mirror_zfs/include
LOLi fd01167ffd Fix hung z_zvol tasks during 'zfs receive'
During a receive operation zvol_create_minors_impl() can wait
needlessly for the prefetch thread because both share the same tasks
queue.  This results in hung tasks:

<3>INFO: task z_zvol:5541 blocked for more than 120 seconds.
<3>      Tainted: P           O  3.16.0-4-amd64
<3>"echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message.

The first z_zvol:5541 (zvol_task_cb) is waiting for the long running
traverse_prefetch_thread:260

root@linux:~# cat /proc/spl/taskq
taskq                       act  nthr  spwn  maxt   pri  mina
spl_system_taskq/0            1     2     0    64   100     1
	active: [260]traverse_prefetch_thread [zfs](0xffff88003347ae40)
	wait: 5541
spl_delay_taskq/0             0     1     0     4   100     1
	delay: spa_deadman [zfs](0xffff880039924000)
z_zvol/1                      1     1     0     1   120     1
	active: [5541]zvol_task_cb [zfs](0xffff88001fde6400)
	pend: zvol_task_cb [zfs](0xffff88001fde6800)

This change adds a dedicated, per-pool, prefetch taskq to prevent the
traverse code from monopolizing the global (and limited) system_taskq by
inappropriately scheduling long running tasks on it.

Reviewed-by: Albert Lee <trisk@forkgnu.org>
Signed-off-by: Brian Behlendorf <behlendorf1@llnl.gov>
Signed-off-by: loli10K <ezomori.nozomu@gmail.com>
Closes #6330
Closes #6890
Closes #7343
2018-05-07 17:19:57 -07:00
..
linux Linux 4.16 compat: get_disk_and_module() 2018-03-14 16:10:38 -07:00
sys Fix hung z_zvol tasks during 'zfs receive' 2018-05-07 17:19:57 -07:00
libnvpair.h Support custom build directories and move includes 2010-09-08 12:38:56 -07:00
libuutil_common.h Support custom build directories and move includes 2010-09-08 12:38:56 -07:00
libuutil_impl.h Support custom build directories and move includes 2010-09-08 12:38:56 -07:00
libuutil.h Correct cppcheck errors (#6662) 2017-09-20 12:59:21 -07:00
libzfs_core.h OpenZFS 7600 - zfs rollback should pass target snapshot to kernel 2017-07-04 15:29:52 -07:00
libzfs_impl.h Multi-modifier protection (MMP) 2017-07-13 13:54:00 -04:00
libzfs.h Report pool suspended due to MMP 2018-05-07 17:19:56 -07:00
Makefile.am Kernel header installation should respect --prefix 2014-10-28 09:37:06 -07:00
zfeature_common.h OpenZFS 2932 - support crash dumps to raidz, etc. pools 2017-04-10 10:24:17 -07:00
zfs_comutil.h Illumos #2882, #2883, #2900 2013-09-04 15:49:00 -07:00
zfs_deleg.h Add support for user/group dnode accounting & quota 2016-10-07 09:45:13 -07:00
zfs_fletcher.h DLPX-44812 integrate EP-220 large memory scalability 2016-11-29 14:34:27 -08:00
zfs_namecheck.h OpenZFS 7386 - zfs get does not work properly with bookmarks 2017-01-26 14:42:15 -08:00
zfs_prop.h Check the dataset type more rigorously when fetching properties. 2014-05-06 10:41:46 -07:00
zpios-ctl.h Fix spelling 2017-01-03 11:31:18 -06:00
zpios-internal.h Fix spelling 2017-01-03 11:31:18 -06:00