netfilter: ipset: remove unnecessary includes
[linux-2.6/linux-acpi-2.6/ibm-acpi-2.6.git] / mm / oom_kill.c
blob7dcca55ede7ca1493df615af994f6ba23c1bb129
1 /*
2 * linux/mm/oom_kill.c
3 *
4 * Copyright (C) 1998,2000 Rik van Riel
5 * Thanks go out to Claus Fischer for some serious inspiration and
6 * for goading me into coding this file...
7 * Copyright (C) 2010 Google, Inc.
8 * Rewritten by David Rientjes
10 * The routines in this file are used to kill a process when
11 * we're seriously out of memory. This gets called from __alloc_pages()
12 * in mm/page_alloc.c when we really run out of memory.
14 * Since we won't call these routines often (on a well-configured
15 * machine) this file will double as a 'coding guide' and a signpost
16 * for newbie kernel hackers. It features several pointers to major
17 * kernel subsystems and hints as to where to find out what things do.
20 #include <linux/oom.h>
21 #include <linux/mm.h>
22 #include <linux/err.h>
23 #include <linux/gfp.h>
24 #include <linux/sched.h>
25 #include <linux/swap.h>
26 #include <linux/timex.h>
27 #include <linux/jiffies.h>
28 #include <linux/cpuset.h>
29 #include <linux/module.h>
30 #include <linux/notifier.h>
31 #include <linux/memcontrol.h>
32 #include <linux/mempolicy.h>
33 #include <linux/security.h>
35 int sysctl_panic_on_oom;
36 int sysctl_oom_kill_allocating_task;
37 int sysctl_oom_dump_tasks = 1;
38 static DEFINE_SPINLOCK(zone_scan_lock);
40 #ifdef CONFIG_NUMA
41 /**
42 * has_intersects_mems_allowed() - check task eligiblity for kill
43 * @tsk: task struct of which task to consider
44 * @mask: nodemask passed to page allocator for mempolicy ooms
46 * Task eligibility is determined by whether or not a candidate task, @tsk,
47 * shares the same mempolicy nodes as current if it is bound by such a policy
48 * and whether or not it has the same set of allowed cpuset nodes.
50 static bool has_intersects_mems_allowed(struct task_struct *tsk,
51 const nodemask_t *mask)
53 struct task_struct *start = tsk;
55 do {
56 if (mask) {
58 * If this is a mempolicy constrained oom, tsk's
59 * cpuset is irrelevant. Only return true if its
60 * mempolicy intersects current, otherwise it may be
61 * needlessly killed.
63 if (mempolicy_nodemask_intersects(tsk, mask))
64 return true;
65 } else {
67 * This is not a mempolicy constrained oom, so only
68 * check the mems of tsk's cpuset.
70 if (cpuset_mems_allowed_intersects(current, tsk))
71 return true;
73 } while_each_thread(start, tsk);
75 return false;
77 #else
78 static bool has_intersects_mems_allowed(struct task_struct *tsk,
79 const nodemask_t *mask)
81 return true;
83 #endif /* CONFIG_NUMA */
86 * If this is a system OOM (not a memcg OOM) and the task selected to be
87 * killed is not already running at high (RT) priorities, speed up the
88 * recovery by boosting the dying task to the lowest FIFO priority.
89 * That helps with the recovery and avoids interfering with RT tasks.
91 static void boost_dying_task_prio(struct task_struct *p,
92 struct mem_cgroup *mem)
94 struct sched_param param = { .sched_priority = 1 };
96 if (mem)
97 return;
99 if (!rt_task(p))
100 sched_setscheduler_nocheck(p, SCHED_FIFO, &param);
104 * The process p may have detached its own ->mm while exiting or through
105 * use_mm(), but one or more of its subthreads may still have a valid
106 * pointer. Return p, or any of its subthreads with a valid ->mm, with
107 * task_lock() held.
