aboutsummaryrefslogtreecommitdiffstats
path: root/mm/oom_kill.c
diff options
context:
space:
mode:
authorDavid Rientjes <rientjes@google.com>2012-03-21 19:33:46 -0400
committerLinus Torvalds <torvalds@linux-foundation.org>2012-03-21 20:54:55 -0400
commit2a1c9b1fc0a0ea2e30cdeb69062647c5c5ae661f (patch)
treea123d061a5d95984e0446a350189f4a310d06b53 /mm/oom_kill.c
parentce24d8a14207c2036df86d2bd3d14b4393eb51e3 (diff)
mm, oom: avoid looping when chosen thread detaches its mm
oom_kill_task() returns non-zero iff the chosen process does not have any threads with an attached ->mm. In such a case, it's better to just return to the page allocator and retry the allocation because memory could have been freed in the interim and the oom condition may no longer exist. It's unnecessary to loop in the oom killer and find another thread to kill. This allows both oom_kill_task() and oom_kill_process() to be converted to void functions. If the oom condition persists, the oom killer will be recalled. Acked-by: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com> Signed-off-by: David Rientjes <rientjes@google.com> Cc: KOSAKI Motohiro <kosaki.motohiro@jp.fujitsu.com> Acked-by: Michal Hocko <mhocko@suse.cz> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Diffstat (limited to 'mm/oom_kill.c')
-rw-r--r--mm/oom_kill.c56
1 files changed, 20 insertions, 36 deletions
diff --git a/mm/oom_kill.c b/mm/oom_kill.c
index 2958fd8e7c9a..a26695fe8833 100644
--- a/mm/oom_kill.c
+++ b/mm/oom_kill.c
@@ -434,14 +434,14 @@ static void dump_header(struct task_struct *p, gfp_t gfp_mask, int order,
434} 434}
435 435
436#define K(x) ((x) << (PAGE_SHIFT-10)) 436#define K(x) ((x) << (PAGE_SHIFT-10))
437static int oom_kill_task(struct task_struct *p) 437static void oom_kill_task(struct task_struct *p)
438{ 438{
439 struct task_struct *q; 439 struct task_struct *q;
440 struct mm_struct *mm; 440 struct mm_struct *mm;
441 441
442 p = find_lock_task_mm(p); 442 p = find_lock_task_mm(p);
443 if (!p) 443 if (!p)
444 return 1; 444 return;
445 445
446 /* mm cannot be safely dereferenced after task_unlock(p) */ 446 /* mm cannot be safely dereferenced after task_unlock(p) */
447 mm = p->mm; 447 mm = p->mm;
@@ -477,15 +477,13 @@ static int oom_kill_task(struct task_struct *p)
477 477
478 set_tsk_thread_flag(p, TIF_MEMDIE); 478 set_tsk_thread_flag(p, TIF_MEMDIE);
479 force_sig(SIGKILL, p); 479 force_sig(SIGKILL, p);
480
481 return 0;
482} 480}
483#undef K 481#undef K
484 482
485static int oom_kill_process(struct task_struct *p, gfp_t gfp_mask, int order, 483static void oom_kill_process(struct task_struct *p, gfp_t gfp_mask, int order,
486 unsigned int points, unsigned long totalpages, 484 unsigned int points, unsigned long totalpages,
487 struct mem_cgroup *memcg, nodemask_t *nodemask, 485 struct mem_cgroup *memcg, nodemask_t *nodemask,
488 const char *message) 486 const char *message)
489{ 487{
490 struct task_struct *victim = p; 488 struct task_struct *victim = p;
491 struct task_struct *child; 489 struct task_struct *child;
@@ -501,7 +499,7 @@ static int oom_kill_process(struct task_struct *p, gfp_t gfp_mask, int order,
501 */ 499 */
502 if (p->flags & PF_EXITING) { 500 if (p->flags & PF_EXITING) {
