On Mon 13-08-12 20:10:41, Hillf Danton wrote: > On Sun, Aug 12, 2012 at 5:31 PM, Michal Hocko <mhocko@xxxxxxx> wrote: > > From d07b88a70ee1dbcc96502c48cde878931e7deb38 Mon Sep 17 00:00:00 2001 > > From: Michal Hocko <mhocko@xxxxxxx> > > 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? That one is surely correct (linear_page_index converts the page offset). Anyway do you actually have any _real_ objection to the patch? I think the generated discussion is not worth the whole discussion. > > 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@xxxxxxxxx> > > Cc: Mel Gorman <mel@xxxxxxxxx> > > Cc: KAMEZAWA Hiroyuki <kamezawa.hiroyu@xxxxxxxxxxxxxx> > > Cc: Andrea Arcangeli <aarcange@xxxxxxxxxx> > > Cc: David Rientjes <rientjes@xxxxxxxxxx> > > Signed-off-by: Michal Hocko <mhocko@xxxxxxx> > > --- > > 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 -- Michal Hocko SUSE Labs -- To unsubscribe, send a message with 'unsubscribe linux-mm' in the body to majordomo@xxxxxxxxx. For more info on Linux MM, see: http://www.linux-mm.org/ . Don't email: <a href=mailto:"dont@xxxxxxxxx";> email@xxxxxxxxx </a>