[PATCH 8/9] mm: swap: factor out helper to drop cache of entries within a single cluster

From: Kemeng Shi
Date: Thu Mar 13 2025 - 08:10:39 EST


Factor out helper swap_entries_put_cache() from put_swap_folio() to server
as a general-purpose routine for dropping cache flag of entries within a
single cluster.

Signed-off-by: Kemeng Shi <shikemeng@xxxxxxxxxxxxxxx>
---
mm/swapfile.c | 25 ++++++++++++++++---------
1 file changed, 16 insertions(+), 9 deletions(-)

diff --git a/mm/swapfile.c b/mm/swapfile.c
index ebac9ff74ba7..343b34eb2a81 100644
--- a/mm/swapfile.c
+++ b/mm/swapfile.c
@@ -1473,6 +1473,21 @@ struct swap_info_struct *get_swap_device(swp_entry_t entry)
return NULL;
}

+static void swap_entries_put_cache(struct swap_info_struct *si,
+ swp_entry_t entry, int nr)
+{
+ unsigned long offset = swp_offset(entry);
+ struct swap_cluster_info *ci;
+
+ ci = lock_cluster(si, offset);
+ if (swap_only_has_cache(si, offset, nr))
+ swap_entries_free(si, ci, entry, nr);
+ else
+ for (int i = 0; i < nr; i++, entry.val++)
+ swap_entry_put_locked(si, ci, entry, SWAP_HAS_CACHE);
+ unlock_cluster(ci);
+}
+
static bool swap_entries_put_map(struct swap_info_struct *si,
swp_entry_t entry, int nr)
{
@@ -1597,8 +1612,6 @@ void swap_free_nr(swp_entry_t entry, int nr_pages)
*/
void put_swap_folio(struct folio *folio, swp_entry_t entry)
{
- unsigned long offset = swp_offset(entry);
- struct swap_cluster_info *ci;
struct swap_info_struct *si;
int size = 1 << swap_entry_order(folio_order(folio));

@@ -1606,13 +1619,7 @@ void put_swap_folio(struct folio *folio, swp_entry_t entry)
if (!si)
return;

- ci = lock_cluster(si, offset);
- if (swap_only_has_cache(si, offset, size))
- swap_entries_free(si, ci, entry, size);
- else
- for (int i = 0; i < size; i++, entry.val++)
- swap_entry_put_locked(si, ci, entry, SWAP_HAS_CACHE);
- unlock_cluster(ci);
+ swap_entries_put_cache(si, entry, size);
}

int __swap_count(swp_entry_t entry)
--
2.30.0