503 set_tsk_thread_flag(p, TIF_MEMDIE); 501 set_tsk_thread_flag(p, TIF_MEMDIE);
504 return 0; 502 return;
505 } 503 }
506 504
507 task_lock(p); 505 task_lock(p);
@@ -533,7 +531,7 @@ static int oom_kill_process(struct task_struct *p, gfp_t gfp_mask, int order,
533 } 531 }
534 } while_each_thread(p, t); 532 } while_each_thread(p, t);
535 533
536 return oom_kill_task(victim); 534 oom_kill_task(victim);
537} 535}
538 536
539/* 537/*
@@ -580,15 +578,10 @@ void mem_cgroup_out_of_memory(struct mem_cgroup *memcg, gfp_t gfp_mask)
580 check_panic_on_oom(CONSTRAINT_MEMCG, gfp_mask, 0, NULL); 578 check_panic_on_oom(CONSTRAINT_MEMCG, gfp_mask, 0, NULL);
581 limit = mem_cgroup_get_limit(memcg) >> PAGE_SHIFT; 579 limit = mem_cgroup_get_limit(memcg) >> PAGE_SHIFT;
582 read_lock(&tasklist_lock); 580 read_lock(&tasklist_lock);
583retry:
584 p = select_bad_process(&points, limit, memcg, NULL); 581 p = select_bad_process(&points, limit, memcg, NULL);
585 if (!p || PTR_ERR(p) == -1UL) 582 if (p && PTR_ERR(p) != -1UL)
586 goto out; 583 oom_kill_process(p, gfp_mask, 0, points, limit, memcg, NULL,
587 584 "Memory cgroup out of memory");
588 if (oom_kill_process(p, gfp_mask, 0, points, limit, memcg, NULL,
589 "Memory cgroup out of memory"))
590 goto retry;
591out:
592 read_unlock(&tasklist_lock); 585 read_unlock(&tasklist_lock);
593} 586}
594#endif 587#endif
@@ -745,33 +738,24 @@ void out_of_memory(struct zonelist *zonelist, gfp_t gfp_mask,
745 if (sysctl_oom_kill_allocating_task && 738 if (sysctl_oom_kill_allocating_task &&
746 !oom_unkillable_task(current, NULL, nodemask) && 739 !oom_unkillable_task(current, NULL, nodemask) &&
747 current->mm) { 740 current->mm) {
748 /* 741 oom_kill_process(current, gfp_mask, order, 0, totalpages, NULL,
749 * oom_kill_process() needs tasklist_lock held. If it returns 742 nodemask,
750 * non-zero, current could not be killed so we must fallback to 743 "Out of memory (oom_kill_allocating_task)");
751 * the tasklist scan. 744 goto out;
752 */
753 if (!oom_kill_process(current, gfp_mask, order, 0, totalpages,
754 NULL, nodemask,
755 "Out of memory (oom_kill_allocating_task)"))
756 goto out;
757 } 745 }
758 746
759retry:
760 p = select_bad_process(&points, totalpages, NULL, mpol_mask); 747 p = select_bad_process(&points, totalpages, NULL, mpol_mask);
761 if (PTR_ERR(p) == -1UL)
762 goto out;
763
764 /* Found nothing?!?! Either we hang forever, or we panic. */ 748 /* Found nothing?!?! Either we hang forever, or we panic. */
765 if (!p) { 749 if (!p) {
766 dump_header(NULL, gfp_mask, order, NULL, mpol_mask); 750 dump_header(NULL, gfp_mask, order, NULL, mpol_mask);
767 read_unlock(&tasklist_lock); 751 read_unlock(&tasklist_lock);
768 panic("Out of memory and no killable processes...\n"); 752 panic("Out of memory and no killable processes...\n");
769 } 753 }
770 754 if (PTR_ERR(p) != -1UL) {
771 if (oom_kill_process(p, gfp_mask, order, points, totalpages, NULL, 755 oom_kill_process(p, gfp_mask, order, points, totalpages, NULL,
772 nodemask, "Out of memory")) 756 nodemask, "Out of memory");
773 goto retry; 757 killed = 1;
774 killed = 1; 758 }
775out: 759out:
776 read_unlock(&tasklist_lock); 760 read_unlock(&tasklist_lock);
777 761