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![Sha Zhengju](/assets/img/avatar_default.png)
Currently when a memcg oom is happening the oom dump messages is still global state and provides few useful info for users. This patch prints more pointed memcg page statistics for memcg-oom and take hierarchy into consideration: Based on Michal's advice, we take hierarchy into consideration: supppose we trigger an OOM on A's limit root_memcg | A (use_hierachy=1) / \ B C | D then the printed info will be: Memory cgroup stats for /A:... Memory cgroup stats for /A/B:... Memory cgroup stats for /A/C:... Memory cgroup stats for /A/B/D:... Following are samples of oom output: (1) Before change: mal-80 invoked oom-killer:gfp_mask=0xd0, order=0, oom_score_adj=0 mal-80 cpuset=/ mems_allowed=0 Pid: 2976, comm: mal-80 Not tainted 3.7.0+ #10 Call Trace: [<ffffffff8167fbfb>] dump_header+0x83/0x1ca ..... (call trace) [<ffffffff8168a818>] page_fault+0x28/0x30 <<<<<<<<<<<<<<<<<<<<< memcg specific information Task in /A/B/D killed as a result of limit of /A memory: usage 101376kB, limit 101376kB, failcnt 57 memory+swap: usage 101376kB, limit 101376kB, failcnt 0 kmem: usage 0kB, limit 9007199254740991kB, failcnt 0 <<<<<<<<<<<<<<<<<<<<< print per cpu pageset stat Mem-Info: Node 0 DMA per-cpu: CPU 0: hi: 0, btch: 1 usd: 0 ...... CPU 3: hi: 0, btch: 1 usd: 0 Node 0 DMA32 per-cpu: CPU 0: hi: 186, btch: 31 usd: 173 ...... CPU 3: hi: 186, btch: 31 usd: 130 <<<<<<<<<<<<<<<<<<<<< print global page state active_anon:92963 inactive_anon:40777 isolated_anon:0 active_file:33027 inactive_file:51718 isolated_file:0 unevictable:0 dirty:3 writeback:0 unstable:0 free:729995 slab_reclaimable:6897 slab_unreclaimable:6263 mapped:20278 shmem:35971 pagetables:5885 bounce:0 free_cma:0 <<<<<<<<<<<<<<<<<<<<< print per zone page state Node 0 DMA free:15836kB ... all_unreclaimable? no lowmem_reserve[]: 0 3175 3899 3899 Node 0 DMA32 free:2888564kB ... all_unrelaimable? no lowmem_reserve[]: 0 0 724 724 lowmem_reserve[]: 0 0 0 0 Node 0 DMA: 1*4kB (U) ... 3*4096kB (M) = 15836kB Node 0 DMA32: 41*4kB (UM) ... 702*4096kB (MR) = 2888316kB 120710 total pagecache pages 0 pages in swap cache <<<<<<<<<<<<<<<<<<<<< print global swap cache stat Swap cache stats: add 0, delete 0, find 0/0 Free swap = 499708kB Total swap = 499708kB 1040368 pages RAM 58678 pages reserved 169065 pages shared 173632 pages non-shared [ pid ] uid tgid total_vm rss nr_ptes swapents oom_score_adj name [ 2693] 0 2693 6005 1324 17 0 0 god [ 2754] 0 2754 6003 1320 16 0 0 god [ 2811] 0 2811 5992 1304 18 0 0 god [ 2874] 0 2874 6005 1323 18 0 0 god [ 2935] 0 2935 8720 7742 21 0 0 mal-30 [ 2976] 0 2976 21520 17577 42 0 0 mal-80 Memory cgroup out of memory: Kill process 2976 (mal-80) score 665 or sacrifice child Killed process 2976 (mal-80) total-vm:86080kB, anon-rss:69964kB, file-rss:344kB We can see that messages dumped by show_free_areas() are longsome and can provide so limited info for memcg that just happen oom. (2) After change mal-80 invoked oom-killer: gfp_mask=0xd0, order=0, oom_score_adj=0 mal-80 cpuset=/ mems_allowed=0 Pid: 2704, comm: mal-80 Not tainted 3.7.0+ #10 Call Trace: [<ffffffff8167fd0b>] dump_header+0x83/0x1d1 .......(call trace) [<ffffffff8168a918>] page_fault+0x28/0x30 Task in /A/B/D killed as a result of limit of /A <<<<<<<<<<<<<<<<<<<<< memcg specific information memory: usage 102400kB, limit 102400kB, failcnt 140 memory+swap: usage 102400kB, limit 102400kB, failcnt 0 kmem: usage 0kB, limit 9007199254740991kB, failcnt 0 Memory cgroup stats for /A: cache:32KB rss:30984KB mapped_file:0KB swap:0KB inactive_anon:6912KB active_anon:24072KB inactive_file:32KB active_file:0KB unevictable:0KB Memory cgroup stats for /A/B: cache:0KB rss:0KB mapped_file:0KB swap:0KB inactive_anon:0KB active_anon:0KB inactive_file:0KB active_file:0KB unevictable:0KB Memory cgroup stats for /A/C: cache:0KB rss:0KB mapped_file:0KB swap:0KB inactive_anon:0KB active_anon:0KB inactive_file:0KB active_file:0KB unevictable:0KB Memory cgroup stats for /A/B/D: cache:32KB rss:71352KB mapped_file:0KB swap:0KB inactive_anon:6656KB active_anon:64696KB inactive_file:16KB active_file:16KB unevictable:0KB [ pid ] uid tgid total_vm rss nr_ptes swapents oom_score_adj name [ 2260] 0 2260 6006 1325 18 0 0 god [ 2383] 0 2383 6003 1319 17 0 0 god [ 2503] 0 2503 6004 1321 18 0 0 god [ 2622] 0 2622 6004 1321 16 0 0 god [ 2695] 0 2695 8720 7741 22 0 0 mal-30 [ 2704] 0 2704 21520 17839 43 0 0 mal-80 Memory cgroup out of memory: Kill process 2704 (mal-80) score 669 or sacrifice child Killed process 2704 (mal-80) total-vm:86080kB, anon-rss:71016kB, file-rss:340kB This version provides more pointed info for memcg in "Memory cgroup stats for XXX" section. Signed-off-by: Sha Zhengju <handai.szj@taobao.com> Acked-by: Michal Hocko <mhocko@suse.cz> Cc: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com> Acked-by: David Rientjes <rientjes@google.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
