The Linux direct reclaim path uses this out of band value to
determine if forward progress is being made. Normally this is
incremented by kmem_freepages() which is part of the various
Linux slab implementations. However, since we are using none
of that infrastructure we're responsible for incrementing this
count.
If no forward progress is detected and a subsequent allocation
fails the OOM killer will be invoked. If there was forward
progress additional reclaim will be attempted via the page
cache and registerd shrinker until the allocation succeeds.
Signed-off-by: Prakash Surya <surya1@llnl.gov>
Signed-off-by: Brian Behlendorf <behlendorf1@llnl.gov>
Closes#107
When memory pressure triggers direct memory reclaim, a slabs age
and delay should not prevent it from being freed. This patch ensures
these values are ignored, allowing an empty slab to be freed in this
code path no matter the value of its age and delay.
This prevents needless scanning of the partial slabs and has been
observed to significantly reduce the total cpu usage. In addition,
it should allow for snappier reclaim under memory pressure.
Signed-off-by: Prakash Surya <surya1@llnl.gov>
Signed-off-by: Brian Behlendorf <behlendorf1@llnl.gov>
Closes#102
Previously, the SPL tried to maintain Solaris semantics by freeing
all available (empty) slabs from its slab caches when the shrinker
was called. This is not desirable when running on Linux. To make
the SPL shrinker more Linux friendly, the actual number of freed
slabs from each of the slab caches is now derived from nr_to_scan
and skc_slab_objs.
Additionally, an accounting bug was fixed in spl_slab_reclaim()
which could cause us to reclaim one more slab than requested.
Signed-off-by: Prakash Surya <surya1@llnl.gov>
Signed-off-by: Brian Behlendorf <behlendorf1@llnl.gov>
Closes#101
Leverage the existing generic 64-bit division operations which
were originally implemented for x86 to support ARM. All that is
required is to make the symbols available to the linker with the
expected names.
Signed-off-by: Brian Behlendorf <behlendorf1@llnl.gov>
This reverts commit ce90208cf9. This
change was observed to cause problems when using a zvol to back a VM
under 2.6.32.59 kernels. This issue was filed as #710.
Signed-off-by: Richard Yao <ryao@cs.stonybrook.edu>
Signed-off-by: Brian Behlendorf <behlendorf1@llnl.gov>
Issue #342
Issue #710
The zfs-test package additionally depends on mdadm and bc to
run the zfault.sh tests.
Signed-off-by: Brian Behlendorf <behlendorf1@llnl.gov>
Closes#690
The mode argument of iops->create()/mkdir()/mknod() was changed from
an 'int' to a 'umode_t'. To prevent a compiler warning an autoconf
check was added to detect the API change and then correctly set a
zpl_umode_t typedef. There is no functional change.
Signed-off-by: Brian Behlendorf <behlendorf1@llnl.gov>
Closes#701
Previously, it was possible for the direct reclaim path to be invoked
when a write to a zvol was made. When a zvol is used as a swap device,
this often causes swap requests to depend on additional swap requests,
which deadlocks. We address this by disabling the direct reclaim path
on zvols.
Signed-off-by: Brian Behlendorf <behlendorf1@llnl.gov>
Closes#342
As of the removal of the taskq work list made in commit:
commit 2c02b71b14
Author: Prakash Surya <surya1@llnl.gov>
Date: Mon Dec 5 17:32:48 2011 -0800
Replace tq_work_list and tq_threads in taskq_t
To lay the ground work for introducing the taskq_dispatch_prealloc()
interface, the tq_work_list and tq_threads fields had to be replaced
with new alternatives in the taskq_t structure.
the comment above taskq_wait_check has been incorrect. This change is an
attempt at bringing that description more in line with the current
implementation. Essentially, references to the old task work list had to
be updated to reference the new taskq thread active list.
