From: Mike Galbraith <efault@gmx.de>
To: Vitaly Wool <vitaly.wool@konsulko.com>
Cc: LKML <linux-kernel@vger.kernel.org>,
linux-mm <linux-mm@kvack.org>,
Barry Song <song.bao.hua@hisilicon.com>,
Sebastian Andrzej Siewior <bigeasy@linutronix.de>,
Minchan Kim <minchan@kernel.org>, NitinGupta <ngupta@vflare.org>
Subject: Re: [patch] zswap: fix zswap_frontswap_load() vs zsmalloc::map/unmap() might_sleep() splat
Date: Sat, 19 Dec 2020 12:03:14 +0100 [thread overview]
Message-ID: <a8e616b333a85606c0da24465c9d7209b6991eba.camel@gmx.de> (raw)
In-Reply-To: <18669bd607ae9efbf4e00e36532c7aa167d0fa12.camel@gmx.de>
(CC zsmalloc maintainers)
On Sat, 2020-12-19 at 11:59 +0100, Mike Galbraith wrote:
> On Sat, 2020-12-19 at 11:46 +0100, Vitaly Wool wrote:
> > On Sat, 19 Dec 2020, 11:27 Mike Galbraith, <efault@gmx.de> wrote:
> >
> > > The kernel that generated that splat was NOT an RT kernel, it was plain
> > > master.today with a PREEMPT config.
> >
> >
> > I see, thanks. I don't think it makes things better for zsmalloc
> > though. From what I can see, the offending code is this:
> >
> > > /* From now on, migration cannot move the object */
> > > pin_tag(handle);
> >
> > Bit spinlock is taken in pin_tag(). I find the comment above somewhat
> > misleading, why is it necessary to take a spinlock to prevent
> > migration? I would guess an atomic flag should normally be enough.
> >
> > zswap is not broken here, it is zsmalloc that needs to be fixed.
>
> Cool, those damn bit spinlocks going away would be a case of happiness
> for RT as well :)
>
> -Mike
next prev parent reply other threads:[~2020-12-19 11:03 UTC|newest]
Thread overview: 47+ messages / expand[flat|nested] mbox.gz Atom feed top
2020-12-19 10:04 Mike Galbraith
2020-12-19 10:12 ` Mike Galbraith
2020-12-19 10:20 ` Vitaly Wool
2020-12-19 10:27 ` Mike Galbraith
2020-12-19 10:46 ` Vitaly Wool
2020-12-19 10:59 ` Mike Galbraith
2020-12-19 11:03 ` Mike Galbraith [this message]
2020-12-20 0:22 ` [PATCH] zsmalloc: do not use bit_spin_lock Vitaly Wool
2020-12-20 1:18 ` Matthew Wilcox
2020-12-20 7:21 ` Vitaly Wool
2021-01-14 16:17 ` Sebastian Andrzej Siewior
2020-12-20 1:23 ` Mike Galbraith
2020-12-20 4:11 ` Mike Galbraith
2020-12-20 7:47 ` Mike Galbraith
2020-12-20 21:20 ` Song Bao Hua (Barry Song)
2020-12-20 22:10 ` Mike Galbraith
2020-12-20 1:56 ` Mike Galbraith
2020-12-21 17:24 ` Minchan Kim
2020-12-21 19:20 ` Vitaly Wool
2020-12-21 19:50 ` Shakeel Butt
2020-12-21 20:05 ` Song Bao Hua (Barry Song)
2020-12-21 21:02 ` Shakeel Butt
2020-12-21 21:25 ` Song Bao Hua (Barry Song)
2020-12-21 22:11 ` Vitaly Wool
2020-12-21 22:42 ` Song Bao Hua (Barry Song)
2020-12-21 23:35 ` Song Bao Hua (Barry Song)
2020-12-22 0:59 ` Vitaly Wool
2020-12-22 1:10 ` Song Bao Hua (Barry Song)
2020-12-22 1:42 ` Song Bao Hua (Barry Song)
2020-12-22 1:57 ` Vitaly Wool
2020-12-22 2:07 ` Song Bao Hua (Barry Song)
2020-12-22 2:10 ` Song Bao Hua (Barry Song)
2020-12-22 9:44 ` Vitaly Wool
2020-12-22 21:06 ` Song Bao Hua (Barry Song)
2020-12-23 0:11 ` Vitaly Wool
2020-12-23 12:44 ` tiantao (H)
2020-12-23 18:25 ` Vitaly Wool
2021-01-14 16:18 ` Sebastian Andrzej Siewior
2021-01-14 16:29 ` Vitaly Wool
2021-01-14 16:56 ` Sebastian Andrzej Siewior
2021-01-14 17:15 ` Vitaly Wool
2021-01-14 17:18 ` Sebastian Andrzej Siewior
2020-12-21 22:46 ` Shakeel Butt
2020-12-21 23:02 ` Song Bao Hua (Barry Song)
2020-12-22 9:20 ` David Laight
2020-12-22 9:32 ` Vitaly Wool
2020-12-21 20:22 ` Minchan Kim
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