688 lines
20 KiB
C
688 lines
20 KiB
C
/*
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* linux/mm/oom_kill.c
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*
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* Copyright (C) 1998,2000 Rik van Riel
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* Thanks go out to Claus Fischer for some serious inspiration and
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* for goading me into coding this file...
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* Copyright (C) 2010 Google, Inc.
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* Rewritten by David Rientjes
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*
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* The routines in this file are used to kill a process when
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* we're seriously out of memory. This gets called from __alloc_pages()
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* in mm/page_alloc.c when we really run out of memory.
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*
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* Since we won't call these routines often (on a well-configured
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* machine) this file will double as a 'coding guide' and a signpost
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* for newbie kernel hackers. It features several pointers to major
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* kernel subsystems and hints as to where to find out what things do.
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*/
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#include <linux/oom.h>
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#include <linux/mm.h>
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#include <linux/err.h>
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#include <linux/gfp.h>
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#include <linux/sched.h>
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#include <linux/swap.h>
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#include <linux/timex.h>
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#include <linux/jiffies.h>
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#include <linux/cpuset.h>
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#include <linux/export.h>
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#include <linux/notifier.h>
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#include <linux/memcontrol.h>
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#include <linux/mempolicy.h>
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#include <linux/security.h>
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#include <linux/ptrace.h>
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#include <linux/freezer.h>
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#include <linux/ftrace.h>
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#include <linux/ratelimit.h>
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#define CREATE_TRACE_POINTS
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#include <trace/events/oom.h>
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int sysctl_panic_on_oom;
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int sysctl_oom_kill_allocating_task;
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int sysctl_oom_dump_tasks = 1;
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static DEFINE_SPINLOCK(zone_scan_lock);
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#ifdef CONFIG_NUMA
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/**
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* has_intersects_mems_allowed() - check task eligiblity for kill
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* @tsk: task struct of which task to consider
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* @mask: nodemask passed to page allocator for mempolicy ooms
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*
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* Task eligibility is determined by whether or not a candidate task, @tsk,
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* shares the same mempolicy nodes as current if it is bound by such a policy
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* and whether or not it has the same set of allowed cpuset nodes.
