Reviewed-by: Matt Ahrens <matt@delphix.com>
Reviewed-by: Ryan Moeller <ryan@ixsystems.com>
Reviewed-by: Richard Laager <rlaager@wiktel.com>
Reviewed-by: Brian Behlendorf <behlendorf1@llnl.gov>
Signed-off-by: Andrea Gelmini <andrea.gelmini@gelma.net>
Closes#9240
ZED can prevent CPU's from properly sleeping.
Rather than periodically waking up in the zevents code, just go to sleep and wait for a wakeup.
Reviewed-by: Brian Behlendorf <behlendorf1@llnl.gov>
Reviewed-by: Tony Hutter <hutter2@llnl.gov>
Signed-off-by: DHE <git@dehacked.net>
Closes#9091
= Motivation
While dealing with another performance issue (see 126118f) we noticed
that we spend a lot of time in various places in the kernel when
constructing long nvlists. The problem is that when an nvlist is created
with the NV_UNIQUE_NAME set (which is the case most of the time), we do
a linear search through the whole list to ensure uniqueness for every
entry we add.
An example of the above scenario can be seen in the following
flamegraph, where more than have the time of the zfsdev_ioctl() is spent
on constructing nvlists. Flamegraph:
https://sdimitro.github.io/img/flame/sdimitro_snap_unmount3.svg
Adding a table to speed up lookups will help situations where we just
construct an nvlist (like the scenario above), in addition to regular
lookups and removals.
= What this patch does
In this diff we've implemented a hash-table on top of the nvlist code
that converts most nvlist operations from O(# number of entries) to
O(1)* (the start is for amortized time as the hash-table grows and
shrinks depending on the # of entries - plain lookup is strictly O(1)).
= Performance Analysis
To analyze the performance improvement I just used the setup from the
snapshot deletion issue mentioned above in the Motivation section.
Basically I created 10K filesystems with one snapshot each and then I
just used the API of libZFS_Core to pass down an nvlist of all the
snapshots to have them deleted. The reason I used my own driver program
was to have clean performance results of what actually happens in the
kernel. The flamegraphs and wall clock times mentioned below were
gathered from the start to the end of the driver program's run. Between
trials the testpool used was completely destroyed, the system was
rebooted and the testpool was completely recreated. The reason for this
dance was to get consistent results.
== Results (before patch):
=== Sampling Flamegraphs
[Trial 1] https://sdimitro.github.io/img/flame/DLPX-53417/trial-A.svg
[Trial 2] https://sdimitro.github.io/img/flame/DLPX-53417/trial-A2.svg
[Trial 3] https://sdimitro.github.io/img/flame/DLPX-53417/trial-A3.svg
=== Wall clock times (in seconds)
```
[Trial 4]
real 5.3
user 0.4
sys 2.3
[Trial 5]
real 8.2
user 0.4
sys 2.4
[Trial 6]
real 6.0
user 0.5
sys 2.3
```
== Results (after patch):
=== Sampling Flamegraphs
[Trial 1] https://sdimitro.github.io/img/flame/DLPX-53417/trial-Ae.svg
[Trial 2] https://sdimitro.github.io/img/flame/DLPX-53417/trial-A2e.svg
[Trial 3] https://sdimitro.github.io/img/flame/DLPX-53417/trial-A3e.svg
=== Wall clock times (in seconds)
```
[Trial 4]
real 4.9
user 0.0
sys 0.9
[Trial 5]
real 3.8
user 0.0
sys 0.9
[Trial 6]
real 3.6
user 0.0
sys 0.9
```
== Analysis
The results between the trials are consistent so in this sections I will
only talk about the flamegraph results from trial-1 and the wall-clock
results from trial-4.
From trial-1 we can see that zfs_dev_ioctl() goes from 2,331 to 996
samples counts. Specifically, the samples from fnvlist_add_nvlist() and
spa_history_log_nvl() are almost gone (~500 & ~800 to 5 & 5 samples),
leaving zfs_ioc_destroy_snaps() to dominate most samples from
zfs_dev_ioctl().
From trial-4 we see that the user time dropped to 0 secods. I believe
the consistent 0.4 seconds before my patch was applied was due to my
driver program constructing the long nvlist of snapshots so it can pass
it to the kernel. As for the system time, the effect there is more clear
(2.3 down to 0.9 seconds).
