diff mbox series

[03/11] mm/ksm: use a folio in remove_stable_node

Message ID 20240320074049.4130552-4-alexs@kernel.org (mailing list archive)
State New
Headers show
Series [01/11] mm/ksm: Convert get_ksm_page to return a folio | expand

Commit Message

alexs@kernel.org March 20, 2024, 7:40 a.m. UTC 
From: "Alex Shi (tencent)" <alexs@kernel.org>

pages in stable tree are all single normal page, use folios could save
3 calls to compound_head().

Signed-off-by: Alex Shi (tencent) <alexs@kernel.org>
Cc: Izik Eidus <izik.eidus@ravellosystems.com>
Cc: Matthew Wilcox <willy@infradead.org>
Cc: Andrea Arcangeli <aarcange@redhat.com>
Cc: Hugh Dickins <hughd@google.com>
Cc: Chris Wright <chrisw@sous-sol.org>
---
 mm/ksm.c | 18 +++++++++---------
 1 file changed, 9 insertions(+), 9 deletions(-)

Comments

Matthew Wilcox March 20, 2024, 1 p.m. UTC | #1 
On Wed, Mar 20, 2024 at 03:40:39PM +0800, alexs@kernel.org wrote:
> @@ -1124,22 +1124,22 @@ static int remove_stable_node(struct ksm_stable_node *stable_node)
>  	 * merge_across_nodes/max_page_sharing be switched.
>  	 */
>  	err = -EBUSY;
> -	if (!page_mapped(page)) {
> +	if (!folio_mapped(folio)) {
>  		/*
>  		 * The stable node did not yet appear stale to get_ksm_page(),
> -		 * since that allows for an unmapped ksm page to be recognized
> +		 * since that allows for an unmapped ksm folio to be recognized
>  		 * right up until it is freed; but the node is safe to remove.
> -		 * This page might be in an LRU cache waiting to be freed,
> +		 * This folio might be in an LRU cache waiting to be freed,
>  		 * or it might be PageSwapCache (perhaps under writeback),

s/PageSwapCache/in the swapcache/

>  		 * or it might have been removed from swapcache a moment ago.
>  		 */
> -		set_page_stable_node(page, NULL);
> +		set_page_stable_node(&folio->page, NULL);

Before this patch, introduce a folio_set_stable_node() (and convert the
one caller which already has a folio).  I'd do it the other way around
from ksm_get_folio(); that is:

static inline void folio_set_stable_node(struct folio *folio,
		struct ksm_stable_node *stable_node)
{
	set_page_stable_node(&folio->page, stable_node);
}

and then we can merge the two later when there are no more calls to
set_page_stable_node().
diff mbox series

Patch

diff --git a/mm/ksm.c b/mm/ksm.c
index 922e33500875..9ea9b5ac44b4 100644
--- a/mm/ksm.c
+++ b/mm/ksm.c
@@ -1107,11 +1107,11 @@  static inline void set_page_stable_node(struct page *page,
  */
 static int remove_stable_node(struct ksm_stable_node *stable_node)
 {
-	struct page *page;
+	struct folio *folio;
 	int err;
 
-	page = get_ksm_page(stable_node, GET_KSM_PAGE_LOCK);
-	if (!page) {
+	folio = get_ksm_page(stable_node, GET_KSM_PAGE_LOCK);
+	if (!folio) {
 		/*
 		 * get_ksm_page did remove_node_from_stable_tree itself.
 		 */
@@ -1124,22 +1124,22 @@  static int remove_stable_node(struct ksm_stable_node *stable_node)
 	 * merge_across_nodes/max_page_sharing be switched.
 	 */
 	err = -EBUSY;
-	if (!page_mapped(page)) {
+	if (!folio_mapped(folio)) {
 		/*
 		 * The stable node did not yet appear stale to get_ksm_page(),
-		 * since that allows for an unmapped ksm page to be recognized
+		 * since that allows for an unmapped ksm folio to be recognized
 		 * right up until it is freed; but the node is safe to remove.
-		 * This page might be in an LRU cache waiting to be freed,
+		 * This folio might be in an LRU cache waiting to be freed,
 		 * or it might be PageSwapCache (perhaps under writeback),
 		 * or it might have been removed from swapcache a moment ago.
 		 */
-		set_page_stable_node(page, NULL);
+		set_page_stable_node(&folio->page, NULL);
 		remove_node_from_stable_tree(stable_node);
 		err = 0;
 	}
 
-	unlock_page(page);
-	put_page(page);
+	folio_unlock(folio);
+	folio_put(folio);
 	return err;
 }