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*/
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static bool has_intersects_mems_allowed(struct task_struct *tsk,
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const nodemask_t *mask)
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{
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struct task_struct *start = tsk;
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do {
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if (mask) {
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/*
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* If this is a mempolicy constrained oom, tsk's
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* cpuset is irrelevant. Only return true if its
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* mempolicy intersects current, otherwise it may be
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* needlessly killed.
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*/
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if (mempolicy_nodemask_intersects(tsk, mask))
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return true;
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} else {
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/*
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* This is not a mempolicy constrained oom, so only
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* check the mems of tsk's cpuset.
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*/
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if (cpuset_mems_allowed_intersects(current, tsk))
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return true;
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}
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} while_each_thread(start, tsk);
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return false;
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}
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#else
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static bool has_intersects_mems_allowed(struct task_struct *tsk,
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const nodemask_t *mask)
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{
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return true;
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}
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#endif /* CONFIG_NUMA */
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/*
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* The process p may have detached its own ->mm while exiting or through
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* use_mm(), but one or more of its subthreads may still have a valid
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* pointer. Return p, or any of its subthreads with a valid ->mm, with
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* task_lock() held.
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*/
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struct task_struct *find_lock_task_mm(struct task_struct *p)
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{
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struct task_struct *t = p;
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do {
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task_lock(t);
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if (likely(t->mm))
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return t;
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task_unlock(t);
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} while_each_thread(p, t);
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return NULL;
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}
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/* return true if the task is not adequate as candidate victim task. */
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static bool oom_unkillable_task(struct task_struct *p,
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const struct mem_cgroup *memcg, const nodemask_t *nodemask)
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{
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if (is_global_init(p))
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return true;
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if (p->flags & PF_KTHREAD)
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return true;
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/* When mem_cgroup_out_of_memory() and p is not member of the group */
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if (memcg && !task_in_mem_cgroup(p, memcg))
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return true;
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/* p may not have freeable memory in nodemask */
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if (!has_intersects_mems_allowed(p, nodemask))
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return true;
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return false;
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}
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/**
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* oom_badness - heuristic function to determine which candidate task to kill
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* @p: task struct of which task we should calculate
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* @totalpages: total present RAM allowed for page allocation
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*
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* The heuristic for determining which task to kill is made to be as simple and
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* predictable as possible. The goal is to return the highest value for the
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* task consuming the most memory to avoid subsequent oom failures.
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*/
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unsigned long oom_badness(struct task_struct *p, struct mem_cgroup *memcg,
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const nodemask_t *nodemask, unsigned long totalpages)
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{
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long points;
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long adj;
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if (oom_unkillable_task(p, memcg, nodemask))
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return 0;
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p = find_lock_task_mm(p);
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if (!p)
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return 0;
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adj = (long)p->signal->oom_score_adj;
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if (adj == OOM_SCORE_ADJ_MIN) {
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task_unlock(p);
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return 0;
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}
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/*
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* The baseline for the badness score is the proportion of RAM that each
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* task's rss, pagetable and swap space use.
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*/
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points = get_mm_rss(p->mm) + p->mm->nr_ptes +
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get_mm_counter(p->mm, MM_SWAPENTS);
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task_unlock(p);
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/*
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* Root processes get 3% bonus, just like the __vm_enough_memory()
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* implementation used by LSMs.
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*/
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if (has_capability_noaudit(p, CAP_SYS_ADMIN))
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adj -= 30;
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/* Normalize to oom_score_adj units */
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adj *= totalpages / 1000;
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points += adj;
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/*
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* Never return 0 for an eligible task regardless of the root bonus and
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* oom_score_adj (oom_score_adj can't be OOM_SCORE_ADJ_MIN here).
