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authorVladimir Davydov <vdavydov@virtuozzo.com>2016-03-25 14:20:39 -0700
committerLinus Torvalds <torvalds@linux-foundation.org>2016-03-25 16:37:42 -0700
commit29c696e1c6eceb5db6b21f0c89495fcfcd40c0eb (patch)
treefe5a096de3c34d3fef0fcc40dd3fbc03a99599a1
parent855b018325737f7691f9b7d86339df40aa4e47c3 (diff)
oom: make oom_reaper_list single linked
Entries are only added/removed from oom_reaper_list at head so we can use a single linked list and hence save a word in task_struct. Signed-off-by: Vladimir Davydov <vdavydov@virtuozzo.com> Signed-off-by: Michal Hocko <mhocko@suse.com> Cc: Tetsuo Handa <penguin-kernel@I-love.SAKURA.ne.jp> Cc: David Rientjes <rientjes@google.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
-rw-r--r--include/linux/sched.h2
-rw-r--r--mm/oom_kill.c15
2 files changed, 8 insertions, 9 deletions
diff --git a/include/linux/sched.h b/include/linux/sched.h
index c2d2d7c5d463..49b1febcf7c3 100644
--- a/include/linux/sched.h
+++ b/include/linux/sched.h
@@ -1852,7 +1852,7 @@ struct task_struct {
#endif
int pagefault_disabled;
#ifdef CONFIG_MMU
- struct list_head oom_reaper_list;
+ struct task_struct *oom_reaper_list;
#endif
/* CPU-specific state of this task */
struct thread_struct thread;
diff --git a/mm/oom_kill.c b/mm/oom_kill.c
index 1a21819a8e5e..a49638f41e45 100644
--- a/mm/oom_kill.c
+++ b/mm/oom_kill.c
@@ -419,7 +419,7 @@ bool oom_killer_disabled __read_mostly;
*/
static struct task_struct *oom_reaper_th;
static DECLARE_WAIT_QUEUE_HEAD(oom_reaper_wait);
-static LIST_HEAD(oom_reaper_list);
+static struct task_struct *oom_reaper_list;
static DEFINE_SPINLOCK(oom_reaper_lock);
@@ -528,13 +528,11 @@ static int oom_reaper(void *unused)
while (true) {
struct task_struct *tsk = NULL;
- wait_event_freezable(oom_reaper_wait,
- (!list_empty(&oom_reaper_list)));
+ wait_event_freezable(oom_reaper_wait, oom_reaper_list != NULL);
spin_lock(&oom_reaper_lock);
- if (!list_empty(&oom_reaper_list)) {
- tsk = list_first_entry(&oom_reaper_list,
- struct task_struct, oom_reaper_list);
- list_del(&tsk->oom_reaper_list);
+ if (oom_reaper_list != NULL) {
+ tsk = oom_reaper_list;
+ oom_reaper_list = tsk->oom_reaper_list;
}
spin_unlock(&oom_reaper_lock);
@@ -553,7 +551,8 @@ static void wake_oom_reaper(struct task_struct *tsk)
get_task_struct(tsk);
spin_lock(&oom_reaper_lock);
- list_add(&tsk->oom_reaper_list, &oom_reaper_list);
+ tsk->oom_reaper_list = oom_reaper_list;
+ oom_reaper_list = tsk;
spin_unlock(&oom_reaper_lock);
wake_up(&oom_reaper_wait);
}

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