Commit d7e69488 authored Apr 28, 2016 by Minchan Kim Committed by Linus Torvalds Apr 28, 2016

mm/hwpoison: fix wrong num_poisoned_pages accounting



Currently, migration code increses num_poisoned_pages on *failed*
migration page as well as successfully migrated one at the trial of
memory-failure.  It will make the stat wrong.  As well, it marks the
page as PG_HWPoison even if the migration trial failed.  It would mean
we cannot recover the corrupted page using memory-failure facility.

This patches fixes it.

Signed-off-by: Minchan Kim <minchan@kernel.org>
Reported-by: Vlastimil Babka <vbabka@suse.cz>
Acked-by: Naoya Horiguchi <n-horiguchi@ah.jp.nec.com>
Cc: <stable@vger.kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

parent b06bad17

mm/migrate.c

+7 −1

Original line number	Original line	Diff line number	Diff line
	@@ -975,7 +975,13 @@ out:
	dec_zone_page_state(page, NR_ISOLATED_ANON +		dec_zone_page_state(page, NR_ISOLATED_ANON +
	page_is_file_cache(page));		page_is_file_cache(page));
	/* Soft-offlined page shouldn't go through lru cache list */		/* Soft-offlined page shouldn't go through lru cache list */
	if (reason == MR_MEMORY_FAILURE) {		if (reason == MR_MEMORY_FAILURE && rc == MIGRATEPAGE_SUCCESS) {
			/*
			* With this release, we free successfully migrated
			* page and set PG_HWPoison on just freed page
			* intentionally. Although it's rather weird, it's how
			* HWPoison flag works at the moment.
			*/
	put_page(page);		put_page(page);
	if (!test_set_page_hwpoison(page))		if (!test_set_page_hwpoison(page))
	num_poisoned_pages_inc();		num_poisoned_pages_inc();

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