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*/
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return points > 0 ? points : 1;
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}
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/*
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* Determine the type of allocation constraint.
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*/
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#ifdef CONFIG_NUMA
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static enum oom_constraint constrained_alloc(struct zonelist *zonelist,
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gfp_t gfp_mask, nodemask_t *nodemask,
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unsigned long *totalpages)
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{
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struct zone *zone;
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struct zoneref *z;
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enum zone_type high_zoneidx = gfp_zone(gfp_mask);
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bool cpuset_limited = false;
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int nid;
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/* Default to all available memory */
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*totalpages = totalram_pages + total_swap_pages;
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if (!zonelist)
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return CONSTRAINT_NONE;
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/*
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* Reach here only when __GFP_NOFAIL is used. So, we should avoid
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* to kill current.We have to random task kill in this case.
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* Hopefully, CONSTRAINT_THISNODE...but no way to handle it, now.
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*/
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if (gfp_mask & __GFP_THISNODE)
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return CONSTRAINT_NONE;
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/*
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* This is not a __GFP_THISNODE allocation, so a truncated nodemask in
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* the page allocator means a mempolicy is in effect. Cpuset policy
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* is enforced in get_page_from_freelist().
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*/
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if (nodemask && !nodes_subset(node_states[N_MEMORY], *nodemask)) {
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*totalpages = total_swap_pages;
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for_each_node_mask(nid, *nodemask)
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*totalpages += node_spanned_pages(nid);
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return CONSTRAINT_MEMORY_POLICY;
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}
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/* Check this allocation failure is caused by cpuset's wall function */
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for_each_zone_zonelist_nodemask(zone, z, zonelist,
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high_zoneidx, nodemask)
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if (!cpuset_zone_allowed_softwall(zone, gfp_mask))
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cpuset_limited = true;
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if (cpuset_limited) {
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*totalpages = total_swap_pages;
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for_each_node_mask(nid, cpuset_current_mems_allowed)
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*totalpages += node_spanned_pages(nid);
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return CONSTRAINT_CPUSET;
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}
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return CONSTRAINT_NONE;
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}
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#else
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static enum oom_constraint constrained_alloc(struct zonelist *zonelist,
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gfp_t gfp_mask, nodemask_t *nodemask,
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unsigned long *totalpages)
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{
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*totalpages = totalram_pages + total_swap_pages;
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return CONSTRAINT_NONE;
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}
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#endif
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enum oom_scan_t oom_scan_process_thread(struct task_struct *task,
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unsigned long totalpages, const nodemask_t *nodemask,
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bool force_kill)
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{
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if (task->exit_state)
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return OOM_SCAN_CONTINUE;
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if (oom_unkillable_task(task, NULL, nodemask))
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return OOM_SCAN_CONTINUE;
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/*
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* This task already has access to memory reserves and is being killed.
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* Don't allow any other task to have access to the reserves.
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*/
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if (test_tsk_thread_flag(task, TIF_MEMDIE)) {
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if (unlikely(frozen(task)))
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__thaw_task(task);
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if (!force_kill)
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return OOM_SCAN_ABORT;
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}
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if (!task->mm)
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return OOM_SCAN_CONTINUE;
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/*
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* If task is allocating a lot of memory and has been marked to be
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* killed first if it triggers an oom, then select it.
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*/
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if (oom_task_origin(task))
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return OOM_SCAN_SELECT;
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if (task->flags & PF_EXITING && !force_kill) {
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/*
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* If this task is not being ptraced on exit, then wait for it
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* to finish before killing some other task unnecessarily.
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*/
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if (!(task->group_leader->ptrace & PT_TRACE_EXIT))
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return OOM_SCAN_ABORT;
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}
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return OOM_SCAN_OK;
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}
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/*
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* Simple selection loop. We chose the process with the highest
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* number of 'points'.
