linux-kernel - [PATCH 6/7] mm: Remove use of folio list from folios

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Date:   Mon, 21 Aug 2023 21:44:24 +0100
From:   "Matthew Wilcox (Oracle)" <willy@...radead.org>
To:     Mateusz Guzik <mjguzik@...il.com>, linux-kernel@...r.kernel.org,
        dennis@...nel.org, tj@...nel.org, cl@...ux.com,
        akpm@...ux-foundation.org, shakeelb@...gle.com, linux-mm@...ck.org
Cc:     "Matthew Wilcox (Oracle)" <willy@...radead.org>
Subject: [PATCH 6/7] mm: Remove use of folio list from folios_put()

Instead of putting the interesting folios on a list, delete the
uninteresting one from the folio_batch.

Signed-off-by: Matthew Wilcox (Oracle) <willy@...radead.org>
---
 mm/swap.c | 16 ++++++++++------
 1 file changed, 10 insertions(+), 6 deletions(-)

diff --git a/mm/swap.c b/mm/swap.c
index 9d31185dc27b..8ebb10d44de7 100644
--- a/mm/swap.c
+++ b/mm/swap.c
@@ -958,12 +958,11 @@ void lru_cache_disable(void)
  */
 void folios_put(struct folio_batch *folios)
 {
-	int i;
-	LIST_HEAD(pages_to_free);
+	int i, j;
 	struct lruvec *lruvec = NULL;
 	unsigned long flags = 0;
 
-	for (i = 0; i < folios->nr; i++) {
+	for (i = 0, j = 0; i < folios->nr; i++) {
 		struct folio *folio = folios->folios[i];
 
 		if (is_huge_zero_page(&folio->page))
@@ -1012,13 +1011,18 @@ void folios_put(struct folio_batch *folios)
 			count_vm_event(UNEVICTABLE_PGCLEARED);
 		}
 
-		list_add(&folio->lru, &pages_to_free);
+		if (j != i)
+			folios->folios[j] = folio;
+		j++;
 	}
 	if (lruvec)
 		unlock_page_lruvec_irqrestore(lruvec, flags);
+	folios->nr = j;
+	if (!j)
+		return;
 
-	mem_cgroup_uncharge_list(&pages_to_free);
-	free_unref_page_list(&pages_to_free);
+	mem_cgroup_uncharge_batch(folios);
+	free_unref_folios(folios);
 }
 EXPORT_SYMBOL(folios_put);
 
-- 
2.40.1