zfs/include
Chunwei Chen 64c259c509 Batch free zpl_posix_acl_release
Currently every calls to zpl_posix_acl_release will schedule a delayed task,
and each delayed task will add a timer. This used to be fine except for
possibly bad performance impact.

However, in Linux 4.8, a new timer wheel implementation[1] is introduced. In
this new implementation, the larger the delay, the less accuracy the timer is.
So when we have a flood of timer from zpl_posix_acl_release, they will expire
at the same time. Couple with the fact that task_expire will do linear search
with lock held. This causes an extreme amount of contention inside interrupt
and would actually lockup the system.

We fix this by doing batch free to prevent a flood of delayed task. Every call
to zpl_posix_acl_release will put the posix_acl to be freed on a lockless
list. Every batch window, 1 sec, the zpl_posix_acl_free will fire up and free
every posix_acl that passed the grace period on the list. This way, we only
have one delayed task every second.

[1] https://lwn.net/Articles/646950/

Signed-off-by: Chunwei Chen <david.chen@osnexus.com>
2017-02-03 10:24:45 -08:00
..
linux Batch free zpl_posix_acl_release 2017-02-03 10:24:45 -08:00
sys Linux 3.14 compat: assign inode->set_acl 2017-02-03 10:24:09 -08:00
Makefile.am Kernel header installation should respect --prefix 2014-10-28 09:37:06 -07:00
libnvpair.h Support custom build directories and move includes 2010-09-08 12:38:56 -07:00
libuutil.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
libzfs.h Add -gLp to zpool subcommands for alt vdev names 2016-03-22 17:54:06 -07:00
libzfs_core.h Illumos 5027 - zfs large block support 2015-05-11 12:23:16 -07:00
libzfs_impl.h Illumos 4368, 4369. 2014-07-29 10:55:29 -07:00
zfeature_common.h Illumos 5027 - zfs large block support 2015-05-11 12:23:16 -07:00
zfs_comutil.h Illumos #2882, #2883, #2900 2013-09-04 15:49:00 -07:00
zfs_deleg.h Illumos 4368, 4369. 2014-07-29 10:55:29 -07:00
zfs_fletcher.h Support custom build directories and move includes 2010-09-08 12:38:56 -07:00
zfs_namecheck.h Illumos 4368, 4369. 2014-07-29 10:55:29 -07:00
zfs_prop.h Check the dataset type more rigorously when fetching properties. 2014-05-06 10:41:46 -07:00
zpios-ctl.h Update code to use misc_register()/misc_deregister() 2014-10-17 14:58:44 -07:00
zpios-internal.h cstyle: Resolve C style issues 2013-12-18 16:46:35 -08:00