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*
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* (not docbooked, we don't want this one cluttering up the manual)
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*/
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static struct task_struct *select_bad_process(unsigned int *ppoints,
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unsigned long totalpages, const nodemask_t *nodemask,
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bool force_kill)
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{
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struct task_struct *g, *p;
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struct task_struct *chosen = NULL;
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unsigned long chosen_points = 0;
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rcu_read_lock();
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do_each_thread(g, p) {
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unsigned int points;
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switch (oom_scan_process_thread(p, totalpages, nodemask,
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force_kill)) {
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case OOM_SCAN_SELECT:
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chosen = p;
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chosen_points = ULONG_MAX;
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/* fall through */
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case OOM_SCAN_CONTINUE:
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continue;
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case OOM_SCAN_ABORT:
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rcu_read_unlock();
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return ERR_PTR(-1UL);
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case OOM_SCAN_OK:
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break;
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};
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points = oom_badness(p, NULL, nodemask, totalpages);
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if (points > chosen_points) {
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chosen = p;
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chosen_points = points;
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}
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} while_each_thread(g, p);
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if (chosen)
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get_task_struct(chosen);
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rcu_read_unlock();
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*ppoints = chosen_points * 1000 / totalpages;
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return chosen;
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}
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/**
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* dump_tasks - dump current memory state of all system tasks
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* @memcg: current's memory controller, if constrained
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* @nodemask: nodemask passed to page allocator for mempolicy ooms
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*
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* Dumps the current memory state of all eligible tasks. Tasks not in the same
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* memcg, not in the same cpuset, or bound to a disjoint set of mempolicy nodes
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* are not shown.
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* State information includes task's pid, uid, tgid, vm size, rss, nr_ptes,
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* swapents, oom_score_adj value, and name.
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*/
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static void dump_tasks(const struct mem_cgroup *memcg, const nodemask_t *nodemask)
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{
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struct task_struct *p;
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struct task_struct *task;
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pr_info("[ pid ] uid tgid total_vm rss nr_ptes swapents oom_score_adj name\n");
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rcu_read_lock();
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for_each_process(p) {
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if (oom_unkillable_task(p, memcg, nodemask))
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continue;
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task = find_lock_task_mm(p);
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if (!task) {
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/*
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* This is a kthread or all of p's threads have already
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* detached their mm's. There's no need to report
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* them; they can't be oom killed anyway.
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*/
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continue;
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}
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pr_info("[%5d] %5d %5d %8lu %8lu %7lu %8lu %5hd %s\n",
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task->pid, from_kuid(&init_user_ns, task_uid(task)),
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task->tgid, task->mm->total_vm, get_mm_rss(task->mm),
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task->mm->nr_ptes,
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get_mm_counter(task->mm, MM_SWAPENTS),
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task->signal->oom_score_adj, task->comm);
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task_unlock(task);
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}
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rcu_read_unlock();
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}
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static void dump_header(struct task_struct *p, gfp_t gfp_mask, int order,
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struct mem_cgroup *memcg, const nodemask_t *nodemask)
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{
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task_lock(current);
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pr_warning("%s invoked oom-killer: gfp_mask=0x%x, order=%d, "
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"oom_score_adj=%hd\n",
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current->comm, gfp_mask, order,
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current->signal->oom_score_adj);
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cpuset_print_task_mems_allowed(current);
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task_unlock(current);
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dump_stack();
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if (memcg)
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mem_cgroup_print_oom_info(memcg, p);
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else
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show_mem(SHOW_MEM_FILTER_NODES);
|
|
if (sysctl_oom_dump_tasks)
|
|
dump_tasks(memcg, nodemask);
|
|
}
|
|
|
|
#define K(x) ((x) << (PAGE_SHIFT-10))
|
|
/*
|
|
* Must be called while holding a reference to p, which will be released upon
|
|
* returning.
