Subject: Re: [bisected a4615d11] Memory DLPAR triggers WARN_ONCE() in mm/page_vma_mapped.c

From: Abdul Haleem <[email-masked]>
Date: Tue, 03 Oct 2017 14:38:30 +0530

On Fri, 2017-09-29 at 10:07 -0400, Zi Yan wrote:
> Hi Abdul,
> 
> I just want to follow up with this.
> 
> Did you have a chance to test my patch? Does it fix your original problem?

Yes I did test the patch. it fixes the warning.

Reported-and-tested-by:  Abdul Haleem <[email-masked]>

Thanks for the fix.

--
Regard's

Abdul Haleem
IBM Linux Technology Centre

> 
> On 13 Sep 2017, at 1:48, abdul wrote:
> 
> > On Mon, 2017-09-11 at 10:53 -0400, Zi Yan wrote:
> >> Hi Abdul,
> >>
> >> Can you try this patch below? I think I missed that pmd entries
> >> can be zapped, so the WARN_ONCE is unnecessary.
> >>
> >> Thanks.
> >>
> >> diff --git a/mm/page_vma_mapped.c b/mm/page_vma_mapped.c
> >> index 6a03946469a9..eb462e7db0a9 100644
> >> --- a/mm/page_vma_mapped.c
> >> +++ b/mm/page_vma_mapped.c
> >> @@ -167,8 +167,7 @@ bool page_vma_mapped_walk(struct page_vma_mapped_walk *pvmw)
> >>                                                 return not_found(pvmw);
> >>                                         return true;
> >>                                 }
> >> -                       } else
> >> -                               WARN_ONCE(1, "Non present huge pmd without pmd migration enabled!");
> >> +                       }
> >>                         return not_found(pvmw);
> >>                 } else {
> >>                         /* THP pmd was split under us: handle on pte level */
> >>
> >> --
> >> Best Regards
> >> Yan Zi