Re: [PATCH 1/1 2.6.25] fbdev: bugfix for multiprocess defio

[Andrew Morton <akpm@linux-foundation.org>]

On Tue, 8 Jul 2008 08:50:30 -0400 "Jaya Kumar" <jayakumar.lkml@gmail.com> wrote:

> On Mon, May 5, 2008 at 3:23 AM, Jaya Kumar <jayakumar.lkml@gmail.com> wrote:
> > On Wed, Apr 30, 2008 at 1:37 PM, Andrew Morton
> > <akpm@linux-foundation.org> wrote:
> >>
> >> On Sun, 27 Apr 2008 22:01:40 -0400
> >>  Jaya Kumar <jayakumar.lkml@gmail.com> wrote:
> >>
> >>  > +     /* we loop through the pagelist before adding in order
> >>  > +     to keep the pagelist sorted */
> >>  > +     list_for_each_entry(cur, &fbdefio->pagelist, lru) {
> >>
> >>  Did you consider using !list_empty(&page->lru) to avoid the linear search?
> >>
> >
> > Ah, no, I didn't think of that. I agree that checking list_empty would
> > be far better. I'll redo the patch using that.
> >
> > Thanks,
> > jaya
> >
> 
> Hi Andrew,
> 
> I encountered some complexity when trying to use page->lru because its
> not empty on its first mkwrite. I think there are probably deeper
> issues that repurposing page->lru for use in defio causes. I'm working
> on it.
> 
> In the meantime, it turns out that suspend/resume of xen pvfb is
> affected by the same bug that raised this patch. Markus suggested,
> http://marc.info/?l=linux-kernel&m=121368814027583&w=2 , that perhaps
> this existing patch could be merged in the interim while a better
> solution is worked on.
> 
> Would you be okay with adding this patch back into the queue? If so,
> should I repost it here?

It never hurts to resend everything.  Especially when "everything" is
several months old!

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