From: Mike Galbraith <efault@gmx.de>
To: Oleksandr Natalenko <oleksandr@natalenko.name>,
linux-kernel@vger.kernel.org
Cc: linux-mm@kvack.org, Andrew Morton <akpm@linux-foundation.org>,
Sebastian Andrzej Siewior <bigeasy@linutronix.de>,
Steven Rostedt <rostedt@goodmis.org>,
Thomas Gleixner <tglx@linutronix.de>,
linux-rt-users@vger.kernel.org
Subject: Re: scheduling while atomic in z3fold
Date: Sun, 29 Nov 2020 11:56:55 +0100 [thread overview]
Message-ID: <e38055ffe19751ba63f1c9beceae222438bcac59.camel@gmx.de> (raw)
In-Reply-To: <f1c39a0504310a97e42b667fc4d458af4a86d97a.camel@gmx.de>
On Sun, 2020-11-29 at 10:21 +0100, Mike Galbraith wrote:
> On Sun, 2020-11-29 at 08:48 +0100, Mike Galbraith wrote:
> > On Sun, 2020-11-29 at 07:41 +0100, Mike Galbraith wrote:
> > > On Sat, 2020-11-28 at 15:27 +0100, Oleksandr Natalenko wrote:
> > > >
> > > > > > Shouldn't the list manipulation be protected with
> > > > > > local_lock+this_cpu_ptr instead of get_cpu_ptr+spin_lock?
> > > >
> > > > Totally untested:
> > >
> > > Hrm, the thing doesn't seem to care deeply about preemption being
> > > disabled, so adding another lock may be overkill. It looks like you
> > > could get the job done via migrate_disable()+this_cpu_ptr().
> >
> > There is however an ever so tiny chance that I'm wrong about that :)
>
> Or not, your local_lock+this_cpu_ptr version exploded too.
>
> Perhaps there's a bit of non-rt related racy racy going on in zswap
> thingy that makes swap an even less wonderful idea for RT than usual.
Raciness seems to be restricted to pool compressor. "zbud" seems to be
solid, virgin "zsmalloc" explodes, as does "z3fold" regardless which of
us puts his grubby fingerprints on it.
Exploding compressors survived zero runs of runltp -f mm, I declared
zbud to be at least kinda sorta stable after box survived five runs.
-Mike
next prev parent reply other threads:[~2020-11-29 10:59 UTC|newest]
Thread overview: 70+ messages / expand[flat|nested] mbox.gz Atom feed top
2020-11-28 14:05 scheduling while atomic in z3fold Oleksandr Natalenko
2020-11-28 14:09 ` Oleksandr Natalenko
2020-11-28 14:27 ` Oleksandr Natalenko
2020-11-29 6:41 ` Mike Galbraith
2020-11-29 6:41 ` Mike Galbraith
2020-11-29 7:48 ` Mike Galbraith
2020-11-29 9:21 ` Mike Galbraith
2020-11-29 9:21 ` Mike Galbraith
2020-11-29 10:56 ` Mike Galbraith [this message]
2020-11-29 10:56 ` Mike Galbraith
2020-11-29 11:29 ` Oleksandr Natalenko
2020-11-29 11:41 ` Mike Galbraith
2020-11-29 11:41 ` Mike Galbraith
2020-11-30 13:20 ` Sebastian Andrzej Siewior
2020-11-30 13:53 ` Oleksandr Natalenko
2020-11-30 14:28 ` Sebastian Andrzej Siewior
2020-11-30 14:42 ` Mike Galbraith
2020-11-30 14:42 ` Mike Galbraith
2020-11-30 14:52 ` Sebastian Andrzej Siewior
2020-11-30 15:01 ` Mike Galbraith
2020-11-30 15:01 ` Mike Galbraith
2020-11-30 15:03 ` Mike Galbraith
2020-11-30 15:03 ` Mike Galbraith
2020-11-30 16:03 ` Sebastian Andrzej Siewior
2020-11-30 16:27 ` Mike Galbraith
2020-11-30 16:27 ` Mike Galbraith
2020-11-30 16:32 ` Sebastian Andrzej Siewior
2020-11-30 16:36 ` Mike Galbraith
2020-11-30 16:36 ` Mike Galbraith
2020-11-30 19:09 ` Mike Galbraith
2020-11-30 19:09 ` Mike Galbraith
2020-11-30 16:53 ` Mike Galbraith
2020-11-30 16:53 ` Mike Galbraith
2020-12-02 2:30 ` Mike Galbraith
2020-12-02 2:30 ` Mike Galbraith
2020-12-02 22:08 ` Sebastian Andrzej Siewior
2020-12-03 2:16 ` Mike Galbraith
2020-12-03 2:16 ` Mike Galbraith
2020-12-03 8:18 ` Mike Galbraith
2020-12-03 8:18 ` Mike Galbraith
2020-12-03 9:40 ` zswap explosion when using zsmalloc pool compression Mike Galbraith
2020-12-03 9:48 ` Sebastian Andrzej Siewior
2020-12-03 11:03 ` Mike Galbraith
2020-12-03 12:51 ` Mike Galbraith
2020-12-03 13:07 ` Mike Galbraith
2020-12-03 13:43 ` Mike Galbraith
2020-12-03 14:04 ` Mike Galbraith
2020-12-04 5:22 ` [patch] mm,zswap: fix zswap::zswap_comp.lock vs zsmalloc::zs_map_area.lock deadlock Mike Galbraith
2020-12-03 13:39 ` scheduling while atomic in z3fold Sebastian Andrzej Siewior
2020-12-03 14:07 ` Vitaly Wool
2020-12-03 14:07 ` Vitaly Wool
2020-12-06 9:18 ` Mike Galbraith
2020-12-06 9:18 ` Mike Galbraith
2020-12-07 1:05 ` Vitaly Wool
2020-12-07 2:18 ` Mike Galbraith
2020-12-07 2:18 ` Mike Galbraith
2020-12-07 11:52 ` Vitaly Wool
2020-12-07 11:52 ` Vitaly Wool
2020-12-07 12:34 ` Mike Galbraith
2020-12-07 12:34 ` Mike Galbraith
2020-12-07 15:21 ` Vitaly Wool
2020-12-07 15:21 ` Vitaly Wool
2020-12-07 15:41 ` Sebastian Andrzej Siewior
2020-12-07 15:41 ` Mike Galbraith
2020-12-07 15:41 ` Mike Galbraith
2020-12-08 23:26 ` Vitaly Wool
2020-12-09 6:13 ` Mike Galbraith
2020-12-09 6:13 ` Mike Galbraith
2020-12-09 6:31 ` Mike Galbraith
2020-12-09 6:31 ` Mike Galbraith
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