Date: Fri, 15 Apr 2022 18:35:30 -0700 From: Mark Millard <marklmi@yahoo.com> To: freebsd07@wayne47.com, Peter Jeremy <peterj@freebsd.org> Cc: FreeBSD Hackers <freebsd-hackers@freebsd.org> Subject: Re: Can not build kernel on 1GB VM Message-ID: <AF35B974-779D-4137-A3B1-48866154F71B@yahoo.com> References: <AF35B974-779D-4137-A3B1-48866154F71B.ref@yahoo.com>
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From: Peter Jeremy <peterj_at_freebsd.org>=20 Date: Sat, 16 Apr 2022 10:25:23 +1000: > On 2022-Apr-15 13:49:53 -0400, Michael Wayne = <freebsd07_at_wayne47.com> wrote: > >I have a VM with 1GB RAM running FreeBSD 12.1-RELEASE-p3 > > > >I'm trying to upgrade the machine to 12.3 and having swap failures. >=20 > Are you using ZFS or UFS and are you swapping to a raw partition > or a file/zvol? Gad, why did I not think to cover that issue in my earlier note to freebsd07@wayne47.com ? Good catch. In bugzilla there is: https://bugs.freebsd.org/bugzilla/show_bug.cgi?id=3D206048 comments #7 and #8 are related to the file/zvol issue. freebsd07@wayne47.com also indicates a VM context as well. > >the machine ran out of swap. with a bunch of messages like: > > Apr 15 12:11:26 g1 kernel: swap_pager: indefinite wait buffer: = bufobj: 0, blkno: 240593, size: 4096 > > Apr 15 12:11:35 g1 kernel: swap_pager: indefinite wait buffer: = bufobj: 0, blkno: 236224, size: 16384 > > Apr 15 12:11:37 g1 kernel: swap_pager: indefinite wait buffer: = bufobj: 0, blkno: 245, size: 12288 > > Apr 15 12:11:46 g1 kernel: swap_pager: indefinite wait buffer: = bufobj: 0, blkno: 240593, size: 4096 > > Apr 15 12:11:55 g1 kernel: swap_pager: indefinite wait buffer: = bufobj: 0, blkno: 236224, size: 16384 > > Apr 15 12:11:57 g1 kernel: swap_pager: indefinite wait buffer: = bufobj: 0, blkno: 245, size: 12288 >=20 > That message doesn't indicate "out of swap", I expect that the "killed due to out of swap space" message that was originally referenced (though not quoted) was of the structure: kernel: pid ???? (???), jid ??, uid ??, was killed: out of swap space That is the message type that I was reporting as being a misnomer when it is reported: the swap space available does not have to be low at all for such kills with such messages. > in indicates that your > swap device isn't responding within a "reasonable" time. If you are > swapping to a local ZFS file or zvol, you may be running into a known > deadlock condition and should switch to using a raw partition for > swap. If you can't improve your swap device performance, adjusting > the vm.pageout_oom_seq and vm.pfault_oom_attempts sysctls should > resolve the problem. freebsd07@wayne47.com later reported they did not help --but I do not know if a swap partition was what was being used or not. > A true "out of swap" will appear as a message similar to > swap_pager_getswapspace(nnn): failed Yea, there are 2 messages that are not misnomers: (Quoting from another list exchange that I had once, that in turn had copy/paste based text from an actual set of messages.) QUOTE Jan 5 21:04:31 r5601g kernel: swap_pager: out of swap space Jan 5 21:04:31 r5601g kernel: swp_pager_getswapspace(7): failed END QUOTE Neither of these messages are announcing kills. But if neither of these types messages have shown up, then any "was killed: out of swap space" message is a misnomer for the "out of swap space" part of the message. =3D=3D=3D Mark Millard marklmi at yahoo.com
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