Signed-off-by: Prakash Surya <surya1@llnl.gov>
Signed-off-by: Brian Behlendorf <behlendorf1@llnl.gov>
Issue #65
23bdb07d4e updated the ARC memory limits
to be 1/2 of memory or all but 4GB. Unfortunately, these values assume
zero internal fragmentation in the SLUB allocator, when in reality, the
internal fragmentation could be as high as 50%, effectively doubling
memory usage. This poses clear safety issues, because it permits the
size of ARC to exceed system memory.
This patch changes this so that the default value of arc_c_max is always
1/2 of system memory. This effectively limits the ARC to the memory that
the system has physically installed.
Signed-off-by: Brian Behlendorf <behlendorf1@llnl.gov>
Closes#660
Under Solaris the ARC was designed to stay one step ahead of the
VM subsystem. It would attempt to recognize low memory situtions
before they occured and evict data from the cache. It would also
make assessments about if there was enough free memory to perform
a specific operation.
This was all possible because Solaris exposes a fairly decent
view of the memory state of the system to other kernel threads.
Linux on the other hand does not make this information easily
available. To avoid extensive modifications to the ARC the SPL
attempts to provide these same interfaces. While this works it
is not ideal and problems can arise when the ARC and Linux have
different ideas about when your out of memory. This has manifested
itself in the past as a spinning arc_reclaim_thread.
This patch abandons the emulated Solaris interfaces in favor of
the prefered Linux interface. That means moving the bulk of the
memory reclaim logic out of the arc_reclaim_thread and in to the
evict driven shrinker callback. The Linux VM will call this
function when it needs memory. The ARC is then responsible for
attempting to free the requested amount of memory if possible.
Several interfaces have been modified to accomidate this approach,
however the basic user space implementation remains the same.
The following changes almost exclusively just apply to the kernel
implementation.
* Removed the hdr_recl() reclaim callback which is redundant
with the broader arc_shrinker_func().
* Reduced arc_grow_retry to 5 seconds from 60. This is now used
internally in the ARC with arc_no_grow to indicate that direct
reclaim was recently performed. This typically indicates a
rapid change in memory demands which the kswapd threads were
unable to keep ahead of. As long as direct reclaim is happening
once every 5 seconds arc growth will be paused to avoid further
contributing to the existing memory pressure. The more common
indirect reclaim paths will not set arc_no_grow.
* arc_shrink() has been extended to take the number of bytes by
which arc_c should be reduced. This allows for a more granual
reduction of the arc target. Since the kernel provides a
reclaim value to the arc_shrinker_func() this value is used
instead of 1<<arc_shrink_shift.
* arc_reclaim_needed() has been removed. It was used to determine
if the system was under memory pressure and relied extensively
on Solaris specific VM interfaces. In most case the new code
just checks arc_no_grow which indicates that within the last
arc_grow_retry seconds direct memory reclaim occurred.
* arc_memory_throttle() has been updated to always include the
amount of evictable memory (arc and page cache) in its free
space calculations. This space is largely available in most
call paths due to direct memory reclaim.
* The Solaris pageout code was also removed to avoid confusion.
It has always been disabled due to proc_pageout being defined
as NULL in the Linux port.
Signed-off-by: Prakash Surya <surya1@llnl.gov>
Signed-off-by: Brian Behlendorf <behlendorf1@llnl.gov>
Expose the zfs_mdcomp_disable variable as a module option. This
can be used to disable compression of zfs meta data which is
enabled by default. This shouldn't need to be tuned but for
most workloads, however there may be very specific instances
where it makes sense to trade disk capacity for extra cpu cycles.