Porting Notes:
* DATA_TYPE_DONTCARE case added to switch in fm_nvprintr() and
zpool_do_events_nvprint().
Authored by: Serapheim Dimitropoulos <serapheim.dimitro@delphix.com>
Reviewed by: Matt Ahrens <matt@delphix.com>
Reviewed by: Sebastien Roy <sebastien.roy@delphix.com>
Approved by: Robert Mustacchi <rm@joyent.com>
Ported-by: Brian Behlendorf <behlendorf1@llnl.gov>
OpenZFS-issue: https://www.illumos.org/issues/9580
OpenZFS-commit: https://github.com/openzfs/openzfs/commit/b5eca7b1Closes#7748
While the autoexpand property may seem like a small feature it
depends on a significant amount of system infrastructure. Enough
of that infrastructure is now in place that with a few modifications
for Linux it can be supported.
Auto-expand works as follows; when a block device is modified
(re-sized, closed after being open r/w, etc) a change uevent is
generated for udev. The ZED, which is monitoring udev events,
passes the change event along to zfs_deliver_dle() if the disk
or partition contains a zfs_member as identified by blkid.
From here the device is matched against all imported pool vdevs
using the vdev_guid which was read from the label by blkid. If
a match is found the ZED reopens the pool vdev. This re-opening
is important because it allows the vdev to be briefly closed so
the disk partition table can be re-read. Otherwise, it wouldn't
be possible to report the maximum possible expansion size.
Finally, if the property autoexpand=on a vdev expansion will be
attempted. After performing some sanity checks on the disk to
verify that it is safe to expand, the primary partition (-part1)
will be expanded and the partition table updated. The partition
is then re-opened (again) to detect the updated size which allows
the new capacity to be used.
In order to make all of the above possible the following changes
were required:
* Updated the zpool_expand_001_pos and zpool_expand_003_pos tests.
These tests now create a pool which is layered on a loopback,
scsi_debug, and file vdev. This allows for testing of non-
partitioned block device (loopback), a partition block device
(scsi_debug), and a file which does not receive udev change
events. This provided for better test coverage, and by removing
the layering on ZFS volumes there issues surrounding layering
one pool on another are avoided.
* zpool_find_vdev_by_physpath() updated to accept a vdev guid.
This allows for matching by guid rather than path which is a
more reliable way for the ZED to reference a vdev.
* Fixed zfs_zevent_wait() signal handling which could result
in the ZED spinning when a signal was not handled.
* Removed vdev_disk_rrpart() functionality which can be abandoned
in favor of kernel provided blkdev_reread_part() function.
* Added a rwlock which is held as a writer while a disk is being
reopened. This is important to prevent errors from occurring
for any configuration related IOs which bypass the SCL_ZIO lock.
The zpool_reopen_007_pos.ksh test case was added to verify IO
error are never observed when reopening. This is not expected
to impact IO performance.
Additional fixes which aren't critical but were discovered and
resolved in the course of developing this functionality.
* Added PHYS_PATH="/dev/zvol/dataset" to the vdev configuration for
ZFS volumes. This is as good as a unique physical path, while the
volumes are not used in the test cases anymore for other reasons
this improvement was included.
Reviewed by: Richard Elling <Richard.Elling@RichardElling.com>
Signed-off-by: Sara Hartse <sara.hartse@delphix.com>
Signed-off-by: Brian Behlendorf <behlendorf1@llnl.gov>
Closes#120Closes#2437Closes#5771Closes#7366Closes#7582Closes#7629
Commit torvalds/linux@95582b0 changes the inode i_atime, i_mtime,
and i_ctime members form timespec's to timespec64's to make them
2038 safe. As part of this change the current_time() function was
also updated to return the timespec64 type.
Resolve this issue by introducing a new inode_timespec_t type which
is defined to match the timespec type used by the inode. It should
be used when working with inode timestamps to ensure matching types.
The timestruc_t type under Illumos was used in a similar fashion but
was specified to always be a timespec_t. Rather than incorrectly
define this type all timespec_t types have been replaced by the new
inode_timespec_t type.
