Commit ee0800c2 authored by Matthew Wilcox (Oracle)'s avatar Matthew Wilcox (Oracle) Committed by Andrew Morton
Browse files

mm: convert page_add_anon_rmap() to use a folio internally 

The API for page_add_anon_rmap() needs to be page-based, because we can
add mappings of individual pages.  But inside the function, we want to
only call compound_head() once and then use the folio APIs instead of the
page APIs that each call compound_head().

Link: https://lkml.kernel.org/r/20230111142915.1001531-7-willy@infradead.org


Signed-off-by: default avatarMatthew Wilcox (Oracle) <willy@infradead.org>
Signed-off-by: default avatarAndrew Morton <akpm@linux-foundation.org>
parent 62beb906

mm/rmap.c

+11 −12
Original line number Diff line number Diff line
@@ -1207,10 +1207,11 @@ static void __page_check_anon_rmap(struct page *page, 
 * and to ensure that PageAnon is not being upgraded racily to PageKsm

 * (but PageKsm is never downgraded to PageAnon).

 */

void page_add_anon_rmap(struct page *page,

	struct vm_area_struct *vma, unsigned long address, rmap_t flags)

void page_add_anon_rmap(struct page *page, struct vm_area_struct *vma,

		unsigned long address, rmap_t flags)

{

	atomic_t *mapped;

	struct folio *folio = page_folio(page);

	atomic_t *mapped = &folio->_nr_pages_mapped;

	int nr = 0, nr_pmdmapped = 0;

	bool compound = flags & RMAP_COMPOUND;

	bool first = true;
@@ -1219,20 +1220,18 @@ void page_add_anon_rmap(struct page *page, 
	if (likely(!compound)) {

		first = atomic_inc_and_test(&page->_mapcount);

		nr = first;

		if (first && PageCompound(page)) {

			mapped = subpages_mapcount_ptr(compound_head(page));

		if (first && folio_test_large(folio)) {

			nr = atomic_inc_return_relaxed(mapped);

			nr = (nr < COMPOUND_MAPPED);

		}

	} else if (PageTransHuge(page)) {

	} else if (folio_test_pmd_mappable(folio)) {

		/* That test is redundant: it's for safety or to optimize out */



		first = atomic_inc_and_test(compound_mapcount_ptr(page));

		first = atomic_inc_and_test(&folio->_entire_mapcount);

		if (first) {

			mapped = subpages_mapcount_ptr(page);

			nr = atomic_add_return_relaxed(COMPOUND_MAPPED, mapped);

			if (likely(nr < COMPOUND_MAPPED + COMPOUND_MAPPED)) {

				nr_pmdmapped = thp_nr_pages(page);

				nr_pmdmapped = folio_nr_pages(folio);

				nr = nr_pmdmapped - (nr & FOLIO_PAGES_MAPPED);

				/* Raced ahead of a remove and another add? */

				if (unlikely(nr < 0))
@@ -1248,11 +1247,11 @@ void page_add_anon_rmap(struct page *page, 
	VM_BUG_ON_PAGE(!first && PageAnonExclusive(page), page);



	if (nr_pmdmapped)

		__mod_lruvec_page_state(page, NR_ANON_THPS, nr_pmdmapped);

		__lruvec_stat_mod_folio(folio, NR_ANON_THPS, nr_pmdmapped);

	if (nr)

		__mod_lruvec_page_state(page, NR_ANON_MAPPED, nr);

		__lruvec_stat_mod_folio(folio, NR_ANON_MAPPED, nr);



	if (likely(!PageKsm(page))) {

	if (likely(!folio_test_ksm(folio))) {

		/* address might be in next vma when migration races vma_adjust */

		if (first)

			__page_set_anon_rmap(page, vma, address,