Messages in this thread | | | Date | Mon, 13 Aug 2012 20:10:41 +0800 | Subject | Re: [patch] hugetlb: correct page offset index for sharing pmd | From | Hillf Danton <> |
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On Sun, Aug 12, 2012 at 5:31 PM, Michal Hocko <mhocko@suse.cz> wrote: > From d07b88a70ee1dbcc96502c48cde878931e7deb38 Mon Sep 17 00:00:00 2001 > From: Michal Hocko <mhocko@suse.cz> > Date: Fri, 10 Aug 2012 15:03:07 +0200 > Subject: [PATCH] hugetlb: do not use vma_hugecache_offset for > vma_prio_tree_foreach > > 0c176d5 (mm: hugetlb: fix pgoff computation when unmapping page > from vma) fixed pgoff calculation but it has replaced it by > vma_hugecache_offset which is not approapriate for offsets used for > vma_prio_tree_foreach because that one expects index in page units > rather than in huge_page_shift.
What if another case of vma_prio_tree_foreach in try_to_unmap_file is correct?
> Using vma_hugecache_offset is not incorrect because the pgoff will fit > into the same vmas but it is confusing so the standard PAGE_SHIFT based > index calculation is used instead. > > Cc: Hillf Danton <dhillf@gmail.com> > Cc: Mel Gorman <mel@csn.ul.ie> > Cc: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com> > Cc: Andrea Arcangeli <aarcange@redhat.com> > Cc: David Rientjes <rientjes@google.com> > Signed-off-by: Michal Hocko <mhocko@suse.cz> > --- > mm/hugetlb.c | 3 ++- > 1 file changed, 2 insertions(+), 1 deletion(-) > > diff --git a/mm/hugetlb.c b/mm/hugetlb.c > index c39e4be..a74ea31 100644 > --- a/mm/hugetlb.c > +++ b/mm/hugetlb.c > @@ -2462,7 +2462,8 @@ static int unmap_ref_private(struct mm_struct *mm, struct vm_area_struct *vma, > * from page cache lookup which is in HPAGE_SIZE units. > */ > address = address & huge_page_mask(h); > - pgoff = vma_hugecache_offset(h, vma, address); > + pgoff = ((address - vma->vm_start) >> PAGE_SHIFT) + > + vma->vm_pgoff; > mapping = vma->vm_file->f_dentry->d_inode->i_mapping; > > /* > -- > 1.7.10.4 > > > -- > Michal Hocko > SUSE Labs
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