Finally, the kernel and user space 'sys/time.h' headers were aligned
with each other. They define as appropriate for the context several
constants as macros and include static inline implementation of
gethrestime(), gethrestime_sec(), and gethrtime().
Reviewed-by: Chunwei Chen <tuxoko@gmail.com>
Signed-off-by: Brian Behlendorf <behlendorf1@llnl.gov>
Closes#7643
Minimal changes required to integrate the SPL sources in to the
ZFS repository build infrastructure and packaging.
Build system and packaging:
* Renamed SPL_* autoconf m4 macros to ZFS_*.
* Removed redundant SPL_* autoconf m4 macros.
* Updated the RPM spec files to remove SPL package dependency.
* The zfs package obsoletes the spl package, and the zfs-kmod
package obsoletes the spl-kmod package.
* The zfs-kmod-devel* packages were updated to add compatibility
symlinks under /usr/src/spl-x.y.z until all dependent packages
can be updated. They will be removed in a future release.
* Updated copy-builtin script for in-kernel builds.
* Updated DKMS package to include the spl.ko.
* Updated stale AUTHORS file to include all contributors.
* Updated stale COPYRIGHT and included the SPL as an exception.
* Renamed README.markdown to README.md
* Renamed OPENSOLARIS.LICENSE to LICENSE.
* Renamed DISCLAIMER to NOTICE.
Required code changes:
* Removed redundant HAVE_SPL macro.
* Removed _BOOT from nvpairs since it doesn't apply for Linux.
* Initial header cleanup (removal of empty headers, refactoring).
* Remove SPL repository clone/build from zimport.sh.
* Use of DEFINE_RATELIMIT_STATE and DEFINE_SPINLOCK removed due
to build issues when forcing C99 compilation.
* Replaced legacy ACCESS_ONCE with READ_ONCE.
* Include needed headers for `current` and `EXPORT_SYMBOL`.
Reviewed-by: Tony Hutter <hutter2@llnl.gov>
Reviewed-by: Olaf Faaland <faaland1@llnl.gov>
Reviewed-by: Matthew Ahrens <mahrens@delphix.com>
Reviewed-by: Pavel Zakharov <pavel.zakharov@delphix.com>
Signed-off-by: Brian Behlendorf <behlendorf1@llnl.gov>
TEST_ZIMPORT_SKIP="yes"
Closes#7556
Fix build errors with gcc 7.2.0 on Gentoo with kernel 4.14
built with CONFIG_GCC_PLUGIN_RANDSTRUCT=y such as:
module/nvpair/nvpair.c:2810:2:error:
positional initialization of field in ?struct? declared with
'designated_init' attribute [-Werror=designated-init]
nvs_native_nvlist,
^~~~~~~~~~~~~~~~~
Reviewed-by: Brian Behlendorf <behlendorf1@llnl.gov>
Signed-off-by: Mark Wright <gienah@gentoo.org>
Closes#5390Closes#6903
Update many return and assignment statements to follow the convention
of using the SET_ERROR macro when returning a hard-coded non-zero
value from a function. This aids debugging by recording the error
codes in the debug log.
Reviewed-by: George Melikov <mail@gmelikov.ru>
Reviewed-by: Giuseppe Di Natale <dinatale2@llnl.gov>
Reviewed-by: Brian Behlendorf <behlendorf1@llnl.gov>
Reviewed by: Matthew Ahrens <mahrens@delphix.com>
Signed-off-by: Ned Bass <bass6@llnl.gov>
Closes#6441
Enable picky cstyle checks and resolve the new warnings. The vast
majority of the changes needed were to handle minor issues with
whitespace formatting. This patch contains no functional changes.
Non-whitespace changes are as follows:
* 8 times ; to { } in for/while loop
* fix missing ; in cmd/zed/agents/zfs_diagnosis.c
* comment (confim -> confirm)
* change endline , to ; in cmd/zpool/zpool_main.c
* a number of /* BEGIN CSTYLED */ /* END CSTYLED */ blocks
* /* CSTYLED */ markers
* change == 0 to !
