Messages in this thread Patch in this message | | | Date | Sun, 12 Aug 2012 11:31:11 +0200 | From | Michal Hocko <> | Subject | Re: [patch] hugetlb: correct page offset index for sharing pmd |
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On Sun 12-08-12 12:08:21, Hillf Danton wrote: > On Fri, Aug 10, 2012 at 9:48 PM, Michal Hocko <mhocko@suse.cz> wrote: > > > It's been compile tested because it only restores the previous code with > > a simple and obvious bug fix. > > It helps more if you elaborate on such a simple and obvious bug and > enrich your change log accordingly?
Hmmm, to be honest I really don't care much about this change. It is just that your previous patch (0c176d5) made the code more confusing and this aims at fixing that.
But anyway. I will post this to Andrew unless somebody has any objections. --- 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. 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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