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* [merged] hugetlb-do-not-use-vma_hugecache_offset-for-vma_prio_tree_foreach.patch removed from -mm tree
@ 2012-10-09 18:14 akpm
  0 siblings, 0 replies; only message in thread
From: akpm @ 2012-10-09 18:14 UTC (permalink / raw)
  To: mhocko, aarcange, dhillf, hannes, kamezawa.hiroyu, mel, rientjes,
	stable, mm-commits


The patch titled
     Subject: hugetlb: do not use vma_hugecache_offset() for vma_prio_tree_foreach
has been removed from the -mm tree.  Its filename was
     hugetlb-do-not-use-vma_hugecache_offset-for-vma_prio_tree_foreach.patch

This patch was dropped because it was merged into mainline or a subsystem tree

------------------------------------------------------
From: Michal Hocko <mhocko@suse.cz>
Subject: 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.

Johannes said:

: The resulting index may not be too big, but it can be too small: assume
: hpage size of 2M and the address to unmap to be 0x200000.  This is regular
: page index 512 and hpage index 1.  If you have a VMA that maps the file
: only starting at the second huge page, that VMAs vm_pgoff will be 512 but
: you ask for offset 1 and miss it even though it does map the page of
: interest.  hugetlb_cow() will try to unmap, miss the vma, and retry the
: cow until the allocation succeeds or the skipped vma(s) go away.

Signed-off-by: Michal Hocko <mhocko@suse.cz>
Acked-by: 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>
Acked-by: Johannes Weiner <hannes@cmpxchg.org>
Cc: <stable@vger.kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
---

 mm/hugetlb.c |    3 ++-
 1 file changed, 2 insertions(+), 1 deletion(-)

diff -puN mm/hugetlb.c~hugetlb-do-not-use-vma_hugecache_offset-for-vma_prio_tree_foreach mm/hugetlb.c
--- a/mm/hugetlb.c~hugetlb-do-not-use-vma_hugecache_offset-for-vma_prio_tree_foreach
+++ a/mm/hugetlb.c
@@ -2480,7 +2480,8 @@ static int unmap_ref_private(struct mm_s
 	 * 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;
 
 	/*
_

Patches currently in -mm which might be from mhocko@suse.cz are

origin.patch
mm-memblock-reduce-overhead-in-binary-search.patch


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2012-10-09 18:14 [merged] hugetlb-do-not-use-vma_hugecache_offset-for-vma_prio_tree_foreach.patch removed from -mm tree akpm

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