Re: [RFC][PATCH -mm] PM: Do not sync from within the freezer during suspend to RAM

Nigel Cunningham
2007-07-05T11:38:17Z

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Hi.

On Thursday 05 July 2007 21:28:49 Rafael J. Wysocki wrote:
> On Thursday, 5 July 2007 00:52, Nigel Cunningham wrote:
> > On Thursday 05 July 2007 08:49:42 Pavel Machek wrote:
> > > On Thu 2007-07-05 08:48:15, Nigel Cunningham wrote:
> > > > On Thursday 05 July 2007 00:58:58 Rafael J. Wysocki wrote:
> > > > > The syncing of filesystems from within the freezer in not needed for
> > suspend
> > > > to
> > > > > RAM. Change freeze_processes() so that it doesn't execute
sys_sync()
> > and
> > > > > introduce the "syncing" version of it to be called from the
hibernation
> > code
> > > > > paths.
> > > > >
> > > > > Signed-off-by: Rafael J. Wysocki <rjw@sisk.pl>
> > > > > ---
> > > > > include/linux/freezer.h | 14 ++++++++++++--
> > > > > kernel/power/disk.c | 2 +-
> > > > > kernel/power/main.c | 6 ++++++
> > > > > kernel/power/process.c | 8 +++++---
> > > > > kernel/power/user.c | 2 +-
> > > > > 5 files changed, 25 insertions(+), 7 deletions(-)
> > > >
> > > > Looks ok, except that I wonder if you want the following fragment. It
> > looks to
> > > > me (looking at rc6) like with this code, you'll currently call
sys_sync
> > twice
> > > > when suspending to ram. Maybe I'm misreading it. Also, shouldn't it be
> > done
> > > > after taking the mutex?
> > >
> > > sys_sync() should be okay to call, mutex or not.
> >
> > Yeah. That wasn't my point, sorry. Calling sys_sync is pointless if you're
> > going to fail to take the mutex. It makes more sense to know you've got it
> > before you start doing things related to actually suspending.
>
> Well, that's a valid point, I'll move it under the mutex.

Okee doke.

> And why do you think it will be called twice?

Hmm. Looking again now, I can't see why I thought that. Maybe I just hadn't
had enough caffeine today at that stage :)

Nigel
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