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: Matthew Wilcox (Oracle) <willy@infradead.org>
Reviewed-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>

diff --git a/mm/vmscan.c b/mm/vmscan.c
index 2ec5bcb..8e22a11 100644 (file)
--- a/mm/vmscan.c
+++ b/mm/vmscan.c
@@ -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);