mm: hwpoison: remove incorrect comments

dequeue_hwpoisoned_huge_page() can be called without page lock hold, so let's remove incorrect comment. The reason why the page lock is not really needed is that dequeue_hwpoisoned_huge_page() checks page_huge_active() inside hugetlb_lock, which allows us to avoid trying to dequeue a hugepage that are just allocated but not linked to active list yet, even without taking page lock. Link: http://lkml.kernel.org/r/[email protected] Signed-off-by: Naoya Horiguchi <[email protected]> Reported-by: Zhan Chen <[email protected]> Acked-by: Michal Hocko <[email protected]> Signed-off-by: Andrew Morton <[email protected]> Signed-off-by: Linus Torvalds <[email protected]>
soumdtt · Jul 28, 2016 · 7c7fd82 · 7c7fd82
1 parent 91fd8b9
commit 7c7fd82
Show file tree

Hide file tree

Showing 2 changed files with 0 additions and 3 deletions.
diff --git a/mm/hugetlb.c b/mm/hugetlb.c
@@ -4391,7 +4391,6 @@ follow_huge_pud(struct mm_struct *mm, unsigned long address,
 
 /*
  * This function is called from memory failure code.
- * Assume the caller holds page lock of the head page.
  */
 int dequeue_hwpoisoned_huge_page(struct page *hpage)
 {

diff --git a/mm/memory-failure.c b/mm/memory-failure.c
@@ -741,8 +741,6 @@ static int me_huge_page(struct page *p, unsigned long pfn)
 	 * page->lru because it can be used in other hugepage operations,
 	 * such as __unmap_hugepage_range() and gather_surplus_pages().
 	 * So instead we use page_mapping() and PageAnon().
-	 * We assume that this function is called with page lock held,
-	 * so there is no race between isolation and mapping/unmapping.
 	 */
 	if (!(page_mapping(hpage) || PageAnon(hpage))) {
 		res = dequeue_hwpoisoned_huge_page(hpage);
-Original file line number
+Diff line change
@@ Expand Up @@
     /*
      * This function is called from memory failure code.
-     * Assume the caller holds page lock of the head page.
      */
     int dequeue_hwpoisoned_huge_page(struct page *hpage)
     {
@@ Expand Down @@