diff options
| author | Minchan Kim <minchan@kernel.org> | 2021-11-19 02:00:08 +0300 |
|---|---|---|
| committer | Greg Kroah-Hartman <gregkh@linuxfoundation.org> | 2021-11-24 15:55:16 +0300 |
| commit | 393c3714081a53795bbff0e985d24146def6f57f (patch) | |
| tree | 188134895692753a0862a1cbd9a8466d56a4245b /fs/kernfs/symlink.c | |
| parent | 136057256686de39cc3a07c2e39ef6bc43003ff6 (diff) | |
| download | linux-393c3714081a53795bbff0e985d24146def6f57f.tar.xz | |
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>
Diffstat (limited to 'fs/kernfs/symlink.c')
| -rw-r--r-- | fs/kernfs/symlink.c | 5 |
1 files changed, 3 insertions, 2 deletions
diff --git a/fs/kernfs/symlink.c b/fs/kernfs/symlink.c index 19a6c71c6ff5..0ab13824822f 100644 --- a/fs/kernfs/symlink.c +++ b/fs/kernfs/symlink.c @@ -113,11 +113,12 @@ static int kernfs_getlink(struct inode *inode, char *path) struct kernfs_node *kn = inode->i_private; struct kernfs_node *parent = kn->parent; struct kernfs_node *target = kn->symlink.target_kn; + struct kernfs_root *root = kernfs_root(parent); int error; - down_read(&kernfs_rwsem); + down_read(&root->kernfs_rwsem); error = kernfs_get_target_path(parent, target, path); - up_read(&kernfs_rwsem); + up_read(&root->kernfs_rwsem); return error; } |