diff options
| author | Mike Kravetz <mike.kravetz@oracle.com> | 2015-09-08 15:01:44 -0700 |
|---|---|---|
| committer | Linus Torvalds <torvalds@linux-foundation.org> | 2015-09-08 15:35:28 -0700 |
| commit | 1fb1b0e9ef2d661488f8053986c3b7641cae529d (patch) | |
| tree | 4fe154e4347f43f023d33065db9170c81d835e18 /mm/hugetlb.c | |
| parent | b5cec28d36f5ee6b4e6f68a0a40aa1e4045d6d99 (diff) | |
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@oracle.com>
Reviewed-by: Naoya Horiguchi <n-horiguchi@ah.jp.nec.com>
Acked-by: Hillf Danton <hillf.zj@alibaba-inc.com>
Cc: Dave Hansen <dave.hansen@linux.intel.com>
Cc: David Rientjes <rientjes@google.com>
Cc: Hugh Dickins <hughd@google.com>
Cc: Davidlohr Bueso <dave@stgolabs.net>
Cc: Aneesh Kumar <aneesh.kumar@linux.vnet.ibm.com>
Cc: Christoph Hellwig <hch@infradead.org>
Cc: Michal Hocko <mhocko@suse.cz>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Diffstat (limited to 'mm/hugetlb.c')
| -rw-r--r-- | mm/hugetlb.c | 15 |
1 files changed, 13 insertions, 2 deletions
diff --git a/mm/hugetlb.c b/mm/hugetlb.c index 61c52cd5f77b..bd12e8c8bc7b 100644 --- a/mm/hugetlb.c +++ b/mm/hugetlb.c @@ -801,8 +801,19 @@ static bool vma_has_reserves(struct vm_area_struct *vma, long chg) } /* 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 |