Date: Thu, 29 Feb 2024 08:02:42 -0800 From: Mark Millard <marklmi@yahoo.com> To: Peter <pmc@citylink.dinoex.sub.org>, FreeBSD-STABLE Mailing List <freebsd-stable@freebsd.org> Cc: "Edward Sanford Sutton, III" <mirror176@hotmail.com> Subject: Re: 13-STABLE high idprio load gives poor responsiveness and excessive CPU time per task Message-ID: <426089C7-A15C-4B04-BC47-D1F77089C492@yahoo.com> References: <426089C7-A15C-4B04-BC47-D1F77089C492.ref@yahoo.com>
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Peter 'PMc' Much <pmc_at_citylink.dinoex.sub.org>wrote on
Date: Thu, 29 Feb 2024 13:40:05 UTC :
> On 2024-02-27, Edward Sanford Sutton, III <mirror176@hotmail.com> wrote:
> > More recently looked and see top showing threads+system processes
> > shows I have one core getting 100% cpu for kernel{arc_prune} which has
> > 21.2 hours over a 2 hour 23 minute uptime.
>
> Ack.
>
> > I started looking to see if
> > https://www.freebsd.org/security/advisories/FreeBSD-EN-23:18.openzfs.asc
> > was available as a fix for 13 but it is not (and doesn't quite sound
> > like it was supposed to apply to this issue). Would a kernel thread time
> > at 100% cpu for only 1 core explain the system becoming unusually
> > unresponsive?
>
> That depends. This arc_prune issue does usually go alongside with some
> other kernel thread (vm-whatever) also blocking, so you have two cores
> busy. How many remain?
>
> There is an updated patch in the PR 275594 (5 pieces), that works for
> 13.3; I have it installed, and only with that I am able to build gcc12
> - otherwise the system would just OOM-crash (vm.pageout_oom_seq=5120
> does not help with this).
The kernel has multiple, distinct OOM messages. Which type are you
seeing? :
"failed to reclaim memory"
"a thread waited too long to allocate a page"
"swblk or swpctrie zone exhausted"
"unknown OOM reason %d"
Also, but only for boot verbose:
"proc %d (%s) failed to alloc page on fault, starting OOM\n"
vm.pageout_oom_seq is specific to delaying just:
"failed to reclaim memory"
===
Mark Millard
marklmi at yahoo.com
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