From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from smtp.kernel.org (aws-us-west-2-korg-mail-alma10-1.taild15c8.ts.net [100.103.45.18]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id BD6CD41B351 for ; Tue, 7 Jul 2026 19:09:36 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=100.103.45.18 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1783451378; cv=none; b=u3aEKZX1uOG+IYhMCEhWhMdIB66xAjdFO22BkllKvoUSO1vjS9JSlzSRcBH4gGO5R89tKP6r/VyNXpOwPShEC35QeeoaI8u74CFCFRzSZ5x9sQ5OJs9sMiK8IPmmt2d5/YuNh+VmSplcBgUxS/CRae2Chu7M5twVmsOIZw56BnU= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1783451378; c=relaxed/simple; bh=gD8GsLK4q4Yf0n5MgL1fvaBsXUIOYROT9oj8pVVC7AU=; h=Date:To:From:Subject:Message-Id; b=T9AHoPtk3HgLwVWElvtoozE2Hv8R2XC8fJ1UMmVlyvE2vW6O9ui8jJCqc1HhejsncDMOxQCqv7A+P39DCRo/xQKSEHHwgvRA3YM8ztvvtHqAcslSGh0zQ70qFfa30yUB55cd5otCXJVbJ2PyyCia9i8u/oBrrbXXCswX5+fvmHc= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=linux-foundation.org header.i=@linux-foundation.org header.b=X/Kr1kBh; arc=none smtp.client-ip=100.103.45.18 Authentication-Results: smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=linux-foundation.org header.i=@linux-foundation.org header.b="X/Kr1kBh" Received: by smtp.kernel.org (Postfix) with ESMTPSA id 94CDC1F000E9; Tue, 7 Jul 2026 19:09:36 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=linux-foundation.org; s=korg; t=1783451376; bh=RjbOHCuYzrbwDcdLfN/5cS5gdVOMmuaxnaZq4Cw4MPI=; h=Date:To:From:Subject; b=X/Kr1kBhpXGj4h7BBIoQyZbcJyF7SOJ+JfO9l8wsONFJ/6UQEQc1d2unDEokQmWU6 8jySlarYAPFnmPcFE1+JWEY130Tp6NX0LOaaAVssZOW1hHNmAw0vxSMAu2f1GDw5aa 01NuU4rdwZ8Iq8Cr+bwlHR0tQGnhhadqbGojOzjE= Date: Tue, 07 Jul 2026 12:09:36 -0700 To: mm-commits@vger.kernel.org,zhen.ni@easystack.cn,akpm@linux-foundation.org From: Andrew Morton Subject: [to-be-updated] mm-page_owner-document-page_owner-filter.patch removed from -mm tree Message-Id: <20260707190936.94CDC1F000E9@smtp.kernel.org> Precedence: bulk X-Mailing-List: mm-commits@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: The quilt patch titled Subject: mm/page_owner: document page_owner filter has been removed from the -mm tree. Its filename was mm-page_owner-document-page_owner-filter.patch This patch was dropped because an updated version will be issued ------------------------------------------------------ From: Zhen Ni Subject: mm/page_owner: document page_owner filter Date: Thu, 25 Jun 2026 12:31:01 +0800 Add documentation for the page_owner_filter userspace tool and kernel-level filtering features. Link: https://lore.kernel.org/20260625043101.338794-5-zhen.ni@easystack.cn Signed-off-by: Zhen Ni Tested-by: Zi Yan Cc: Brendan Jackman Cc: David Hildenbrand Cc: Johannes Weiner Cc: Jonathan Corbet Cc: Liam Howlett Cc: Lorenzo Stoakes Cc: Michal Hocko Cc: Mike Rapoport Cc: Shuah Khan Cc: Suren Baghdasaryan Cc: Vlastimil Babka Cc: Ye Liu Cc: Yichong Chen Signed-off-by: Andrew Morton --- Documentation/mm/page_owner.rst | 77 +++++++++++++++++++++++++++++- 1 file changed, 75 insertions(+), 2 deletions(-) --- a/Documentation/mm/page_owner.rst~mm-page_owner-document-page_owner-filter +++ a/Documentation/mm/page_owner.rst @@ -65,7 +65,14 @@ un-tracking state. Usage ===== -1) Build user-space helper:: +1) Build user-space helpers:: + +To filter page_owner output: + + cd tools/mm + make page_owner_filter + +To sort and analyze page_owner output: cd tools/mm make page_owner_sort @@ -74,7 +81,11 @@ Usage 3) Do the job that you want to debug. -4) Analyze information from page owner:: +4) (Optional) Filter page_owner output:: + + ./page_owner_filter -m handle -n 0,1,2 > filtered_page_owner.txt + +5) Analyze information from page owner:: cat /sys/kernel/debug/page_owner_stacks/show_stacks > stacks.txt cat stacks.txt @@ -263,3 +274,65 @@ STANDARD FORMAT SPECIFIERS f free whether the page has been released or not st stacktrace stack trace of the page allocation ator allocator memory allocator for pages + +Filtering page_owner output +============================ + +page_owner supports filtering output at the kernel level before reading, +which reduces the amount of data that needs to be processed in userspace. + +The page_owner_filter tool provides a convenient interface for this filtering +capability. It supports two types of filters: + +1. **print_mode filter**: Control what information is printed for each page + - ``stack``: Print full stack traces (default, compatible with existing usage) + - ``handle``: Print only stack handle numbers (much faster, smaller output) + - ``stack_handle``: Print both stack traces and handle numbers + + The ``handle`` mode uses numeric identifiers instead of full stack traces. + The mapping from handles to actual stack traces can be obtained via the + show_stacks_handles interface. + +2. **NUMA node filter**: Filter pages by NUMA node ID + - Supports single node: ``-n 0`` + - Multiple nodes: ``-n 0,1,2`` + - Ranges: ``-n 0-3`` + - Mixed format: ``-n 0,2-3,5`` + +Usage examples:: + + # Filter by print mode + ./page_owner_filter -m handle + ./page_owner_filter -m stack_handle + + # Filter by NUMA node + ./page_owner_filter -n 0 + ./page_owner_filter -n 0-3 + + # Combined filters + ./page_owner_filter -m stack -n 0,1,2 + ./page_owner_filter -m handle -n 0,2-3 + + # Save to file + ./page_owner_filter -m handle -o filtered_output.txt + +The handle mode is particularly useful for monitoring and performance-critical +scenarios as it dramatically reduces output size. Testing shows handle mode can +reduce output size by ~66% (84MB vs 244MB) and improve read performance by ~4.4x +compared to full stack output. + +The NUMA node filter is useful for NUMA-aware memory allocation analysis and debugging. + +Behind the scenes, page_owner_filter opens /sys/kernel/debug/page_owner and +writes filter commands before reading the filtered output. The filtering uses +per-file-descriptor state, allowing each open() to have independent filter settings. + +Each file descriptor maintains its own filter state, so you can have multiple +independent filtering operations running concurrently. For example, in different +terminals you can run different filters simultaneously:: + + # Terminal 1: Filter node 0 + ./page_owner_filter -n 0 > node0_output.txt + + # Terminal 2: Filter node 1 (runs concurrently) + ./page_owner_filter -n 1 > node1_output.txt _ Patches currently in -mm which might be from zhen.ni@easystack.cn are