Commit 8cce5475 authored by Kirill A. Shutemov's avatar Kirill A. Shutemov Committed by Linus Torvalds
Browse files

mm/huge_memory: fix split assumption of page size 



File THPs may now be of arbitrary size, and we can't rely on that size
after doing the split so remember the number of pages before we start the
split.

Signed-off-by: default avatarKirill A. Shutemov <kirill@shutemov.name>
Signed-off-by: default avatarMatthew Wilcox (Oracle) <willy@infradead.org>
Signed-off-by: default avatarAndrew Morton <akpm@linux-foundation.org>
Reviewed-by: default avatarSeongJae Park <sjpark@amazon.de>
Cc: Huang Ying <ying.huang@intel.com>
Link: https://lkml.kernel.org/r/20200908195539.25896-6-willy@infradead.org


Signed-off-by: default avatarLinus Torvalds <torvalds@linux-foundation.org>
parent 86b562b6

mm/huge_memory.c

+8 −7
Original line number Diff line number Diff line
@@ -2335,13 +2335,13 @@ static void unmap_page(struct page *page) 
	VM_BUG_ON_PAGE(!unmap_success, page);

}



static void remap_page(struct page *page)

static void remap_page(struct page *page, unsigned int nr)

{

	int i;

	if (PageTransHuge(page)) {

		remove_migration_ptes(page, page, true);

	} else {

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

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

			remove_migration_ptes(page + i, page + i, true);

	}

}
@@ -2419,6 +2419,7 @@ static void __split_huge_page(struct page *page, struct list_head *list, 
	struct lruvec *lruvec;

	struct address_space *swap_cache = NULL;

	unsigned long offset = 0;

	unsigned int nr = thp_nr_pages(head);

	int i;



	lruvec = mem_cgroup_page_lruvec(head, pgdat);
@@ -2434,7 +2435,7 @@ static void __split_huge_page(struct page *page, struct list_head *list, 
		xa_lock(&swap_cache->i_pages);

	}



	for (i = HPAGE_PMD_NR - 1; i >= 1; i--) {

	for (i = nr - 1; i >= 1; i--) {

		__split_huge_page_tail(head, i, lruvec, list);

		/* Some pages can be beyond i_size: drop them from page cache */

		if (head[i].index >= end) {
@@ -2454,7 +2455,7 @@ static void __split_huge_page(struct page *page, struct list_head *list, 


	ClearPageCompound(head);



	split_page_owner(head, HPAGE_PMD_NR);

	split_page_owner(head, nr);



	/* See comment in __split_huge_page_tail() */

	if (PageAnon(head)) {
@@ -2473,9 +2474,9 @@ static void __split_huge_page(struct page *page, struct list_head *list, 


	spin_unlock_irqrestore(&pgdat->lru_lock, flags);



	remap_page(head);

	remap_page(head, nr);



	for (i = 0; i < HPAGE_PMD_NR; i++) {

	for (i = 0; i < nr; i++) {

		struct page *subpage = head + i;

		if (subpage == page)

			continue;
@@ -2729,7 +2730,7 @@ int split_huge_page_to_list(struct page *page, struct list_head *list) 
fail:		if (mapping)

			xa_unlock(&mapping->i_pages);

		spin_unlock_irqrestore(&pgdata->lru_lock, flags);

		remap_page(head);

		remap_page(head, thp_nr_pages(head));

		ret = -EBUSY;

	}