Re: less aggressive contigmalloc ?

From: Luigi Rizzo <rizzo_at_iet.unipi.it>
Date: Fri, 24 Aug 2012 16:57:08 +0200
On Fri, Aug 24, 2012 at 12:43:33AM -0500, Alan Cox wrote:
> On 08/23/2012 12:45, Luigi Rizzo wrote:
> >On Thu, Aug 23, 2012 at 12:08:40PM -0500, Alan Cox wrote:
> >...
> >>>yes i do see that.
> >>>
> >>>Maybe less aggressive with M_NOWAIT but still kills processes.
> >>Are you compiling world with MALLOC_PRODUCTION?  The latest version of
> >whatever the default is. But:
> >
> >>jemalloc uses significantly more memory when debugging options are
> >>enabled.  This first came up in a thread titled "10-CURRENT and swap
> >>usage" back in June.
> >>
> >>Even at its most aggressive, M_WAITOK, contigmalloc() does not directly
> >>kill processes.  If process death coincides with the use of
> >>contigmalloc(), then it is simply the result of earlier, successful
> >>contigmalloc() calls, or for that matter any other physical memory
> >>allocation calls, having depleted the pool of free pages to the point
> >>that the page daemon runs and invokes vm_pageout_oom().
> >does it mean that those previous allocations relied on memory overbooking ?
> 
> Yes.
> 
> >Is there a way to avoid that, then ?
> 
> I believe that malloc()'s default minimum allocation size is 4MB.  You 
> could reduce that.
> 
> Alternatively, you can enable MALLOC_PRODUCTION.

i tried this, and as others mentioned it makes life
better and reduces the problem but contigmalloc still triggers
random process kills.

Thanks for the hints.

cheers
luigi
Received on Fri Aug 24 2012 - 12:38:05 UTC

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