|
|
*/
|
|
void oom_kill_process(struct task_struct *p, gfp_t gfp_mask, int order,
|
|
unsigned int points, unsigned long totalpages,
|
|
struct mem_cgroup *memcg, nodemask_t *nodemask,
|
|
const char *message)
|
|
{
|
|
struct task_struct *victim = p;
|
|
struct task_struct *child;
|
|
struct task_struct *t = p;
|
|
struct mm_struct *mm;
|
|
unsigned int victim_points = 0;
|
|
static DEFINE_RATELIMIT_STATE(oom_rs, DEFAULT_RATELIMIT_INTERVAL,
|
|
DEFAULT_RATELIMIT_BURST);
|
|
|
|
/*
|
|
* If the task is already exiting, don't alarm the sysadmin or kill
|
|
* its children or threads, just set TIF_MEMDIE so it can die quickly
|
|
*/
|
|
if (p->flags & PF_EXITING) {
|
|
set_tsk_thread_flag(p, TIF_MEMDIE);
|
|
put_task_struct(p);
|
|
return;
|
|
}
|
|
|
|
if (__ratelimit(&oom_rs))
|
|
dump_header(p, gfp_mask, order, memcg, nodemask);
|
|
|
|
task_lock(p);
|
|
pr_err("%s: Kill process %d (%s) score %d or sacrifice child\n",
|
|
message, task_pid_nr(p), p->comm, points);
|
|
task_unlock(p);
|
|
|
|
/*
|
|
* If any of p's children has a different mm and is eligible for kill,
|
|
* the one with the highest oom_badness() score is sacrificed for its
|
|
* parent. This attempts to lose the minimal amount of work done while
|
|
* still freeing memory.
|
|
*/
|
|
read_lock(&tasklist_lock);
|
|
do {
|
|
list_for_each_entry(child, &t->children, sibling) {
|
|
unsigned int child_points;
|
|
|
|
if (child->mm == p->mm)
|
|
continue;
|
|
/*
|
|
* oom_badness() returns 0 if the thread is unkillable
|
|
*/
|
|
child_points = oom_badness(child, memcg, nodemask,
|
|
totalpages);
|
|
if (child_points > victim_points) {
|
|
put_task_struct(victim);
|
|
victim = child;
|
|
victim_points = child_points;
|
|
get_task_struct(victim);
|
|
}
|
|
}
|
|
} while_each_thread(p, t);
|
|
read_unlock(&tasklist_lock);
|
|
|
|
rcu_read_lock();
|
|
p = find_lock_task_mm(victim);
|
|
if (!p) {
|
|
rcu_read_unlock();
|
|
put_task_struct(victim);
|
|
return;
|
|
} else if (victim != p) {
|
|
get_task_struct(p);
|
|
put_task_struct(victim);
|
|
victim = p;
|
|
}
|
|
|
|
/* mm cannot safely be dereferenced after task_unlock(victim) */
|
|
mm = victim->mm;
|
|
pr_err("Killed process %d (%s) total-vm:%lukB, anon-rss:%lukB, file-rss:%lukB\n",
|
|
task_pid_nr(victim), victim->comm, K(victim->mm->total_vm),
|
|
K(get_mm_counter(victim->mm, MM_ANONPAGES)),
|
|
K(get_mm_counter(victim->mm, MM_FILEPAGES)));
|
|
task_unlock(victim);
|
|
|
|
/*
|
|
* Kill all user processes sharing victim->mm in other thread groups, if
|
|
* any. They don't get access to memory reserves, though, to avoid
|
|
* depletion of all memory. This prevents mm->mmap_sem livelock when an
|
|
* oom killed thread cannot exit because it requires the semaphore and
|
|
* its contended by another thread trying to allocate memory itself.
|
|
* That thread will now get access to memory reserves since it has a
|
|
* pending fatal signal.
|
|
*/
|
|
for_each_process(p)
|
|
if (p->mm == mm && !same_thread_group(p, victim) &&
|
|
!(p->flags & PF_KTHREAD)) {
|
|
if (p->signal->oom_score_adj == OOM_SCORE_ADJ_MIN)
|
|
continue;
|
|
|
|
task_lock(p); /* Protect ->comm from prctl() */
|
|
pr_err("Kill process %d (%s) sharing same memory\n",
|
|
task_pid_nr(p), p->comm);
|
|
task_unlock(p);
|
|
do_send_sig_info(SIGKILL, SEND_SIG_FORCED, p, true);
|
|
}
|
|
rcu_read_unlock();
|
|
|
|
set_tsk_thread_flag(victim, TIF_MEMDIE);
|
|
do_send_sig_info(SIGKILL, SEND_SIG_FORCED, victim, true);
|
|
put_task_struct(victim);
|
|
}
|
|
#undef K
|
|
|
|
/*
|
|
* Determines whether the kernel must panic because of the panic_on_oom sysctl.
