From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mail203.messagelabs.com (mail203.messagelabs.com [216.82.254.243]) by kanga.kvack.org (Postfix) with ESMTP id 61FD8900001 for ; Thu, 12 May 2011 15:38:34 -0400 (EDT) Received: from hpaq2.eem.corp.google.com (hpaq2.eem.corp.google.com [172.25.149.2]) by smtp-out.google.com with ESMTP id p4CJcWZA008143 for ; Thu, 12 May 2011 12:38:32 -0700 Received: from pwi9 (pwi9.prod.google.com [10.241.219.9]) by hpaq2.eem.corp.google.com with ESMTP id p4CJc6wO020851 (version=TLSv1/SSLv3 cipher=RC4-SHA bits=128 verify=NOT) for ; Thu, 12 May 2011 12:38:30 -0700 Received: by pwi9 with SMTP id 9so889732pwi.10 for ; Thu, 12 May 2011 12:38:30 -0700 (PDT) Date: Thu, 12 May 2011 12:38:28 -0700 (PDT) From: David Rientjes Subject: Re: OOM Killer don't works at all if the system have >gigabytes memory (was Re: [PATCH] mm: check zone->all_unreclaimable in all_unreclaimable()) In-Reply-To: Message-ID: References: <1889981320.330808.1305081044822.JavaMail.root@zmail06.collab.prod.int.phx2.redhat.com> MIME-Version: 1.0 Content-Type: MULTIPART/MIXED; BOUNDARY="531368966-109542298-1305229109=:2407" Sender: owner-linux-mm@kvack.org List-ID: To: Minchan Kim Cc: CAI Qian , KOSAKI Motohiro , avagin@gmail.com, Andrey Vagin , Andrew Morton , Mel Gorman , linux-mm@kvack.org, linux-kernel@vger.kernel.org, Hugh Dickins , Oleg Nesterov This message is in MIME format. The first part should be readable text, while the remaining parts are likely unreadable without MIME-aware tools. --531368966-109542298-1305229109=:2407 Content-Type: TEXT/PLAIN; charset=UTF-8 Content-Transfer-Encoding: 8BIT On Thu, 12 May 2011, Minchan Kim wrote: > > processes a 1% bonus for every 30% of memory they use as proposed > > earlier.) > > I didn't follow earlier your suggestion. > But it's not formal patch so I expect if you send formal patch to > merge, you would write down the rationale. > Yes, I'm sure we'll still have additional discussion when KOSAKI-san replies to my review of his patchset, so this quick patch was written only for CAI's testing at this point. In reference to the above, I think that giving root processes a 3% bonus at all times may be a bit aggressive. As mentioned before, I don't think that all root processes using 4% of memory and the remainder of system threads are using 1% should all be considered equal. At the same time, I do not believe that two threads using 50% of memory should be considered equal if one is root and one is not. So my idea was to discount 1% for every 30% of memory that a root process uses rather than a strict 3%. That change can be debated and I think we'll probably settle on something more aggressive like 1% for every 10% of memory used since oom scores are only useful in comparison to other oom scores: in the above scenario where there are two threads, one by root and one not by root, using 50% of memory each, I think it would be legitimate to give the root task a 5% bonus so that it would only be selected if no other threads used more than 44% of memory (even though the root thread is truly using 50%). This is a heuristic within the oom killer badness scoring that can always be debated back and forth, but I think a 1% bonus for root processes for every 10% of memory used is plausible. Comments? > > diff --git a/mm/oom_kill.c b/mm/oom_kill.c > > --- a/mm/oom_kill.c > > +++ b/mm/oom_kill.c > > @@ -160,7 +160,7 @@ unsigned int oom_badness(struct task_struct *p, struct mem_cgroup *mem, > > A A A A */ > > A A A A if (p->flags & PF_OOM_ORIGIN) { > > A A A A A A A A task_unlock(p); > > - A A A A A A A return 1000; > > + A A A A A A A return 10000; > > A A A A } > > > > A A A A /* > > @@ -177,32 +177,32 @@ unsigned int oom_badness(struct task_struct *p, struct mem_cgroup *mem, > > A A A A points = get_mm_rss(p->mm) + p->mm->nr_ptes; > > A A A A points += get_mm_counter(p->mm, MM_SWAPENTS); > > > > - A A A points *= 1000; > > + A A A points *= 10000; > > A A A A points /= totalpages; > > A A A A task_unlock(p); > > > > A A A A /* > > - A A A A * Root processes get 3% bonus, just like the __vm_enough_memory() > > - A A A A * implementation used by LSMs. > > + A A A A * Root processes get 1% bonus per 30% memory used for a total of 3% > > + A A A A * possible just like LSMs. > > A A A A */ > > A A A A if (has_capability_noaudit(p, CAP_SYS_ADMIN)) > > - A A A A A A A points -= 30; > > + A A A A A A A points -= 100 * (points / 3000); > > > > A A A A /* > > A A A A * /proc/pid/oom_score_adj ranges from -1000 to +1000 such that it may > > A A A A * either completely disable oom killing or always prefer a certain > > A A A A * task. > > A A A A */ > > - A A A points += p->signal->oom_score_adj; > > + A A A points += p->signal->oom_score_adj * 10; > > > > A A A A /* > > A A A A * Never return 0 for an eligible task that may be killed since it's > > - A A A A * possible that no single user task uses more than 0.1% of memory and > > + A A A A * possible that no single user task uses more than 0.01% of memory and > > A A A A * no single admin tasks uses more than 3.0%. > > A A A A */ > > A A A A if (points <= 0) > > A A A A A A A A return 1; > > - A A A return (points < 1000) ? points : 1000; > > + A A A return (points < 10000) ? points : 10000; > > A } > > > > A /* > > @@ -314,7 +314,7 @@ static struct task_struct *select_bad_process(unsigned int *ppoints, > > A A A A A A A A A A A A */ > > A A A A A A A A A A A A if (p == current) { > > A A A A A A A A A A A A A A A A chosen = p; > > - A A A A A A A A A A A A A A A *ppoints = 1000; > > + A A A A A A A A A A A A A A A *ppoints = 10000; > > Scattering constant value isn't good. > You are proving it now. > I think you did it since this is not a formal patch. > I expect you will define new value (ex, OOM_INTERNAL_MAX_SCORE or whatever) > Right, we could probably do something like #define OOM_SCORE_MAX_FACTOR 10 #define OOM_SCORE_MAX (OOM_SCORE_ADJ_MAX * OOM_SCORE_MAX_FACTOR) in mm/oom_kill.c, which would then be used to replace all of the constants above since OOM_SCORE_ADJ_MAX is already defined to be 1000 in include/linux/oom.h. --531368966-109542298-1305229109=:2407-- -- To unsubscribe, send a message with 'unsubscribe linux-mm' in the body to majordomo@kvack.org. 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