Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1752041Ab2KHMhp (ORCPT ); Thu, 8 Nov 2012 07:37:45 -0500 Received: from mail-da0-f46.google.com ([209.85.210.46]:49227 "EHLO mail-da0-f46.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751477Ab2KHMhn (ORCPT ); Thu, 8 Nov 2012 07:37:43 -0500 Message-ID: <509BA799.505@gmail.com> Date: Thu, 08 Nov 2012 20:37:45 +0800 From: Sha Zhengju User-Agent: Mozilla/5.0 (X11; U; Linux x86_64; en-US; rv:1.9.2.23) Gecko/20110922 Thunderbird/3.1.15 MIME-Version: 1.0 To: David Rientjes CC: Sha Zhengju , linux-mm@kvack.org, cgroups@vger.kernel.org, mhocko@suse.cz, kamezawa.hiroyu@jp.fujitsu.com, akpm@linux-foundation.org, linux-kernel@vger.kernel.org Subject: Re: [PATCH 1/2] memcg, oom: provide more precise dump info while memcg oom happening References: <1352277602-21687-1-git-send-email-handai.szj@taobao.com> <1352277696-21724-1-git-send-email-handai.szj@taobao.com> In-Reply-To: Content-Type: text/plain; charset=UTF-8; format=flowed Content-Transfer-Encoding: 8bit Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 6049 Lines: 191 On 11/08/2012 02:02 AM, David Rientjes wrote: > On Wed, 7 Nov 2012, Sha Zhengju wrote: > >> diff --git a/mm/memcontrol.c b/mm/memcontrol.c >> index 0eab7d5..2df5e72 100644 >> --- a/mm/memcontrol.c >> +++ b/mm/memcontrol.c >> @@ -118,6 +118,14 @@ static const char * const mem_cgroup_events_names[] = { >> "pgmajfault", >> }; >> >> +static const char * const mem_cgroup_lru_names[] = { >> + "inactive_anon", >> + "active_anon", >> + "inactive_file", >> + "active_file", >> + "unevictable", >> +}; >> + >> /* >> * Per memcg event counter is incremented at every pagein/pageout. With THP, >> * it will be incremated by the number of pages. This counter is used for >> @@ -1501,8 +1509,59 @@ static void move_unlock_mem_cgroup(struct mem_cgroup *memcg, >> spin_unlock_irqrestore(&memcg->move_lock, *flags); >> } >> >> +#define K(x) ((x)<< (PAGE_SHIFT-10)) >> +static void mem_cgroup_print_oom_stat(struct mem_cgroup *memcg) >> +{ >> + struct mem_cgroup *mi; >> + unsigned int i; >> + >> + if (!memcg->use_hierarchy&& memcg != root_mem_cgroup) { >> + for (i = 0; i< MEM_CGROUP_STAT_NSTATS; i++) { >> + if (i == MEM_CGROUP_STAT_SWAP&& !do_swap_account) >> + continue; >> + printk(KERN_CONT "%s:%ldKB ", mem_cgroup_stat_names[i], > This printk isn't continuing any previous printk, so using KERN_CONT here > will require a short header to be printed first ("Memcg: "?) with > KERN_INFO before the iterations. > Yep...I think I lost it while rebasing... sorry for the stupid mistake. >> + K(mem_cgroup_read_stat(memcg, i))); >> + } >> + >> + for (i = 0; i< MEM_CGROUP_EVENTS_NSTATS; i++) >> + printk(KERN_CONT "%s:%lu ", mem_cgroup_events_names[i], >> + mem_cgroup_read_events(memcg, i)); >> + >> + for (i = 0; i< NR_LRU_LISTS; i++) >> + printk(KERN_CONT "%s:%luKB ", mem_cgroup_lru_names[i], >> + K(mem_cgroup_nr_lru_pages(memcg, BIT(i)))); >> + } else { >> + > Spurious newline. > > Eek, is there really no way to avoid this if-conditional and just use > for_each_mem_cgroup_tree() for everything and use > > mem_cgroup_iter_break(memcg, iter); > break; > > for !memcg->use_hierarchy? > Now I'm shamed at my bad brain of yesterday by sending this chunk out... Yes, the if-part code above is obviously unwanted, and the for_each_mem_cgroup_tree can handle hierarchy already. >> + for (i = 