|
|
*/
|
|
void check_panic_on_oom(enum oom_constraint constraint, gfp_t gfp_mask,
|
|
int order, const nodemask_t *nodemask)
|
|
{
|
|
if (likely(!sysctl_panic_on_oom))
|
|
return;
|
|
if (sysctl_panic_on_oom != 2) {
|
|
/*
|
|
* panic_on_oom == 1 only affects CONSTRAINT_NONE, the kernel
|
|
* does not panic for cpuset, mempolicy, or memcg allocation
|
|
* failures.
|
|
*/
|
|
if (constraint != CONSTRAINT_NONE)
|
|
return;
|
|
}
|
|
dump_header(NULL, gfp_mask, order, NULL, nodemask);
|
|
panic("Out of memory: %s panic_on_oom is enabled\n",
|
|
sysctl_panic_on_oom == 2 ? "compulsory" : "system-wide");
|
|
}
|
|
|
|
static BLOCKING_NOTIFIER_HEAD(oom_notify_list);
|
|
|
|
int register_oom_notifier(struct notifier_block *nb)
|
|
{
|
|
return blocking_notifier_chain_register(&oom_notify_list, nb);
|
|
}
|
|
EXPORT_SYMBOL_GPL(register_oom_notifier);
|
|
|
|
int unregister_oom_notifier(struct notifier_block *nb)
|
|
{
|
|
return blocking_notifier_chain_unregister(&oom_notify_list, nb);
|
|
}
|
|
EXPORT_SYMBOL_GPL(unregister_oom_notifier);
|
|
|
|
/*
|
|
* Try to acquire the OOM killer lock for the zones in zonelist. Returns zero
|
|
* if a parallel OOM killing is already taking place that includes a zone in
|
|
* the zonelist. Otherwise, locks all zones in the zonelist and returns 1.
|
|
*/
|
|
int try_set_zonelist_oom(struct zonelist *zonelist, gfp_t gfp_mask)
|
|
{
|
|
struct zoneref *z;
|
|
struct zone *zone;
|
|
int ret = 1;
|
|
|
|
spin_lock(&zone_scan_lock);
|
|
for_each_zone_zonelist(zone, z, zonelist, gfp_zone(gfp_mask)) {
|
|
if (zone_is_oom_locked(zone)) {
|
|
ret = 0;
|
|
goto out;
|
|
}
|
|
}
|
|
|
|
for_each_zone_zonelist(zone, z, zonelist, gfp_zone(gfp_mask)) {
|
|
/*
|
|
* Lock each zone in the zonelist under zone_scan_lock so a
|
|
* parallel invocation of try_set_zonelist_oom() doesn't succeed
|
|
* when it shouldn't.
|
|
*/
|
|
zone_set_flag(zone, ZONE_OOM_LOCKED);
|
|
}
|
|
|
|
out:
|
|
spin_unlock(&zone_scan_lock);
|
|
return ret;
|
|
}
|
|
|
|
/*
|
|
* Clears the ZONE_OOM_LOCKED flag for all zones in the zonelist so that failed
|
|
* allocation attempts with zonelists containing them may now recall the OOM
|
|
* killer, if necessary.
|
|
*/
|
|
void clear_zonelist_oom(struct zonelist *zonelist, gfp_t gfp_mask)
|
|
{
|
|
struct zoneref *z;
|
|
struct zone *zone;
|
|
|
|
spin_lock(&zone_scan_lock);
|
|
for_each_zone_zonelist(zone, z, zonelist, gfp_zone(gfp_mask)) {
|
|
zone_clear_flag(zone, ZONE_OOM_LOCKED);
|
|
}
|
|
spin_unlock(&zone_scan_lock);
|
|
}
|
|
|
|
/**
|
|
* out_of_memory - kill the "best" process when we run out of memory
|
|
* @zonelist: zonelist pointer
|
|
* @gfp_mask: memory allocation flags
|
|
* @order: amount of memory being requested as a power of 2
|
|
* @nodemask: nodemask passed to page allocator
|
|
* @force_kill: true if a task must be killed, even if others are exiting
|
|
*
|
|
* If we run out of memory, we have the choice between either
|
|
* killing a random task (bad), letting the system crash (worse)
|
|
* OR try to be smart about which process to kill. Note that we
|
|
* don't have to be perfect here, we just have to be good.