Signed-off-by: Brian Behlendorf <behlendorf1@llnl.gov>
Reviewed by: Richard Elling <richard.elling@richardelling.com>
Reviewed by: Joshua M. Clulow <josh@sysmgr.org>
Approved by: Richard Lowe <richlowe@richlowe.net>
Reference to Illumos issue:
https://www.illumos.org/issues/1946
Ported by: Richard Yao <ryao@cs.stonybrook.edu>
Signed-off-by: Brian Behlendorf <behlendorf1@llnl.gov>
Reviewed by: Adam Leventhal <ahl@delphix.com>
Reviewed by: Matt Ahrens <mahrens@delphix.com>
Reviewed by: Eric Schrock <eric.schrock@delphix.com>
Reviewed by: Dan McDonald <danmcd@nexenta.com>
Reviewed by: Garrett D'Amore <garrett@nexenta.com>
Approved by: Eric Schrock <eric.schrock@delphix.com>
Refererce to Illumos issue:
https://www.illumos.org/issues/952
Ported-by: Richard Yao <ryao@cs.stonybrook.edu>
Signed-off-by: Brian Behlendorf <behlendorf1@llnl.gov>
Closes#607
Reviewed by: Matt Ahrens <matt@delphix.com>
Reviewed by: Eric Schrock <eric.schrock@delphix.com>
Reviewed by: Robert Mustacchi <rm@joyent.com>
Reviewed by: Bill Pijewski <wdp@joyent.com>
Reviewed by: Richard Elling <richard.elling@richardelling.com>
Reviewed by: Steve Gonczi <gonczi@comcast.net>
Reviewed by: Garrett D'Amore <garrett.damore@gmail.com>
Reviewed by: Dan McDonald <danmcd@nexenta.com>
Reviewed by: Albert Lee <trisk@nexenta.com>
Approved by: Eric Schrock <eric.schrock@delphix.com>
Refererces to Illumos issue:
https://www.illumos.org/issues/1909
Signed-off-by: Brian Behlendorf <behlendorf1@llnl.gov>
Closes#680
There is potential for deadlock in the l2arc_feed thread if KM_PUSHPAGE
is not used for the allocations made in l2arc_write_buffers.
Specifically, if KM_PUSHPAGE is not used for these allocations, it is
possible for reclaim to be triggered which can cause the l2arc_feed
thread to deadlock itself on the ARC_mru mutex. An example of this is
demonstrated in the following backtrace of the l2arc_feed thread:
crash> bt 4123
PID: 4123 TASK: ffff88062f8c1500 CPU: 6 COMMAND: "l2arc_feed"
0 [ffff88062511d610] schedule at ffffffff814eeee0
1 [ffff88062511d6d8] __mutex_lock_slowpath at ffffffff814f057e
2 [ffff88062511d748] mutex_lock at ffffffff814f041b
3 [ffff88062511d768] arc_evict at ffffffffa05130ca [zfs]
4 [ffff88062511d858] arc_adjust at ffffffffa05139a9 [zfs]
5 [ffff88062511d878] arc_shrink at ffffffffa0513a95 [zfs]
6 [ffff88062511d898] arc_kmem_reap_now at ffffffffa0513be8 [zfs]
7 [ffff88062511d8c8] arc_shrinker_func at ffffffffa0513ccc [zfs]
8 [ffff88062511d8f8] shrink_slab at ffffffff8112a17a
9 [ffff88062511d958] do_try_to_free_pages at ffffffff8112bfdf
10 [ffff88062511d9e8] try_to_free_pages at ffffffff8112c3ed
11 [ffff88062511da98] __alloc_pages_nodemask at ffffffff8112431d
12 [ffff88062511dbb8] kmem_getpages at ffffffff8115e632
13 [ffff88062511dbe8] fallback_alloc at ffffffff8115f24a
14 [ffff88062511dc68] ____cache_alloc_node at ffffffff8115efc9
15 [ffff88062511dcc8] __kmalloc at ffffffff8115fbf9
16 [ffff88062511dd18] kmem_alloc_debug at ffffffffa047b8cb [spl]
17 [ffff88062511dda8] l2arc_feed_thread at ffffffffa0511e71 [zfs]
18 [ffff88062511dea8] thread_generic_wrapper at ffffffffa047d1a1 [spl]
19 [ffff88062511dee8] kthread at ffffffff81090a86
20 [ffff88062511df48] kernel_thread at ffffffff8100c14a
Signed-off-by: Prakash Surya <surya1@llnl.gov>
Signed-off-by: Brian Behlendorf <behlendorf1@llnl.gov>
Add support for the `zfs list -t snap` alias which is available under
Oracle Solaris 11.
