From: Kairui Song Since commit f1879e8a0c60 ("mm, swap: never bypass the swap cache even for SWP_SYNCHRONOUS_IO"), all swap-in operations go through the swap cache, including those from SWP_SYNCHRONOUS_IO devices like zram. Which means the workaround for swap cache bypassing introduced by commit 25cd241408a2 ("mm: zswap: fix data loss on SWP_SYNCHRONOUS_IO devices") is no longer needed. Remove it, but keep the comments that are still helpful. Suggested-by: Yosry Ahmed Signed-off-by: Kairui Song --- mm/zswap.c | 19 ++++++------------- 1 file changed, 6 insertions(+), 13 deletions(-) diff --git a/mm/zswap.c b/mm/zswap.c index 3d2d59ac3f9c..8cd61603ff79 100644 --- a/mm/zswap.c +++ b/mm/zswap.c @@ -1589,11 +1589,11 @@ int zswap_load(struct folio *folio) { swp_entry_t swp = folio->swap; pgoff_t offset = swp_offset(swp); - bool swapcache = folio_test_swapcache(folio); struct xarray *tree = swap_zswap_tree(swp); struct zswap_entry *entry; VM_WARN_ON_ONCE(!folio_test_locked(folio)); + VM_WARN_ON_ONCE(!folio_test_swapcache(folio)); if (zswap_never_enabled()) return -ENOENT; @@ -1624,22 +1624,15 @@ int zswap_load(struct folio *folio) count_objcg_events(entry->objcg, ZSWPIN, 1); /* - * When reading into the swapcache, invalidate our entry. The - * swapcache can be the authoritative owner of the page and + * We are reading into the swapcache, invalidate zswap entry. + * The swapcache is the authoritative owner of the page and * its mappings, and the pressure that results from having two * in-memory copies outweighs any benefits of caching the * compression work. - * - * (Most swapins go through the swapcache. The notable - * exception is the singleton fault on SWP_SYNCHRONOUS_IO - * files, which reads into a private page and may free it if - * the fault fails. We remain the primary owner of the entry.) */ - if (swapcache) { - folio_mark_dirty(folio); - xa_erase(tree, offset); - zswap_entry_free(entry); - } + folio_mark_dirty(folio); + xa_erase(tree, offset); + zswap_entry_free(entry); folio_unlock(folio); return 0; --- base-commit: 2c263046cbe6d9d5fce3dfeba063f199f7e6298f change-id: 20251226-zswap-syncio-cleanup-a05b7fc6180f Best regards, -- Kairui Song