Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1754374AbbFTH6N (ORCPT ); Sat, 20 Jun 2015 03:58:13 -0400 Received: from www262.sakura.ne.jp ([202.181.97.72]:44311 "EHLO www262.sakura.ne.jp" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1753305AbbFTH6G (ORCPT ); Sat, 20 Jun 2015 03:58:06 -0400 To: mhocko@suse.cz Cc: linux-mm@kvack.org, rientjes@google.com, hannes@cmpxchg.org, tj@kernel.org, akpm@linux-foundation.org, linux-kernel@vger.kernel.org Subject: Re: [RFC -v2] panic_on_oom_timeout From: Tetsuo Handa References: <201506172259.EAI00575.OFQtVFFSHMOLJO@I-love.SAKURA.ne.jp> <20150617154159.GJ25056@dhcp22.suse.cz> <201506192030.CAH00597.FQVOtFFLOJMHOS@I-love.SAKURA.ne.jp> <20150619153620.GI4913@dhcp22.suse.cz> <201506200354.ABC87533.OFFMtSLOFHJVQO@I-love.SAKURA.ne.jp> In-Reply-To: <201506200354.ABC87533.OFFMtSLOFHJVQO@I-love.SAKURA.ne.jp> Message-Id: <201506201657.JCI48462.MFFFJVSOOLOtQH@I-love.SAKURA.ne.jp> X-Mailer: Winbiff [Version 2.51 PL2] X-Accept-Language: ja,en,zh Date: Sat, 20 Jun 2015 16:57:38 +0900 Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 7980 Lines: 215 Tetsuo Handa wrote: > One case is that the system can not panic of threads are unable to call > out_of_memory() for some reason. ^ if > Well, if without analysis purpose, > > if (time_after(jiffies, oom_start + sysctl_panic_on_oom_timeout * HZ)) > panic(); > > (that is, pass the jiffies as of calling out_of_memory() for the first time > of this memory allocation request as an argument to out_of_memory(), and > compare at check_panic_on_oom()) is sufficient? Very simple implementation > because we do not use mod_timer()/del_timer(). Here is an untested patch. diff --git a/drivers/tty/sysrq.c b/drivers/tty/sysrq.c index b5b4278..4c64b92 100644 --- a/drivers/tty/sysrq.c +++ b/drivers/tty/sysrq.c @@ -355,7 +355,7 @@ static void moom_callback(struct work_struct *ignored) { mutex_lock(&oom_lock); if (!out_of_memory(node_zonelist(first_memory_node, GFP_KERNEL), - GFP_KERNEL, 0, NULL, true)) + GFP_KERNEL, 0, NULL, true, NULL)) pr_info("OOM request ignored because killer is disabled\n"); mutex_unlock(&oom_lock); } diff --git a/include/linux/oom.h b/include/linux/oom.h index 7deecb7..75525e9 100644 --- a/include/linux/oom.h +++ b/include/linux/oom.h @@ -64,14 +64,16 @@ extern void oom_kill_process(struct task_struct *p, gfp_t gfp_mask, int order, extern void check_panic_on_oom(enum oom_constraint constraint, gfp_t gfp_mask, int order, const nodemask_t *nodemask, - struct mem_cgroup *memcg); + struct mem_cgroup *memcg, + const unsigned long *oom_start); extern enum oom_scan_t oom_scan_process_thread(struct task_struct *task, unsigned long totalpages, const nodemask_t *nodemask, bool force_kill); extern bool out_of_memory(struct zonelist *zonelist, gfp_t gfp_mask, - int order, nodemask_t *mask, bool force_kill); + int order, nodemask_t *mask, bool force_kill, + const unsigned long *oom_start); extern void exit_oom_victim(void); @@ -99,4 +101,5 @@ static inline bool task_will_free_mem(struct task_struct *task) extern int sysctl_oom_dump_tasks; extern int sysctl_oom_kill_allocating_task; extern int sysctl_panic_on_oom; +extern int sysctl_panic_on_oom_timeout; #endif /* _INCLUDE_LINUX_OOM_H */ diff --git a/kernel/sysctl.c b/kernel/sysctl.c index c566b56..74a1b68 100644 --- a/kernel/sysctl.c +++ b/kernel/sysctl.c @@ -1162,6 +1162,14 @@ static struct ctl_table vm_table[] = { .extra2 = &two, }, { + .procname = "panic_on_oom_timeout", + .data = &sysctl_panic_on_oom_timeout, + .maxlen = sizeof(sysctl_panic_on_oom_timeout), + .mode = 0644, + .proc_handler = proc_dointvec_minmax, + .extra1 = &zero, + }, + { .procname = "oom_kill_allocating_task", .data = &sysctl_oom_kill_allocating_task, .maxlen = sizeof(sysctl_oom_kill_allocating_task), diff --git a/mm/memcontrol.c b/mm/memcontrol.c index acb93c5..ab1ae3e 100644 --- a/mm/memcontrol.c +++ b/mm/memcontrol.c @@ -1563,7 +1563,8 @@ static void mem_cgroup_out_of_memory(struct mem_cgroup *memcg, gfp_t gfp_mask, goto unlock; } - check_panic_on_oom(CONSTRAINT_MEMCG, gfp_mask, order, NULL, memcg); + check_panic_on_oom(CONSTRAINT_MEMCG, gfp_mask, order, NULL, memcg, + NULL); totalpages = mem_cgroup_get_limit(memcg) ? : 1; for_each_mem_cgroup_tree(iter, memcg) { struct css_task_iter it; diff --git a/mm/oom_kill.c b/mm/oom_kill.c index dff991e..9d30f2e 100644 --- a/mm/oom_kill.c +++ b/mm/oom_kill.c @@ -40,6 +40,7 @@ #include int sysctl_panic_on_oom; +int sysctl_panic_on_oom_timeout; int sysctl_oom_kill_allocating_task; int sysctl_oom_dump_tasks = 1; @@ -602,7 +603,8 @@ void oom_kill_process(struct task_struct *p, gfp_t gfp_mask, int order, */ void check_panic_on_oom(enum oom_constraint constraint, gfp_t gfp_mask, int order, const nodemask_t *nodemask, - struct mem_cgroup *memcg) + struct mem_cgroup *memcg, + const unsigned long *oom_start) { if (likely(!sysctl_panic_on_oom)) return; @@ -614,6 +616,14 @@ void check_panic_on_oom(enum oom_constraint constraint, gfp_t gfp_mask, */ if (constraint != CONSTRAINT_NONE) return; + /* + * panic_on_oom_timeout only affects panic_on_oom == 1 and + * CONSTRAINT_NONE. + */ + if (sysctl_panic_on_oom_timeout && oom_start && + time_before(jiffies, + *oom_start + sysctl_panic_on_oom_timeout * HZ)) + return; } dump_header(NULL, gfp_mask, order, memcg, nodemask); panic("Out of memory: %s panic_on_oom is enabled\n", @@ -641,6 +651,8 @@ EXPORT_SYMBOL_GPL(unregister_oom_notifier); * @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 + * @oom_start: Pointer to jiffies as of calling this function for the first + * time of this memory allocation request. Ignored if NULL. * * If we run out of memory, we have the choice between either * killing a random task (bad), letting the system crash (worse) @@ -648,7 +660,8 @@ EXPORT_SYMBOL_GPL(unregister_oom_notifier); * don't have to be perfect here, we just have to be good. */ bool out_of_memory(struct zonelist *zonelist, gfp_t gfp_mask, - int order, nodemask_t *nodemask, bool force_kill) + int order, nodemask_t *nodemask, bool force_kill, + const unsigned long *oom_start) { const nodemask_t *mpol_mask; struct task_struct *p; @@ -687,7 +700,8 @@ bool out_of_memory(struct zonelist *zonelist, gfp_t gfp_mask, 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, NULL); + check_panic_on_oom(constraint, gfp_mask, order, mpol_mask, NULL, + oom_start); if (sysctl_oom_kill_allocating_task && current->mm && !oom_unkillable_task(current, NULL, nodemask) && @@ -734,7 +748,7 @@ void pagefault_out_of_memory(void) if (!mutex_trylock(&oom_lock)) return; - if (!out_of_memory(NULL, 0, 0, NULL, false)) { + if (!out_of_memory(NULL, 0, 0, NULL, false, NULL)) { /* * There shouldn't be any user tasks runnable while the * OOM killer is disabled, so the current task has to diff --git a/mm/page_alloc.c b/mm/page_alloc.c index 73aa335..3a75fe8 100644 --- a/mm/page_alloc.c +++ b/mm/page_alloc.c @@ -2678,7 +2678,9 @@ void warn_alloc_failed(gfp_t gfp_mask, int order, const char *fmt, ...) static inline struct page * __alloc_pages_may_oom(gfp_t gfp_mask, unsigned int order, - const struct alloc_context *ac, unsigned long *did_some_progress) + const struct alloc_context *ac, + unsigned long *did_some_progress, + unsigned long *oom_start) { struct page *page; @@ -2731,7 +2733,10 @@ __alloc_pages_may_oom(gfp_t gfp_mask, unsigned int order, goto out; } /* Exhausted what can be done so it's blamo time */ - if (out_of_memory(ac->zonelist, gfp_mask, order, ac->nodemask, false) + if (!*oom_start) + *oom_start = jiffies; + if (out_of_memory(ac->zonelist, gfp_mask, order, ac->nodemask, false, + oom_start) || WARN_ON_ONCE(gfp_mask & __GFP_NOFAIL)) *did_some_progress = 1; out: @@ -2968,6 +2973,7 @@ __alloc_pages_slowpath(gfp_t gfp_mask, unsigned int order, enum migrate_mode migration_mode = MIGRATE_ASYNC; bool deferred_compaction = false; int contended_compaction = COMPACT_CONTENDED_NONE; + unsigned long oom_start = 0; /* * In the slowpath, we sanity check order to avoid ever trying to @@ -3122,7 +3128,8 @@ retry: } /* Reclaim has failed us, start killing things */ - page = __alloc_pages_may_oom(gfp_mask, order, ac, &did_some_progress); + page = __alloc_pages_may_oom(gfp_mask, order, ac, &did_some_progress, + &oom_start); if (page) goto got_pg; -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in Please read the FAQ at http://www.tux.org/lkml/