Signed-off-by: Brian Behlendorf <behlendorf1@llnl.gov>
Closes#640
For consistency, and because it's handy, add the 'zfs snap' alias which
was introduced by Oracle Solaris 11. This includes an update to the
man page to reflect all the available alias (snap, umount, and recv).
Signed-off-by: Brian Behlendorf <behlendorf1@llnl.gov>
Closes#640
1356 zfs dataset prefetch code not working
Reviewed by: Matthew Ahrens <matt@delphix.com>
Reviewed by: Dan McDonald <danmcd@nexenta.com>
Approved by: Gordon Ross <gwr@nexenta.com>
References to Illumos issue:
https://www.illumos.org/issues/1346https://www.illumos.org/issues/1356
Ported-by: Richard Yao <ryao@cs.stonybrook.edu>
Signed-off-by: Brian Behlendorf <behlendorf1@llnl.gov>
Closes#647
Reviewed by: Dan McDonald <danmcd@nexenta.com>
Reviewed by: Gordon Ross <gwr@nexenta.com>
Reviewed by: Matthew Ahrens <mahrens@delphix.com>
Reviewed by: George Wilson <gwilson@zfsmail.com>
Approved by: Garrett D'Amore <garrett@nexenta.com>
References to Illumos issue:
https://www.illumos.org/issues/1475
Ported-by: Richard Yao <ryao@cs.stonybrook.edu>
Signed-off-by: Brian Behlendorf <behlendorf1@llnl.gov>
Closes#648
1952 memory leak when adding a file-based l2arc device
1954 leak in ZFS from metaslab_group_create and zfs_ereport_checksum
Reviewed by: Adam Leventhal <ahl@delphix.com>
Reviewed by: Matt Ahrens <matt@delphix.com>
Reviewed by: Eric Schrock <eric.schrock@delphix.com>
Reviewed by: Bill Pijewski <wdp@joyent.com>
Reviewed by: Dan McDonald <danmcd@nexenta.com>
Approved by: Eric Schrock <eric.schrock@delphix.com>
References to Illumos issues:
https://www.illumos.org/issues/1951https://www.illumos.org/issues/1952https://www.illumos.org/issues/1954
Ported-by: Richard Yao <ryao@cs.stonybrook.edu>
Signed-off-by: Brian Behlendorf <behlendorf1@llnl.gov>
Closes#650
This change appears to be exclusive to SmartOS. It is not present in
illumos-gate but it just adds some needed error handling. This is
clearly preferable to simply ASSERTING which is what would occur
prior to the patch.
Reviewed by: Jerry Jelinek <jerry.jelinek@joyent.com>
Reviewed by: Matt Ahrens <matt@delphix.com>
Ported-by: Richard Yao <ryao@cs.stonybrook.edu>
Signed-off-by: Brian Behlendorf <behlendorf1@llnl.gov>
Closes#652
vdev_tsd can be NULL for certain vdev states.
At least in userland testing with ztest.
References to Illumos issue:
https://www.illumos.org/issues/1680
Ported-by: Richard Yao <ryao@cs.stonybrook.edu>
Signed-off-by: Brian Behlendorf <behlendorf1@llnl.gov>
Closes#655
Principly these symbols were exported to get access to the
dsl_prop_register/dsl_prop_unregister functions. They allow
us to cleanly register a callback which is called when a
dataset property is modified.
Signed-off-by: Brian Behlendorf <behlendorf1@llnl.gov>
Long ago I added support to the spl for condition variable names
because I thought they might be needed. It turns out they aren't.
In fact the official Solaris cv_init(9F) man page discourages
their use in the kernel.
cv_init(9F)
Parameters
name - Descriptive string. This is obsolete and should be
NULL. (Non-NULL strings are legal, but they're a
waste of kernel memory.)
