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Commit 7013febc authored by Naoya Horiguchi's avatar Naoya Horiguchi Committed by Andi Kleen
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HWPOISON, hugetlb: set/clear PG_hwpoison bits on hugepage 



To avoid race condition between concurrent memory errors on identified
hugepage, we atomically test and set PG_hwpoison bit on the head page.
All pages in the error hugepage are considered as hwpoisoned
for now, so set and clear all PG_hwpoison bits in the hugepage
with page lock of the head page held.

Dependency:
  "HWPOISON, hugetlb: enable error handling path for hugepage"

Signed-off-by: default avatarNaoya Horiguchi <n-horiguchi@ah.jp.nec.com>
Cc: Andrew Morton <akpm@linux-foundation.org>
Acked-by: default avatarFengguang Wu <fengguang.wu@intel.com>
Signed-off-by: default avatarAndi Kleen <ak@linux.intel.com>
parent 7af446a8

mm/memory-failure.c

+38 −0
Original line number Diff line number Diff line
@@ -920,6 +920,22 @@ static int hwpoison_user_mappings(struct page *p, unsigned long pfn, 
	return ret;

}



static void set_page_hwpoison_huge_page(struct page *hpage)

{

	int i;

	int nr_pages = 1 << compound_order(hpage);

	for (i = 0; i < nr_pages; i++)

		SetPageHWPoison(hpage + i);

}



static void clear_page_hwpoison_huge_page(struct page *hpage)

{

	int i;

	int nr_pages = 1 << compound_order(hpage);

	for (i = 0; i < nr_pages; i++)

		ClearPageHWPoison(hpage + i);

}



int __memory_failure(unsigned long pfn, int trapno, int flags)

{

	struct page_state *ps;
@@ -1014,6 +1030,26 @@ int __memory_failure(unsigned long pfn, int trapno, int flags) 
		return 0;

	}



	/*

	 * For error on the tail page, we should set PG_hwpoison

	 * on the head page to show that the hugepage is hwpoisoned

	 */

	if (PageTail(p) && TestSetPageHWPoison(hpage)) {

		action_result(pfn, "hugepage already hardware poisoned",

				IGNORED);

		unlock_page(hpage);

		put_page(hpage);

		return 0;

	}

	/*

	 * Set PG_hwpoison on all pages in an error hugepage,

	 * because containment is done in hugepage unit for now.

	 * Since we have done TestSetPageHWPoison() for the head page with

	 * page lock held, we can safely set PG_hwpoison bits on tail pages.

	 */

	if (PageHuge(p))

		set_page_hwpoison_huge_page(hpage);



	wait_on_page_writeback(p);



	/*
@@ -1118,6 +1154,8 @@ int unpoison_memory(unsigned long pfn) 
		atomic_long_dec(&mce_bad_pages);

		freeit = 1;

	}

	if (PageHuge(p))

		clear_page_hwpoison_huge_page(page);

	unlock_page(page);



	put_page(page);