From: Martin Wilck <Martin.Wilck@suse.com>
To: "chris@chris-wilson.co.uk" <chris@chris-wilson.co.uk>
Cc: "torvalds@linux-foundation.org" <torvalds@linux-foundation.org>,
"Michal Koutny" <MKoutny@suse.com>,
"intel-gfx@lists.freedesktop.org"
<intel-gfx@lists.freedesktop.org>,
"leho@kraav.com" <leho@kraav.com>,
"tiwai@suse.de" <tiwai@suse.de>,
"linux-kernel@vger.kernel.org" <linux-kernel@vger.kernel.org>
Subject: Re: 5.3-rc3: Frozen graphics with kcompactd migrating i915 pages
Date: Thu, 12 Sep 2019 11:23:09 +0000 [thread overview]
Message-ID: <3dcff41048621ff440687dd6691aae31a8647a1e.camel@suse.com> (raw)
In-Reply-To: <20190910142047.GB3029@papaya>
Hi Chris,
On Tue, 2019-09-10 at 17:20 +0300, Leho Kraav wrote:
> On Fri, Aug 09, 2019 at 01:53:43PM +0100, Chris Wilson wrote:
> > Quoting Martin Wilck (2019-08-09 13:41:42)
> > > This happened to me today, running kernel 5.3.0-rc3-1.g571863b-
> > > default
> > > (5.3-rc3 with just a few patches on top), after starting a KVM
> > > virtual
> > > machine. The X screen was frozen. Remote login via ssh was still
> > > possible, thus I was able to retrieve basic logs.
> > >
> > > sysrq-w showed two blocked processes (kcompactd0 and KVM). After
> > > a
> > > minute, the same two processes were still blocked. KVM seems to
> > > try to
> > > acquire a lock that kcompactd is holding. kcompactd is waiting
> > > for IO
> > > to complete on pages owned by the i915 driver.
> >
> > My bad, it's known. We haven't decided on whether to revert the
> > unfortunate recursive locking (and so hit another warn elsewhere)
> > or to
> > ignore the dirty pages (and so risk losing data across swap).
> >
> > cb6d7c7dc7ff ("drm/i915/userptr: Acquire the page lock around
> > set_page_dirty()")
> > -Chris
>
> Hi Chris. Is this exactly what I'm hitting at
> https://bugs.freedesktop.org/show_bug.cgi?id=111500 perhaps?
>
> It reliably breaks the graphics userland, as the machine consistently
> freezes at any random moment.
>
> Any workaround options, even if with a performance penalty? Revert
> cb6d7c7dc7ff but side effects?
>
> 5.3 has useful NVMe power mgmt updates for laptops, I'd like to stick
> with the newest if possible.
There's a considerable risk that many users will start seeing this
regression when 5.3 is released. I am not aware of a workaround.
Is there an alternative to reverting aa56a292ce62 ("drm/i915/userptr:
Acquire the page lock around set_page_dirty()")? And if we do, what
would be the consequences? Would other patches need to be reverted,
too?
Thanks,
Martin
next prev parent reply other threads:[~2019-09-12 12:27 UTC|newest]
Thread overview: 9+ messages / expand[flat|nested] mbox.gz Atom feed top
2019-08-09 12:41 5.3-rc3: Frozen graphics with kcompactd migrating i915 pages Martin Wilck
2019-08-09 12:53 ` Chris Wilson
2019-09-10 14:20 ` Leho Kraav
2019-09-12 11:23 ` Martin Wilck [this message]
2019-09-12 11:58 ` leho
2019-09-12 11:59 ` Linus Torvalds
2019-09-12 12:47 ` Chris Wilson
2019-09-12 12:56 ` [PATCH] Revert "drm/i915/userptr: Acquire the page lock around set_page_dirty()" Chris Wilson
2019-09-12 14:39 ` [Intel-gfx] " Tvrtko Ursulin
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