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| 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 /ipc | |
| parent | a80c4adcb574821e534779c48ae13953b7d1d996 (diff) | |
| download | lwn-da27f796a832122ee533c7685438dad1c4e338dd.tar.gz lwn-da27f796a832122ee533c7685438dad1c4e338dd.zip | |
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 'ipc')
| -rw-r--r-- | ipc/mqueue.c | 5 | ||||
| -rw-r--r-- | ipc/namespace.c | 13 | ||||
| -rw-r--r-- | ipc/util.h | 2 |
3 files changed, 10 insertions, 10 deletions
diff --git a/ipc/mqueue.c b/ipc/mqueue.c index d09aa1c1e3e6..6c5bf7cce7fe 100644 --- a/ipc/mqueue.c +++ b/ipc/mqueue.c @@ -1709,11 +1709,6 @@ void mq_clear_sbinfo(struct ipc_namespace *ns) ns->mq_mnt->mnt_sb->s_fs_info = NULL; } -void mq_put_mnt(struct ipc_namespace *ns) -{ - kern_unmount(ns->mq_mnt); -} - static int __init init_mqueue_fs(void) { int error; diff --git a/ipc/namespace.c b/ipc/namespace.c index a26860a41dac..6ecc30effd3e 100644 --- a/ipc/namespace.c +++ b/ipc/namespace.c @@ -145,10 +145,11 @@ void free_ipcs(struct ipc_namespace *ns, struct ipc_ids *ids, static void free_ipc_ns(struct ipc_namespace *ns) { - /* mq_put_mnt() waits for a grace period as kern_unmount() - * uses synchronize_rcu(). + /* + * Caller needs to wait for an RCU grace period to have passed + * after making the mount point inaccessible to new accesses. */ - mq_put_mnt(ns); + mntput(ns->mq_mnt); sem_exit_ns(ns); msg_exit_ns(ns); shm_exit_ns(ns); @@ -169,6 +170,12 @@ static void free_ipc(struct work_struct *unused) struct ipc_namespace *n, *t; llist_for_each_entry_safe(n, t, node, mnt_llist) + mnt_make_shortterm(n->mq_mnt); + + /* Wait for any last users to have gone away. */ + synchronize_rcu(); + + llist_for_each_entry_safe(n, t, node, mnt_llist) free_ipc_ns(n); } diff --git a/ipc/util.h b/ipc/util.h index b2906e366539..67bdd2aa2c28 100644 --- a/ipc/util.h +++ b/ipc/util.h @@ -56,10 +56,8 @@ struct pid_namespace; #ifdef CONFIG_POSIX_MQUEUE extern void mq_clear_sbinfo(struct ipc_namespace *ns); -extern void mq_put_mnt(struct ipc_namespace *ns); #else static inline void mq_clear_sbinfo(struct ipc_namespace *ns) { } -static inline void mq_put_mnt(struct ipc_namespace *ns) { } #endif #ifdef CONFIG_SYSVIPC |