|
|
*/
|
|
void out_of_memory(struct zonelist *zonelist, gfp_t gfp_mask,
|
|
int order, nodemask_t *nodemask, bool force_kill)
|
|
{
|
|
const nodemask_t *mpol_mask;
|
|
struct task_struct *p;
|
|
unsigned long totalpages;
|
|
unsigned long freed = 0;
|
|
unsigned int uninitialized_var(points);
|
|
enum oom_constraint constraint = CONSTRAINT_NONE;
|
|
int killed = 0;
|
|
|
|
blocking_notifier_call_chain(&oom_notify_list, 0, &freed);
|
|
if (freed > 0)
|
|
/* Got some memory back in the last second. */
|
|
return;
|
|
|
|
/*
|
|
* If current has a pending SIGKILL or is exiting, then automatically
|
|
* select it. The goal is to allow it to allocate so that it may
|
|
* quickly exit and free its memory.
|
|
*/
|
|
if (fatal_signal_pending(current) || current->flags & PF_EXITING) {
|
|
set_thread_flag(TIF_MEMDIE);
|
|
return;
|
|
}
|
|
|
|
/*
|
|
* Check if there were limitations on the allocation (only relevant for
|
|
* NUMA) that may require different handling.
|
|
*/
|
|
constraint = constrained_alloc(zonelist, gfp_mask, nodemask,
|
|
&totalpages);
|
|
mpol_mask = (constraint == CONSTRAINT_MEMORY_POLICY) ? nodemask : NULL;
|
|
check_panic_on_oom(constraint, gfp_mask, order, mpol_mask);
|
|
|
|
if (sysctl_oom_kill_allocating_task && current->mm &&
|
|
!oom_unkillable_task(current, NULL, nodemask) &&
|
|
current->signal->oom_score_adj != OOM_SCORE_ADJ_MIN) {
|
|
get_task_struct(current);
|
|
oom_kill_process(current, gfp_mask, order, 0, totalpages, NULL,
|
|
nodemask,
|
|
"Out of memory (oom_kill_allocating_task)");
|
|
goto out;
|
|
}
|
|
|
|
p = select_bad_process(&points, totalpages, mpol_mask, force_kill);
|
|
/* Found nothing?!?! Either we hang forever, or we panic. */
|
|
if (!p) {
|
|
dump_header(NULL, gfp_mask, order, NULL, mpol_mask);
|
|
panic("Out of memory and no killable processes...\n");
|
|
}
|
|
if (PTR_ERR(p) != -1UL) {
|
|
oom_kill_process(p, gfp_mask, order, points, totalpages, NULL,
|
|
nodemask, "Out of memory");
|
|
killed = 1;
|
|
}
|
|
out:
|
|
/*
|
|
* Give the killed threads a good chance of exiting before trying to
|
|
* allocate memory again.
|
|
*/
|
|
if (killed)
|
|
schedule_timeout_killable(1);
|
|
}
|
|
|
|
/*
|
|
* The pagefault handler calls here because it is out of memory, so kill a
|
|
* memory-hogging task. If any populated zone has ZONE_OOM_LOCKED set, a
|
|
* parallel oom killing is already in progress so do nothing.
|
|
*/
|
|
void pagefault_out_of_memory(void)
|
|
{
|
|
struct zonelist *zonelist = node_zonelist(first_online_node,
|
|
GFP_KERNEL);
|
|
|
|
if (try_set_zonelist_oom(zonelist, GFP_KERNEL)) {
|
|
out_of_memory(NULL, 0, 0, NULL, false);
|
|
clear_zonelist_oom(zonelist, GFP_KERNEL);
|
|
}
|
|
}
|