+ mm-zswap-remove-unnecessary-dlen-writes-for-incompressible-pages.patch added to mm-new branch

[Andrew Morton <akpm@linux-foundation.org>]

The patch titled
     Subject: mm/zswap: remove unnecessary dlen writes for incompressible pages
has been added to the -mm mm-new branch.  Its filename is
     mm-zswap-remove-unnecessary-dlen-writes-for-incompressible-pages.patch

This patch will shortly appear at
     https://git.kernel.org/pub/scm/linux/kernel/git/akpm/25-new.git/tree/patches/mm-zswap-remove-unnecessary-dlen-writes-for-incompressible-pages.patch

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

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patches, and acceptance into mm-new is a notification for others take
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------------------------------------------------------
From: SeongJae Park <sj@kernel.org>
Subject: mm/zswap: remove unnecessary dlen writes for incompressible pages
Date: Fri, 3 Oct 2025 13:38:48 -0700

Patch series "mm/zswap: misc cleanup of code and documentations".

Clean up an unnecessary local variable write in incompressible pages
handling, typos (s/zwap/zswap/) and outdated comments/documentations about
the zswap's red-black tree, which is replaced by xarray.


This patch (of 4):

Incompressible pages handling logic in zswap_compress() is setting 'dlen'
as PAGE_SIZE twice.  Once before deciding whether to save the content as
is, and once again after it is decided to save it as is.  But the value of
'dlen' is used only if it is decided to save the content as is, so the
first write is unnecessary.  It is not causing real user issues, but
making code confusing to read.  Remove the unnecessary write operation.

Link: https://lkml.kernel.org/r/20251003203851.43128-1-sj@kernel.org
Link: https://lkml.kernel.org/r/20251003203851.43128-2-sj@kernel.org
Signed-off-by: SeongJae Park <sj@kernel.org>
Cc: Chengming Zhou <chengming.zhou@linux.dev>
Cc: David Hildenbrand <david@redhat.com>
Cc: Johannes Weiner <hannes@cmpxchg.org>
Cc: Jonathan Corbet <corbet@lwn.net>
Cc: Liam Howlett <liam.howlett@oracle.com>
Cc: Lorenzo Stoakes <lorenzo.stoakes@oracle.com>
Cc: Michal Hocko <mhocko@kernel.org>
Cc: Mike Rapoport <rppt@kernel.org>
Cc: Muchun Song <muchun.song@linux.dev>
Cc: Nhat Pham <nphamcs@gmail.com>
Cc: Roman Gushchin <roman.gushchin@linux.dev>
Cc: Shakeel Butt <shakeel.butt@linux.dev>
Cc: Suren Baghdasaryan <surenb@google.com>
Cc: Vlastimil Babka <vbabka@suse.cz>
Cc: Chris Li <chrisl@kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
---

 mm/zswap.c |    1 -
 1 file changed, 1 deletion(-)

--- a/mm/zswap.c~mm-zswap-remove-unnecessary-dlen-writes-for-incompressible-pages
+++ a/mm/zswap.c
@@ -894,7 +894,6 @@ static bool zswap_compress(struct page *
 	 * to the active LRU list in the case.
 	 */
 	if (comp_ret || !dlen || dlen >= PAGE_SIZE) {
-		dlen = PAGE_SIZE;
 		if (!mem_cgroup_zswap_writeback_enabled(
 					folio_memcg(page_folio(page)))) {
 			comp_ret = comp_ret ? comp_ret : -EINVAL;
_

Patches currently in -mm which might be from sj@kernel.org are

mm-zswap-remove-unnecessary-dlen-writes-for-incompressible-pages.patch
mm-zswap-fix-typos-s-zwap-zswap.patch
mm-zswap-s-red-black-tree-xarray.patch
docs-admin-guide-mm-zswap-s-red-black-tree-xarray.patch