* ulong to unsigned long in module/zfs/dsl_scan.c
* rearrangement of module_param lines in module/zfs/metaslab.c
* add { } block around statement after for_each_online_node
Reviewed-by: Giuseppe Di Natale <dinatale2@llnl.gov>
Reviewed-by: Håkan Johansson <f96hajo@chalmers.se>
Signed-off-by: Brian Behlendorf <behlendorf1@llnl.gov>
Closes#5465
1. Enable multipath autoreplace support for FMA.
This extends FMA autoreplace to work with multipath disks. This
requires libdevmapper to be installed at build time.
2. Turn on/off fault LEDs when VDEVs become degraded/faulted/online
Set ZED_USE_ENCLOSURE_LEDS=1 in zed.rc to have ZED turn on/off the enclosure
LED for a drive when a drive becomes FAULTED/DEGRADED. Your enclosure must
be supported by the Linux SES driver for this to work. The enclosure LED
scripts work for multipath devices as well. The scripts will clear the LED
when the fault is cleared.
3. Rate limit ZIO delay and checksum events so as not to flood ZED
ZIO delay and checksum events are rate limited to 5/sec in the zfs module.
Reviewed-by: Richard Laager <rlaager@wiktel.com>
Reviewed by: Don Brady <don.brady@intel.com>
Reviewed-by: Brian Behlendorf <behlendorf1@llnl.gov>
Signed-off-by: Tony Hutter <hutter2@llnl.gov>
Closes#2449Closes#3017Closes#5159
These allocations can never fail. Leaving the error handling
code here gives the impression they can so it has been removed.
Signed-off-by: luozhengzheng <luo.zhengzheng@zte.com.cn>
Signed-off-by: Brian Behlendorf <behlendorf1@llnl.gov>
Closes#5048
zfsctl_snapdir_inactive is defined in zfs-0.6.3. In zfs-0.6.5.7
this is declaration remains even though the implementation was
removed in commit 278bee93. Removed fastreboot_disable_highpil
which is also unused.
Signed-off-by: caoxuewen cao.xuewen@zte.com.cn
Signed-off-by: Brian Behlendorf <behlendorf1@llnl.gov>
Closes#5042
The indefinite article before nvlist should be "an", not "a".
We have 27 "an nvlist" and 7 "a nvlist" in our comment, they should
stay the same as we are such a strict filesystem.
Signed-off-by: GeLiXin <ge.lixin@zte.com.cn>
Signed-off-by: Brian Behlendorf <behlendorf1@llnl.gov>
Closes#4941
5045 use atomic_{inc,dec}_* instead of atomic_add_*
Reviewed by: Matthew Ahrens <mahrens@delphix.com>
Reviewed by: Garrett D'Amore <garrett@damore.org>
Approved by: Robert Mustacchi <rm@joyent.com>
References:
https://www.illumos.org/issues/5045https://github.com/illumos/illumos-gate/commit/1a5e258
Porting notes:
- All changes to non-ZFS files dropped.
- Changes to zfs_vfsops.c dropped because they were Illumos specific.
Ported-by: Brian Behlendorf <behlendorf1@llnl.gov>
Closes#4220
Unit testing at ClusterHQ found that passing an invalid file handle to
zfs_ioc_hold results in a NULL pointer dereference on a system without
assertions:
IP: [<ffffffffa0218aa0>] zfsdev_getminor+0x10/0x20 [zfs]
Call Trace:
[<ffffffffa021b4b0>] zfs_onexit_fd_hold+0x20/0x40 [zfs]
[<ffffffffa0214043>] zfs_ioc_hold+0x93/0xd0 [zfs]
[<ffffffffa0215890>] zfsdev_ioctl+0x200/0x500 [zfs]
An assertion would have caught this had they been enabled, but this is
something that the kernel module should handle without failing. We
resolve this by searching the linked list to ensure that the file
handle's private_data points to a valid zfsdev_state_t.
Signed-off-by: Richard Yao <ryao@gentoo.org>
Signed-off-by: Andriy Gapon <avg@FreeBSD.org>
Signed-off-by: Brian Behlendorf <behlendorf1@llnl.gov>
Closes#3506
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
By marking DMU transaction processing contexts with PF_FSTRANS
we can revert the KM_PUSHPAGE -> KM_SLEEP changes. This brings
us back in line with upstream. In some cases this means simply
swapping the flags back. For others fnvlist_alloc() was replaced
by nvlist_alloc(..., KM_PUSHPAGE) and must be reverted back to
fnvlist_alloc() which assumes KM_SLEEP.
