+ mm-swapfilec-optimize-code-in-setup_clusters.patch added to mm-unstable branch

+ mm-swapfilec-optimize-code-in-setup_clusters.patch added to mm-unstable branch

[Andrew Morton]

The patch titled
     Subject: mm/swapfile.c: optimize code in setup_clusters()
has been added to the -mm mm-unstable branch.  Its filename is
     mm-swapfilec-optimize-code-in-setup_clusters.patch

This patch will shortly appear at
     https://git.kernel.org/pub/scm/linux/kernel/git/akpm/25-new.git/tree/patches/mm-swapfilec-optimize-code-in-setup_clusters.patch

This patch will later appear in the mm-unstable branch at
    git://git.kernel.org/pub/scm/linux/kernel/git/akpm/mm

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------------------------------------------------------
From: Baoquan He <bhe@redhat.com>
Subject: mm/swapfile.c: optimize code in setup_clusters()
Date: Wed, 5 Feb 2025 17:27:16 +0800

In the last 'for' loop inside setup_clusters(), using two local variable
'k' and 'j' are obvisouly redundant.  Using 'j' is enough and simpler.

And also move macro SWAP_CLUSTER_COLS close to its only user
setup_clusters().

Link: https://lkml.kernel.org/r/20250205092721.9395-8-bhe@redhat.com
Signed-off-by: Baoquan He <bhe@redhat.com>
Cc: Chis Li <chrisl@kernel.org>
Cc: Kairui Song <ryncsn@gmail.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
---

 mm/swapfile.c |   19 +++++++++----------
 1 file changed, 9 insertions(+), 10 deletions(-)

--- a/mm/swapfile.c~mm-swapfilec-optimize-code-in-setup_clusters
+++ a/mm/swapfile.c
@@ -3123,13 +3123,6 @@ static unsigned long read_swap_header(st
 	return maxpages;
 }
 
-#define SWAP_CLUSTER_INFO_COLS						\
-	DIV_ROUND_UP(L1_CACHE_BYTES, sizeof(struct swap_cluster_info))
-#define SWAP_CLUSTER_SPACE_COLS						\
-	DIV_ROUND_UP(SWAP_ADDRESS_SPACE_PAGES, SWAPFILE_CLUSTER)
-#define SWAP_CLUSTER_COLS						\
-	max_t(unsigned int, SWAP_CLUSTER_INFO_COLS, SWAP_CLUSTER_SPACE_COLS)
-
 static int setup_swap_map_and_extents(struct swap_info_struct *si,
 					union swap_header *swap_header,
 					unsigned char *swap_map,
@@ -3169,13 +3162,20 @@ static int setup_swap_map_and_extents(st
 	return nr_extents;
 }
 
+#define SWAP_CLUSTER_INFO_COLS						\
+	DIV_ROUND_UP(L1_CACHE_BYTES, sizeof(struct swap_cluster_info))
+#define SWAP_CLUSTER_SPACE_COLS						\
+	DIV_ROUND_UP(SWAP_ADDRESS_SPACE_PAGES, SWAPFILE_CLUSTER)
+#define SWAP_CLUSTER_COLS						\
+	max_t(unsigned int, SWAP_CLUSTER_INFO_COLS, SWAP_CLUSTER_SPACE_COLS)
+
 static struct swap_cluster_info *setup_clusters(struct swap_info_struct *si,
 						union swap_header *swap_header,
 						unsigned long maxpages)
 {
 	unsigned long nr_clusters = DIV_ROUND_UP(maxpages, SWAPFILE_CLUSTER);
 	struct swap_cluster_info *cluster_info;
-	unsigned long i, j, k, idx;
+	unsigned long i, j, idx;
 	int cpu, err = -ENOMEM;
 
 	cluster_info = kvcalloc(nr_clusters, sizeof(*cluster_info), GFP_KERNEL);
@@ -3236,8 +3236,7 @@ static struct swap_cluster_info *setup_c
 	 * Reduce false cache line sharing between cluster_info and
 	 * sharing same address space.
 	 */
-	for (k = 0; k < SWAP_CLUSTER_COLS; k++) {
-		j = k % SWAP_CLUSTER_COLS;
+	for (j = 0; j < SWAP_CLUSTER_COLS; j++) {
 		for (i = 0; i < DIV_ROUND_UP(nr_clusters, SWAP_CLUSTER_COLS); i++) {
 			struct swap_cluster_info *ci;
 			idx = i * SWAP_CLUSTER_COLS + j;
_

Patches currently in -mm which might be from bhe@redhat.com are

mm-swap_statec-fix-the-obsolete-code-comment.patch
mm-swap_statec-optimize-the-code-in-clear_shadow_from_swap_cache.patch
mm-swap-remove-swap_flag_prio_shift.patch
mm-swap-skip-scanning-cluster-range-if-its-empty-cluster.patch
mm-swap-rename-swap_is_has_cache-to-swap_only_has_cache.patch
mm-swapfilec-update-the-code-comment-above-swap_count_continued.patch
mm-swapfilec-optimize-code-in-setup_clusters.patch
mm-swap_statec-remove-the-meaningless-code-comment.patch
mm-swapfilec-remove-the-unneeded-checking.patch
mm-swap-rename-swap_swapcount-to-swap_entry_swapped.patch
mm-swapfilec-remove-the-incorrect-code-comment.patch
mm-swapfilec-open-code-cluster_alloc_swap.patch