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Commit 761ad8d7 authored by Naoya Horiguchi's avatar Naoya Horiguchi Committed by Linus Torvalds
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mm: hwpoison: introduce memory_failure_hugetlb() 

memory_failure() is a big function and hard to maintain.  Handling
hugetlb- and non-hugetlb- case in a single function is not good, so this
patch separates PageHuge() branch into a new function, which saves many
PageHuge() check.

Link: http://lkml.kernel.org/r/1496305019-5493-7-git-send-email-n-horiguchi@ah.jp.nec.com


Signed-off-by: default avatarNaoya Horiguchi <n-horiguchi@ah.jp.nec.com>
Signed-off-by: default avatarAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: default avatarLinus Torvalds <torvalds@linux-foundation.org>
parent d4a3a60b

mm/memory-failure.c

+82 −52
Original line number Diff line number Diff line
@@ -1009,6 +1009,76 @@ static bool hwpoison_user_mappings(struct page *p, unsigned long pfn, 
	return unmap_success;

}



static int memory_failure_hugetlb(unsigned long pfn, int trapno, int flags)

{

	struct page_state *ps;

	struct page *p = pfn_to_page(pfn);

	struct page *head = compound_head(p);

	int res;

	unsigned long page_flags;



	if (TestSetPageHWPoison(head)) {

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

		       pfn);

		return 0;

	}



	num_poisoned_pages_inc();



	if (!(flags & MF_COUNT_INCREASED) && !get_hwpoison_page(p)) {

		/*

		 * Check "filter hit" and "race with other subpage."

		 */

		lock_page(head);

		if (PageHWPoison(head)) {

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

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

				num_poisoned_pages_dec();

				unlock_page(head);

				return 0;

			}

		}

		unlock_page(head);

		dissolve_free_huge_page(p);

		action_result(pfn, MF_MSG_FREE_HUGE, MF_DELAYED);

		return 0;

	}



	lock_page(head);

	page_flags = head->flags;



	if (!PageHWPoison(head)) {

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

		num_poisoned_pages_dec();

		unlock_page(head);

		put_hwpoison_page(head);

		return 0;

	}



	if (!hwpoison_user_mappings(p, pfn, trapno, flags, &head)) {

		action_result(pfn, MF_MSG_UNMAP_FAILED, MF_IGNORED);

		res = -EBUSY;

		goto out;

	}



	res = -EBUSY;



	for (ps = error_states;; ps++)

		if ((p->flags & ps->mask) == ps->res)

			break;



	page_flags |= (p->flags & (1UL << PG_dirty));



	if (!ps->mask)

		for (ps = error_states;; ps++)

			if ((page_flags & ps->mask) == ps->res)

				break;

	res = page_action(ps, p, pfn);

out:

	unlock_page(head);

	return res;

}



/**

 * memory_failure - Handle memory failure of a page.

 * @pfn: Page Number of the corrupted page
@@ -1046,33 +1116,22 @@ 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 (PageHuge(p))

		return memory_failure_hugetlb(pfn, trapno, flags);

	if (TestSetPageHWPoison(p)) {

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

			pfn);

		return 0;

	}



tmp:

	orig_head = hpage = compound_head(p);

	num_poisoned_pages_inc();



	/*

	 * We need/can do nothing about count=0 pages.

	 * 1) it's a free page, and therefore in safe hand:

	 *    prep_new_page() will be the gate keeper.

	 * 2) it's a free hugepage, which is also safe:

	 *    an affected hugepage will be dequeued from hugepage freelist,

	 *    so there's no concern about reusing it ever after.

	 * 3) it's part of a non-compound high order page.

	 * 2) it's part of a non-compound high order page.

	 *    Implies some kernel user: cannot stop them from

	 *    R/W the page; let's pray that the page has been

	 *    used and will be freed some time later.
@@ -1083,31 +1142,13 @@ int memory_failure(unsigned long pfn, int trapno, int flags) 
		if (is_free_buddy_page(p)) {

			action_result(pfn, MF_MSG_BUDDY, MF_DELAYED);

			return 0;

		} else if (PageHuge(hpage)) {

			/*

			 * Check "filter hit" and "race with other subpage."

			 */

			lock_page(hpage);

			if (PageHWPoison(hpage)) {

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

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

					num_poisoned_pages_dec();

					unlock_page(hpage);

					return 0;

				}

			}

			res = dequeue_hwpoisoned_huge_page(hpage);

			action_result(pfn, MF_MSG_FREE_HUGE,

				      res ? MF_IGNORED : MF_DELAYED);

			unlock_page(hpage);

			return res;

		} else {

			action_result(pfn, MF_MSG_KERNEL_HIGH_ORDER, MF_IGNORED);

			return -EBUSY;

		}

	}



	if (!PageHuge(p) && PageTransHuge(hpage)) {

	if (PageTransHuge(hpage)) {

		lock_page(p);

		if (!PageAnon(p) || unlikely(split_huge_page(p))) {

			unlock_page(p);
@@ -1145,7 +1186,7 @@ int memory_failure(unsigned long pfn, int trapno, int flags) 
		return 0;

	}



	lock_page(hpage);

	lock_page(p);



	/*

	 * The page could have changed compound pages during the locking.
@@ -1175,32 +1216,21 @@ 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_dec();

		unlock_page(hpage);

		put_hwpoison_page(hpage);

		unlock_page(p);

		put_hwpoison_page(p);

		return 0;

	}

	if (hwpoison_filter(p)) {

		if (TestClearPageHWPoison(p))

			num_poisoned_pages_dec();

		unlock_page(hpage);

		put_hwpoison_page(hpage);

		unlock_page(p);

		put_hwpoison_page(p);

		return 0;

	}



	if (!PageHuge(p) && !PageTransTail(p) && !PageLRU(p))

	if (!PageTransTail(p) && !PageLRU(p))

		goto identify_page_state;



	/*

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

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

	 */

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

		action_result(pfn, MF_MSG_POISONED_HUGE, MF_IGNORED);

		unlock_page(hpage);

		put_hwpoison_page(hpage);

		return 0;

	}



	/*

	 * It's very difficult to mess with pages currently under IO

	 * and in many cases impossible, so we just avoid it here.
@@ -1248,7 +1278,7 @@ int memory_failure(unsigned long pfn, int trapno, int flags) 
				break;

	res = page_action(ps, p, pfn);

out:

	unlock_page(hpage);

	unlock_page(p);

	return res;

}

EXPORT_SYMBOL_GPL(memory_failure);