Re: [patch 2/3] mmu_notifier: Callbacks to invalidate addressranges

From: Robin Holt
Date: Fri Feb 01 2008 - 05:37:49 EST


On Fri, Feb 01, 2008 at 04:32:21AM -0600, Robin Holt wrote:
> On Thu, Jan 31, 2008 at 08:43:58PM -0800, Christoph Lameter wrote:
> > On Thu, 31 Jan 2008, Robin Holt wrote:
> >
> > > > Index: linux-2.6/mm/memory.c
> > > ...
> > > > @@ -1668,6 +1678,7 @@ gotten:
> > > > page_cache_release(old_page);
> > > > unlock:
> > > > pte_unmap_unlock(page_table, ptl);
> > > > + mmu_notifier(invalidate_range_end, mm, 0);
> > >
> > > I think we can get an _end call without the _begin call before it.
> >
> > If that would be true then also the pte would have been left locked.
> >
> > We always hit unlock. Maybe I just do not see it?
>
> Maybe I haven't looked closely enough, but let's start with some common
> assumptions. Looking at do_wp_page from 2.6.24 (I believe that is what
> my work area is based upon). On line 1559, the function begins being
> declared.
>
> On lines 1614 and 1630, we do "goto unlock" where the _end callout is
> soon made. The _begin callout does not come until after those branches
> have been taken (occurs on line 1648).
>
> Thanks,
> Robin

Ignore this thread, I am going to throw a patch against the new version.

Thanks,
Robin
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