0; i< MEM_CGROUP_STAT_NSTATS; i++) { >> + long long val = 0; >> + >> + if (i == MEM_CGROUP_STAT_SWAP&& !do_swap_account) >> + continue; >> + for_each_mem_cgroup_tree(mi, memcg) >> + val += mem_cgroup_read_stat(mi, i); >> + printk(KERN_CONT "%s:%lldKB ", mem_cgroup_stat_names[i], K(val)); >> + } >> + >> + for (i = 0; i< MEM_CGROUP_EVENTS_NSTATS; i++) { >> + unsigned long long val = 0; >> + >> + for_each_mem_cgroup_tree(mi, memcg) >> + val += mem_cgroup_read_events(mi, i); >> + printk(KERN_CONT "%s:%llu ", >> + mem_cgroup_events_names[i], val); >> + } >> + >> + for (i = 0; i< NR_LRU_LISTS; i++) { >> + unsigned long long val = 0; >> + >> + for_each_mem_cgroup_tree(mi, memcg) >> + val += mem_cgroup_nr_lru_pages(mi, BIT(i)); >> + printk(KERN_CONT "%s:%lluKB ", mem_cgroup_lru_names[i], K(val)); >> + } >> + } >> + printk(KERN_CONT "\n"); >> +} >> /** >> - * mem_cgroup_print_oom_info: Called from OOM with tasklist_lock held in read mode. >> * @memcg: The memory cgroup that went over limit >> * @p: Task that is going to be killed >> * >> @@ -1569,6 +1628,8 @@ done: >> res_counter_read_u64(&memcg->kmem, RES_USAGE)>> 10, >> res_counter_read_u64(&memcg->kmem, RES_LIMIT)>> 10, >> res_counter_read_u64(&memcg->kmem, RES_FAILCNT)); >> + >> + mem_cgroup_print_oom_stat(memcg); > I think this should be folded into mem_cgroup_print_oom_info(), I don't > see a need for a new function. > >> } >> >> /* >> @@ -5195,14 +5256,6 @@ static int memcg_numa_stat_show(struct cgroup *cont, struct cftype *cft, >> } >> #endif /* CONFIG_NUMA */ >> >> -static const char * const mem_cgroup_lru_names[] = { >> - "inactive_anon", >> - "active_anon", >> - "inactive_file", >> - "active_file", >> - "unevictable", >> -}; >> - >> static inline void mem_cgroup_lru_names_not_uptodate(void) >> { >> BUILD_BUG_ON(ARRAY_SIZE(mem_cgroup_lru_names) != NR_LRU_LISTS); >> diff --git a/mm/oom_kill.c b/mm/oom_kill.c >> index 7e9e911..4b8a6dd 100644 >> --- a/mm/oom_kill.c >> +++ b/mm/oom_kill.c >> @@ -421,8 +421,10 @@ static void dump_header(struct task_struct *p, gfp_t gfp_mask, int order, >> cpuset_print_task_mems_allowed(current); >> task_unlock(current); >> dump_stack(); >> - mem_cgroup_print_oom_info(memcg, p); >> - show_mem(SHOW_MEM_FILTER_NODES); >> + if (memcg) >> + mem_cgroup_print_oom_info(memcg, p); > mem_cgroup_print_oom_info() already returns immediately for !memcg, so I'm > not sure why this change is made. > Here the if-else checking is aiming at printing distinct messages for memcg & non-memcg. IMHO, global state has little actual use for memcg-oom and why not we wipe off it？ Though mem_cgroup_print_oom_info already checking for !memcg, the if-statement can avoid one function call and save the deep-enough oom call stack a little. >> + else >> + show_mem(SHOW_MEM_FILTER_NODES); > Well that's disappointing if memcg == root_mem_cgroup, we'd probably like > to know the global memory state to determine what the problem is. > I really wondering if there is any case that can pass root_mem_cgroup down here. It's called by global or memcg oom killer and the global oom will set memcg=NULL directly instead of root_mem_cgroup. Besides, root memcg will not go through charging and there is no chance to call mem_cgroup_out_of_memory for root cgroup tasks. Thanks, Sha >> if (sysctl_oom_dump_tasks) >> dump_tasks(memcg, nodemask); >> } > . > -- 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/