+ mm-hwpoison-retry-with-shake_page-for-unhandlable-pages.patch added to -mm tree

The patch titled
     Subject: mm/hwpoison: retry with shake_page() for unhandlable pages
has been added to the -mm tree.  Its filename is
     mm-hwpoison-retry-with-shake_page-for-unhandlable-pages.patch

This patch should soon appear at
    https://ozlabs.org/~akpm/mmots/broken-out/mm-hwpoison-retry-with-shake_page-for-unhandlable-pages.patch
and later at
    https://ozlabs.org/~akpm/mmotm/broken-out/mm-hwpoison-retry-with-shake_page-for-unhandlable-pages.patch

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*** Remember to use Documentation/process/submit-checklist.rst when testing your code ***

The -mm tree is included into linux-next and is updated
there every 3-4 working days

------------------------------------------------------
From: Naoya Horiguchi <redacted>
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.

Link: https://lkml.kernel.org/r/20210817053703.2267588-1-naoya.horiguchi@linux.dev
Fixes: 25182f05ffed ("mm,hwpoison: fix race with hugetlb page allocation")
Signed-off-by: Naoya Horiguchi <redacted>
Reported-by: Tony Luck <tony.luck@intel.com>
Cc: Oscar Salvador <osalvador@suse.de>
Cc: Muchun Song <redacted>
Cc: Mike Kravetz <redacted>
Cc: Michal Hocko <mhocko@suse.com>
Cc: <redacted>		[5.13]
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
---

 mm/memory-failure.c |   11 ++++++++---
 1 file changed, 8 insertions(+), 3 deletions(-)

--- 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 +1199,14 @@ 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;
+			}
 			goto out;
 		}
 	}

_

Patches currently in -mm which might be from naoya.horiguchi@nec.com are

mm-hwpoison-retry-with-shake_page-for-unhandlable-pages.patch
mm-sparse-set-section_nid_shift-to-6.patch