Date: Sat, 14 Sep 2019 09:10:14 -0700 From: bob prohaska <fbsd@www.zefox.net> To: Mark Millard <marklmi@yahoo.com> Cc: FreeBSD Current <freebsd-current@freebsd.org>, freebsd-arm@freebsd.org Subject: Re: spurious out of swap kills Message-ID: <20190914161014.GA33442@www.zefox.net> In-Reply-To: <28BF21DA-8B16-4CD8-8E5E-C1B596FE3684@yahoo.com> References: <28BF21DA-8B16-4CD8-8E5E-C1B596FE3684@yahoo.com>
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On Fri, Sep 13, 2019 at 10:59:58PM -0700, Mark Millard wrote: > bob prohaska fbsd at www.zefox.net wrote on > Fri Sep 13 16:24:57 UTC 2019 : > > > Not sure this is relevant, but in compiling chromium on a Pi3 with 6 GB > > of swap the job completed successfully some months ago, with peak swap > > use around 3.5 GB. The swap layout was sub-optimal, with a 2 GB partition > > combined with a 4 GB partition. A little over 4GB total seems usable. > > > > A few days ago the same attempt stopped with a series of OOMA kills, > > but in each case simply restarting allowed the compile to pick up > > where it left off and continue, eventually finishing with a runnable > > version of chromium. In this case swap use peaked a little over 4 GB. > > > > Might this suggest the machine isn't freeing swap in a timely manner? > > Are you saying that your increases to: > > vm.pageout_oom_seq > > no longer prove sufficient? What value for vm.pageout_oom_seq were > you using that got the recent failures? > Correct. Initial value was 2048, later raised to 4096. Far as I could tell the change didn't help. No explict j value was set for make, but no more than four jobs were observed in top A log of storage activity along with swap total and the last two console messages is at http://www.zefox.net/~fbsd/rpi3/swaptests/r351586/swapscript.log along with a sorted list of total swap use, which can be used as a sort of index to the log file. The initial "out of swap space" at the very beginning is a relic from before logging started. Da0 is a Sandisk SDCZ80 usb 3.0 device, mmcsd0 is a Samsung Evo + 128 GB device. The two points of curiosity to me are: 1. Why did swap use increase from 3.5 GB months ago to 4.2 GB now? 2. Why does stopping and restarting make (which would seem to free un-needed swap) allow the job to finish? > If more or different configuration/tuning is required, I'm going to > eventually want to learn about it as well. > You will have some company. Thanks for reading, bob prohaska
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