lkml.org 
[lkml]   [2007]   [Jul]   [3]   [last100]   RSS Feed
Views: [wrap][no wrap]   [headers]  [forward] 
 
Messages in this thread
/
From
SubjectRe: [PATCH] Remove process freezer from suspend to RAM pathway
Date
On Tuesday, 3 July 2007 19:20, Oliver Neukum wrote:
> Am Dienstag, 3. Juli 2007 schrieb Rafael J. Wysocki:
> > On Tuesday, 3 July 2007 15:08, Rafael J. Wysocki wrote:
> > > On Tuesday, 3 July 2007 07:51, Benjamin Herrenschmidt wrote:
> > > > On Tue, 2007-07-03 at 05:29 +0100, Matthew Garrett wrote:
> > > > > Suspend to RAM on a machine with / on a fuse filesystem turns out to be
> > > > > a screaming nightmare - either the suspend fails because syslog (for
> > > > > instance) can't be frozen, or the machine deadlocks for some other
> > > > > reason I haven't tracked down. We could "fix" fuse, or alternatively we
> > > > > could do what we do for suspend to RAM on other platforms (PPC and APM)
> > > > > and just not use the freezer.
> > > >
> > > > The main reason for deadlocks is because we do a sys_sync() after the
> > > > freeze, which we shouldn't do.
> > >
> > > So why don't we remove the sys_sync() from freeze_processes() instead?
> >
> > The patch follows (untested).
> >
> > Greetings,
> > Rafael
> >
> >
> > ---
> > From: Rafael J. Wysocki <rjw@sisk.pl>
> >
> > We shouldn't sync filesystems from within the freezer, because it's not needed
> > for suspend to RAM and leads to problems with FUSE.
>
> This seems fishy. Swsusp needs enough clean memory to make enough
> room for the image. If you sync before you freeze, the running tasks can
> redirty memory.
> What makes you sure that you don't die as shrink_all_memory() writes out
> pages?

I don't think that would matter.

Still, I can remove the sync from the suspend code path only, leaving it in
the hibernation code path. The patch will be bigger, but well.

Any objection to that?

Greetings,
Rafael


--
"Premature optimization is the root of all evil." - Donald Knuth
-
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: 2007-07-03 22:55    [W:0.225 / U:4.584 seconds]
©2003-2020 Jasper Spaans|hosted at Digital Ocean and TransIP|Read the blog|Advertise on this site