The patch titled
Subject: mm/swap: skip scanning cluster range if it's empty cluster
has been added to the -mm mm-unstable branch. Its filename is
mm-swap-skip-scanning-cluster-range-if-its-empty-cluster.patch
This patch will shortly appear at
https://git.kernel.org/pub/scm/linux/kernel/git/akpm/25-new.git/tree/patches/mm-swap-skip-scanning-cluster-range-if-its-empty-cluster.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@xxxxxxxxxx>
Subject: mm/swap: skip scanning cluster range if it's empty cluster
Date: Wed, 5 Feb 2025 17:27:13 +0800
Since ci->lock has been taken when isolating cluster from
si->free_clusters or taking si->percpu_cluster->next[order], it's
unnecessary to scan and check the cluster range availability if i'ts empty
cluster, and this can accelerate the huge page swapping.
Link: https://lkml.kernel.org/r/20250205092721.9395-5-bhe@xxxxxxxxxx
Signed-off-by: Baoquan He <bhe@xxxxxxxxxx>
Cc: Chis Li <chrisl@xxxxxxxxxx>
Cc: Kairui Song <ryncsn@xxxxxxxxx>
Signed-off-by: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx>
---
mm/swapfile.c | 3 +++
1 file changed, 3 insertions(+)
--- a/mm/swapfile.c~mm-swap-skip-scanning-cluster-range-if-its-empty-cluster
+++ a/mm/swapfile.c
@@ -729,6 +729,9 @@ static bool cluster_scan_range(struct sw
unsigned long offset, end = start + nr_pages;
unsigned char *map = si->swap_map;
+ if (cluster_is_empty(ci))
+ return true;
+
for (offset = start; offset < end; offset++) {
switch (READ_ONCE(map[offset])) {
case 0:
_
Patches currently in -mm which might be from bhe@xxxxxxxxxx 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
