Date: Tue, 26 Jun 2018 15:22:51 -0700 From: Steve Kargl <sgk@troutmask.apl.washington.edu> To: Adrian Chadd <adrian.chadd@gmail.com> Cc: Alexander Leidinger <Alexander@leidinger.net>, "current@freebsd.org" <current@freebsd.org> Subject: Re: numa involved in instability and swap usage despite RAM free? Message-ID: <20180626222251.GA30202@troutmask.apl.washington.edu> In-Reply-To: <CAJ-VmokW6bfTov8tvKQcpcVaKj=dxvPjmuTsejPVEh0mpKGrPg@mail.gmail.com> References: <20180624120329.Horde.HWORumQ7Ng1KAUeviJNtoc3@webmail.leidinger.net> <20180625182250.GA40651@troutmask.apl.washington.edu> <CAJ-VmokW6bfTov8tvKQcpcVaKj=dxvPjmuTsejPVEh0mpKGrPg@mail.gmail.com>
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On Tue, Jun 26, 2018 at 02:39:27PM -0700, Adrian Chadd wrote: > On Mon, 25 Jun 2018 at 11:23, Steve Kargl > <sgk@troutmask.apl.washington.edu> wrote: > > > > On Sun, Jun 24, 2018 at 12:03:29PM +0200, Alexander Leidinger wrote: > > > > > > I don't have hard evidence, but there is enough "smell" to open up a > > > discussion... > > > > > > Short: > > > Can it be that enabling numa in the kernel is the reason why some > > > people see instability with zfs and usage of swap while a lot of free > > > RAM is available? > > > > Interesting observation. I do have NUMA in my kernel, and swap > > seems to be used instead of recycling freeing inactive memory. > > Top shows > > > > Mem: 506M Active, 27G Inact, 98M Laundry, 2735M Wired, 1474M Buf, 1536M Free > > Swap: 16G Total, 120M Used, 16G Free > > > > Perhaps, I don't understand what is meant by inactive memory. I > > thought that this means memory is still available in the buffer > > cache, but nothing is current using what is there. > > > > Aren't there now per-domain VM counters you can query via sysctl? > Maybe they'd help in diagnosing what's going on. > I upgraded to a r335642 yesterday. I haven't seen the swapping problem, yet; although I've tried to force it. There are 158 sysctl knobs that contain the string "vm". Do you have a pointer any particular one to monitor? -- Steve
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