If we fail with a allocated hugepage, it is hard to recover properly.
One such example is reserve count. We don't have any method to recover
reserve count. Although, I will introduce a function to recover reserve
count in following patch, 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.
Signed-off-by: Joonsoo Kim <iamjoonsoo.kim@xxxxxxx>
diff --git a/mm/hugetlb.c b/mm/hugetlb.c
index 683fd38..bb8a45f 100644
--- a/mm/hugetlb.c
+++ b/mm/hugetlb.c
@@ -2536,6 +2536,15 @@ retry_avoidcopy:
/* Drop page_table_lock as buddy allocator may be called */
spin_unlock(&mm->page_table_lock);
+ /*
+ * When the original hugepage is shared one, it does not have
+ * anon_vma prepared.
+ */
+ if (unlikely(anon_vma_prepare(vma))) {
+ ret = VM_FAULT_OOM;
+ goto out_old_page;
+ }
+
use_reserve = vma_has_reserves(h, vma, address);
if (use_reserve == -ENOMEM) {
ret = VM_FAULT_OOM;
@@ -2590,15 +2599,6 @@ retry_avoidcopy:
goto out_lock;
}
- /*
- * When the original hugepage is shared one, it does not have
- * anon_vma prepared.
- */
- if (unlikely(anon_vma_prepare(vma))) {
- ret = VM_FAULT_OOM;
- goto out_new_page;
- }
-
copy_user_huge_page(new_page, old_page, address, vma,
pages_per_huge_page(h));
__SetPageUptodate(new_page);
@@ -2625,7 +2625,6 @@ retry_avoidcopy:
spin_unlock(&mm->page_table_lock);
mmu_notifier_invalidate_range_end(mm, mmun_start, mmun_end);
-out_new_page:
page_cache_release(new_page);
out_old_page:
page_cache_release(old_page);
--
1.7.9.5
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