Commit 07e09c48 authored by David Hildenbrand's avatar David Hildenbrand Committed by Andrew Morton
Browse files

mm/huge_memory: work on folio->swap instead of page->private when splitting folio 

Let's work on folio->swap instead.  While at it, use folio_test_anon() and
folio_test_swapcache() -- the original folio remains valid even after
splitting (but is then an order-0 folio).

We can probably convert a lot more to folios in that code, let's focus on
folio->swap handling only for now.

Link: https://lkml.kernel.org/r/20230821160849.531668-5-david@redhat.com


Signed-off-by: default avatarDavid Hildenbrand <david@redhat.com>
Reviewed-by: default avatarChris Li <chrisl@kernel.org>
Cc: Catalin Marinas <catalin.marinas@arm.com>
Cc: Dan Streetman <ddstreet@ieee.org>
Cc: Hugh Dickins <hughd@google.com>
Cc: Matthew Wilcox (Oracle) <willy@infradead.org>
Cc: Peter Xu <peterx@redhat.com>
Cc: Seth Jennings <sjenning@redhat.com>
Cc: Vitaly Wool <vitaly.wool@konsulko.com>
Cc: Will Deacon <will@kernel.org>
Signed-off-by: default avatarAndrew Morton <akpm@linux-foundation.org>
parent 3d2c9087

mm/huge_memory.c

+15 −14
Original line number Diff line number Diff line
@@ -2401,10 +2401,16 @@ static void lru_add_page_tail(struct page *head, struct page *tail, 
	}

}



static void __split_huge_page_tail(struct page *head, int tail,

static void __split_huge_page_tail(struct folio *folio, int tail,

		struct lruvec *lruvec, struct list_head *list)

{

	struct page *head = &folio->page;

	struct page *page_tail = head + tail;

	/*

	 * Careful: new_folio is not a "real" folio before we cleared PageTail.

	 * Don't pass it around before clear_compound_head().

	 */

	struct folio *new_folio = (struct folio *)page_tail;



	VM_BUG_ON_PAGE(atomic_read(&page_tail->_mapcount) != -1, page_tail);
@@ -2453,8 +2459,8 @@ static void __split_huge_page_tail(struct page *head, int tail, 
		VM_WARN_ON_ONCE_PAGE(true, page_tail);

		page_tail->private = 0;

	}

	if (PageSwapCache(head))

		set_page_private(page_tail, (unsigned long)head->private + tail);

	if (folio_test_swapcache(folio))

		new_folio->swap.val = folio->swap.val + tail;



	/* Page flags must be visible before we make the page non-compound. */

	smp_wmb();
@@ -2500,11 +2506,9 @@ static void __split_huge_page(struct page *page, struct list_head *list, 
	/* complete memcg works before add pages to LRU */

	split_page_memcg(head, nr);



	if (PageAnon(head) && PageSwapCache(head)) {

		swp_entry_t entry = { .val = page_private(head) };



		offset = swp_offset(entry);

		swap_cache = swap_address_space(entry);

	if (folio_test_anon(folio) && folio_test_swapcache(folio)) {

		offset = swp_offset(folio->swap);

		swap_cache = swap_address_space(folio->swap);

		xa_lock(&swap_cache->i_pages);

	}
@@ -2514,7 +2518,7 @@ static void __split_huge_page(struct page *page, struct list_head *list, 
	ClearPageHasHWPoisoned(head);



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

		__split_huge_page_tail(head, i, lruvec, list);

		__split_huge_page_tail(folio, i, lruvec, list);

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

		if (head[i].index >= end) {

			struct folio *tail = page_folio(head + i);
@@ -2559,11 +2563,8 @@ static void __split_huge_page(struct page *page, struct list_head *list, 


	remap_page(folio, nr);



	if (PageSwapCache(head)) {

		swp_entry_t entry = { .val = page_private(head) };



		split_swap_cluster(entry);

	}

	if (folio_test_swapcache(folio))

		split_swap_cluster(folio->swap);



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

		struct page *subpage = head + i;