lkml.org 
[lkml]   [2006]   [Oct]   [24]   [last100]   RSS Feed
Views: [wrap][no wrap]   [headers]  [forward] 
 
Messages in this thread
/
SubjectRe: [PATCH] Freeze bdevs when freezing processes.
From
Date
Hi David.

On Wed, 2006-10-25 at 00:44 +1000, David Chinner wrote:
> On Mon, Oct 23, 2006 at 12:36:53PM +0200, Rafael J. Wysocki wrote:
> > On Monday, 23 October 2006 06:12, Nigel Cunningham wrote:
> > > XFS can continue to submit I/O from a timer routine, even after
> > > freezeable kernel and userspace threads are frozen. This doesn't seem to
> > > be an issue for current swsusp code,
> >
> > So it doesn't look like we need the patch _now_.
> >
> > > but is definitely an issue for Suspend2, where the pages being written could
> > > be overwritten by Suspend2's atomic copy.
> >
> > And IMO that's a good reason why we shouldn't use RCU pages for storing the
> > image. XFS is one known example that breaks things if we do so and
> > there may be more such things that we don't know of. The fact that they
> > haven't appeared in testing so far doesn't mean they don't exist and
> > moreover some things like that may appear in the future.
>
> Could you please tell us which XFS bits are broken so we can get
> them fixed? The XFS daemons should all be checking if they are
> supposed to freeze (i.e. they call try_to_freeze() after they wake
> up due to timer expiry) so I thought they were doing the right
> thing.

The problem (in my experience) isn't the threads but a timer that
submits I/O even when the threads are frozen. It stops when the bdev is
frozen. The last report I've seen was before I added bdev freezing to
suspend2, which was 2.6.14, so you guys may have fixed it since then.

I can seek to get a trace if you like.

Regards,

Nigel

-
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to majordomo@vger.kernel.org
More majordomo info at http://vger.kernel.org/majordomo-info.html
Please read the FAQ at http://www.tux.org/lkml/

\
 
 \ /
  Last update: 2006-10-25 00:21    [W:0.188 / U:2.468 seconds]
©2003-2020 Jasper Spaans|hosted at Digital Ocean and TransIP|Read the blog|Advertise on this site