+ tools-mm-page_owner_sort-fix-sort-option-being-silently-ignored.patch added to mm-new branch

+ tools-mm-page_owner_sort-fix-sort-option-being-silently-ignored.patch added to mm-new branch

[Andrew Morton]

The patch titled
     Subject: tools/mm/page_owner_sort: fix --sort option being silently ignored
has been added to the -mm mm-new branch.  Its filename is
     tools-mm-page_owner_sort-fix-sort-option-being-silently-ignored.patch

This patch will shortly appear at
     https://git.kernel.org/pub/scm/linux/kernel/git/akpm/25-new.git/tree/patches/tools-mm-page_owner_sort-fix-sort-option-being-silently-ignored.patch

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

Note, mm-new is a provisional staging ground for work-in-progress
patches, and acceptance into mm-new is a notification for others take
notice and to finish up reviews.  Please do not hesitate to respond to
review feedback and post updated versions to replace or incrementally
fixup patches in mm-new.

The mm-new branch of mm.git is not included in linux-next

If a few days of testing in mm-new is successful, the patch will me moved
into mm.git's mm-unstable branch, which is included in linux-next

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and is updated there most days

------------------------------------------------------
From: Ye Liu <liuye@kylinos.cn>
Subject: tools/mm/page_owner_sort: fix --sort option being silently ignored
Date: Wed, 19 Aug 2026 10:16:09 +0800

Patch series "tools/mm/page_owner_sort: fix --sort, add module filter,
improve usage", v3.

This series improves the page_owner_sort tool with a bug fix, a new
module-name feature, and better usage text.

Patch 1 fixes a long-standing bug where --sort was silently ignored when
used without a short option (-a, -m, -p, etc.).  The COMP_NO_FLAG case
fell through to COMP_NUM and overwrote the sort conditions configured by
parse_sort_args().

Patch 2 adds kernel module name support for sort, cull, and filter
operations.  Page owner stack traces already contain module names in the
"function+0xNN/0xNN [module]" format produced by %pS, but page_owner_sort
had no way to use them.  Records without module frames are assigned
"vmlinux".

  # Aggregate page usage per module
  ./page_owner_sort input.txt output.txt --cull=mod

  # Filter to records from xfs module only
  ./page_owner_sort input.txt output.txt --module xfs

  # Sort by module name, then by pid descending
  ./page_owner_sort input.txt output.txt --sort=mod,-pid

Patch 3 lists all available sort keys with abbreviations and examples
directly in the --sort help section so users no longer need to read the
source to discover valid keys.


This patch (of 3):

When --sort is used without any short option (-a, -m, -p, etc.),
compare_flag remains COMP_NO_FLAG.  The switch (compare_flag) then falls
through to the COMP_NUM case and calls set_single_cmp(), which
unconditionally overwrites the sort conditions that parse_sort_args()
already configured.  This makes --sort silently ineffective unless a short
option is also supplied.

Split COMP_NO_FLAG out of the COMP_NUM fallthrough so that --sort is
respected when no short option is present.

Reproduction:
  # Before fix: ascending order (ignored --sort=-pid)
  ./page_owner_sort --sort=-pid input.txt output.txt
  # After fix: descending order as expected

Link: https://lore.kernel.org/20260819021611.2910835-1-ye.liu@linux.dev
Link: https://lore.kernel.org/20260819021611.2910835-2-ye.liu@linux.dev
Signed-off-by: Ye Liu <liuye@kylinos.cn>
Cc: David Hildenbrand <david@kernel.org>
Cc: Jonathan Corbet <corbet@lwn.net>
Cc: Liam R. Howlett <liam@infradead.org>
Cc: Lorenzo Stoakes <ljs@kernel.org>
Cc: Michal Hocko <mhocko@suse.com>
Cc: Mike Rapoport <rppt@kernel.org>
Cc: Suren Baghdasaryan <surenb@google.com>
Cc: Vlastimil Babka <vbabka@kernel.org>
Cc: Liu Jing <liujing@cmss.chinamobile.com>
Cc: Yichong Chen <chenyichong@uniontech.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
---

 tools/mm/page_owner_sort.c |    3 +++
 1 file changed, 3 insertions(+)

--- a/tools/mm/page_owner_sort.c~tools-mm-page_owner_sort-fix-sort-option-being-silently-ignored
+++ a/tools/mm/page_owner_sort.c
@@ -821,6 +821,9 @@ int main(int argc, char **argv)
 		set_single_cmp(compare_stacktrace, SORT_ASC);
 		break;
 	case COMP_NO_FLAG:
+		if (sc.size > 0)
+			break;
+		/* fallthrough */
 	case COMP_NUM:
 		set_single_cmp(compare_num, SORT_DESC);
 		break;
_

Patches currently in -mm which might be from liuye@kylinos.cn are

mm-vmalloc-fix-vmap_purge_lock-livelock-under-memory-pressure.patch
tools-mm-page_owner_sort-fix-sort-option-being-silently-ignored.patch
tools-mm-page_owner_sort-add-module-name-sort-cull-filter-support.patch
tools-mm-page_owner_sort-show-available-sort-keys-in-usage-text.patch