Date: Fri, 13 Sep 2019 16:39:10 -0700 (PDT) From: Don Lewis <truckman@FreeBSD.org> To: Mark Johnston <markj@freebsd.org> Cc: FreeBSD Current <freebsd-current@freebsd.org>, kib@freebsd.org Subject: Re: spurious out of swap kills Message-ID: <tkrat.e0c4dd73c3a5b2fe@FreeBSD.org> In-Reply-To: <tkrat.1a0e98a230c1a223@FreeBSD.org> References: <tkrat.84b3295682c83162@FreeBSD.org> <20190913000635.GG8397@raichu> <tkrat.1a0e98a230c1a223@FreeBSD.org>
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On 12 Sep, Don Lewis wrote:
> On 12 Sep, Mark Johnston wrote:
>> On Thu, Sep 12, 2019 at 04:00:17PM -0700, Don Lewis wrote:
>>> My poudriere machine is running 13.0-CURRENT and gets updated to the
>>> latest version of -CURRENT periodically. At least in the last week or
>>> so, I've been seeing occasional port build failures when building my
>>> default set of ports, and I finally had some time to do some
>>> investigation.
>>>
>>> It's a 16-thread Ryzen machine, with 64 GB of RAM and 40 GB of swap.
>>> Poudriere is configured with
>>> USE_TMPFS="wrkdir data localbase"
>>> and I have
>>> .if ${.CURDIR:M*/www/chromium}
>>> MAKE_JOBS_NUMBER=16
>>> .else
>>> MAKE_JOBS_NUMBER=7
>>> .endif
>>> in /usr/local/etc/poudriere.d/make.conf, since this gives me the best
>>> overall build time for my set of ports. This hits memory pretty hard,
>>> especially when chromium, firefox, libreoffice, and both versions of
>>> openoffice are all building at the same time. During this time, the
>>> amount of space consumed by tmpfs for /wrkdir gets large when building
>>> these large ports. There is not enough RAM to hold it all, so some of
>>> the older data spills over to swap. Swap usage peaks at about 10 GB,
>>> leaving about 30 GB of free swap. Nevertheless, I see these errors,
>>> with rustc being the usual victim:
>>>
>>> Sep 11 23:21:43 zipper kernel: pid 16581 (rustc), jid 43, uid 65534, was killed: out of swap space
>>> Sep 12 02:48:23 zipper kernel: pid 1209 (rustc), jid 62, uid 65534, was killed: out of swap space
>>>
>>> Top shows the size of rustc being about 2 GB, so I doubt that it
>>> suddenly needs an additional 30 GB of swap.
>>>
>>> I'm wondering if there might be a transient kmem shortage that is
>>> causing a malloc(..., M_NOWAIT) failure in the swap allocation path
>>> that is the cause of the problem.
>>
>> Perhaps this is a consequence of r351114? To confirm this, you might
>> try increasing the value of vm.pfault_oom_wait to a larger value, like
>> 20 or 30, and see if the OOM kills still occur.
>
> I wonder if increasing vm.pfault_oom_attempts might also be a good idea.
sysctl vm.pfault_oom_attempts=10 by itself seemed to work well.
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