From: Oleksandr Natalenko <oleksandr@natalenko.name>
To: Mike Galbraith <efault@gmx.de>
Cc: linux-kernel@vger.kernel.org, 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 12:29:22 +0100 [thread overview]
Message-ID: <20201129112922.db53kmtpu76xxukj@spock.localdomain> (raw)
In-Reply-To: <e38055ffe19751ba63f1c9beceae222438bcac59.camel@gmx.de>
On Sun, Nov 29, 2020 at 11:56:55AM +0100, Mike Galbraith wrote:
> 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.
Ummm so do compressors explode under non-rt kernel in your tests as
well, or it is just -rt that triggers this?
I've never seen that on both -rt and non-rt, thus asking.
--
Oleksandr Natalenko (post-factum)
next prev parent reply other threads:[~2020-11-29 11:30 UTC|newest]
Thread overview: 38+ 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 7:48 ` Mike Galbraith
2020-11-29 9:21 ` Mike Galbraith
2020-11-29 10:56 ` Mike Galbraith
2020-11-29 11:29 ` Oleksandr Natalenko [this message]
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 14:52 ` Sebastian Andrzej Siewior
2020-11-30 15:01 ` 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 16:32 ` Sebastian Andrzej Siewior
2020-11-30 16:36 ` Mike Galbraith
2020-11-30 19:09 ` Mike Galbraith
2020-11-30 16:53 ` 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 8:18 ` Mike Galbraith
2020-12-03 13:39 ` Sebastian Andrzej Siewior
2020-12-03 14:07 ` Vitaly Wool
2020-12-06 9:18 ` Mike Galbraith
[not found] ` <cad7848c-7fd3-b4a4-c079-5896bb47ee49@konsulko.com>
2020-12-07 2:18 ` Mike Galbraith
2020-12-07 11:52 ` Vitaly Wool
2020-12-07 12:34 ` Mike Galbraith
2020-12-07 15:21 ` Vitaly Wool
2020-12-07 15:41 ` Sebastian Andrzej Siewior
2020-12-07 15:41 ` Mike Galbraith
2020-12-08 23:26 ` Vitaly Wool
2020-12-09 6:13 ` Mike Galbraith
2020-12-09 6:31 ` Mike Galbraith
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