diff options
| author | Hugh Dickins <hughd@google.com> | 2012-03-21 16:34:21 -0700 |
|---|---|---|
| committer | Linus Torvalds <torvalds@linux-foundation.org> | 2012-03-21 17:55:01 -0700 |
| commit | 42aee6c495e07dba7410b863a360db6bb9ec6d66 (patch) | |
| tree | d014b2b5c7aa9d1a1f13686fa06699f9f734ee1c /include | |
| parent | 9f7de8275b46d9d11b1505adbfe6c2bb48df4741 (diff) | |
cgroup: revert ss_id_lock to spinlock
Commit c1e2ee2dc436 ("memcg: replace ss->id_lock with a rwlock") has now
been seen to cause the unfair behavior we should have expected from
converting a spinlock to an rwlock: softlockup in cgroup_mkdir(), whose
get_new_cssid() is waiting for the wlock, while there are 19 tasks using
the rlock in css_get_next() to get on with their memcg workload (in an
artificial test, admittedly). Yet lib/idr.c was made suitable for RCU
way back: revert that commit, restoring ss->id_lock to a spinlock.
Signed-off-by: Hugh Dickins <hughd@google.com>
Acked-by: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com>
Acked-by: Li Zefan <lizf@cn.fujitsu.com>
Cc: Eric Dumazet <eric.dumazet@gmail.com>
Acked-by: Tejun Heo <tj@kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Diffstat (limited to 'include')
| -rw-r--r-- | include/linux/cgroup.h | 2 |
1 files changed, 1 insertions, 1 deletions
diff --git a/include/linux/cgroup.h b/include/linux/cgroup.h index 501adb1b2f4..5a85b3415c1 100644 --- a/include/linux/cgroup.h +++ b/include/linux/cgroup.h @@ -498,7 +498,7 @@ struct cgroup_subsys { struct list_head sibling; /* used when use_id == true */ struct idr idr; - rwlock_t id_lock; + spinlock_t id_lock; /* should be defined only by modular subsystems */ struct module *module; |