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Commit 3c5c213e authored by Naoya Horiguchi's avatar Naoya Horiguchi Committed by Sasha Levin
Browse files

mm: hwpoison: change PageHWPoison behavior on hugetlb pages 

[ Upstream commit b37ff71cc626a0c1b5e098ff9a0b723815f6aaeb ]

We'd like to narrow down the error region in memory error on hugetlb
pages.  However, currently we set PageHWPoison flags on all subpages in
the error hugepage and add # of subpages to num_hwpoison_pages, which
doesn't fit our purpose.

So this patch changes the behavior and we only set PageHWPoison on the
head page then increase num_hwpoison_pages only by 1.  This is a
preparation for narrow-down part which comes in later patches.

Link: http://lkml.kernel.org/r/1496305019-5493-4-git-send-email-n-horiguchi@ah.jp.nec.com


Signed-off-by: default avatarNaoya Horiguchi <n-horiguchi@ah.jp.nec.com>
Cc: Michal Hocko <mhocko@kernel.org>
Cc: "Aneesh Kumar K.V" <aneesh.kumar@linux.vnet.ibm.com>
Cc: Anshuman Khandual <khandual@linux.vnet.ibm.com>
Signed-off-by: default avatarAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: default avatarLinus Torvalds <torvalds@linux-foundation.org>
Signed-off-by: default avatarSasha Levin <sashal@kernel.org>
parent ffcf4e92

include/linux/swapops.h

+0 −9
Original line number Diff line number Diff line
@@ -196,15 +196,6 @@ static inline void num_poisoned_pages_dec(void) 
	atomic_long_dec(&num_poisoned_pages);

}



static inline void num_poisoned_pages_add(long num)

{

	atomic_long_add(num, &num_poisoned_pages);

}



static inline void num_poisoned_pages_sub(long num)

{

	atomic_long_sub(num, &num_poisoned_pages);

}

#else



static inline swp_entry_t make_hwpoison_entry(struct page *page)

mm/memory-failure.c

+24 −63
Original line number Diff line number Diff line
@@ -1010,22 +1010,6 @@ 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);

}



/**

 * memory_failure - Handle memory failure of a page.

 * @pfn: Page Number of the corrupted page
@@ -1051,7 +1035,6 @@ int memory_failure(unsigned long pfn, int trapno, int flags) 
	struct page *hpage;

	struct page *orig_head;

	int res;

	unsigned int nr_pages;

	unsigned long page_flags;



	if (!sysctl_memory_failure_recovery)
@@ -1065,24 +1048,23 @@ int memory_failure(unsigned long pfn, int trapno, int flags) 


	p = pfn_to_page(pfn);

	orig_head = hpage = compound_head(p);



	/* tmporary check code, to be updated in later patches */

	if (PageHuge(p)) {

		if (TestSetPageHWPoison(hpage)) {

			pr_err("Memory failure: %#lx: already hardware poisoned\n", pfn);

			return 0;

		}

		goto tmp;

	}

	if (TestSetPageHWPoison(p)) {

		pr_err("Memory failure: %#lx: already hardware poisoned\n",

			pfn);

		return 0;

	}



	/*

	 * Currently errors on hugetlbfs pages are measured in hugepage units,

	 * so nr_pages should be 1 << compound_order.  OTOH when errors are on

	 * transparent hugepages, they are supposed to be split and error

	 * measurement is done in normal page units.  So nr_pages should be one

	 * in this case.

	 */

	if (PageHuge(p))

		nr_pages = 1 << compound_order(hpage);

	else /* normal page or thp */

		nr_pages = 1;

	num_poisoned_pages_add(nr_pages);

tmp:

	num_poisoned_pages_inc();



	/*

	 * We need/can do nothing about count=0 pages.
@@ -1110,12 +1092,11 @@ int memory_failure(unsigned long pfn, int trapno, int flags) 
			if (PageHWPoison(hpage)) {

				if ((hwpoison_filter(p) && TestClearPageHWPoison(p))

				    || (p != hpage && TestSetPageHWPoison(hpage))) {

					num_poisoned_pages_sub(nr_pages);

					num_poisoned_pages_dec();

					unlock_page(hpage);

					return 0;

