mirror_zfs/module
Matthew Ahrens 325d288c5d Add fast path for zfs_ioc_space_snaps() handling of empty_bpobj
When there are many snapshots, calls to zfs_ioc_space_snaps() (e.g. from
`zfs destroy -nv pool/fs@snap1%snap10000`) can be very slow, resulting
in poor performance because we are holding the dp_config_rwlock the
entire time, blocking spa_sync() from continuing.  With around ten
thousand snapshots, we've seen up to 500 seconds in this ioctl,
iterating over up to 50,000,000 bpobjs, ~99% of which are the empty
bpobj.

By creating a fast path for zfs_ioc_space_snaps() handling of the
empty_bpobj, we can achieve a ~5x performance improvement of this ioctl
(when there are many snapshots, and the deadlist is mostly
empty_bpobj's).

Reviewed-by: Pavel Zakharov <pavel.zakharov@delphix.com>
Reviewed-by: Brian Behlendorf <behlendorf1@llnl.gov>
Reviewed-by: Paul Dagnelie <pcd@delphix.com>
Signed-off-by: Matthew Ahrens <mahrens@delphix.com>
External-issue: DLPX-58348
Closes #8744
2019-08-20 11:34:52 -07:00
..
avl Update build system and packaging 2018-05-29 16:00:33 -07:00
icp Minor style cleanup 2019-07-16 17:22:31 -07:00
lua Fix channel programs on s390x 2019-07-28 18:15:26 -07:00
nvpair Use NV_ENCODE_NATIVE for nvlist encoding variable 2019-04-26 11:24:31 -07:00
spl Drop KMC_NOEMERGENCY 2019-08-13 07:46:12 -06:00
unicode Update build system and packaging 2018-05-29 16:00:33 -07:00
zcommon Fast Clone Deletion 2019-07-26 10:54:14 -07:00
zfs Add fast path for zfs_ioc_space_snaps() handling of empty_bpobj 2019-08-20 11:34:52 -07:00
.gitignore Prepare SPL repo to merge with ZFS repo 2018-05-29 14:51:39 -07:00
Makefile.in Linux 5.3 compat: Makefile subdir-m no longer supported 2019-08-19 15:22:52 -07:00