109 struct task_struct *find_lock_task_mm(struct task_struct *p)
111 struct task_struct *t = p;
113 do {
114 task_lock(t);
115 if (likely(t->mm))
116 return t;
117 task_unlock(t);
118 } while_each_thread(p, t);
120 return NULL;
123 /* return true if the task is not adequate as candidate victim task. */
124 static bool oom_unkillable_task(struct task_struct *p,
125 const struct mem_cgroup *mem, const nodemask_t *nodemask)
127 if (is_global_init(p))
128 return true;
129 if (p->flags & PF_KTHREAD)
130 return true;
132 /* When mem_cgroup_out_of_memory() and p is not member of the group */
133 if (mem && !task_in_mem_cgroup(p, mem))
134 return true;
136 /* p may not have freeable memory in nodemask */
137 if (!has_intersects_mems_allowed(p, nodemask))
138 return true;
140 return false;
144 * oom_badness - heuristic function to determine which candidate task to kill
145 * @p: task struct of which task we should calculate
146 * @totalpages: total present RAM allowed for page allocation
148 * The heuristic for determining which task to kill is made to be as simple and
149 * predictable as possible. The goal is to return the highest value for the
150 * task consuming the most memory to avoid subsequent oom failures.
152 unsigned int oom_badness(struct task_struct *p, struct mem_cgroup *mem,
153 const nodemask_t *nodemask, unsigned long totalpages)
155 int points;
157 if (oom_unkillable_task(p, mem, nodemask))
158 return 0;
160 p = find_lock_task_mm(p);
161 if (!p)
162 return 0;
165 * Shortcut check for a thread sharing p->mm that is OOM_SCORE_ADJ_MIN
166 * so the entire heuristic doesn't need to be executed for something
167 * that cannot be killed.
169 if (atomic_read(&p->mm->oom_disable_count)) {
170 task_unlock(p);
171 return 0;
175 * When the PF_OOM_ORIGIN bit is set, it indicates the task should have
176 * priority for oom killing.
178 if (p->flags & PF_OOM_ORIGIN) {
179 task_unlock(p);
180 return 1000;
184 * The memory controller may have a limit of 0 bytes, so avoid a divide
185 * by zero, if necessary.
187 if (!totalpages)
188 totalpages = 1;
191 * The baseline for the badness score is the proportion of RAM that each
192 * task's rss and swap space use.
194 points = (get_mm_rss(p->mm) + get_mm_counter(p->mm, MM_SWAPENTS)) * 1000 /
195 totalpages;
196 task_unlock(p);
199 * Root processes get 3% bonus, just like the __vm_enough_memory()
200 * implementation used by LSMs.
202 if (has_capability_noaudit(p, CAP_SYS_ADMIN))
203 points -= 30;
206 * /proc/pid/oom_score_adj ranges from -1000 to +1000 such that it may
207 * either completely disable oom killing or always prefer a certain
208 * task.
210 points += p->signal->oom_score_adj;
213 * Never return 0 for an eligible task that may be killed since it's
214 * possible that no single user task uses more than 0.1% of memory and
215 * no single admin tasks uses more than 3.0%.
217 if (points <= 0)
218 return 1;
219 return (points < 1000) ? points : 1000;
223 * Determine the type of allocation constraint.
225 #ifdef CONFIG_NUMA
226 static enum oom_constraint constrained_alloc(struct zonelist *zonelist,
227 gfp_t gfp_mask, nodemask_t *nodemask,
228 unsigned long *totalpages)
230 struct zone *zone;
231 struct zoneref *z;
232 enum zone_type high_zoneidx = gfp_zone(gfp_mask);
233 bool cpuset_limited = false;
234 int nid;
236 /* Default to all available memory */
237 *totalpages = totalram_pages + total_swap_pages;
239 if (!zonelist)
240 return CONSTRAINT_NONE;
242 * Reach here only when __GFP_NOFAIL is used. So, we should avoid
243 * to kill current.We have to random task kill in this case.
244 * Hopefully, CONSTRAINT_THISNODE...but no way to handle it, now.
246 if (gfp_mask & __GFP_THISNODE)
247 return CONSTRAINT_NONE;
250 * This is not a __GFP_THISNODE allocation, so a truncated nodemask in
251 * the page allocator means a mempolicy is in effect. Cpuset policy
252 * is enforced in get_page_from_freelist().
