[PATCH v2 05/20] mm, hugetlb: grab a page_table_lock after page_cache_release

[Joonsoo Kim]

We don't need to grab a page_table_lock when we try to release a page.
So, defer to grab a page_table_lock.

Reviewed-by: Naoya Horiguchi <n-horiguchi@xxxxxxxxxxxxx>
Signed-off-by: Joonsoo Kim <iamjoonsoo.kim@xxxxxxx>

diff --git a/mm/hugetlb.c b/mm/hugetlb.c
index c017c52..6c8eec2 100644
--- a/mm/hugetlb.c
+++ b/mm/hugetlb.c
@@ -2627,10 +2627,11 @@ retry_avoidcopy:
 	}
 	spin_unlock(&mm->page_table_lock);
 	mmu_notifier_invalidate_range_end(mm, mmun_start, mmun_end);
-	/* Caller expects lock to be held */
-	spin_lock(&mm->page_table_lock);
 	page_cache_release(new_page);
 	page_cache_release(old_page);
+
+	/* Caller expects lock to be held */
+	spin_lock(&mm->page_table_lock);
 	return 0;
 }
 
-- 
1.7.9.5

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