Commit eb01a2ad authored by Matthew Wilcox (Oracle)'s avatar Matthew Wilcox (Oracle) Committed by Andrew Morton
Browse files

mm: convert page_add_file_rmap() to use a folio internally 

The API for page_add_file_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/20230111142915.1001531-8-willy@infradead.org


Signed-off-by: default avatarMatthew Wilcox (Oracle) <willy@infradead.org>
Signed-off-by: default avatarAndrew Morton <akpm@linux-foundation.org>
parent ee0800c2

mm/rmap.c

+10 −11
Original line number Diff line number Diff line
@@ -1309,10 +1309,11 @@ void page_add_new_anon_rmap(struct page *page, 
 *

 * The caller needs to hold the pte lock.

 */

void page_add_file_rmap(struct page *page,

	struct vm_area_struct *vma, bool compound)

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

		bool compound)

{

	atomic_t *mapped;

	struct folio *folio = page_folio(page);

	atomic_t *mapped = &folio->_nr_pages_mapped;

	int nr = 0, nr_pmdmapped = 0;

	bool first;
@@ -1322,20 +1323,18 @@ void page_add_file_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))
@@ -1348,10 +1347,10 @@ void page_add_file_rmap(struct page *page, 
	}



	if (nr_pmdmapped)

		__mod_lruvec_page_state(page, PageSwapBacked(page) ?

		__lruvec_stat_mod_folio(folio, folio_test_swapbacked(folio) ?

			NR_SHMEM_PMDMAPPED : NR_FILE_PMDMAPPED, nr_pmdmapped);

	if (nr)

		__mod_lruvec_page_state(page, NR_FILE_MAPPED, nr);

		__lruvec_stat_mod_folio(folio, NR_FILE_MAPPED, nr);



	mlock_vma_page(page, vma, compound);

}