Therefore, I'm removing them from the spl to reclaim this memory
and adding an ASSERT() to ensure no new consumers are added which
make use of the name.
Signed-off-by: Brian Behlendorf <behlendorf1@llnl.gov>
When zpl_fill_super -> zfs_domount fails (e.g. because the dataset
was destroyed before it could be successfully mounted) the subsequent
call to zpl_kill_sb -> zfs_preumount would derefence a NULL pointer.
This bug can be reproduced using this shell script:
#!/bin/sh
(
while true; do
zfs create -o mountpoint=legacz tank/bar
zfs destroy tank/bar
done
) &
(
while true; do
mount -t zfs tank/bar /mnt
umount /mnt
done
) &
Signed-off-by: Brian Behlendorf <behlendorf1@llnl.gov>
Closes#639
The -l parameter to modprobe has been removed from the latest upstream
code and this change has entered Gentoo. Using modinfo as a substitute
addresses this.
Signed-off-by: Brian Behlendorf <behlendorf1@llnl.gov>
Closes#636
A cryptic error code is printed when mounting a legacy dataset to a
non-existent mountpoint. This patch changes this behavior to print
"mount point '%s' does not exist", which is similar to the error
message printed when mounting procfs.
The single quotes were added to be consistent with the existing EBUSY
error message, which is the only difference between this error message
and the one that is printed when the same condition occurs when mounting
procfs.
Signed-off-by: Brian Behlendorf <behlendorf1@llnl.gov>
Closes#633
Due to a typo the mru ghost lists stats were accidentally being
exposed as the mfu ghost list stats. This was harmless but
confusing since memory usage could be over reported.
Signed-off-by: Brian Behlendorf <behlendorf1@llnl.gov>
When stdout is detected to be a tty use the number of columns
specified by the terminal. If that fails fall back to a default
80 column width. In the non-tty case allow for 999 column lines.
Signed-off-by: Brian Behlendorf <behlendorf1@llnl.gov>
Caught by lint, this permission change was accidentally introduced
by commit 42cb3819f1. Restore the
correct permissions and while I'm at it add a missing whack-bang
to config/ltmain.sh.
lint: executable-not-elf-or-script: zpool_main.c zfs_main.c
Signed-off-by: Brian Behlendorf <behlendorf1@llnl.gov>
Closes#620
Allow rigorous (and expensive) tx validation to be enabled/disabled
indepentantly from the standard zfs debugging. When enabled these
checks ensure that all txs are constructed properly and that a dbuf
is never dirtied without taking the correct tx hold.
This checking is particularly helpful when adding new dmu consumers
like Lustre. However, for established consumers such as the zpl
with no known outstanding tx construction problems this is just
overhead.
--enable-debug-dmu-tx - Enable/disable validation of each tx as
--disable-debug-dmu-tx it is constructed. By default validation
is disabled due to performance concerns.
Signed-off-by: Brian Behlendorf <behlendorf1@llnl.gov>
The following assertion is good to validate the correctness of
new DMU consumers, but it doesn't quite provide enough information.
Slightly rework the assertion so that when it is hit the actual
offending values will be included in the output.
SPLError: 4787:0:(dmu_tx.c:828:dmu_tx_dirty_buf())
ASSERTION(dn == NULL || dn->dn_assigned_txg == tx->tx_txg) failed
Signed-off-by: Brian Behlendorf <behlendorf1@llnl.gov>
Include the ZFS_META_RELEASE in the module load/unload messages
to more clearly indidcate exactly what version of ZFS has been
loaded.
Signed-off-by: Brian Behlendorf <behlendorf1@llnl.gov>
Include the ZFS_META_RELEASE in the module load/unload messages
to more clearly indicate exactly what version of the SPL has
been loaded.
