Commit 435a7554 authored by Matthew Wilcox (Oracle)'s avatar Matthew Wilcox (Oracle) Committed by Andrew Morton
Browse files

mm: use folio more widely in __split_huge_page 

We already have a folio; use it instead of the head page where reasonable.
Saves a couple of calls to compound_head() and elimimnates a few
references to page->mapping.

Link: https://lkml.kernel.org/r/20240228164326.1355045-1-willy@infradead.org


Signed-off-by: default avatarMatthew Wilcox (Oracle) <willy@infradead.org>
Reviewed-by: default avatarSidhartha Kumar <sidhartha.kumar@oracle.com>
Signed-off-by: default avatarAndrew Morton <akpm@linux-foundation.org>
parent d3246b6e

mm/huge_memory.c

+11 −10
Original line number Diff line number Diff line
@@ -2919,7 +2919,7 @@ static void __split_huge_page(struct page *page, struct list_head *list, 
		if (head[i].index >= end) {

			struct folio *tail = page_folio(head + i);



			if (shmem_mapping(head->mapping))

			if (shmem_mapping(folio->mapping))

				nr_dropped++;

			else if (folio_test_clear_dirty(tail))

				folio_account_cleaned(tail,
@@ -2927,7 +2927,7 @@ static void __split_huge_page(struct page *page, struct list_head *list, 
			__filemap_remove_folio(tail, NULL);

			folio_put(tail);

		} else if (!PageAnon(page)) {

			__xa_store(&head->mapping->i_pages, head[i].index,

			__xa_store(&folio->mapping->i_pages, head[i].index,

					head + i, 0);

		} else if (swap_cache) {

			__xa_store(&swap_cache->i_pages, offset + i,
@@ -2948,23 +2948,23 @@ static void __split_huge_page(struct page *page, struct list_head *list, 
	split_page_owner(head, order, new_order);



	/* See comment in __split_huge_page_tail() */

	if (PageAnon(head)) {

	if (folio_test_anon(folio)) {

		/* Additional pin to swap cache */

		if (PageSwapCache(head)) {

			page_ref_add(head, 1 + new_nr);

		if (folio_test_swapcache(folio)) {

			folio_ref_add(folio, 1 + new_nr);

			xa_unlock(&swap_cache->i_pages);

		} else {

			page_ref_inc(head);

			folio_ref_inc(folio);

		}

	} else {

		/* Additional pin to page cache */

		page_ref_add(head, 1 + new_nr);

		xa_unlock(&head->mapping->i_pages);

		folio_ref_add(folio, 1 + new_nr);

		xa_unlock(&folio->mapping->i_pages);

	}

	local_irq_enable();



	if (nr_dropped)

		shmem_uncharge(head->mapping->host, nr_dropped);

		shmem_uncharge(folio->mapping->host, nr_dropped);

	remap_page(folio, nr);



	if (folio_test_swapcache(folio))
@@ -2980,9 +2980,10 @@ static void __split_huge_page(struct page *page, struct list_head *list, 


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

		struct page *subpage = head + i;

		struct folio *new_folio = page_folio(subpage);

		if (subpage == page)

			continue;

		unlock_page(subpage);

		folio_unlock(new_folio);



		/*

		 * Subpages may be freed if there wasn't any mapping