The patch titled
Subject: mm/hugetlb: vma_has_reserves() needs to handle fallocate hole punch
has been added to the -mm tree. Its filename is
mm-hugetlb-vma_has_reserves-needs-to-handle-fallocate-hole-punch.patch
This patch should soon appear at
http://ozlabs.org/~akpm/mmots/broken-out/mm-hugetlb-vma_has_reserves-needs-to-handle-fallocate-hole-punch.patch
and later at
http://ozlabs.org/~akpm/mmotm/broken-out/mm-hugetlb-vma_has_reserves-needs-to-handle-fallocate-hole-punch.patch
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------------------------------------------------------
From: Mike Kravetz <mike.kravetz@xxxxxxxxxx>
Subject: mm/hugetlb: vma_has_reserves() needs to handle fallocate hole punch
In vma_has_reserves(), the current assumption is that reserves are always
present for shared mappings. However, this will not be the case with
fallocate hole punch. When punching a hole, the present page will be
deleted as well as the region/reserve map entry (and hence any
reservation). vma_has_reserves is passed "chg" which indicates whether or
not a region/reserve map is present. Use this to determine if reserves
are actually present or were removed via hole punch.
Signed-off-by: Mike Kravetz <mike.kravetz@xxxxxxxxxx>
Reviewed-by: Naoya Horiguchi <n-horiguchi@xxxxxxxxxxxxx>
Acked-by: Hillf Danton <hillf.zj@xxxxxxxxxxxxxxx>
Cc: Dave Hansen <dave.hansen@xxxxxxxxxxxxxxx>
Cc: David Rientjes <rientjes@xxxxxxxxxx>
Cc: Hugh Dickins <hughd@xxxxxxxxxx>
Cc: Davidlohr Bueso <dave@xxxxxxxxxxxx>
Cc: Aneesh Kumar <aneesh.kumar@xxxxxxxxxxxxxxxxxx>
Cc: Christoph Hellwig <hch@xxxxxxxxxxxxx>
Cc: Michal Hocko <mhocko@xxxxxxx>
Signed-off-by: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx>
---
mm/hugetlb.c | 15 +++++++++++++--
1 file changed, 13 insertions(+), 2 deletions(-)
diff -puN mm/hugetlb.c~mm-hugetlb-vma_has_reserves-needs-to-handle-fallocate-hole-punch mm/hugetlb.c
--- a/mm/hugetlb.c~mm-hugetlb-vma_has_reserves-needs-to-handle-fallocate-hole-punch
+++ a/mm/hugetlb.c
@@ -801,8 +801,19 @@ static bool vma_has_reserves(struct vm_a
}
/* Shared mappings always use reserves */
- if (vma->vm_flags & VM_MAYSHARE)
- return true;
+ if (vma->vm_flags & VM_MAYSHARE) {
+ /*
+ * We know VM_NORESERVE is not set. Therefore, there SHOULD
+ * be a region map for all pages. The only situation where
+ * there is no region map is if a hole was punched via
+ * fallocate. In this case, there really are no reverves to
+ * use. This situation is indicated if chg != 0.
+ */
+ if (chg)
+ return false;
+ else
+ return true;
+ }
/*
* Only the process that called mmap() has reserves for
_
Patches currently in -mm which might be from mike.kravetz@xxxxxxxxxx are
hugetlb-make-the-function-vma_shareable-bool.patch
mm-hugetlb-add-cache-of-descriptors-to-resv_map-for-region_add.patch
mm-hugetlb-add-cache-of-descriptors-to-resv_map-for-region_add-fix.patch
mm-hugetlb-add-region_del-to-delete-a-specific-range-of-entries.patch
mm-hugetlb-expose-hugetlb-fault-mutex-for-use-by-fallocate.patch
hugetlbfs-hugetlb_vmtruncate_list-needs-to-take-a-range-to-delete.patch
hugetlbfs-truncate_hugepages-takes-a-range-of-pages.patch
mm-hugetlb-vma_has_reserves-needs-to-handle-fallocate-hole-punch.patch
mm-hugetlb-alloc_huge_page-handle-areas-hole-punched-by-fallocate.patch
hugetlbfs-new-huge_add_to_page_cache-helper-routine.patch
hugetlbfs-add-hugetlbfs_fallocate.patch
mm-madvise-allow-remove-operation-for-hugetlbfs.patch
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