Commit bf6445bc authored by Miaohe Lin's avatar Miaohe Lin Committed by Linus Torvalds
Browse files

mm/memory-failure.c: make non-LRU movable pages unhandlable 

We can not really handle non-LRU movable pages in memory failure.
Typically they are balloon, zsmalloc, etc.

Assuming we run into a base (4K) non-LRU movable page, we could reach as
far as identify_page_state(), it should not fall into any category
except me_unknown.

For the non-LRU compound movable pages, they could be taken for
transhuge pages but it's unexpected to split non-LRU movable pages using
split_huge_page_to_list in memory_failure.  So we could just simply make
non-LRU movable pages unhandlable to avoid these possible nasty cases.

Link: https://lkml.kernel.org/r/20220312074613.4798-4-linmiaohe@huawei.com


Signed-off-by: default avatarMiaohe Lin <linmiaohe@huawei.com>
Suggested-by: default avatarYang Shi <shy828301@gmail.com>
Reviewed-by: default avatarYang Shi <shy828301@gmail.com>
Acked-by: default avatarNaoya Horiguchi <naoya.horiguchi@nec.com>
Cc: Borislav Petkov <bp@alien8.de>
Cc: Mike Kravetz <mike.kravetz@oracle.com>
Cc: Tony Luck <tony.luck@intel.com>
Signed-off-by: default avatarAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: default avatarLinus Torvalds <torvalds@linux-foundation.org>
parent 593396b8

mm/memory-failure.c

+13 −7
Original line number Diff line number Diff line
@@ -1176,12 +1176,18 @@ void ClearPageHWPoisonTakenOff(struct page *page) 
 * does not return true for hugetlb or device memory pages, so it's assumed

 * to be called only in the context where we never have such pages.

 */

static inline bool HWPoisonHandlable(struct page *page)

static inline bool HWPoisonHandlable(struct page *page, unsigned long flags)

{

	return PageLRU(page) || __PageMovable(page) || is_free_buddy_page(page);

	bool movable = false;



	/* Soft offline could mirgate non-LRU movable pages */

	if ((flags & MF_SOFT_OFFLINE) && __PageMovable(page))

		movable = true;



	return movable || PageLRU(page) || is_free_buddy_page(page);

}



static int __get_hwpoison_page(struct page *page)

static int __get_hwpoison_page(struct page *page, unsigned long flags)

{

	struct page *head = compound_head(page);

	int ret = 0;
@@ -1196,7 +1202,7 @@ static int __get_hwpoison_page(struct page *page) 
	 * for any unsupported type of page in order to reduce the risk of

	 * unexpected races caused by taking a page refcount.

	 */

	if (!HWPoisonHandlable(head))

	if (!HWPoisonHandlable(head, flags))

		return -EBUSY;



	if (get_page_unless_zero(head)) {
@@ -1221,7 +1227,7 @@ static int get_any_page(struct page *p, unsigned long flags) 


try_again:

	if (!count_increased) {

		ret = __get_hwpoison_page(p);

		ret = __get_hwpoison_page(p, flags);

		if (!ret) {

			if (page_count(p)) {

				/* We raced with an allocation, retry. */
@@ -1249,7 +1255,7 @@ static int get_any_page(struct page *p, unsigned long flags) 
		}

	}



	if (PageHuge(p) || HWPoisonHandlable(p)) {

	if (PageHuge(p) || HWPoisonHandlable(p, flags)) {

		ret = 1;

	} else {

		/*
@@ -2302,7 +2308,7 @@ int soft_offline_page(unsigned long pfn, int flags) 


retry:

	get_online_mems();

	ret = get_hwpoison_page(page, flags);

	ret = get_hwpoison_page(page, flags | MF_SOFT_OFFLINE);

	put_online_mems();



	if (ret > 0) {