Re: 2.6.13-rc3-mm3

[Richard Purdie <rpurdie@rpsys.net>]

On Thu, 2005-08-04 at 07:04 -0700, Christoph Lameter wrote:
> On Thu, 4 Aug 2005, Richard Purdie wrote:
> 
> > On Wed, 2005-08-03 at 17:19 -0700, Christoph Lameter wrote:
> > > Could you try the following patch? I think the problem was that higher 
> > > addressses were not mappable via the page fault handler. This patch 
> > > inserts the pmd entry into the pgd as necessary if the pud level is 
> > > folded.
> > 
> > I tried this patch against 2.6.13-rc4-mm1 and there was no change - X
> > still hung in memcpy as before and the cmpxchg_fail_flag_update just
> > increases...
> 
> Is there some way you can give us more information about the problem? 
> Something that would allow us to determine where the thing is looping?

I'm at a disadvantage here as the linux mm system is one area I've
avoided getting too deeply involved with so far. My knowledge is
therefore limited and I won't know what correct or incorrect behaviour
would look like.

We know the the failure case can be identified by the
cmpxchg_fail_flag_update condition being met. Can you provide me with a
patch to dump useful debugging information when that occurs?

Richard