The one place KM_PUSHPAGE is kept is when allocating ARC buffers
which allows us to dip in to reserved memory. This is again the
same as upstream.
Signed-off-by: Brian Behlendorf <behlendorf1@llnl.gov>
Some nvlist_t could be leaked in error handling paths.
Also make sure cb argument to zfs_zevent_post() cannnot
be NULL.
Signed-off-by: Isaac Huang <he.huang@intel.com>
Signed-off-by: Brian Behlendorf <behlendorf1@llnl.gov>
Closes#2158
The ZFS_IOC_EVENTS_SEEK ioctl was added to allow user space callers
to seek around the zevent file descriptor by EID. When a specific
EID is passed and it exists the cursor will be positioned there.
If the EID is no longer cached by the kernel ENOENT is returned.
The caller may also pass ZEVENT_SEEK_START or ZEVENT_SEEK_END to seek
to those respective locations.
Signed-off-by: Brian Behlendorf <behlendorf1@llnl.gov>
Signed-off-by: Chris Dunlap <cdunlap@llnl.gov>
Issue #2
Tagging each zevent with a unique monotonically increasing EID
(Event IDentifier) provides the required infrastructure for a user
space daemon to reliably process zevents. By writing the EID to
persistent storage the daemon can safely resume where it left off
in the event stream when it's restarted.
Signed-off-by: Brian Behlendorf <behlendorf1@llnl.gov>
Signed-off-by: Chris Dunlap <cdunlap@llnl.gov>
Issue #2
The vast majority of these changes are in Linux specific code.
They are the result of not having an automated style checker to
validate the code when it was originally written. Others were
caused when the common code was slightly adjusted for Linux.
This patch contains no functional changes. It only refreshes
the code to conform to style guide.
Everyone submitting patches for inclusion upstream should now
run 'make checkstyle' and resolve any warning prior to opening
a pull request. The automated builders have been updated to
fail a build if when 'make checkstyle' detects an issue.
Signed-off-by: Brian Behlendorf <behlendorf1@llnl.gov>
Closes#1821
The following incorrect usage of cv_broadcast() was caught by
code inspection. The cv_broadcast() function must be called
under the associated mutex to preventing racing with cv_wait().
Signed-off-by: Brian Behlendorf <behlendorf1@llnl.gov>
This warning indicates the incorrect use of KM_SLEEP in a call
path which must use KM_PUSHPAGE to avoid deadlocking in direct
reclaim. See commit b8d06fca08
for additional details.
SPL: Fixing allocation for task txg_sync (6093) which
used GFP flags 0x297bda7c with PF_NOFS set
Signed-off-by: Chris Dunlop <chris@onthe.net.au>
Signed-off-by: Brian Behlendorf <behlendorf1@llnl.gov>
Issue #917
This warning indicates the incorrect use of KM_SLEEP in a call
path which must use KM_PUSHPAGE to avoid deadlocking in direct
reclaim. See commit b8d06fca08
for additional details.
SPL: Fixing allocation for task txg_sync (6093) which
used GFP flags 0x297bda7c with PF_NOFS set
Signed-off-by: Brian Behlendorf <behlendorf1@llnl.gov>
Issue #917
After surveying the code, the few places where smp_processor_id is used
were deemed to be safe to use with a preempt enabled kernel. As such, no
core logic had to be changed. These smp_processor_id call sites are simply
are wrapped in kpreempt_disable and kpreempt_enabled to prevent the
Linux kernel from emitting scary warnings.
Signed-off-by: Prakash Surya <surya1@llnl.gov>
Signed-off-by: Brian Behlendorf <behlendorf1@llnl.gov>
Signed-off-by: Richard Yao <ryao@cs.stonybrook.edu>
Issue #83
This commit adds module options for all existing zfs tunables.
