Commit 49bd2bf9 authored by Matthew Wilcox (Oracle)'s avatar Matthew Wilcox (Oracle) Committed by Andrew Morton
Browse files

vmscan: convert dirty page handling to folios 

Mostly this just eliminates calls to compound_head(), but
NR_VMSCAN_IMMEDIATE was being incremented by 1 instead of by nr_pages.

Link: https://lkml.kernel.org/r/20220504182857.4013401-10-willy@infradead.org


Signed-off-by: default avatarMatthew Wilcox (Oracle) <willy@infradead.org>
Reviewed-by: default avatarChristoph Hellwig <hch@lst.de>
Signed-off-by: default avatarAndrew Morton <akpm@linux-foundation.org>
parent 09c02e56

mm/vmscan.c

+26 −22
Original line number Diff line number Diff line
@@ -1787,28 +1787,31 @@ static unsigned int shrink_page_list(struct list_head *page_list, 
			}

		}



		if (PageDirty(page)) {

		if (folio_test_dirty(folio)) {

			/*

			 * Only kswapd can writeback filesystem pages

			 * Only kswapd can writeback filesystem folios

			 * to avoid risk of stack overflow. But avoid

			 * injecting inefficient single-page IO into

			 * injecting inefficient single-folio I/O into

			 * flusher writeback as much as possible: only

			 * write pages when we've encountered many

			 * dirty pages, and when we've already scanned

			 * the rest of the LRU for clean pages and see

			 * the same dirty pages again (PageReclaim).

			 */

			if (page_is_file_lru(page) &&

			    (!current_is_kswapd() || !PageReclaim(page) ||

			 * write folios when we've encountered many

			 * dirty folios, and when we've already scanned

			 * the rest of the LRU for clean folios and see

			 * the same dirty folios again (with the reclaim

			 * flag set).

			 */

			if (folio_is_file_lru(folio) &&

			    (!current_is_kswapd() ||

			     !folio_test_reclaim(folio) ||

			     !test_bit(PGDAT_DIRTY, &pgdat->flags))) {

				/*

				 * Immediately reclaim when written back.

				 * Similar in principal to deactivate_page()

				 * except we already have the page isolated

				 * Similar in principle to deactivate_page()

				 * except we already have the folio isolated

				 * and know it's dirty

				 */

				inc_node_page_state(page, NR_VMSCAN_IMMEDIATE);

				SetPageReclaim(page);

				node_stat_mod_folio(folio, NR_VMSCAN_IMMEDIATE,

						nr_pages);

				folio_set_reclaim(folio);



				goto activate_locked;

			}
@@ -1821,8 +1824,8 @@ static unsigned int shrink_page_list(struct list_head *page_list, 
				goto keep_locked;



			/*

			 * Page is dirty. Flush the TLB if a writable entry

			 * potentially exists to avoid CPU writes after IO

			 * Folio is dirty. Flush the TLB if a writable entry

			 * potentially exists to avoid CPU writes after I/O

			 * starts and then write it out here.

			 */

			try_to_unmap_flush_dirty();
@@ -1834,23 +1837,24 @@ static unsigned int shrink_page_list(struct list_head *page_list, 
			case PAGE_SUCCESS:

				stat->nr_pageout += nr_pages;



				if (PageWriteback(page))

				if (folio_test_writeback(folio))

					goto keep;

				if (PageDirty(page))

				if (folio_test_dirty(folio))

					goto keep;



				/*

				 * A synchronous write - probably a ramdisk.  Go

				 * ahead and try to reclaim the page.

				 * ahead and try to reclaim the folio.

				 */

				if (!trylock_page(page))

				if (!folio_trylock(folio))

					goto keep;

				if (PageDirty(page) || PageWriteback(page))

				if (folio_test_dirty(folio) ||

				    folio_test_writeback(folio))

					goto keep_locked;

				mapping = page_mapping(page);

				mapping = folio_mapping(folio);

				fallthrough;

			case PAGE_CLEAN:

				; /* try to free the page below */

				; /* try to free the folio below */

			}

		}