Signed-off-by: Brian Behlendorf <behlendorf1@llnl.gov>
Because the .zfs ctldir inodes are not backed by physical storage
they use a different create path which was not properly accounting
for them as used. This could result in ->nr_cached_objects()
returning 0 and cause a divide by zero error in prune_super().
In my option there's a kernel bug here too which allows this to
happen. They should either be checking for 0 or adding +1 like
they correctly do earlier in the function.
Signed-off-by: Brian Behlendorf <behlendorf1@llnl.gov>
Closes#617
Add support for the .zfs control directory. This was accomplished
by leveraging as much of the existing ZFS infrastructure as posible
and updating it for Linux as required. The bulk of the core
functionality is now all there with the following limitations.
*) The .zfs/snapshot directory automount support requires a 2.6.37
or newer kernel. The exception is RHEL6.2 which has backported
the d_automount patches.
*) Creating/destroying/renaming snapshots with mkdir/rmdir/mv
in the .zfs/snapshot directory works as expected. However,
this functionality is only available to root until zfs
delegations are finished.
* mkdir - create a snapshot
* rmdir - destroy a snapshot
* mv - rename a snapshot
The following issues are known defeciences, but we expect them to
be addressed by future commits.
*) Add automount support for kernels older the 2.6.37. This should
be possible using follow_link() which is what Linux did before.
*) Accessing the .zfs/snapshot directory via NFS is not yet possible.
The majority of the ground work for this is complete. However,
finishing this work will require resolving some lingering
integration issues with the Linux NFS kernel server.
*) The .zfs/shares directory exists but no futher smb functionality
has yet been implemented.
Contributions-by: Rohan Puri <rohan.puri15@gmail.com>
Contributiobs-by: Andrew Barnes <barnes333@gmail.com>
Signed-off-by: Brian Behlendorf <behlendorf1@llnl.gov>
Closes#173
Add a standard zio constructor and destructor. Normally, this is
done to reduce to cost of allocating a new structure by reducing
expensive operations such as memory allocations. However, in this
case none of the operations moved out of zio_create() were really
very expensive.
This change was principly made as a debug patch (and workaround)
for a zio_destroy() race. The is good evidence that zio_create()
is reinitializing a mutex which is really still in use by another
thread. This would completely explain the observed symptoms in
the issue report.
This patch doesn't fix the root cause of the race, but it should
make it less likely by only initializing the mutex once in the
constructor. Also, this particular flaw might have gone unnoticed
in other zfs implementations due to the specific implementation
details of Linux ticket spinlocks.
Once the real root cause is determined and resolved this change
can be safely reverted. Until then this should help workaround
the issue.
Signed-off-by: Brian Behlendorf <behlendorf1@llnl.gov>
Issue #496
This patch was slightly flawed and allowed for zio->io_logical
to potentially not be reinitialized for a new zio. This could
lead to assertion failures in specific cases when debugging is
enabled (--enable-debug) and I/O errors are encountered. It
may also have caused problems when issues logical I/Os.
Since we want to make sure this workaround can be easily removed
in the future (when we have the real fix). I'm reverting this
change and applying a new version of the patch which includes
the zio->io_logical fix.
This reverts commit 2c6d0b1e07.
Signed-off-by: Brian Behlendorf <behlendorf1@llnl.gov>
Issue #602
Issue #604
The xattr_resolve_name() helper function expects the registered
list of xattr handlers to be NULL terminated. This NULL was
accidentally missing which could result in a NULL dereference.
Interestingly this issue only manifested itself on certain 32-bit
systems. Presumably on 64-bit kernels we just always happen to
get lucky and the memory following the structure is zeroed.
Signed-off-by: Brian Behlendorf <behlendorf1@llnl.gov>
Issue #594
The 'zfs list' and 'zpool list' commands output the message
'no datasets/pools available' to stdout. This should go to
stderr and only the available datasets/pools should go to
stdout. Returning nothing to stdout is expected behavior
when there is nothing to list.
Signed-off-by: Brian Behlendorf <behlendorf1@llnl.gov>
Closes#581
