and associated type and macros are unused, remove them.
In `arc_memory_throttle()`, use a less confusing variable name to store
the result of `arc_free_memory()`.
Reviewed-by: George Wilson <gwilson@delphix.com>
Reviewed-by: Pavel Zakharov <pavel.zakharov@delphix.com>
Reviewed-by: Brian Behlendorf <behlendorf1@llnl.gov>
Reviewed-by: Ryan Moeller <ryan@ixsystems.com>
Signed-off-by: Matthew Ahrens <mahrens@delphix.com>
Closes#10499
The SPL provides a wrapper for the kernel's shrinker callbacks, which
enables the ZFS code to interface with multiple versions of the shrinker
API's from different kernel versions. Specifically, Linux kernels 3.0 -
3.11 has a single "combined" callback, and Linux kernels 3.12 and later
have two "split" callbacks. The SPL provides a wrapper function so that
the ZFS code only needs to implement one version of the callbacks.
Currently the SPL's wrappers are designed such that the ZFS code
implements the older, "combined" callback. There are a few downsides to
this approach:
* The general design within ZFS is for the latest Linux kernel to be
considered the "first class" API.
* The newer, "split" callback API is easier to understand, because each
callback has one purpose.
* The current wrappers do not completely abstract out the differing
API's, so ZFS code needs `#ifdef` code to handle the differing return
values required for different kernel versions.
This commit addresses these drawbacks by having the ZFS code provide the
latest, "split" callbacks, and the SPL provides a wrapping function for
the older, "combined" API.
Reviewed-by: Pavel Zakharov <pavel.zakharov@delphix.com>
Reviewed-by: Brian Behlendorf <behlendorf1@llnl.gov>
Signed-off-by: Matthew Ahrens <mahrens@delphix.com>
Closes#10502
A previous commit enabled the tracking of object allocations
in Linux-backed caches from the SPL layer for debuggability.
The commit is: 9a170fc6fe54f1e852b6c39630fe5ef2bbd97c16
Unfortunately, it also introduced minor performance regressions
that were highlighted by the ZFS perf test-suite. Within Delphix
we found that the regression would be from -1%, all the way up
to -8% for some workloads.
This commit brings performance back up to par by creating a
separate counter for those caches and making it a percpu in
order to avoid lock-contention.
The initial performance testing was done by myself, and the
final round was conducted by @tonynguien who was also the one
that discovered the regression and highlighted the culprit.
Reviewed-by: Matt Ahrens <matt@delphix.com>
Reviewed-by: Brian Behlendorf <behlendorf1@llnl.gov>
Signed-off-by: Serapheim Dimitropoulos <serapheim@delphix.com>
Closes#10397
ZFS registers a memory hook, `__arc_shrinker_func`, which is supposed to
allow the ARC to shrink when the kernel experiences memory pressure.
The ARC shrinker changes `arc_c` via a call to
`arc_reduce_target_size()`. Before commit 3ec34e5527, the ARC
shrinker would also evict data from the ARC to bring `arc_size` down to
the new `arc_c`. However, that commit (seemingly inadvertently) made it
so that the ARC shrinker no longer evicts any data or waits for eviction
to complete.
Repeated calls to the ARC shrinker can reduce `arc_c` drastically, often
all the way to `arc_c_min`. Since it doesn't wait for the actual
eviction of data from the ARC, this creates a situation where `arc_size`
is more than `arc_c` for the several seconds/minutes it takes for
`arc_adjust_zthr` to evict data from the ARC. During this time,
arc_get_data_impl() will block, so ZFS can't process read/write requests
(e.g. from iSCSI, NFS, or read/write syscalls).
To ensure that `arc_c` doesn't shrink faster than the adjust thread can
keep up, this commit makes the ARC shrinker wait for the eviction to
complete, resulting in similar behavior to what we had before commit
3ec34e5527.
Note: commit 3ec34e5527 is `OpenZFS 9284 - arc_reclaim_thread
has 2 jobs` and was integrated in December 2018, and is part of ZoL
0.8.x but not 0.7.x.
Additionally, when the ARC size is reduced drastically, the
`arc_adjust_zthr` can be on-CPU for many seconds without blocking. Any
threads that are bound to the same CPU that arc_adjust_zthr is running
on will not able to run for a long time.
To ensure that CPU-bound threads can make progress, this commit changes
`arc_evict_state_impl()` make a voluntary preemption call,
`cond_resched()`.