254 if (nodemask && !nodes_subset(node_states[N_HIGH_MEMORY], *nodemask)) {
255 *totalpages = total_swap_pages;
256 for_each_node_mask(nid, *nodemask)
257 *totalpages += node_spanned_pages(nid);
258 return CONSTRAINT_MEMORY_POLICY;
261 /* Check this allocation failure is caused by cpuset's wall function */
262 for_each_zone_zonelist_nodemask(zone, z, zonelist,
263 high_zoneidx, nodemask)
264 if (!cpuset_zone_allowed_softwall(zone, gfp_mask))
265 cpuset_limited = true;
267 if (cpuset_limited) {
268 *totalpages = total_swap_pages;
269 for_each_node_mask(nid, cpuset_current_mems_allowed)
270 *totalpages += node_spanned_pages(nid);
271 return CONSTRAINT_CPUSET;
273 return CONSTRAINT_NONE;
275 #else
276 static enum oom_constraint constrained_alloc(struct zonelist *zonelist,
277 gfp_t gfp_mask, nodemask_t *nodemask,
278 unsigned long *totalpages)
280 *totalpages = totalram_pages + total_swap_pages;
281 return CONSTRAINT_NONE;
283 #endif
286 * Simple selection loop. We chose the process with the highest
287 * number of 'points'. We expect the caller will lock the tasklist.
289 * (not docbooked, we don't want this one cluttering up the manual)
291 static struct task_struct *select_bad_process(unsigned int *ppoints,
292 unsigned long totalpages, struct mem_cgroup *mem,
293 const nodemask_t *nodemask)
295 struct task_struct *p;
296 struct task_struct *chosen = NULL;
297 *ppoints = 0;
299 for_each_process(p) {
300 unsigned int points;
302 if (oom_unkillable_task(p, mem, nodemask))
303 continue;
306 * This task already has access to memory reserves and is
307 * being killed. Don't allow any other task access to the
308 * memory reserve.
310 * Note: this may have a chance of deadlock if it gets
311 * blocked waiting for another task which itself is waiting
312 * for memory. Is there a better alternative?
314 if (test_tsk_thread_flag(p, TIF_MEMDIE))
315 return ERR_PTR(-1UL);
318 * This is in the process of releasing memory so wait for it
319 * to finish before killing some other task by mistake.
321 * However, if p is the current task, we allow the 'kill' to
322 * go ahead if it is exiting: this will simply set TIF_MEMDIE,
323 * which will allow it to gain access to memory reserves in
324 * the process of exiting and releasing its resources.
325 * Otherwise we could get an easy OOM deadlock.
327 if (thread_group_empty(p) && (p->flags & PF_EXITING) && p->mm) {
328 if (p != current)
329 return ERR_PTR(-1UL);
331 chosen = p;
332 *ppoints = 1000;
335 points = oom_badness(p, mem, nodemask, totalpages);
336 if (points > *ppoints) {
337 chosen = p;
338 *ppoints = points;
342 return chosen;
346 * dump_tasks - dump current memory state of all system tasks
347 * @mem: current's memory controller, if constrained
348 * @nodemask: nodemask passed to page allocator for mempolicy ooms
350 * Dumps the current memory state of all eligible tasks. Tasks not in the same
351 * memcg, not in the same cpuset, or bound to a disjoint set of mempolicy nodes
352 * are not shown.
353 * State information includes task's pid, uid, tgid, vm size, rss, cpu, oom_adj
354 * value, oom_score_adj value, and name.
356 * Call with tasklist_lock read-locked.
358 static void dump_tasks(const struct mem_cgroup *mem, const nodemask_t *nodemask)
360 struct task_struct *p;
361 struct task_struct *task;
363 pr_info("[ pid ] uid tgid total_vm rss cpu oom_adj oom_score_adj name\n");
364 for_each_process(p) {
365 if (oom_unkillable_task(p, mem, nodemask))
366 continue;
368 task = find_lock_task_mm(p);
369 if (!task) {
371 * This is a kthread or all of p's threads have already
372 * detached their mm's. There's no need to report
373 * them; they can't be oom killed anyway.
