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b=jo4lfrDb7Ln2/ekILrcZTwpfHy ovbXmao2JZNNpAUTrE4TW71cJIenl9mkQPyMufLmibgYOnkD4vbFyB9vgDiawMZpvJa2PzWjrmCV2 y2luluqHqYGX+pBCFLuB1omuC7KUjIdsD/L5LY8+WFYrZaah5JqcODcnIUoals4FvmMXVzb7YKY8R GB6QZAPxELiecJKph7kxb5KiONOEhiqRjcn+WQ7hNmCe7sV5vKtyfzKISls4Zz5pdKtsMdPG7Mk9K 0XCVIVJpZOdPL4PAVwW59CLEiCpWltbNqy8CA4Rl2jxgxYnxN+tI9xXXYeF7YgpM3j1s1y6kre/np vBbhq2Aw==; Received: from [179.159.118.139] (helo=localhost.localdomain) by fanzine2.igalia.com with esmtpsa (Cipher TLS1.3:ECDHE_X25519__RSA_PSS_RSAE_SHA256__AES_256_GCM:256) (Exim) id 1v414E-002xd4-DL; Wed, 01 Oct 2025 19:56:43 +0200 From: Mauricio Faria de Oliveira To: Michal Hocko , Vlastimil Babka , Andrew Morton Cc: Oscar Salvador , Suren Baghdasaryan , Brendan Jackman , Johannes Weiner , Zi Yan , linux-mm@kvack.org, linux-kernel@vger.kernel.org, kernel-dev@igalia.com Subject: [PATCH v2 5/5] mm/page_owner: update Documentation with 'show_handles' and 'show_stacks_handles' Date: Wed, 1 Oct 2025 14:56:11 -0300 Message-ID: <20251001175611.575861-6-mfo@igalia.com> X-Mailer: git-send-email 2.48.1 In-Reply-To: <20251001175611.575861-1-mfo@igalia.com> References: <20251001175611.575861-1-mfo@igalia.com> MIME-Version: 1.0 Content-Transfer-Encoding: 8bit X-Rspamd-Queue-Id: 7B007A0016 X-Stat-Signature: c85uwatayyk8mbjfqe8gwd1i8mc5wpux X-Rspam-User: X-Rspamd-Server: rspam01 X-HE-Tag: 1759341407-891639 X-HE-Meta: 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 CyYKXBbj A+2tXd7Nk/4l26lE= X-Bogosity: Ham, tests=bogofilter, spamicity=0.000000, version=1.2.4 Sender: owner-linux-mm@kvack.org Precedence: bulk X-Loop: owner-majordomo@kvack.org List-ID: List-Subscribe: List-Unsubscribe: Describe and provide examples for 'show_handles' and 'show_stacks_handles'. Signed-off-by: Mauricio Faria de Oliveira --- Documentation/mm/page_owner.rst | 32 +++++++++++++++++++++++++++++++- 1 file changed, 31 insertions(+), 1 deletion(-) diff --git a/Documentation/mm/page_owner.rst b/Documentation/mm/page_owner.rst index 3a45a20fc05a..6b12f3b007ec 100644 --- a/Documentation/mm/page_owner.rst +++ b/Documentation/mm/page_owner.rst @@ -27,7 +27,10 @@ enabled. Other usages are more than welcome. It can also be used to show all the stacks and their current number of allocated base pages, which gives us a quick overview of where the memory is going without the need to screen through all the pages and match the -allocation and free operation. +allocation and free operation. It's also possible to show only a numeric +identifier of all the stacks (without stack traces) and their number of +allocated base pages (faster to read and parse, eg, for monitoring) that +can be matched with stacks later (show_handles and show_stacks_handles). page owner is disabled by default. So, if you'd like to use it, you need to add "page_owner=on" to your boot cmdline. If the kernel is built @@ -116,6 +119,33 @@ Usage nr_base_pages: 20824 ... + cat /sys/kernel/debug/page_owner_stacks/show_handles > handles_7000.txt + cat handles_7000.txt + handle: 42 + nr_base_pages: 20824 + ... + + cat /sys/kernel/debug/page_owner_stacks/show_stacks_handles > stacks_handles.txt + cat stacks_handles.txt + post_alloc_hook+0x177/0x1a0 + get_page_from_freelist+0xd01/0xd80 + __alloc_pages+0x39e/0x7e0 + alloc_pages_mpol+0x22e/0x490 + folio_alloc+0xd5/0x110 + filemap_alloc_folio+0x78/0x230 + page_cache_ra_order+0x287/0x6f0 + filemap_get_pages+0x517/0x1160 + filemap_read+0x304/0x9f0 + xfs_file_buffered_read+0xe6/0x1d0 [xfs] + xfs_file_read_iter+0x1f0/0x380 [xfs] + __kernel_read+0x3b9/0x730 + kernel_read_file+0x309/0x4d0 + __do_sys_finit_module+0x381/0x730 + do_syscall_64+0x8d/0x150 + entry_SYSCALL_64_after_hwframe+0x62/0x6a + handle: 42 + ... + cat /sys/kernel/debug/page_owner > page_owner_full.txt ./page_owner_sort page_owner_full.txt sorted_page_owner.txt -- 2.48.1