Date: Fri, 24 Aug 2012 11:12:51 -0500 From: Alan Cox <alc@rice.edu> To: Luigi Rizzo <rizzo@iet.unipi.it> Cc: alc@freebsd.org, current@freebsd.org Subject: Re: less aggressive contigmalloc ? Message-ID: <5037A803.6030100@rice.edu> In-Reply-To: <20120824145708.GA16557@onelab2.iet.unipi.it> References: <20120822120105.GA63763@onelab2.iet.unipi.it> <CAJUyCcPOte19TJXpCVAskhf%2BDia_Zg5uj6J_idW67rGsOLaZXw@mail.gmail.com> <20120823163145.GA3999@onelab2.iet.unipi.it> <50366398.2070700@rice.edu> <20120823174504.GB4820@onelab2.iet.unipi.it> <50371485.1020409@rice.edu> <20120824145708.GA16557@onelab2.iet.unipi.it>
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On 08/24/2012 09:57, Luigi Rizzo wrote: > 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. I would be curious to see a stack backtrace when vm_pageout_oom() is called.
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