Date: Fri, 2 Mar 2018 12:47:53 -0500 From: Mike <the.lists@mgm51.com> To: "freebsd-arm@freebsd.org" <freebsd-arm@freebsd.org> Subject: Re: Is maximum swap usage tunable? Message-ID: <b53c3af5-1ae6-3768-80db-c8f57e59949e@mgm51.com> In-Reply-To: <CANCZdfq_MpxjUyVd-=%2BMiAQAER4TeDh9irhx_evdXwa3yt3h0g@mail.gmail.com> References: <20180228170311.GA26187@www.zefox.net> <a759ecea-83f4-b0b2-7113-c39633f68637@mgm51.com> <20180228185517.GB26187@www.zefox.net> <8f422161-885e-aa91-eacd-018540222d65@mgm51.com> <20180228214301.GA29481@www.zefox.net> <b82801b8-bc29-414c-1170-621bb4a5d937@mgm51.com> <CANCZdfq_MpxjUyVd-=%2BMiAQAER4TeDh9irhx_evdXwa3yt3h0g@mail.gmail.com>
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On 3/2/2018 12:04 PM, Warner Losh wrote: > >[snip] > > buildworld is still running. I started it around 3PM (EST) on March 1. > > I'm seeing a lot of swap messages on the console. The text is: > > swap_pager: indefinite wait buffer: bufobj: 0, > blkno: [varies], size: [varies] > > > This message comes from the swap pager when the I/O doesn't complete > quickly enough. It has nothing to do with sizes of the swap space. > > I've seen three causes for this: (1) The driver going crazy and not > completing I/Os it gets notified as being done; (2) The driver not > having a backstop timer on I/Os to fail them with timeout; (3) timeouts > not firing for the driver to fail the I/O up the stack. (4) when a drive > suddenly slow way way down (~100x or more slower), the I/O queues > balloons and you can get these. Thanks for the explanation. So far, buildworld is continuing to run. That is something that has not happened before, buildworld would usually abort by now. swap is on an older Adata (U1) microSD card. I have a Sandisk Extreme Pro (V30) microSD card arriving over the weekend (hopefully), so I'd be interested in seeing if that makes any difference, either to the number of messages or the speed of the build.
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