Reviewed-by: Brian Behlendorf <behlendorf1@llnl.gov>
Reviewed-by: George Wilson <gwilson@delphix.com>
Reviewed-by: Prakash Surya <prakash.surya@delphix.com>
Reviewed-by: Pavel Zakharov <pavel.zakharov@delphix.com>
Reviewed-by: Tony Nguyen <tony.nguyen@delphix.com>
Signed-off-by: Matthew Ahrens <mahrens@delphix.com>
External-issue: DLPX-70703
Closes#10496
These targets look to have been copied from an automake-generated
Makefile.in, and can't work since none of the auto-generated automake
variables are defined here.
Moreover, ctags has been overridden in the top-level Makefile, so the
target is pointless anyway, and gtags is not a recursive target.
Fix cscopelist by moving it to the top-level Makefile as well, in line
with ctags and etags.
Also, add -a to ctags command as well, otherwise it won't work if more
than one xargs invocation takes place.
Add assembler files to ctags/etags, prune all dotted-dirs, and restrict
the find to files only.
Cleanup: add .PHONY to module/Makefile.in, and fix one recipe with a
missing continuation character.
Reviewed-by: Ryan Moeller <ryan@iXsystems.com>
Reviewed-by: Brian Behlendorf <behlendorf1@llnl.gov>
Signed-off-by: Arvind Sankar <nivedita@alum.mit.edu>
Closes#10493
Currently an out-of-tree build does not work with read-only source
directory because zfs_gitrev.h can't be created. Move this file to the
build directory, which is more appropriate for a generated file, and
drop the dist-hook for zfs_gitrev.h. There is no need to distribute this
file since it will be regenerated as part of the compilation in any
case.
scripts/make_gitrev.sh tries to avoid updating zfs_gitrev.h if there has
been no change, however this doesn't cover the case when the source
directory is not in git: in that case zfs_gitrev.h gets overwritten even
though it's always "unknown". Simplify the logic to always write out a
new version of zfs_gitrev.h, compare against the old and overwrite only
if different. This is now simple enough to just include in the
Makefile, so drop the script.
Reviewed-by: Ryan Moeller <ryan@iXsystems.com>
Reviewed-by: Brian Behlendorf <behlendorf1@llnl.gov>
Signed-off-by: Arvind Sankar <nivedita@alum.mit.edu>
Closes#10493
If srcdir != builddir, pass down MAKEOBJDIR to the FreeBSD make to
support out-of-tree builds.
Also allow passing all the gmake options that FreeBSD make understands
to support useful flags like -k, -n, -q etc, and detect the number of
CPUs if -j was specified without an argument.
Reviewed-by: Ryan Moeller <ryan@iXsystems.com>
Reviewed-by: Brian Behlendorf <behlendorf1@llnl.gov>
Signed-off-by: Arvind Sankar <nivedita@alum.mit.edu>
Closes#10493
This tunable required a handler to be implemented for
ZFS_MODULE_PARAM_CALL.
Add the handler so the tunable can be declared in common code.
Reviewed-by: Brian Behlendorf <behlendorf1@llnl.gov>
Signed-off-by: Ryan Moeller <ryan@iXsystems.com>
Closes#10490
Rephrase comments to be more clear.
Reviewed-by: Serapheim Dimitropoulos <serapheim@delphix.com>
Reviewed-by: Brian Behlendorf <behlendorf1@llnl.gov>
Reviewed-by: Ryan Moeller <ryan@iXsystems.com>
Signed-off-by: Matthew Ahrens <mahrens@delphix.com>
Closes#10481
Resolve the FreeBSD head build failure.
Reviewed-by: Brian Behlendorf <behlendorf1@llnl.gov>
Signed-off-by: Ryan Moeller <ryan@iXsystems.com>
Closes#10480
KPI changed in FreeBSD, update accordingly.
Reviewed-by: Brian Behlendorf <behlendorf1@llnl.gov>
Signed-off-by: Ryan Moeller <ryan@iXsystems.com>
Closes#10475
Switch on warning flags to detect mismatch between declaration and
definition.
Reviewed-by: Ryan Moeller <ryan@iXsystems.com>
Reviewed-by: Brian Behlendorf <behlendorf1@llnl.gov>
Signed-off-by: Arvind Sankar <nivedita@alum.mit.edu>
Closes#10470
spl-generic.c defines some of the libgcc integer library functions on
32-bit. Don't bother checking -Wmissing-prototypes since nothing should
directly call these functions from C code.
Reviewed-by: Ryan Moeller <ryan@iXsystems.com>
Reviewed-by: Brian Behlendorf <behlendorf1@llnl.gov>
Signed-off-by: Arvind Sankar <nivedita@alum.mit.edu>
Closes#10470