Ideally the average user should never need to modify any of these
values. However, in practice sometimes you do need to tweak these
values for one reason or another. In those cases it's nice not to
have to resort to rebuilding from source. All tunables are visable
to modinfo and the list is as follows:
$ modinfo module/zfs/zfs.ko
filename: module/zfs/zfs.ko
license: CDDL
author: Sun Microsystems/Oracle, Lawrence Livermore National Laboratory
description: ZFS
srcversion: 8EAB1D71DACE05B5AA61567
depends: spl,znvpair,zcommon,zunicode,zavl
vermagic: 2.6.32-131.0.5.el6.x86_64 SMP mod_unload modversions
parm: zvol_major:Major number for zvol device (uint)
parm: zvol_threads:Number of threads for zvol device (uint)
parm: zio_injection_enabled:Enable fault injection (int)
parm: zio_bulk_flags:Additional flags to pass to bulk buffers (int)
parm: zio_delay_max:Max zio millisec delay before posting event (int)
parm: zio_requeue_io_start_cut_in_line:Prioritize requeued I/O (bool)
parm: zil_replay_disable:Disable intent logging replay (int)
parm: zfs_nocacheflush:Disable cache flushes (bool)
parm: zfs_read_chunk_size:Bytes to read per chunk (long)
parm: zfs_vdev_max_pending:Max pending per-vdev I/Os (int)
parm: zfs_vdev_min_pending:Min pending per-vdev I/Os (int)
parm: zfs_vdev_aggregation_limit:Max vdev I/O aggregation size (int)
parm: zfs_vdev_time_shift:Deadline time shift for vdev I/O (int)
parm: zfs_vdev_ramp_rate:Exponential I/O issue ramp-up rate (int)
parm: zfs_vdev_read_gap_limit:Aggregate read I/O over gap (int)
parm: zfs_vdev_write_gap_limit:Aggregate write I/O over gap (int)
parm: zfs_vdev_scheduler:I/O scheduler (charp)
parm: zfs_vdev_cache_max:Inflate reads small than max (int)
parm: zfs_vdev_cache_size:Total size of the per-disk cache (int)
parm: zfs_vdev_cache_bshift:Shift size to inflate reads too (int)
parm: zfs_scrub_limit:Max scrub/resilver I/O per leaf vdev (int)
parm: zfs_recover:Set to attempt to recover from fatal errors (int)
parm: spa_config_path:SPA config file (/etc/zfs/zpool.cache) (charp)
parm: zfs_zevent_len_max:Max event queue length (int)
parm: zfs_zevent_cols:Max event column width (int)
parm: zfs_zevent_console:Log events to the console (int)
parm: zfs_top_maxinflight:Max I/Os per top-level (int)
parm: zfs_resilver_delay:Number of ticks to delay resilver (int)
parm: zfs_scrub_delay:Number of ticks to delay scrub (int)
parm: zfs_scan_idle:Idle window in clock ticks (int)
parm: zfs_scan_min_time_ms:Min millisecs to scrub per txg (int)
parm: zfs_free_min_time_ms:Min millisecs to free per txg (int)
parm: zfs_resilver_min_time_ms:Min millisecs to resilver per txg (int)
parm: zfs_no_scrub_io:Set to disable scrub I/O (bool)
parm: zfs_no_scrub_prefetch:Set to disable scrub prefetching (bool)
parm: zfs_txg_timeout:Max seconds worth of delta per txg (int)
parm: zfs_no_write_throttle:Disable write throttling (int)
parm: zfs_write_limit_shift:log2(fraction of memory) per txg (int)
parm: zfs_txg_synctime_ms:Target milliseconds between tgx sync (int)
parm: zfs_write_limit_min:Min tgx write limit (ulong)
parm: zfs_write_limit_max:Max tgx write limit (ulong)
parm: zfs_write_limit_inflated:Inflated tgx write limit (ulong)
parm: zfs_write_limit_override:Override tgx write limit (ulong)
parm: zfs_prefetch_disable:Disable all ZFS prefetching (int)
parm: zfetch_max_streams:Max number of streams per zfetch (uint)
parm: zfetch_min_sec_reap:Min time before stream reclaim (uint)
parm: zfetch_block_cap:Max number of blocks to fetch at a time (uint)
parm: zfetch_array_rd_sz:Number of bytes in a array_read (ulong)
parm: zfs_pd_blks_max:Max number of blocks to prefetch (int)
parm: zfs_dedup_prefetch:Enable prefetching dedup-ed blks (int)
parm: zfs_arc_min:Min arc size (ulong)
parm: zfs_arc_max:Max arc size (ulong)
parm: zfs_arc_meta_limit:Meta limit for arc size (ulong)
parm: zfs_arc_reduce_dnlc_percent:Meta reclaim percentage (int)
parm: zfs_arc_grow_retry:Seconds before growing arc size (int)
parm: zfs_arc_shrink_shift:log2(fraction of arc to reclaim) (int)
parm: zfs_arc_p_min_shift:arc_c shift to calc min/max arc_p (int)
It turns out that 'zpool events' over 1024 bytes in size where being
silently dropped. This was discovered while writing the zfault.sh
tests to validate common failure modes.
