linux-stable/fs/kernfs
Minchan Kim 393c371408 kernfs: switch global kernfs_rwsem lock to per-fs lock
The kernfs implementation has big lock granularity(kernfs_rwsem) so
every kernfs-based(e.g., sysfs, cgroup) fs are able to compete the
lock. It makes trouble for some cases to wait the global lock
for a long time even though they are totally independent contexts
each other.

A general example is process A goes under direct reclaim with holding
the lock when it accessed the file in sysfs and process B is waiting
the lock with exclusive mode and then process C is waiting the lock
until process B could finish the job after it gets the lock from
process A.

This patch switches the global kernfs_rwsem to per-fs lock, which
put the rwsem into kernfs_root.

Suggested-by: Tejun Heo <tj@kernel.org>
Acked-by: Tejun Heo <tj@kernel.org>
Signed-off-by: Minchan Kim <minchan@kernel.org>
Link: https://lore.kernel.org/r/20211118230008.2679780-1-minchan@kernel.org
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2021-11-24 13:55:16 +01:00
..
dir.c kernfs: switch global kernfs_rwsem lock to per-fs lock 2021-11-24 13:55:16 +01:00
file.c kernfs: switch global kernfs_rwsem lock to per-fs lock 2021-11-24 13:55:16 +01:00
inode.c kernfs: switch global kernfs_rwsem lock to per-fs lock 2021-11-24 13:55:16 +01:00
Kconfig treewide: Add SPDX license identifier - Makefile/Kconfig 2019-05-21 10:50:46 +02:00
kernfs-internal.h kernfs: switch kernfs to use an rwsem 2021-07-27 09:29:15 +02:00
Makefile treewide: Add SPDX license identifier - Makefile/Kconfig 2019-05-21 10:50:46 +02:00
mount.c kernfs: switch global kernfs_rwsem lock to per-fs lock 2021-11-24 13:55:16 +01:00
symlink.c kernfs: switch global kernfs_rwsem lock to per-fs lock 2021-11-24 13:55:16 +01:00