mirror_zfs/include
Shaan Nobee 9e5a297de6 Speed up WB_SYNC_NONE when a WB_SYNC_ALL occurs simultaneously
Page writebacks with WB_SYNC_NONE can take several seconds to complete
since they wait for the transaction group to close before being
committed. This is usually not a problem since the caller does not
need to wait. However, if we're simultaneously doing a writeback
with WB_SYNC_ALL (e.g via msync), the latter can block for several
seconds (up to zfs_txg_timeout) due to the active WB_SYNC_NONE
writeback since it needs to wait for the transaction to complete
and the PG_writeback bit to be cleared.

This commit deals with 2 cases:

- No page writeback is active. A WB_SYNC_ALL page writeback starts
  and even completes. But when it's about to check if the PG_writeback
  bit has been cleared, another writeback with WB_SYNC_NONE starts.
  The sync page writeback ends up waiting for the non-sync page
  writeback to complete.

- A page writeback with WB_SYNC_NONE is already active when a
  WB_SYNC_ALL writeback starts. The WB_SYNC_ALL writeback ends up
  waiting for the WB_SYNC_NONE writeback.

The fix works by carefully keeping track of active sync/non-sync
writebacks and committing when beneficial.

Reviewed-by: Brian Behlendorf <behlendorf1@llnl.gov>
Signed-off-by: Shaan Nobee <sniper111@gmail.com>
Closes #12662
Closes #12790
2023-06-05 10:59:02 -07:00
..
os Speed up WB_SYNC_NONE when a WB_SYNC_ALL occurs simultaneously 2023-06-05 10:59:02 -07:00
sys Speed up WB_SYNC_NONE when a WB_SYNC_ALL occurs simultaneously 2023-06-05 10:59:02 -07:00
.gitignore OpenZFS restructuring - move platform specific sources 2019-09-06 11:26:26 -07:00
cityhash.h Compile cityhash code into libzfs 2020-03-27 09:11:22 -07:00
libnvpair.h Add JSON output support to channel programs 2018-03-19 12:40:58 -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 2017-09-19 12:17:29 -07:00
libzfs_core.h zfs label bootenv should store data as nvlist 2020-09-15 15:42:27 -07:00
libzfs_impl.h zfs, libzfs: diff: accept -h/ZFS_DIFF_NO_MANGLE, disabling path escaping 2022-04-01 09:58:45 -07:00
libzfs.h Use setproctitle to report progress of zfs send 2023-03-29 14:45:34 -07:00
libzfsbootenv.h zfs label bootenv should store data as nvlist 2020-09-15 15:42:27 -07:00
libzutil.h Fix "Add colored output to zfs list" 2023-04-13 09:39:53 -07:00
Makefile.am zfs label bootenv should store data as nvlist 2020-09-15 15:42:27 -07:00
thread_pool.h Add libtpool (thread pools) 2017-08-09 15:31:08 -07:00
zfeature_common.h FreeBSD: disable edonr in zfs_mod_supported_feature() 2021-02-17 08:14:51 -08:00
zfs_comutil.h Fix "zpool add -n" for dedup, special and log devices 2020-01-06 15:40:06 -08:00
zfs_deleg.h Remove code for zfs remap 2019-06-24 16:44:01 -07:00
zfs_fletcher.h Add AVX512BW variant of fletcher 2019-10-30 12:26:14 -07:00
zfs_namecheck.h Implement bookmark copying 2020-02-11 13:19:12 -08:00
zfs_prop.h Add zfs module feature and property info to sysfs 2018-09-02 12:09:53 -07:00