375 continue;
378 pr_info("[%5d] %5d %5d %8lu %8lu %3u %3d %5d %s\n",
379 task->pid, task_uid(task), task->tgid,
380 task->mm->total_vm, get_mm_rss(task->mm),
381 task_cpu(task), task->signal->oom_adj,
382 task->signal->oom_score_adj, task->comm);
383 task_unlock(task);
387 static void dump_header(struct task_struct *p, gfp_t gfp_mask, int order,
388 struct mem_cgroup *mem, const nodemask_t *nodemask)
390 task_lock(current);
391 pr_warning("%s invoked oom-killer: gfp_mask=0x%x, order=%d, "
392 "oom_adj=%d, oom_score_adj=%d\n",
393 current->comm, gfp_mask, order, current->signal->oom_adj,
394 current->signal->oom_score_adj);
395 cpuset_print_task_mems_allowed(current);
396 task_unlock(current);
397 dump_stack();
398 mem_cgroup_print_oom_info(mem, p);
399 show_mem();
400 if (sysctl_oom_dump_tasks)
401 dump_tasks(mem, nodemask);
404 #define K(x) ((x) << (PAGE_SHIFT-10))
405 static int oom_kill_task(struct task_struct *p, struct mem_cgroup *mem)
407 struct task_struct *q;
408 struct mm_struct *mm;
410 p = find_lock_task_mm(p);
411 if (!p)
412 return 1;
414 /* mm cannot be safely dereferenced after task_unlock(p) */
415 mm = p->mm;
417 pr_err("Killed process %d (%s) total-vm:%lukB, anon-rss:%lukB, file-rss:%lukB\n",
418 task_pid_nr(p), p->comm, K(p->mm->total_vm),
419 K(get_mm_counter(p->mm, MM_ANONPAGES)),
420 K(get_mm_counter(p->mm, MM_FILEPAGES)));
421 task_unlock(p);
424 * Kill all processes sharing p->mm in other thread groups, if any.
425 * They don't get access to memory reserves or a higher scheduler
426 * priority, though, to avoid depletion of all memory or task
427 * starvation. This prevents mm->mmap_sem livelock when an oom killed
428 * task cannot exit because it requires the semaphore and its contended
429 * by another thread trying to allocate memory itself. That thread will
430 * now get access to memory reserves since it has a pending fatal
431 * signal.
433 for_each_process(q)
434 if (q->mm == mm && !same_thread_group(q, p)) {
435 task_lock(q); /* Protect ->comm from prctl() */
436 pr_err("Kill process %d (%s) sharing same memory\n",
437 task_pid_nr(q), q->comm);
438 task_unlock(q);
439 force_sig(SIGKILL, q);
442 set_tsk_thread_flag(p, TIF_MEMDIE);
443 force_sig(SIGKILL, p);
446 * We give our sacrificial lamb high priority and access to
447 * all the memory it needs. That way it should be able to
448 * exit() and clear out its resources quickly...
450 boost_dying_task_prio(p, mem);
452 return 0;
454 #undef K
456 static int oom_kill_process(struct task_struct *p, gfp_t gfp_mask, int order,
457 unsigned int points, unsigned long totalpages,
458 struct mem_cgroup *mem, nodemask_t *nodemask,
459 const char *message)
461 struct task_struct *victim = p;
462 struct task_struct *child;
463 struct task_struct *t = p;
464 unsigned int victim_points = 0;
466 if (printk_ratelimit())
467 dump_header(p, gfp_mask, order, mem, nodemask);
470 * If the task is already exiting, don't alarm the sysadmin or kill
471 * its children or threads, just set TIF_MEMDIE so it can die quickly
473 if (p->flags & PF_EXITING) {
474 set_tsk_thread_flag(p, TIF_MEMDIE);
475 boost_dying_task_prio(p, mem);
476 return 0;
479 task_lock(p);
480 pr_err("%s: Kill process %d (%s) score %d or sacrifice child\n",
481 message, task_pid_nr(p), p->comm, points);
482 task_unlock(p);
485 * If any of p's children has a different mm and is eligible for kill,
486 * the one with the highest badness() score is sacrificed for its
487 * parent. This attempts to lose the minimal amount of work done while
488 * still freeing memory.
490 do {
491 list_for_each_entry(child, &t->children, sibling) {
492 unsigned int child_points;
495 * oom_badness() returns 0 if the thread is unkillable
497 child_points = oom_badness(child, mem, nodemask,
498 totalpages);
499 if (child_points > victim_points) {
500 victim = child;
501 victim_points = child_points;
504 } while_each_thread(p, t);
506 return oom_kill_task(victim, mem);
510 * Determines whether the kernel must panic because of the panic_on_oom sysctl.
