+ mm-hwpoison-use-compound_head-flags-for-huge-pages.patch added to -mm tree

The patch titled
     Subject: mm/memory-failure.c: use compound_head() flags for huge pages
has been added to the -mm tree.  Its filename is
     mm-hwpoison-use-compound_head-flags-for-huge-pages.patch

This patch should soon appear at
    http://ozlabs.org/~akpm/mmots/broken-out/mm-hwpoison-use-compound_head-flags-for-huge-pages.patch
and later at
    http://ozlabs.org/~akpm/mmotm/broken-out/mm-hwpoison-use-compound_head-flags-for-huge-pages.patch

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------------------------------------------------------
From: James Morse <james.morse@arm.com>
Subject: mm/memory-failure.c: use compound_head() flags for huge pages

memory_failure() chooses a recovery action function based on the page
flags. For huge pages it uses the tail page flags which don't have
anything interesting set, resulting in:

Memory failure: 0x9be3b4: Unknown page state
Memory failure: 0x9be3b4: recovery action for unknown page: Failed

Instead, save a copy of the head page's flags if this is a huge page, this
means if there are no relevant flags for this tail page, we use the head
pages flags instead.  This results in the me_huge_page() recovery action
being called:

Memory failure: 0x9b7969: recovery action for huge page: Delayed

For hugepages that have not yet been allocated, this allows the hugepage
to be dequeued.

Fixes: 524fca1e7356 ("HWPOISON: fix misjudgement of page_action() for errors on mlocked pages")
Link: http://lkml.kernel.org/r/20170524130204.21845-1-james.morse@arm.com
Signed-off-by: James Morse <james.morse@arm.com>
Tested-by: Punit Agrawal <redacted>
Acked-by: Punit Agrawal <redacted>
Acked-by: Naoya Horiguchi <redacted>
Cc: <redacted>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
---

 mm/memory-failure.c |    5 ++++-
 1 file changed, 4 insertions(+), 1 deletion(-)

diff -puN mm/memory-failure.c~mm-hwpoison-use-compound_head-flags-for-huge-pages mm/memory-failure.c

--- a/mm/memory-failure.c~mm-hwpoison-use-compound_head-flags-for-huge-pages
+++ a/mm/memory-failure.c

@@ -1184,7 +1184,10 @@ int memory_failure(unsigned long pfn, in
 	 * page_remove_rmap() in try_to_unmap_one(). So to determine page status
 	 * correctly, we save a copy of the page flags at this time.
 	 */
-	page_flags = p->flags;
+	if (PageHuge(p))
+		page_flags = hpage->flags;
+	else
+		page_flags = p->flags;
 
 	/*
 	 * unpoison always clear PG_hwpoison inside page lock

_

Patches currently in -mm which might be from james.morse@arm.com are

mm-hugetlb-report-ehwpoison-not-efault-when-foll_hwpoison-is-specified.patch
mm-hugetlb-report-ehwpoison-not-efault-when-foll_hwpoison-is-specified-v2.patch
mm-hwpoison-use-compound_head-flags-for-huge-pages.patch