				}

			}

			set_page_hwpoison_huge_page(hpage);

			res = dequeue_hwpoisoned_huge_page(hpage);

			action_result(pfn, MF_MSG_FREE_HUGE,

				      res ? MF_IGNORED : MF_DELAYED);
@@ -1138,7 +1119,7 @@ int memory_failure(unsigned long pfn, int trapno, int flags) 
				pr_err("Memory failure: %#lx: thp split failed\n",

					pfn);

			if (TestClearPageHWPoison(p))

				num_poisoned_pages_sub(nr_pages);

				num_poisoned_pages_dec();

			put_hwpoison_page(p);

			return -EBUSY;

		}
@@ -1202,14 +1183,14 @@ int memory_failure(unsigned long pfn, int trapno, int flags) 
	 */

	if (!PageHWPoison(p)) {

		pr_err("Memory failure: %#lx: just unpoisoned\n", pfn);

		num_poisoned_pages_sub(nr_pages);

		num_poisoned_pages_dec();

		unlock_page(hpage);

		put_hwpoison_page(hpage);

		return 0;

	}

	if (hwpoison_filter(p)) {

		if (TestClearPageHWPoison(p))

			num_poisoned_pages_sub(nr_pages);

			num_poisoned_pages_dec();

		unlock_page(hpage);

		put_hwpoison_page(hpage);

		return 0;
@@ -1228,14 +1209,6 @@ int memory_failure(unsigned long pfn, int trapno, int flags) 
		put_hwpoison_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);



	/*

	 * It's very difficult to mess with pages currently under IO
@@ -1407,7 +1380,6 @@ int unpoison_memory(unsigned long pfn) 
	struct page *page;

	struct page *p;

	int freeit = 0;

	unsigned int nr_pages;

	static DEFINE_RATELIMIT_STATE(unpoison_rs, DEFAULT_RATELIMIT_INTERVAL,

					DEFAULT_RATELIMIT_BURST);
@@ -1452,8 +1424,6 @@ int unpoison_memory(unsigned long pfn) 
		return 0;

	}



	nr_pages = 1 << compound_order(page);



	if (!get_hwpoison_page(p)) {

		/*

		 * Since HWPoisoned hugepage should have non-zero refcount,
@@ -1483,10 +1453,8 @@ int unpoison_memory(unsigned long pfn) 
	if (TestClearPageHWPoison(page)) {

		unpoison_pr_info("Unpoison: Software-unpoisoned page %#lx\n",

				 pfn, &unpoison_rs);

		num_poisoned_pages_sub(nr_pages);

		num_poisoned_pages_dec();

		freeit = 1;

		if (PageHuge(page))

			clear_page_hwpoison_huge_page(page);

	}

	unlock_page(page);
@@ -1612,15 +1580,11 @@ static int soft_offline_huge_page(struct page *page, int flags) 
			ret = -EIO;

	} else {

		/* overcommit hugetlb page will be freed to buddy */

		if (PageHuge(page)) {

			set_page_hwpoison_huge_page(hpage);

			dequeue_hwpoisoned_huge_page(hpage);

			num_poisoned_pages_add(1 << compound_order(hpage));

		} else {

		SetPageHWPoison(page);

		if (PageHuge(page))

			dequeue_hwpoisoned_huge_page(hpage);

		num_poisoned_pages_inc();

	}

	}

	return ret;

}
@@ -1728,15 +1692,12 @@ static int soft_offline_in_use_page(struct page *page, int flags) 


static void soft_offline_free_page(struct page *page)

{

	if (PageHuge(page)) {

		struct page *hpage = compound_head(page);

	struct page *head = compound_head(page);



		set_page_hwpoison_huge_page(hpage);

		if (!dequeue_hwpoisoned_huge_page(hpage))

			num_poisoned_pages_add(1 << compound_order(hpage));

	} else {

		if (!TestSetPageHWPoison(page))

	if (!TestSetPageHWPoison(head)) {

		num_poisoned_pages_inc();

		if (PageHuge(head))

			dequeue_hwpoisoned_huge_page(head);

	}

}