Commit 07f67a8d authored by Matthew Wilcox (Oracle)'s avatar Matthew Wilcox (Oracle) Committed by Andrew Morton
Browse files

mm/vmscan: convert shrink_active_list() to use a folio 

Remove a few hidden calls to compound_head, saving 411 bytes of text.

Link: https://lkml.kernel.org/r/20220617154248.700416-5-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 ff00a170

mm/vmscan.c

+29 −32
Original line number Diff line number Diff line
@@ -26,8 +26,7 @@ 
#include <linux/file.h>

#include <linux/writeback.h>

#include <linux/blkdev.h>

#include <linux/buffer_head.h>	/* for try_to_release_page(),

					buffer_heads_over_limit */

#include <linux/buffer_head.h>	/* for buffer_heads_over_limit */

#include <linux/mm_inline.h>

#include <linux/backing-dev.h>

#include <linux/rmap.h>
@@ -2483,21 +2482,21 @@ shrink_inactive_list(unsigned long nr_to_scan, struct lruvec *lruvec, 
}



/*

 * shrink_active_list() moves pages from the active LRU to the inactive LRU.

 * shrink_active_list() moves folios from the active LRU to the inactive LRU.

 *

 * We move them the other way if the page is referenced by one or more

 * We move them the other way if the folio is referenced by one or more

 * processes.

 *

 * If the pages are mostly unmapped, the processing is fast and it is

 * If the folios are mostly unmapped, the processing is fast and it is

 * appropriate to hold lru_lock across the whole operation.  But if

 * the pages are mapped, the processing is slow (folio_referenced()), so

 * we should drop lru_lock around each page.  It's impossible to balance

 * this, so instead we remove the pages from the LRU while processing them.

 * It is safe to rely on PG_active against the non-LRU pages in here because

 * nobody will play with that bit on a non-LRU page.

 * the folios are mapped, the processing is slow (folio_referenced()), so

 * we should drop lru_lock around each folio.  It's impossible to balance

 * this, so instead we remove the folios from the LRU while processing them.

 * It is safe to rely on the active flag against the non-LRU folios in here

 * because nobody will play with that bit on a non-LRU folio.

 *

 * The downside is that we have to touch page->_refcount against each page.

 * But we had to alter page->flags anyway.

 * The downside is that we have to touch folio->_refcount against each folio.

 * But we had to alter folio->flags anyway.

 */

static void shrink_active_list(unsigned long nr_to_scan,

			       struct lruvec *lruvec,
@@ -2507,7 +2506,7 @@ static void shrink_active_list(unsigned long nr_to_scan, 
	unsigned long nr_taken;

	unsigned long nr_scanned;

	unsigned long vm_flags;

	LIST_HEAD(l_hold);	/* The pages which were snipped off */

	LIST_HEAD(l_hold);	/* The folios which were snipped off */

	LIST_HEAD(l_active);

	LIST_HEAD(l_inactive);

	unsigned nr_deactivate, nr_activate;
@@ -2532,23 +2531,21 @@ static void shrink_active_list(unsigned long nr_to_scan, 


	while (!list_empty(&l_hold)) {

		struct folio *folio;

		struct page *page;



		cond_resched();

		folio = lru_to_folio(&l_hold);

		list_del(&folio->lru);

		page = &folio->page;



		if (unlikely(!page_evictable(page))) {

			putback_lru_page(page);

		if (unlikely(!folio_evictable(folio))) {

			folio_putback_lru(folio);

			continue;

		}



		if (unlikely(buffer_heads_over_limit)) {

			if (page_has_private(page) && trylock_page(page)) {

				if (page_has_private(page))

					try_to_release_page(page, 0);

				unlock_page(page);

			if (folio_get_private(folio) && folio_trylock(folio)) {

				if (folio_get_private(folio))

					filemap_release_folio(folio, 0);

				folio_unlock(folio);

			}

		}
@@ -2556,34 +2553,34 @@ static void shrink_active_list(unsigned long nr_to_scan, 
		if (folio_referenced(folio, 0, sc->target_mem_cgroup,

				     &vm_flags) != 0) {

			/*

			 * Identify referenced, file-backed active pages and

			 * Identify referenced, file-backed active folios and

			 * give them one more trip around the active list. So

			 * that executable code get better chances to stay in

			 * memory under moderate memory pressure.  Anon pages

			 * memory under moderate memory pressure.  Anon folios

			 * are not likely to be evicted by use-once streaming

			 * IO, plus JVM can create lots of anon VM_EXEC pages,

			 * IO, plus JVM can create lots of anon VM_EXEC folios,

			 * so we ignore them here.

			 */

			if ((vm_flags & VM_EXEC) && page_is_file_lru(page)) {

				nr_rotated += thp_nr_pages(page);

				list_add(&page->lru, &l_active);

			if ((vm_flags & VM_EXEC) && folio_is_file_lru(folio)) {

				nr_rotated += folio_nr_pages(folio);

				list_add(&folio->lru, &l_active);

				continue;

			}

		}



		ClearPageActive(page);	/* we are de-activating */

		SetPageWorkingset(page);

		list_add(&page->lru, &l_inactive);

		folio_clear_active(folio);	/* we are de-activating */

		folio_set_workingset(folio);

		list_add(&folio->lru, &l_inactive);

	}



	/*

	 * Move pages back to the lru list.

	 * Move folios back to the lru list.

	 */

	spin_lock_irq(&lruvec->lru_lock);



	nr_activate = move_pages_to_lru(lruvec, &l_active);

	nr_deactivate = move_pages_to_lru(lruvec, &l_inactive);

	/* Keep all free pages in l_active list */

	/* Keep all free folios in l_active list */

	list_splice(&l_inactive, &l_active);



	__count_vm_events(PGDEACTIVATE, nr_deactivate);