512 static void check_panic_on_oom(enum oom_constraint constraint, gfp_t gfp_mask,
513 int order, const nodemask_t *nodemask)
515 if (likely(!sysctl_panic_on_oom))
516 return;
517 if (sysctl_panic_on_oom != 2) {
519 * panic_on_oom == 1 only affects CONSTRAINT_NONE, the kernel
520 * does not panic for cpuset, mempolicy, or memcg allocation
521 * failures.
523 if (constraint != CONSTRAINT_NONE)
524 return;
526 read_lock(&tasklist_lock);
527 dump_header(NULL, gfp_mask, order, NULL, nodemask);
528 read_unlock(&tasklist_lock);
529 panic("Out of memory: %s panic_on_oom is enabled\n",
530 sysctl_panic_on_oom == 2 ? "compulsory" : "system-wide");
533 #ifdef CONFIG_CGROUP_MEM_RES_CTLR
534 void mem_cgroup_out_of_memory(struct mem_cgroup *mem, gfp_t gfp_mask)
536 unsigned long limit;
537 unsigned int points = 0;
538 struct task_struct *p;
540 check_panic_on_oom(CONSTRAINT_MEMCG, gfp_mask, 0, NULL);
541 limit = mem_cgroup_get_limit(mem) >> PAGE_SHIFT;
542 read_lock(&tasklist_lock);
543 retry:
544 p = select_bad_process(&points, limit, mem, NULL);
545 if (!p || PTR_ERR(p) == -1UL)
546 goto out;
548 if (oom_kill_process(p, gfp_mask, 0, points, limit, mem, NULL,
549 "Memory cgroup out of memory"))
550 goto retry;
551 out:
552 read_unlock(&tasklist_lock);
554 #endif
556 static BLOCKING_NOTIFIER_HEAD(oom_notify_list);
558 int register_oom_notifier(struct notifier_block *nb)
560 return blocking_notifier_chain_register(&oom_notify_list, nb);
562 EXPORT_SYMBOL_GPL(register_oom_notifier);
564 int unregister_oom_notifier(struct notifier_block *nb)
566 return blocking_notifier_chain_unregister(&oom_notify_list, nb);
568 EXPORT_SYMBOL_GPL(unregister_oom_notifier);
571 * Try to acquire the OOM killer lock for the zones in zonelist. Returns zero
572 * if a parallel OOM killing is already taking place that includes a zone in
573 * the zonelist. Otherwise, locks all zones in the zonelist and returns 1.
575 int try_set_zonelist_oom(struct zonelist *zonelist, gfp_t gfp_mask)
577 struct zoneref *z;
578 struct zone *zone;
579 int ret = 1;
581 spin_lock(&zone_scan_lock);
582 for_each_zone_zonelist(zone, z, zonelist, gfp_zone(gfp_mask)) {
583 if (zone_is_oom_locked(zone)) {
584 ret = 0;
585 goto out;
589 for_each_zone_zonelist(zone, z, zonelist, gfp_zone(gfp_mask)) {
591 * Lock each zone in the zonelist under zone_scan_lock so a
592 * parallel invocation of try_set_zonelist_oom() doesn't succeed
593 * when it shouldn't.
595 zone_set_flag(zone, ZONE_OOM_LOCKED);
598 out:
599 spin_unlock(&zone_scan_lock);
600 return ret;
604 * Clears the ZONE_OOM_LOCKED flag for all zones in the zonelist so that failed
605 * allocation attempts with zonelists containing them may now recall the OOM
606 * killer, if necessary.
608 void clear_zonelist_oom(struct zonelist *zonelist, gfp_t gfp_mask)
610 struct zoneref *z;
611 struct zone *zone;
613 spin_lock(&zone_scan_lock);
614 for_each_zone_zonelist(zone, z, zonelist, gfp_zone(gfp_mask)) {
615 zone_clear_flag(zone, ZONE_OOM_LOCKED);
617 spin_unlock(&zone_scan_lock);
621 * Try to acquire the oom killer lock for all system zones. Returns zero if a
622 * parallel oom killing is taking place, otherwise locks all zones and returns
623 * non-zero.
625 static int try_set_system_oom(void)
627 struct zone *zone;
628 int ret = 1;
630 spin_lock(&zone_scan_lock);
631 for_each_populated_zone(zone)
632 if (zone_is_oom_locked(zone)) {
633 ret = 0;
634 goto out;
636 for_each_populated_zone(zone)
637 zone_set_flag(zone, ZONE_OOM_LOCKED);
638 out:
639 spin_unlock(&zone_scan_lock);
640 return ret;
644 * Clears ZONE_OOM_LOCKED for all system zones so that failed allocation
645 * attempts or page faults may now recall the oom killer, if necessary.
