Re: [PATCH] oom_kill: use rss value instead of vm size for badness
From: Minchan Kim
Date: Wed Oct 28 2009 - 22:32:02 EST
On Thu, Oct 29, 2009 at 10:00 AM, KAMEZAWA Hiroyuki
<kamezawa.hiroyu@xxxxxxxxxxxxxx> wrote:
>> I'll wait until the next week to post a new patch.
>> We don't need rapid way.
>>
> I wrote above...but for my mental health, this is bug-fixed version.
> Sorry for my carelessness. David, thank you for your review.
> Regards,
> -Kame
> ==
> From: KAMEZAWA Hiroyuki <kamezawa.hiroyu@xxxxxxxxxxxxxx>
>
> It's reported that OOM-Killer kills Gnone/KDE at first...
> And yes, we can reproduce it easily.
>
> Now, oom-killer uses mm->total_vm as its base value. But in recent
> applications, there are a big gap between VM size and RSS size.
> Because
> - Applications attaches much dynamic libraries. (Gnome, KDE, etc...)
> - Applications may alloc big VM area but use small part of them.
> (Java, and multi-threaded applications has this tendency because
> of default-size of stack.)
>
> I think using mm->total_vm as score for oom-kill is not good.
> By the same reason, overcommit memory can't work as expected.
> (In other words, if we depends on total_vm, using overcommit more positive
> is a good choice.)
>
> This patch uses mm->anon_rss/file_rss as base value for calculating badness.
>
> Following is changes to OOM score(badness) on an environment with 1.6G memory
> plus memory-eater(500M & 1G).
>
> Top 10 of badness score. (The highest one is the first candidate to be killed)
> Before
> badness program
> 91228 gnome-settings-
> 94210 clock-applet
> 103202 mixer_applet2
> 106563 tomboy
> 112947 gnome-terminal
> 128944 mmap <----------- 500M malloc
> 129332 nautilus
> 215476 bash <----------- parent of 2 mallocs.
> 256944 mmap <----------- 1G malloc
> 423586 gnome-session
>
> After
> badness
> 1911 mixer_applet2
> 1955 clock-applet
> 1986 xinit
> 1989 gnome-session
> 2293 nautilus
> 2955 gnome-terminal
> 4113 tomboy
> 104163 mmap <----------- 500M malloc.
> 168577 bash <----------- parent of 2 mallocs
> 232375 mmap <----------- 1G malloc
>
> seems good for me. Maybe we can tweak this patch more,
> but this one will be a good one as a start point.
>
> Changelog: 2009/10/29
> - use get_mm_rss() instead of get_mm_counter()
>
> Signed-off-by: KAMEZAWA Hiroyuki <kamezawa.hiroyu@xxxxxxxxxxxxxx>
Reviewed-by: Minchan Kim <minchan.kim@xxxxxxxxx>
Let's start from this.
--
Kind regards,
Minchan Kim
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