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Subject: Re: [BUG] 2.6.30-rc3: BUG triggered on some hugepage usages
From: Benjamin Herrenschmidt <benh@kernel.crashing.org>
To: Mel Gorman <mel@csn.ul.ie>
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Date: Fri, 01 May 2009 07:48:46 +1000
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On Thu, 2009-04-30 at 21:59 +0100, Mel Gorman wrote:

> This patch fixes the problem by not asseting the PTE is locked for VMAs
> backed by huge pages.

Thanks, will apply.

Cheers,
Ben.

> Signed-off-by: Mel Gorman <mel@csn.ul.ie>
> --- 
>  arch/powerpc/mm/pgtable.c |    3 ++-
>  1 file changed, 2 insertions(+), 1 deletion(-)
> 
> diff --git a/arch/powerpc/mm/pgtable.c b/arch/powerpc/mm/pgtable.c
> index f5c6fd4..ae1d67c 100644
> --- a/arch/powerpc/mm/pgtable.c
> +++ b/arch/powerpc/mm/pgtable.c
> @@ -219,7 +219,8 @@ int ptep_set_access_flags(struct vm_area_struct *vma, unsigned long address,
>  		entry = do_dcache_icache_coherency(entry);
>  	changed = !pte_same(*(ptep), entry);
>  	if (changed) {
> -		assert_pte_locked(vma->vm_mm, address);
> +		if (!(vma->vm_flags & VM_HUGETLB))
> +			assert_pte_locked(vma->vm_mm, address);
>  		__ptep_set_access_flags(ptep, entry);
>  		flush_tlb_page_nohash(vma, address);
>  	}