647 static void clear_system_oom(void)
649 struct zone *zone;
651 spin_lock(&zone_scan_lock);
652 for_each_populated_zone(zone)
653 zone_clear_flag(zone, ZONE_OOM_LOCKED);
654 spin_unlock(&zone_scan_lock);
658 * out_of_memory - kill the "best" process when we run out of memory
659 * @zonelist: zonelist pointer
660 * @gfp_mask: memory allocation flags
661 * @order: amount of memory being requested as a power of 2
662 * @nodemask: nodemask passed to page allocator
664 * If we run out of memory, we have the choice between either
665 * killing a random task (bad), letting the system crash (worse)
666 * OR try to be smart about which process to kill. Note that we
667 * don't have to be perfect here, we just have to be good.
669 void out_of_memory(struct zonelist *zonelist, gfp_t gfp_mask,
670 int order, nodemask_t *nodemask)
672 const nodemask_t *mpol_mask;
673 struct task_struct *p;
674 unsigned long totalpages;
675 unsigned long freed = 0;
676 unsigned int points;
677 enum oom_constraint constraint = CONSTRAINT_NONE;
678 int killed = 0;
680 blocking_notifier_call_chain(&oom_notify_list, 0, &freed);
681 if (freed > 0)
682 /* Got some memory back in the last second. */
683 return;
686 * If current has a pending SIGKILL, then automatically select it. The
687 * goal is to allow it to allocate so that it may quickly exit and free
688 * its memory.
690 if (fatal_signal_pending(current)) {
691 set_thread_flag(TIF_MEMDIE);
692 boost_dying_task_prio(current, NULL);
693 return;
697 * Check if there were limitations on the allocation (only relevant for
698 * NUMA) that may require different handling.
700 constraint = constrained_alloc(zonelist, gfp_mask, nodemask,
701 &totalpages);
702 mpol_mask = (constraint == CONSTRAINT_MEMORY_POLICY) ? nodemask : NULL;
703 check_panic_on_oom(constraint, gfp_mask, order, mpol_mask);
705 read_lock(&tasklist_lock);
706 if (sysctl_oom_kill_allocating_task &&
707 !oom_unkillable_task(current, NULL, nodemask) &&
708 current->mm && !atomic_read(&current->mm->oom_disable_count)) {
710 * oom_kill_process() needs tasklist_lock held. If it returns
711 * non-zero, current could not be killed so we must fallback to
712 * the tasklist scan.
714 if (!oom_kill_process(current, gfp_mask, order, 0, totalpages,
715 NULL, nodemask,
716 "Out of memory (oom_kill_allocating_task)"))
717 goto out;
720 retry:
721 p = select_bad_process(&points, totalpages, NULL, mpol_mask);
722 if (PTR_ERR(p) == -1UL)
723 goto out;
725 /* Found nothing?!?! Either we hang forever, or we panic. */
726 if (!p) {
727 dump_header(NULL, gfp_mask, order, NULL, mpol_mask);
728 read_unlock(&tasklist_lock);
729 panic("Out of memory and no killable processes...\n");
732 if (oom_kill_process(p, gfp_mask, order, points, totalpages, NULL,
733 nodemask, "Out of memory"))
734 goto retry;
735 killed = 1;
736 out:
737 read_unlock(&tasklist_lock);
740 * Give "p" a good chance of killing itself before we
741 * retry to allocate memory unless "p" is current
743 if (killed && !test_thread_flag(TIF_MEMDIE))
744 schedule_timeout_uninterruptible(1);
748 * The pagefault handler calls here because it is out of memory, so kill a
749 * memory-hogging task. If a populated zone has ZONE_OOM_LOCKED set, a parallel
750 * oom killing is already in progress so do nothing. If a task is found with
751 * TIF_MEMDIE set, it has been killed so do nothing and allow it to exit.
753 void pagefault_out_of_memory(void)
755 if (try_set_system_oom()) {
756 out_of_memory(NULL, 0, 0, NULL);
757 clear_system_oom();
759 if (!test_thread_flag(TIF_MEMDIE))
760 schedule_timeout_uninterruptible(1);