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imf08.hostedemail.com; dkim=none; spf=pass (imf08.hostedemail.com: domain of zhen.ni@easystack.cn designates 156.224.82.136 as permitted sender) smtp.mailfrom=zhen.ni@easystack.cn; dmarc=pass (policy=none) header.from=easystack.cn ARC-Seal: i=1; s=arc-20220608; d=hostedemail.com; t=1777360295; a=rsa-sha256; cv=none; b=ksicMfi+NtNAj9uWqWQAHXPfPAsHzKAuYZWAk0ZP+swlNTn/xOOK8Dn8TEzl1yV58a3Hyp 4Mz7avLiKoJatd5jqtMyN216Xdg+Ku08RyCBQDC9hXFyqC7MalGotcI6XfXpUNwLtEvCuf A8o7MlHX16tWt/+51ZcJ3miMKPjbzWE= Received: from localhost.localdomain (unknown [218.94.118.90]) by smtp.qiye.163.com (Hmail) with ESMTP id 197b49313; Tue, 28 Apr 2026 15:11:29 +0800 (GMT+08:00) From: Zhen Ni To: akpm@linux-foundation.org, vbabka@kernel.org Cc: surenb@google.com, mhocko@suse.com, jackmanb@google.com, hannes@cmpxchg.org, ziy@nvidia.com, linux-mm@kvack.org, linux-kernel@vger.kernel.org, Zhen Ni Subject: [PATCH v3 4/4] mm/page_owner: document page_owner filter features Date: Tue, 28 Apr 2026 15:11:12 +0800 Message-Id: <20260428071112.1420380-5-zhen.ni@easystack.cn> X-Mailer: git-send-email 2.20.1 In-Reply-To: <20260428071112.1420380-1-zhen.ni@easystack.cn> References: <20260428071112.1420380-1-zhen.ni@easystack.cn> MIME-Version: 1.0 Content-Transfer-Encoding: 8bit X-HM-Tid: 0a9dd2edc0af0229kunmb0c223f1156f39 X-HM-MType: 1 X-HM-Spam-Status: e1kfGhgUHx5ZQUpXWQgPGg8OCBgUHx5ZQUlOS1dZFg8aDwILHllBWSg2Ly tZV1koWUFJQjdXWRgWCB1ZQUpXWS1ZQUlXWQ8JGhUIEh9ZQVlCTENPVkxNSk4ZTk5DGU1JHlYVFA kWGhdVGRETFhoSFyQUDg9ZV1kYEgtZQVlJSkNVQk9VSkpDVUJLWVdZFhoPEhUdFFlBWU9LSFVKS0 lPT09IVUpLS1VKQktLWQY+ X-Rspam-User: X-Rspamd-Queue-Id: A2A2D160009 X-Rspamd-Server: rspam06 X-Stat-Signature: hhj3rbey3znasfndx7exzmaff7d7sz1w X-HE-Tag: 1777360294-26831 X-HE-Meta: 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 xZI2LMLU M5Zq9sri6is5iPlEMYDNEUgJs1Cf5fdS6gnkIv4jsmRuUDhRjeeFTlVa9dVcu0WE20fYl5/3CUHIXVTjZ5rOrQUF2pG6C75g5kRX+H9kHXBCPqDjKw7/FaQYEJz6iqAZSoRleIvUn+uiN2vU= Sender: owner-linux-mm@kvack.org Precedence: bulk X-Loop: owner-majordomo@kvack.org List-ID: List-Subscribe: List-Unsubscribe: Add documentation for the page_owner filter functionality, including: - Print mode filter (full stack vs stack handle) - NUMA node filter (single node, multiple nodes, ranges) - Usage examples for both filters Signed-off-by: Zhen Ni --- Changes in v3: - New patch to document filter features as requested by Andrew Morton --- Documentation/mm/page_owner.rst | 55 ++++++++++++++++++++++++++++++++- 1 file changed, 54 insertions(+), 1 deletion(-) diff --git a/Documentation/mm/page_owner.rst b/Documentation/mm/page_owner.rst index 6b12f3b007ec..6261366d33fe 100644 --- a/Documentation/mm/page_owner.rst +++ b/Documentation/mm/page_owner.rst @@ -74,7 +74,17 @@ Usage 3) Do the job that you want to debug. -4) Analyze information from page owner:: +4) (Optional) Use filters to focus on specific memory allocations:: + + cd /sys/kernel/debug/page_owner_filter + + # Print only stack handles instead of full traces + echo 1 > print_mode + + # Filter by NUMA nodes + echo "0,2-3" > nid + +5) Analyze information from page owner:: cat /sys/kernel/debug/page_owner_stacks/show_stacks > stacks.txt cat stacks.txt @@ -238,6 +248,49 @@ Usage ./page_owner_sort --tgid=1,2,3 ./page_owner_sort --name name1,name2 +Page Owner Filters +================== + +The page_owner feature provides filtering capabilities to focus on specific +memory allocations (e.g., by NUMA node). Filters are controlled through debugfs +files in ``/sys/kernel/debug/page_owner_filter/``. + +Print Mode Filter +----------------- + +The ``print_mode`` file controls the level of detail in stack trace output. + +Available modes: + +- ``0`` (default): Print full stack traces +- ``1``: Print only stack handles + +The ``print_mode=1`` output format:: + + Page allocated via order 0, mask 0x42800(GFP_NOWAIT|__GFP_COMP), + pid 1, tgid 1 (systemd), ts 349667370 ns + PFN 0xa00a2 type Unmovable Block 1280 type Unmovable + Flags 0x33fffe0000004124(...) + handle: 17432583 + +To retrieve the full stack trace for a handle, use:: + + cat /sys/kernel/debug/page_owner_stacks/show_stacks_handles + +NUMA Node Filter +---------------- + +The ``nid`` file filters pages by NUMA node. This is useful for NUMA-aware +environments to analyze node-specific memory allocation. + +Supported input formats: + +- Single node: ``echo "2" > nid`` +- Multiple nodes: ``echo "0,2,3" > nid`` +- Node range: ``echo "0-3" > nid`` +- Mixed format: ``echo "0,2-4,7" > nid`` +- Disable filter: ``echo "-1" > nid`` + STANDARD FORMAT SPECIFIERS ========================== :: -- 2.20.1