vmscan: convert lazy freeing to folios

Remove a hidden call to compound_head(), and account nr_pages instead of a
single page.  This matches the code in lru_lazyfree_fn() that accounts
nr_pages to PGLAZYFREE.

Link: https://lkml.kernel.org/r/20220504182857.4013401-12-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/include/linux/memcontrol.h b/include/linux/memcontrol.h
index fe580cb..8ea4b54 100644 (file)
--- a/include/linux/memcontrol.h
+++ b/include/linux/memcontrol.h
@@ -1057,6 +1057,15 @@ static inline void count_memcg_page_event(struct page *page,
                count_memcg_events(memcg, idx, 1);
 }
 
+static inline void count_memcg_folio_events(struct folio *folio,
+               enum vm_event_item idx, unsigned long nr)
+{
+       struct mem_cgroup *memcg = folio_memcg(folio);
+
+       if (memcg)
+               count_memcg_events(memcg, idx, nr);
+}
+
 static inline void count_memcg_event_mm(struct mm_struct *mm,
                                        enum vm_event_item idx)
 {
@@ -1494,6 +1503,11 @@ static inline void count_memcg_page_event(struct page *page,
 {
 }
 
+static inline void count_memcg_folio_events(struct folio *folio,
+               enum vm_event_item idx, unsigned long nr)
+{
+}
+
 static inline
 void count_memcg_event_mm(struct mm_struct *mm, enum vm_event_item idx)
 {

diff --git a/mm/vmscan.c b/mm/vmscan.c
index 00b985c..972557e 100644 (file)
--- a/mm/vmscan.c
+++ b/mm/vmscan.c
@@ -1902,20 +1902,20 @@ retry:
                        }
                }
 
-               if (PageAnon(page) && !PageSwapBacked(page)) {
+               if (folio_test_anon(folio) && !folio_test_swapbacked(folio)) {
                        /* follow __remove_mapping for reference */
-                       if (!page_ref_freeze(page, 1))
+                       if (!folio_ref_freeze(folio, 1))
                                goto keep_locked;
                        /*
-                        * The page has only one reference left, which is
+                        * The folio has only one reference left, which is
                         * from the isolation. After the caller puts the
-                        * page back on lru and drops the reference, the
-                        * page will be freed anyway. It doesn't matter
-                        * which lru it goes. So we don't bother checking
-                        * PageDirty here.
+                        * folio back on the lru and drops the reference, the
+                        * folio will be freed anyway. It doesn't matter
+                        * which lru it goes on. So we don't bother checking
+                        * the dirty flag here.
                         */
-                       count_vm_event(PGLAZYFREED);
-                       count_memcg_page_event(page, PGLAZYFREED);
+                       count_vm_events(PGLAZYFREED, nr_pages);
+                       count_memcg_folio_events(folio, PGLAZYFREED, nr_pages);
                } else if (!mapping || !__remove_mapping(mapping, folio, true,
                                                         sc->target_mem_cgroup))
                        goto keep_locked;