thp: allow a hwpoisoned head page to be put back to LRU (385de357) · Commits · 戴 / test

Andrea Arcangeli pointed out to me that a check in __memory_failure() which was intended to prevent THP tail pages from being checked for the absence of the PG_lru flag (something that is always the case), was also preventing THP head pages from being checked. A THP head page could actually benefit from the call to shake_page() by ending up being put back to a LRU, provided it had been waiting in a pagevec array. Andrea suggested that the "!PageTransCompound(p)" in the if-statement should be replaced by a "!PageTransTail(p)", thus allowing THP head pages to be checked and possibly shaken. Signed-off-by:

Dean Nelson <dnelson@redhat.com> Cc: Jin Dongming <jin.dongming@np.css.fujitsu.com> Reviewed-by:

Andrea Arcangeli <aarcange@redhat.com> Cc: Andi Kleen <andi@firstfloor.org> Cc: Hidetoshi Seto <seto.hidetoshi@jp.fujitsu.com> Signed-off-by:

Andrew Morton <akpm@linux-foundation.org> Signed-off-by:

Linus Torvalds <torvalds@linux-foundation.org>

include/linux/page-flags.h

+20 −0

Original line number	Diff line number	Diff line
		@@ -414,11 +414,26 @@ static inline int PageTransHuge(struct page *page)
		return PageHead(page);
		}

		/*
		* PageTransCompound returns true for both transparent huge pages
		* and hugetlbfs pages, so it should only be called when it's known
		* that hugetlbfs pages aren't involved.
		*/
		static inline int PageTransCompound(struct page *page)
		{
		return PageCompound(page);
		}

		/*
		* PageTransTail returns true for both transparent huge pages
		* and hugetlbfs pages, so it should only be called when it's known
		* that hugetlbfs pages aren't involved.
		*/
		static inline int PageTransTail(struct page *page)
		{
		return PageTail(page);
		}

		#else

		static inline int PageTransHuge(struct page *page)
		@@ -430,6 +445,11 @@ static inline int PageTransCompound(struct page *page)
		{
		return 0;
		}

		static inline int PageTransTail(struct page *page)
		{
		return 0;
		}
		#endif

		#ifdef CONFIG_MMU

mm/memory-failure.c

+1 −1

Original line number	Diff line number	Diff line
		@@ -1063,7 +1063,7 @@ int __memory_failure(unsigned long pfn, int trapno, int flags)
		* The check (unnecessarily) ignores LRU pages being isolated and
		* walked by the page reclaim code, however that's not a big loss.
		*/
		if (!PageHuge(p) && !PageTransCompound(p)) {
		if (!PageHuge(p) && !PageTransTail(p)) {
		if (!PageLRU(p))
		shake_page(p, 0);
		if (!PageLRU(p)) {

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