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 240D238F65C for ; Wed, 29 Jul 2026 04:14:05 +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=1785298446; cv=none; b=sqESvwjlVlbT2cf5tR/UkkciGRGaRUMdYU9+CdqJVaF17EDUdiHtY67D3xVfQXVJXN65rnMxwqBbikCpjm7BrG1jyCxC4v4DPHUKHhuTfQ6RI3v/pNt/5GDBLHCdMA1ZF0jHRCh7Retxz3hLiHF/5dwIp29YHyOJ6htKTo7PsF0= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1785298446; c=relaxed/simple; bh=BeZD0VHADnB6LURkRCOhsxLF4S68JAprlkvj0hZsC6E=; h=Date:To:From:Subject:Message-Id; b=mGtqKpt/shhe9EWj2Gh/PxdG8wzpyjamTipE2ZMToA+uo/3ZcrEgfEcR46BRDniYAZD2gCm3+cwYjjy6HGDirfu65YQuvEKWRQr2pSia6p8OD4aZxiHXs7dZc+xvHWi3MUFF2hK8aKe6pNrCDQ4+r9Az5Ya0vP028KzC6hhFXts= 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=UDdh9k/q; 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="UDdh9k/q" Received: by smtp.kernel.org (Postfix) with ESMTPSA id ED1D41F00A3A; Wed, 29 Jul 2026 04:14:04 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=linux-foundation.org; s=korg; t=1785298445; bh=zEMoafoJTolCy2yL4YkROQdAT9AkUYGzWEabEkSF9L4=; h=Date:To:From:Subject; b=UDdh9k/qrJss0lSodS1+vJWzRN1njZ9uHNl9//HUj6r3uKtWWZUhn62wv/HrkjR5V fK6uOy5mn6zuo2oYtC0nIDlXOwJeqS/6e+CLXpbuUjYBjf3pCLjh8anJeRpGulm2we QkF3UqgxKdCGxISlnukfy4v+iUxoT9/p/i20Fcno= Date: Tue, 28 Jul 2026 21:14:04 -0700 To: mm-commits@vger.kernel.org,ziy@nvidia.com,vbabka@kernel.org,surenb@google.com,rdunlap@infradead.org,mhocko@suse.com,jackmanb@google.com,hannes@cmpxchg.org,zhen.ni@easystack.cn,akpm@linux-foundation.org From: Andrew Morton Subject: [merged mm-stable] mm-page_owner-document-page_owner-filter.patch removed from -mm tree Message-Id: <20260729041404.ED1D41F00A3A@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 it was merged into the mm-stable branch of git://git.kernel.org/pub/scm/linux/kernel/git/akpm/mm ------------------------------------------------------ From: Zhen Ni Subject: mm/page_owner: document page_owner filter Date: Tue, 7 Jul 2026 19:54:11 +0800 Add documentation for the page_owner_filter userspace tool and kernel-level filtering features. [rdunlap@infradead.org: avoid docs build warning] Link: https://lore.kernel.org/20260708213548.469155-1-rdunlap@infradead.org Link: https://lore.kernel.org/20260707115411.1714314-5-zhen.ni@easystack.cn Signed-off-by: Zhen Ni Signed-off-by: Randy Dunlap Acked-by: Vlastimil Babka (SUSE) Acked-by: Zi Yan Cc: Brendan Jackman Cc: Johannes Weiner Cc: Michal Hocko Cc: Suren Baghdasaryan Signed-off-by: Andrew Morton --- Documentation/mm/page_owner.rst | 78 +++++++++++++++++++++++++++++- 1 file changed, 76 insertions(+), 2 deletions(-) --- a/Documentation/mm/page_owner.rst~mm-page_owner-document-page_owner-filter +++ a/Documentation/mm/page_owner.rst @@ -65,7 +65,15 @@ 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 +82,11 @@ 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 +275,65 @@ 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