If we fail with a allocated hugepage, we need some effort to recover
properly. So, it is better not to allocate a hugepage as much as possible.
So move up anon_vma_prepare() which can be failed in OOM situation.
Reviewed-by: Aneesh Kumar K.V <aneesh.kumar@xxxxxxxxxxxxxxxxxx>
Signed-off-by: Joonsoo Kim <iamjoonsoo.kim@xxxxxxx>
diff --git a/mm/hugetlb.c b/mm/hugetlb.c
index 03ab285..1817720 100644
--- a/mm/hugetlb.c
+++ b/mm/hugetlb.c
@@ -2597,6 +2597,17 @@ retry_avoidcopy:
spin_unlock(ptl);
/*
+ * When the original hugepage is shared one, it does not have
+ * anon_vma prepared.
+ */
+ if (unlikely(anon_vma_prepare(vma))) {
+ page_cache_release(old_page);
+ /* Caller expects lock to be held */
+ spin_lock(ptl);
+ return VM_FAULT_OOM;
+ }
+
+ /*
* If the process that created a MAP_PRIVATE mapping is about to
* perform a COW due to a shared page count, attempt to satisfy
* the allocation without using the existing reserves. The pagecache
@@ -2655,18 +2666,6 @@ retry_avoidcopy:
return VM_FAULT_SIGBUS;
}
- /*
- * When the original hugepage is shared one, it does not have
- * anon_vma prepared.
- */
- if (unlikely(anon_vma_prepare(vma))) {
- page_cache_release(new_page);
- page_cache_release(old_page);
- /* Caller expects lock to be held */
- spin_lock(ptl);
- return VM_FAULT_OOM;
- }
-
copy_user_huge_page(new_page, old_page, address, vma,
pages_per_huge_page(h));
__SetPageUptodate(new_page);
--
1.7.9.5
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