[07/10] mm/hwpoison: retry with shake_page() for unhandlable pages

Commit Message

Andrew Morton Aug. 20, 2021, 2:04 a.m. UTC

From: Naoya Horiguchi <[e-mail]>
Subject: mm/hwpoison: retry with shake_page() for unhandlable pages

HWPoisonHandlable() sometimes returns false for typical user pages due to
races with average memory events like transfers over LRU lists.  This
causes failures in hwpoison handling.

There's retry code for such a case but does not work because the retry
loop reaches the retry limit too quickly before the page settles down to
handlable state.  Let get_any_page() call shake_page() to fix it.

[[e-mail]: get_any_page(): return -EIO when retry limit reached]
  Link: https://lkml.kernel.org/r/[e-mail]
Link: https://lkml.kernel.org/r/[e-mail]
Fixes: 25182f05ffed ("mm,hwpoison: fix race with hugetlb page allocation")
Signed-off-by: Naoya Horiguchi <[e-mail]>
Reported-by: Tony Luck <[e-mail]>
Reviewed-by: Yang Shi <[e-mail]>
Cc: Oscar Salvador <[e-mail]>
Cc: Muchun Song <[e-mail]>
Cc: Mike Kravetz <[e-mail]>
Cc: Michal Hocko <[e-mail]>
Cc: <[e-mail]>		[5.13+]
Signed-off-by: Andrew Morton <[e-mail]>
---

 mm/memory-failure.c |   12 +++++++++---
 1 file changed, 9 insertions(+), 3 deletions(-)

Patch

--- a/mm/memory-failure.c~mm-hwpoison-retry-with-shake_page-for-unhandlable-pages
+++ a/mm/memory-failure.c
@@ -1146,7 +1146,7 @@  static int __get_hwpoison_page(struct pa
 	 * unexpected races caused by taking a page refcount.
 	 */
 	if (!HWPoisonHandlable(head))
-		return 0;
+		return -EBUSY;
 
 	if (PageTransHuge(head)) {
 		/*
@@ -1199,9 +1199,15 @@  try_again:
 			}
 			goto out;
 		} else if (ret == -EBUSY) {
-			/* We raced with freeing huge page to buddy, retry. */
-			if (pass++ < 3)
+			/*
+			 * We raced with (possibly temporary) unhandlable
+			 * page, retry.
+			 */
+			if (pass++ < 3) {
+				shake_page(p, 1);
 				goto try_again;
+			}
+			ret = -EIO;
 			goto out;
 		}
 	}