From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mail191.messagelabs.com (mail191.messagelabs.com [216.82.242.19]) by kanga.kvack.org (Postfix) with SMTP id 00B086B0044 for ; Tue, 27 Oct 2009 14:39:05 -0400 (EDT) Date: Tue, 27 Oct 2009 18:39:07 +0000 (GMT) From: Hugh Dickins Subject: Re: [RFC][PATCH] oom_kill: avoid depends on total_vm and use real RSS/swap value for oom_score (Re: Memory overcommit In-Reply-To: <20091027164526.da6a23cb.kamezawa.hiroyu@jp.fujitsu.com> Message-ID: References: <20091014135119.e1baa07f.kamezawa.hiroyu@jp.fujitsu.com> <4ADE3121.6090407@gmail.com> <20091026105509.f08eb6a3.kamezawa.hiroyu@jp.fujitsu.com> <4AE5CB4E.4090504@gmail.com> <20091027122213.f3d582b2.kamezawa.hiroyu@jp.fujitsu.com> <2f11576a0910262310g7aea23c0n9bfc84c900879d45@mail.gmail.com> <20091027153429.b36866c4.minchan.kim@barrios-desktop> <20091027153626.c5a4b5be.kamezawa.hiroyu@jp.fujitsu.com> <28c262360910262355p3cac5c1bla4de9d42ea67fb4e@mail.gmail.com> <20091027164526.da6a23cb.kamezawa.hiroyu@jp.fujitsu.com> MIME-Version: 1.0 Content-Type: TEXT/PLAIN; charset=US-ASCII Sender: owner-linux-mm@kvack.org To: KAMEZAWA Hiroyuki Cc: Minchan Kim , KOSAKI Motohiro , vedran.furac@gmail.com, linux-mm@kvack.org, linux-kernel@vger.kernel.org, akpm@linux-foundation.org, rientjes@google.com, aarcange@redhat.com List-ID: On Tue, 27 Oct 2009, KAMEZAWA Hiroyuki wrote: > Now, oom-killer's score uses mm->total_vm as its base value. > But, in these days, applications like GUI program tend to use > much shared libraries and total_vm grows too high even when > pages are not fully mapped. > > For example, running a program "mmap" which allocates 1 GBbytes of > anonymous memory, oom_score top 10 on system will be.. > > score PID name > 89924 3938 mixer_applet2 > 90210 3942 tomboy > 94753 3936 clock-applet > 101994 3919 pulseaudio > 113525 4028 gnome-terminal > 127340 1 init > 128177 3871 nautilus > 151003 11515 bash > 256944 11653 mmap <-----------------use 1G of anon > 425561 3829 gnome-session > > No one believes gnome-session is more guilty than "mmap". > > Instead of total_vm, we should use anon/file/swap usage of a process, I think. > This patch adds mm->swap_usage and calculate oom_score based on > anon_rss + file_rss + swap_usage. > Considering usual applications, this will be much better information than > total_vm. After this patch, the score on my desktop is > > score PID name > 4033 3176 gnome-panel > 4077 3113 xinit > 4526 3190 python > 4820 3161 gnome-settings- > 4989 3289 gnome-terminal > 7105 3271 tomboy > 8427 3177 nautilus > 17549 3140 gnome-session > 128501 3299 bash > 256106 3383 mmap > > This order is not bad, I think. > > Note: This adss new counter...then new cost is added. I've often thought we ought to supply such a swap_usage statistic; and show it in /proc/pid/statsomething, presumably VmSwap in /proc/pid/status, even an additional field on the end of statm. A slight new cost, yes: doesn't matter at the swapping end, but would slightly impact fork and exit - I do hope we can afford it, because I think it should have been available all along. I've not checked your patch in detail; but I do agree that basing OOM (physical memory) decisions on total_vm (virtual memory) has seemed weird, so it's well worth trying this approach. Whether swap should be included along with rss isn't quite clear to me: I'm not saying you're wrong, not at all, just that it's not quite obvious. I've several observations to make about bad OOM kill decisions, but it's probably better that I make them in the original "Memory overcommit" thread, rather than divert this thread. Hugh -- To unsubscribe, send a message with 'unsubscribe linux-mm' in the body to majordomo@kvack.org. For more info on Linux MM, see: http://www.linux-mm.org/ . Don't email: email@kvack.org