Date: Fri, 1 Feb 2019 15:52:15 -0800 From: Mark Millard <marklmi@yahoo.com> To: Mark Johnston <markj@FreeBSD.org> Cc: bob prohaska <fbsd@www.zefox.net>, 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: <6348018B-D21D-409E-9AE0-44BE65A56BE7@yahoo.com> In-Reply-To: <20180809170900.GD68459@raichu> References: <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> <20180808204841.GA19379@raichu> <20180809065648.GB30347@www.zefox.net> <20180809152152.GC68459@raichu> <915DFC7F-7AC9-484F-8619-C386FF077769@yahoo.com> <20180809170900.GD68459@raichu>
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[Your old changes for reporting information no longer matches sys/vm/swap_pager.c as of head -r343030 and later.] On 2018-Aug-9, at 10:09, Mark Johnston <markj at FreeBSD.org> wrote: > On Thu, Aug 09, 2018 at 09:21:38AM -0700, Mark Millard wrote: >> Would something like the patch that produced the messages >> like: >> >> waited 3s for async swap write >> waited 3s for swap buffer >> >> be appropriate as able to be enabled via a sysctl or in >> some other way? In other words: in the source code by standard, >> off by default, but able to be enabled without patching, >> possibly without rebuilding? > > Yes, I think so. We don't have a lot of visibility into the behaviour > of the pageout threads, and I have some ideas on how to improve that. > Swap I/O latency measurements are something I've wanted in the past. Your old changes for reporting information no longer matches sys/vm/swap_pager.c as of head -r343030 and later and nothing for this was merged into head or stable/12. Are you still planning to have an update for monitoring for such issues at some point? >> I ask because I've been thinking of having such on the >> FreeBSD's where I buildworld buildkernel and use poudriere-devel >> for port builds. It might warning me of marginal contexts and >> help explain any OOM kills that might occur. (Somethings >> things are difficult or time consuming to reproduce.) >> >> If monitored at the time, it might even help identify contexts >> that "machine-gun down requests" in environments were such can >> be a problem for swapping. === Mark Millard marklmi at yahoo.com ( dsl-only.net went away in early 2018-Mar)
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