Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S933930Ab0BQB6e (ORCPT ); Tue, 16 Feb 2010 20:58:34 -0500 Received: from smtp-out.google.com ([216.239.44.51]:30253 "EHLO smtp-out.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S933879Ab0BQB6V (ORCPT ); Tue, 16 Feb 2010 20:58:21 -0500 DomainKey-Signature: a=rsa-sha1; s=beta; d=google.com; c=nofws; q=dns; h=date:from:x-x-sender:to:cc:subject:in-reply-to:message-id: references:user-agent:mime-version:content-type:x-system-of-record; b=EYH4sFdB7PqIdigKCKjiqb1fd7jMC8BE5MwhNegV53+hvwSuUNZebKwAEUJ2Y0PKD GovSpcH73OOmruioFqCgA== Date: Tue, 16 Feb 2010 17:58:05 -0800 (PST) From: David Rientjes X-X-Sender: rientjes@chino.kir.corp.google.com To: KAMEZAWA Hiroyuki cc: Andrew Morton , Rik van Riel , Nick Piggin , Andrea Arcangeli , Balbir Singh , Lubos Lunak , KOSAKI Motohiro , linux-kernel@vger.kernel.org, linux-mm@kvack.org Subject: Re: [patch -mm 4/9 v2] oom: remove compulsory panic_on_oom mode In-Reply-To: Message-ID: References: <20100216090005.f362f869.kamezawa.hiroyu@jp.fujitsu.com> <20100216092311.86bceb0c.kamezawa.hiroyu@jp.fujitsu.com> <20100217084239.265c65ea.kamezawa.hiroyu@jp.fujitsu.com> <20100217090124.398769d5.kamezawa.hiroyu@jp.fujitsu.com> <20100217094137.a0d26fbb.kamezawa.hiroyu@jp.fujitsu.com> User-Agent: Alpine 2.00 (DEB 1167 2008-08-23) MIME-Version: 1.0 Content-Type: TEXT/PLAIN; charset=US-ASCII X-System-Of-Record: true Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 8917 Lines: 309 On Tue, 16 Feb 2010, David Rientjes wrote: > Ok, I'll eliminate pagefault_out_of_memory() and get it to use > out_of_memory() by only checking for constrained_alloc() when > gfp_mask != 0. > What do you think about making pagefaults use out_of_memory() directly and respecting the sysctl_panic_on_oom settings? This removes the check for a parallel memcg oom killing since we can guarantee that's not going to happen if we take ZONE_OOM_LOCKED for all populated zones (nobody is currently executing the oom killer) and no tasks have TIF_MEMDIE set. Signed-off-by: David Rientjes --- diff --git a/include/linux/memcontrol.h b/include/linux/memcontrol.h --- a/include/linux/memcontrol.h +++ b/include/linux/memcontrol.h @@ -124,7 +124,6 @@ static inline bool mem_cgroup_disabled(void) return false; } -extern bool mem_cgroup_oom_called(struct task_struct *task); void mem_cgroup_update_file_mapped(struct page *page, int val); unsigned long mem_cgroup_soft_limit_reclaim(struct zone *zone, int order, gfp_t gfp_mask, int nid, @@ -258,11 +257,6 @@ static inline bool mem_cgroup_disabled(void) return true; } -static inline bool mem_cgroup_oom_called(struct task_struct *task) -{ - return false; -} - static inline int mem_cgroup_inactive_anon_is_low(struct mem_cgroup *memcg) { diff --git a/mm/memcontrol.c b/mm/memcontrol.c --- a/mm/memcontrol.c +++ b/mm/memcontrol.c @@ -200,7 +200,6 @@ struct mem_cgroup { * Should the accounting and control be hierarchical, per subtree? */ bool use_hierarchy; - unsigned long last_oom_jiffies; atomic_t refcnt; unsigned int swappiness; @@ -1234,34 +1233,6 @@ static int mem_cgroup_hierarchical_reclaim(struct mem_cgroup *root_mem, return total; } -bool mem_cgroup_oom_called(struct task_struct *task) -{ - bool ret = false; - struct mem_cgroup *mem; - struct mm_struct *mm; - - rcu_read_lock(); - mm = task->mm; - if (!mm) - mm = &init_mm; - mem = mem_cgroup_from_task(rcu_dereference(mm->owner)); - if (mem && time_before(jiffies, mem->last_oom_jiffies + HZ/10)) - ret = true; - rcu_read_unlock(); - return ret; -} - -static int record_last_oom_cb(struct mem_cgroup *mem, void *data) -{ - mem->last_oom_jiffies = jiffies; - return 0; -} - -static void record_last_oom(struct mem_cgroup *mem) -{ - mem_cgroup_walk_tree(mem, NULL, record_last_oom_cb); -} - /* * Currently used to update mapped file statistics, but the routine can be * generalized to update other statistics as well. @@ -1549,10 +1520,8 @@ static int __mem_cgroup_try_charge(struct mm_struct *mm, } if (!nr_retries--) { - if (oom) { + if (oom) mem_cgroup_out_of_memory(mem_over_limit, gfp_mask); - record_last_oom(mem_over_limit); - } goto nomem; } } @@ -2408,8 +2377,6 @@ void mem_cgroup_end_migration(struct mem_cgroup *mem, /* * A call to try to shrink memory usage on charge failure at shmem's swapin. - * Calling hierarchical_reclaim is not enough because we should update - * last_oom_jiffies to prevent pagefault_out_of_memory from invoking global OOM. * Moreover considering hierarchy, we should reclaim from the mem_over_limit, * not from the memcg which this page would be charged to. * try_charge_swapin does all of these works properly. diff --git a/mm/oom_kill.c b/mm/oom_kill.c --- a/mm/oom_kill.c +++ b/mm/oom_kill.c @@ -490,29 +490,6 @@ static int oom_kill_process(struct task_struct *p, gfp_t gfp_mask, int order, return oom_kill_task(victim); } -#ifdef CONFIG_CGROUP_MEM_RES_CTLR -void mem_cgroup_out_of_memory(struct mem_cgroup *mem, gfp_t gfp_mask) -{ - unsigned long points = 0; - struct task_struct *p; - - read_lock(&tasklist_lock); -retry: - p = select_bad_process(&points, mem, CONSTRAINT_NONE, NULL); - if (PTR_ERR(p) == -1UL) - goto out; - - if (!p) - p = current; - - if (oom_kill_process(p, gfp_mask, 0, points, mem, - "Memory cgroup out of memory")) - goto retry; -out: - read_unlock(&tasklist_lock); -} -#endif - static BLOCKING_NOTIFIER_HEAD(oom_notify_list); int register_oom_notifier(struct notifier_block *nb) @@ -578,6 +555,70 @@ void clear_zonelist_oom(struct zonelist *zonelist, gfp_t gfp_mask) } /* + * Try to acquire the oom killer lock for all system zones. Returns zero if a + * parallel oom killing is taking place, otherwise locks all zones and returns + * non-zero. + */ +static int try_set_system_oom(void) +{ + struct zone *zone; + int ret = 1; + + spin_lock(&zone_scan_lock); + for_each_populated_zone(zone) + if (zone_is_oom_locked(zone)) { + ret = 0; + goto out; + } + for_each_populated_zone(zone) + zone_set_flag(zone, ZONE_OOM_LOCKED); +out: + spin_unlock(&zone_scan_lock); + return ret; +} + +/* + * Clears ZONE_OOM_LOCKED for all system zones so that failed allocation + * attempts or page faults may now recall the oom killer, if necessary. + */ +static void clear_system_oom(void) +{ + struct zone *zone; + + spin_lock(&zone_scan_lock); + for_each_populated_zone(zone) + zone_clear_flag(zone, ZONE_OOM_LOCKED); + spin_unlock(&zone_scan_lock); +} + + +#ifdef CONFIG_CGROUP_MEM_RES_CTLR +void mem_cgroup_out_of_memory(struct mem_cgroup *mem, gfp_t gfp_mask) +{ + unsigned long points = 0; + struct task_struct *p; + + if (!try_set_system_oom()) + return; + read_lock(&tasklist_lock); +retry: + p = select_bad_process(&points, mem, CONSTRAINT_NONE, NULL); + if (PTR_ERR(p) == -1UL) + goto out; + + if (!p) + p = current; + + if (oom_kill_process(p, gfp_mask, 0, points, mem, + "Memory cgroup out of memory")) + goto retry; +out: + read_unlock(&tasklist_lock); + clear_system_oom(); +} +#endif + +/* * Must be called with tasklist_lock held for read. */ static void __out_of_memory(gfp_t gfp_mask, int order, @@ -612,46 +653,9 @@ retry: goto retry; } -/* - * pagefault handler calls into here because it is out of memory but - * doesn't know exactly how or why. - */ -void pagefault_out_of_memory(void) -{ - unsigned long freed = 0; - - blocking_notifier_call_chain(&oom_notify_list, 0, &freed); - if (freed > 0) - /* Got some memory back in the last second. */ - return; - - /* - * If this is from memcg, oom-killer is already invoked. - * and not worth to go system-wide-oom. - */ - if (mem_cgroup_oom_called(current)) - goto rest_and_return; - - if (sysctl_panic_on_oom) - panic("out of memory from page fault. panic_on_oom is selected.\n"); - - read_lock(&tasklist_lock); - /* unknown gfp_mask and order */ - __out_of_memory(0, 0, CONSTRAINT_NONE, NULL); - read_unlock(&tasklist_lock); - - /* - * Give "p" a good chance of killing itself before we - * retry to allocate memory. - */ -rest_and_return: - if (!test_thread_flag(TIF_MEMDIE)) - schedule_timeout_uninterruptible(1); -} - /** * out_of_memory - kill the "best" process when we run out of memory - * @zonelist: zonelist pointer + * @zonelist: zonelist pointer passed to page allocator * @gfp_mask: memory allocation flags * @order: amount of memory being requested as a power of 2 * @nodemask: nodemask passed to page allocator @@ -665,7 +669,7 @@ void out_of_memory(struct zonelist *zonelist, gfp_t gfp_mask, int order, nodemask_t *nodemask) { unsigned long freed = 0; - enum oom_constraint constraint; + enum oom_constraint constraint = CONSTRAINT_NONE; blocking_notifier_call_chain(&oom_notify_list, 0, &freed); if (freed > 0) @@ -681,7 +685,8 @@ void out_of_memory(struct zonelist *zonelist, gfp_t gfp_mask, * Check if there were limitations on the allocation (only relevant for * NUMA) that may require different handling. */ - constraint = constrained_alloc(zonelist, gfp_mask, nodemask); + if (zonelist) + constraint = constrained_alloc(zonelist, gfp_mask, nodemask); read_lock(&tasklist_lock); if (unlikely(sysctl_panic_on_oom)) { /* @@ -691,6 +696,7 @@ void out_of_memory(struct zonelist *zonelist, gfp_t gfp_mask, */ if (constraint == CONSTRAINT_NONE) { dump_header(NULL, gfp_mask, order, NULL); + read_unlock(&tasklist_lock); panic("Out of memory: panic_on_oom is enabled\n"); } } @@ -704,3 +710,17 @@ void out_of_memory(struct zonelist *zonelist, gfp_t gfp_mask, if (!test_thread_flag(TIF_MEMDIE)) schedule_timeout_uninterruptible(1); } + +/* + * The pagefault handler calls here because it is out of memory, so kill a + * memory-hogging task. If a populated zone has ZONE_OOM_LOCKED set, a parallel + * oom killing is already in progress so do nothing. If a task is found with + * TIF_MEMDIE set, it has been killed so do nothing and allow it to exit. + */ +void pagefault_out_of_memory(void) +{ + if (!try_set_system_oom()) + return; + out_of_memory(NULL, 0, 0, NULL); + clear_system_oom(); +} -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/