From: Zhang Peng <bruzzhang@tencent.com>

The activate_locked label in shrink_folio_list() handles swap cache
reclaim, marks the folio active, and updates activation statistics.
Extract this block into folio_active_bounce() to make shrink_folio_list()
easier to follow.

No functional change

Suggested-by: Kairui Song <kasong@tencent.com>
Signed-off-by: Zhang Peng <bruzzhang@tencent.com>
---
 mm/vmscan.c | 30 +++++++++++++++++++-----------
 1 file changed, 19 insertions(+), 11 deletions(-)

diff --git a/mm/vmscan.c b/mm/vmscan.c
index f3f03a44042e..0860a48d5bf3 100644
--- a/mm/vmscan.c
+++ b/mm/vmscan.c
@@ -1052,6 +1052,24 @@ static bool may_enter_fs(struct folio *folio, gfp_t gfp_mask)
 	return !data_race(folio_swap_flags(folio) & SWP_FS_OPS);
 }
 
+/* Mark folio as active and prepare to bounce back to head of LRU */
+static void folio_active_bounce(struct folio *folio, struct reclaim_stat *stat,
+		unsigned int nr_pages)
+{
+	/* Not a candidate for swapping, so reclaim swap space. */
+	if (folio_test_swapcache(folio) &&
+		(mem_cgroup_swap_full(folio) || folio_test_mlocked(folio)))
+		folio_free_swap(folio);
+	VM_BUG_ON_FOLIO(folio_test_active(folio), folio);
+	if (!folio_test_mlocked(folio)) {
+		int type = folio_is_file_lru(folio);
+
+		folio_set_active(folio);
+		stat->nr_activate[type] += nr_pages;
+		count_memcg_folio_events(folio, PGACTIVATE, nr_pages);
+	}
+}
+
 /*
  * Reclaimed folios are counted in stat->nr_reclaimed.
  */
@@ -1527,17 +1545,7 @@ static void shrink_folio_list(struct list_head *folio_list,
 			nr_pages = 1;
 		}
 activate_locked:
-		/* Not a candidate for swapping, so reclaim swap space. */
-		if (folio_test_swapcache(folio) &&
-		    (mem_cgroup_swap_full(folio) || folio_test_mlocked(folio)))
-			folio_free_swap(folio);
-		VM_BUG_ON_FOLIO(folio_test_active(folio), folio);
-		if (!folio_test_mlocked(folio)) {
-			int type = folio_is_file_lru(folio);
-			folio_set_active(folio);
-			stat->nr_activate[type] += nr_pages;
-			count_memcg_folio_events(folio, PGACTIVATE, nr_pages);
-		}
+		folio_active_bounce(folio, stat, nr_pages);
 keep_locked:
 		folio_unlock(folio);
 keep:

-- 
2.43.7

On Fri, Apr 10, 2026 at 8:47 PM Zhang Peng <zippermonkey@icloud.com> wrote:
>
> From: Zhang Peng <bruzzhang@tencent.com>
>
> The activate_locked label in shrink_folio_list() handles swap cache
> reclaim, marks the folio active, and updates activation statistics.
> Extract this block into folio_active_bounce() to make shrink_folio_list()
> easier to follow.
>
> No functional change
>
> Suggested-by: Kairui Song <kasong@tencent.com>
> Signed-off-by: Zhang Peng <bruzzhang@tencent.com>
> ---
>  mm/vmscan.c | 30 +++++++++++++++++++-----------
>  1 file changed, 19 insertions(+), 11 deletions(-)
>
> diff --git a/mm/vmscan.c b/mm/vmscan.c
> index f3f03a44042e..0860a48d5bf3 100644
> --- a/mm/vmscan.c
> +++ b/mm/vmscan.c
> @@ -1052,6 +1052,24 @@ static bool may_enter_fs(struct folio *folio, gfp_t gfp_mask)
>         return !data_race(folio_swap_flags(folio) & SWP_FS_OPS);
>  }
>
> +/* Mark folio as active and prepare to bounce back to head of LRU */
> +static void folio_active_bounce(struct folio *folio, struct reclaim_stat *stat,
> +               unsigned int nr_pages)

Not a native speaker, but “bounce” sounds quite odd to me.
Also, folio_free_swap() doesn’t seem closely related to
“active”. I don’t think this extraction improves the
readability of the code.

> +{
> +       /* Not a candidate for swapping, so reclaim swap space. */
> +       if (folio_test_swapcache(folio) &&
> +               (mem_cgroup_swap_full(folio) || folio_test_mlocked(folio)))
> +               folio_free_swap(folio);
> +       VM_BUG_ON_FOLIO(folio_test_active(folio), folio);
> +       if (!folio_test_mlocked(folio)) {
> +               int type = folio_is_file_lru(folio);
> +
> +               folio_set_active(folio);
> +               stat->nr_activate[type] += nr_pages;
> +               count_memcg_folio_events(folio, PGACTIVATE, nr_pages);
> +       }
> +}
> +
>  /*
>   * Reclaimed folios are counted in stat->nr_reclaimed.
>   */
> @@ -1527,17 +1545,7 @@ static void shrink_folio_list(struct list_head *folio_list,
>                         nr_pages = 1;
>                 }
>  activate_locked:
> -               /* Not a candidate for swapping, so reclaim swap space. */
> -               if (folio_test_swapcache(folio) &&
> -                   (mem_cgroup_swap_full(folio) || folio_test_mlocked(folio)))
> -                       folio_free_swap(folio);
> -               VM_BUG_ON_FOLIO(folio_test_active(folio), folio);
> -               if (!folio_test_mlocked(folio)) {
> -                       int type = folio_is_file_lru(folio);
> -                       folio_set_active(folio);
> -                       stat->nr_activate[type] += nr_pages;
> -                       count_memcg_folio_events(folio, PGACTIVATE, nr_pages);
> -               }
> +               folio_active_bounce(folio, stat, nr_pages);
>  keep_locked:
>                 folio_unlock(folio);
>  keep:
>

Thanks
Barry