Re: Found the commit that causes the OOMs

[Wu Fengguang <fengguang.wu@gmail.com>]

On Wed, Jul 01, 2009 at 01:18:39PM +0900, KOSAKI Motohiro wrote:
> > On Tue, Jun 30, 2009 at 10:57:02PM -0400, Rik van Riel wrote:
> > > KOSAKI Motohiro wrote:
> > >
> > >>> [ 1522.019259] Active_anon:11 active_file:6 inactive_anon:0
> > >>> [ 1522.019260]  inactive_file:0 unevictable:0 dirty:0 writeback:0 unstable:0
> > >>> [ 1522.019261]  free:1985 slab:44399 mapped:132 pagetables:61830 bounce:0
> > >>> [ 1522.019262]  isolate:69817
> > >>
> > >> OK. thanks.
> > >> I plan to submit this patch after small more tests. it is useful for OOM analysis.
> > >
> > > It is also useful for throttling page reclaim.
> > >
> > > If more than half of the inactive pages in a zone are
> > > isolated, we are probably beyond the point where adding
> > > additional reclaim processes will do more harm than good.
> > 
> > There are probably more problems in this case. For example,
> > followed is the vmstat after first (successful) run of msgctl11.
> > 
> > The question is: Why kswapd reclaims are absent here?
> 
> if direct reclaim isolate all pages, kswapd can't reclaim any pages.

OOM will occur in that condition. What happened before that time?

> I believe Rik's idea solve this problem.

Me too :)

Thanks,
Fengguang