lkml.org 
[lkml]   [2007]   [Jan]   [30]   [last100]   RSS Feed
Views: [wrap][no wrap]   [headers]  [forward] 
 
Messages in this thread
/
Date
From
SubjectRe: Fw: Re: [mm PATCH 4/6] RCU: (now) CPU hotplug
On Tue, Jan 30, 2007 at 10:27:18AM -0800, Andrew Morton wrote:
> On Tue, 30 Jan 2007 17:44:47 +0100
> "Rafael J. Wysocki" <rjw@sisk.pl> wrote:
>
> > > I need to look at all uses of PF_NOFREEZE -- as I understand the
> > > code, processes marked PF_NOFREEZE will continue running, potentially
> > > interfering with the hotplug operation. :-(
> > >
> > > I will pass my findings on to this list.
> >
> > Well, I did it some time ago, although not very thoroughly.
> >
> > AFAICS there are not so many, but one that stands out is the worker threads.
> > We needed two of them to actually go to sleep, so now it's possible to create
> > a "freezeable workqueue" the worker thread of which will not set PF_NOFREEZE,
> > but currently this is only used by XFS.
>
> Or we can create a variant of freeze_processes which ignores PF_NOFREEZE.
>
> As I said eariler, we might need to change the freezer code for this
> application. In fact we should do so: that sys_sync() call in there is
> quite inappropriate, as is, I suppose, the two-pass freeze attempt. As are
> the nice printks, come to that.
>
> Pretty simple stuff though.

And we might need to change some of the processes that currently set
PF_NOFREEZE so that they periodically go somewhere that the freezer can
find them -- if I remember correctly, at least some of the PF_NOFREEZE
tasks were so marked in order to prevent suspend hangs.

Part of what I need to look at. ;-)

Thanx, Paul
-
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: 2007-01-30 20:53    [W:1.952 / U:0.048 seconds]
©2003-2020 Jasper Spaans|hosted at Digital Ocean and TransIP|Read the blog|Advertise on this site