This could occur because the zfs interface for passing an arbitrary
size nvlist_t over an ioctl() is to provide a buffer for the packed
nvlist which is usually big enough. In this case 1024 byte is the
default. If the kernel determines the buffer is to small it returns
ENOMEM and the minimum required size of the nvlist_t. This was
working properly but in the case of 'zpool events' the event stream
was advanced dispite the error. Thus the retry with the bigger
buffer would succeed but it would skip over the previous event.
The fix is to pass this size to zfs_zevent_next() and determine
before removing the event from the list if it will fit. This was
preferable to checking after the event was returned because this
avoids the need to rewind the stream.
This topic branch leverages the Solaris style FMA call points
in ZFS to create a user space visible event notification system
under Linux. This new system is called zevent and it unifies
all previous Solaris style ereports and sysevent notifications.
Under this Linux specific scheme when a sysevent or ereport event
occurs an nvlist describing the event is created which looks almost
exactly like a Solaris ereport. These events are queued up in the
kernel when they occur and conditionally logged to the console.
It is then up to a user space application to consume the events
and do whatever it likes with them.
To make this possible the existing /dev/zfs ABI has been extended
with two new ioctls which behave as follows.
* ZFS_IOC_EVENTS_NEXT
Get the next pending event. The kernel will keep track of the last
event consumed by the file descriptor and provide the next one if
available. If no new events are available the ioctl() will block
waiting for the next event. This ioctl may also be called in a
non-blocking mode by setting zc.zc_guid = ZEVENT_NONBLOCK. In the
non-blocking case if no events are available ENOENT will be returned.
It is possible that ESHUTDOWN will be returned if the ioctl() is
called while module unloading is in progress. And finally ENOMEM
may occur if the provided nvlist buffer is not large enough to
contain the entire event.
* ZFS_IOC_EVENTS_CLEAR
Clear are events queued by the kernel. The kernel will keep a fairly
large number of recent events queued, use this ioctl to clear the
in kernel list. This will effect all user space processes consuming
events.
The zpool command has been extended to use this events ABI with the
'events' subcommand. You may run 'zpool events -v' to output a
verbose log of all recent events. This is very similar to the
Solaris 'fmdump -ev' command with the key difference being it also
includes what would be considered sysevents under Solaris. You
may also run in follow mode with the '-f' option. To clear the
in kernel event queue use the '-c' option.
$ sudo cmd/zpool/zpool events -fv
TIME CLASS
May 13 2010 16:31:15.777711000 ereport.fs.zfs.config.sync
class = "ereport.fs.zfs.config.sync"
ena = 0x40982b7897700001
detector = (embedded nvlist)
version = 0x0
scheme = "zfs"
pool = 0xed976600de75dfa6
(end detector)
time = 0x4bec8bc3 0x2e5aed98
pool = "zpios"
pool_guid = 0xed976600de75dfa6
pool_context = 0x0
While the 'zpool events' command is handy for interactive debugging
it is not expected to be the primary consumer of zevents. This ABI
was primarily added to facilitate the addition of a user space
monitoring daemon. This daemon would consume all events posted by
the kernel and based on the type of event perform an action. For
most events simply forwarding them on to syslog is likely enough.
But this interface also cleanly allows for more sophisticated
actions to be taken such as generating an email for a failed drive.
Signed-off-by: Brian Behlendorf <behlendorf1@llnl.gov>
