Date: Wed, 8 Aug 2018 16:48:41 -0400 From: Mark Johnston <markj@freebsd.org> To: bob prohaska <fbsd@www.zefox.net> Cc: Mark Millard <marklmi@yahoo.com>, freebsd-arm@freebsd.org Subject: Re: RPI3 swap experiments ["was killed: out of swap space" with: "v_free_count: 5439, v_inactive_count: 1"] Message-ID: <20180808204841.GA19379@raichu> In-Reply-To: <20180808153800.GF26133@www.zefox.net> References: <20180731231912.GF94742@www.zefox.net> <2222ABBD-E689-4C3B-A7D3-50AECCC5E7B2@yahoo.com> <20180801034511.GA96616@www.zefox.net> <201808010405.w7145RS6086730@donotpassgo.dyslexicfish.net> <6BFE7B77-A0E2-4FAF-9C68-81951D2F6627@yahoo.com> <20180802002841.GB99523@www.zefox.net> <20180802015135.GC99523@www.zefox.net> <EC74A5A6-0DF4-48EB-88DA-543FD70FEA07@yahoo.com> <20180806155837.GA6277@raichu> <20180808153800.GF26133@www.zefox.net>
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On Wed, Aug 08, 2018 at 08:38:00AM -0700, bob prohaska wrote: > The patched kernel ran longer than default but OOMA still halted buildworld around > 13 MB. That's considerably farther than a default build world have run but less than > observed when setting vm.pageout_oom_seq=120 alone. Log files are at > http://www.zefox.net/~fbsd/rpi3/swaptests/r337226M/1gbsdflash_1gbusbflash/batchqueue/ > > Both changes are now in place and -j4 buildworld has been restarted. Looking through the gstat output, I'm seeing some pretty abysmal average write latencies for da0, the flash drive. I also realized that my reference to r329882 lowering the pagedaemon sleep period was wrong - things have been this way for much longer than that. Moreover, as you pointed out, bumping oom_seq to a much larger value wasn't quite sufficient. I'm curious as to what the worst case swap I/O latencies are in your test, since the average latencies reported in your logs are high enough to trigger OOM kills even with the increased oom_seq value. When the current test finishes, could you try repeating it with this patch applied on top? https://people.freebsd.org/~markj/patches/slow_swap.diff That is, keep the non-default oom_seq setting and modification to VM_BATCHQUEUE_SIZE, and apply this patch on top. It'll cause the kernel to print messages to the console under certain conditions, so a log of console output will be interesting.
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