diff options
author | Michal Hocko <mhocko@suse.cz> | 2011-07-26 23:08:24 (GMT) |
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committer | Linus Torvalds <torvalds@linux-foundation.org> | 2011-07-26 23:49:42 (GMT) |
commit | 1af8efe965676ab30d6c8a5b1fccc9229f339a3b (patch) | |
tree | 832cfd92cae498d9af1687bccc77344143df97a1 /mm/memcontrol.c | |
parent | 79dfdaccd1d5b40ff7cf4a35a0e63696ebb78b4d (diff) | |
download | linux-1af8efe965676ab30d6c8a5b1fccc9229f339a3b.tar.xz |
memcg: change memcg_oom_mutex to spinlock
memcg_oom_mutex is used to protect memcg OOM path and eventfd interface
for oom_control. None of the critical sections which it protects sleep
(eventfd_signal works from atomic context and the rest are simple linked
list resp. oom_lock atomic operations).
Mutex is also too heavyweight for those code paths because it triggers a
lot of scheduling. It also makes makes convoying effects more visible
when we have a big number of oom killing because we take the lock
mutliple times during mem_cgroup_handle_oom so we have multiple places
where many processes can sleep.
Signed-off-by: Michal Hocko <mhocko@suse.cz>
Cc: Balbir Singh <bsingharora@gmail.com>
Cc: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Diffstat (limited to 'mm/memcontrol.c')
-rw-r--r-- | mm/memcontrol.c | 22 |
1 files changed, 11 insertions, 11 deletions
diff --git a/mm/memcontrol.c b/mm/memcontrol.c index 95d6c25..c0b065e 100644 --- a/mm/memcontrol.c +++ b/mm/memcontrol.c @@ -1725,7 +1725,7 @@ static int mem_cgroup_hierarchical_reclaim(struct mem_cgroup *root_mem, /* * Check OOM-Killer is already running under our hierarchy. * If someone is running, return false. - * Has to be called with memcg_oom_mutex + * Has to be called with memcg_oom_lock */ static bool mem_cgroup_oom_lock(struct mem_cgroup *mem) { @@ -1770,7 +1770,7 @@ done: } /* - * Has to be called with memcg_oom_mutex + * Has to be called with memcg_oom_lock */ static int mem_cgroup_oom_unlock(struct mem_cgroup *mem) { @@ -1802,7 +1802,7 @@ static void mem_cgroup_unmark_under_oom(struct mem_cgroup *mem) atomic_add_unless(&iter->under_oom, -1, 0); } -static DEFINE_MUTEX(memcg_oom_mutex); +static DEFINE_SPINLOCK(memcg_oom_lock); static DECLARE_WAIT_QUEUE_HEAD(memcg_oom_waitq); struct oom_wait_info { @@ -1864,7 +1864,7 @@ bool mem_cgroup_handle_oom(struct mem_cgroup *mem, gfp_t mask) mem_cgroup_mark_under_oom(mem); /* At first, try to OOM lock hierarchy under mem.*/ - mutex_lock(&memcg_oom_mutex); + spin_lock(&memcg_oom_lock); locked = mem_cgroup_oom_lock(mem); /* * Even if signal_pending(), we can't quit charge() loop without @@ -1876,7 +1876,7 @@ bool mem_cgroup_handle_oom(struct mem_cgroup *mem, gfp_t mask) need_to_kill = false; if (locked) mem_cgroup_oom_notify(mem); - mutex_unlock(&memcg_oom_mutex); + spin_unlock(&memcg_oom_lock); if (need_to_kill) { finish_wait(&memcg_oom_waitq, &owait.wait); @@ -1885,11 +1885,11 @@ bool mem_cgroup_handle_oom(struct mem_cgroup *mem, gfp_t mask) schedule(); finish_wait(&memcg_oom_waitq, &owait.wait); } - mutex_lock(&memcg_oom_mutex); + spin_lock(&memcg_oom_lock); if (locked) mem_cgroup_oom_unlock(mem); memcg_wakeup_oom(mem); - mutex_unlock(&memcg_oom_mutex); + spin_unlock(&memcg_oom_lock); mem_cgroup_unmark_under_oom(mem); @@ -4553,7 +4553,7 @@ static int mem_cgroup_oom_register_event(struct cgroup *cgrp, if (!event) return -ENOMEM; - mutex_lock(&memcg_oom_mutex); + spin_lock(&memcg_oom_lock); event->eventfd = eventfd; list_add(&event->list, &memcg->oom_notify); @@ -4561,7 +4561,7 @@ static int mem_cgroup_oom_register_event(struct cgroup *cgrp, /* already in OOM ? */ if (atomic_read(&memcg->under_oom)) eventfd_signal(eventfd, 1); - mutex_unlock(&memcg_oom_mutex); + spin_unlock(&memcg_oom_lock); return 0; } @@ -4575,7 +4575,7 @@ static void mem_cgroup_oom_unregister_event(struct cgroup *cgrp, BUG_ON(type != _OOM_TYPE); - mutex_lock(&memcg_oom_mutex); + spin_lock(&memcg_oom_lock); list_for_each_entry_safe(ev, tmp, &mem->oom_notify, list) { if (ev->eventfd == eventfd) { @@ -4584,7 +4584,7 @@ static void mem_cgroup_oom_unregister_event(struct cgroup *cgrp, } } - mutex_unlock(&memcg_oom_mutex); + spin_unlock(&memcg_oom_lock); } static int mem_cgroup_oom_control_read(struct cgroup *cgrp, |