diff options
| author | Rik van Riel <riel@surriel.com> | 2023-01-27 13:46:51 -0500 |
|---|---|---|
| committer | Al Viro <viro@zeniv.linux.org.uk> | 2023-01-27 19:08:00 -0500 |
| commit | da27f796a832122ee533c7685438dad1c4e338dd (patch) | |
| tree | f65cbf61db048942e78fc877732d60be814eebb0 /fs/namespace.c | |
| parent | a80c4adcb574821e534779c48ae13953b7d1d996 (diff) | |
ipc,namespace: batch free ipc_namespace structures
Instead of waiting for an RCU grace period between each ipc_namespace
structure that is being freed, wait an RCU grace period for every batch
of ipc_namespace structures.
Thanks to Al Viro for the suggestion of the helper function.
This speeds up the run time of the test case that allocates ipc_namespaces
in a loop from 6 minutes, to a little over 1 second:
real 0m1.192s
user 0m0.038s
sys 0m1.152s
Signed-off-by: Rik van Riel <riel@surriel.com>
Reported-by: Chris Mason <clm@meta.com>
Tested-by: Giuseppe Scrivano <gscrivan@redhat.com>
Suggested-by: Al Viro <viro@zeniv.linux.org.uk>
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
Diffstat (limited to 'fs/namespace.c')
| -rw-r--r-- | fs/namespace.c | 18 |
1 files changed, 14 insertions, 4 deletions
diff --git a/fs/namespace.c b/fs/namespace.c index ab467ee58341..1ad4e5acef06 100644 --- a/fs/namespace.c +++ b/fs/namespace.c @@ -1397,6 +1397,17 @@ struct vfsmount *mntget(struct vfsmount *mnt) } EXPORT_SYMBOL(mntget); +/* + * Make a mount point inaccessible to new lookups. + * Because there may still be current users, the caller MUST WAIT + * for an RCU grace period before destroying the mount point. + */ +void mnt_make_shortterm(struct vfsmount *mnt) +{ + if (mnt) + real_mount(mnt)->mnt_ns = NULL; +} + /** * path_is_mountpoint() - Check if path is a mount in the current namespace. * @path: path to check @@ -4573,8 +4584,8 @@ EXPORT_SYMBOL_GPL(kern_mount); void kern_unmount(struct vfsmount *mnt) { /* release long term mount so mount point can be released */ - if (!IS_ERR_OR_NULL(mnt)) { - real_mount(mnt)->mnt_ns = NULL; + if (!IS_ERR(mnt)) { + mnt_make_shortterm(mnt); synchronize_rcu(); /* yecchhh... */ mntput(mnt); } @@ -4586,8 +4597,7 @@ void kern_unmount_array(struct vfsmount *mnt[], unsigned int num) unsigned int i; for (i = 0; i < num; i++) - if (mnt[i]) - real_mount(mnt[i])->mnt_ns = NULL; + mnt_make_shortterm(mnt[i]); synchronize_rcu_expedited(); for (i = 0; i < num; i++) mntput(mnt[i]); |