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b=ehiW3hcK5usEjwMir539AUX6Ta8F9pPK4R5M2qPBBUKPcfTkXpSx8Ydo+DmZ3hVKF aL8W68NDTvx0Tzleh5WTNoMEQcRg7iDNm3hi5W1aRBjP1dAJA4IXGzIFWWk2m2Ug+3 ORZH+CSE4ujGfTnglWseL4BYrtij933eKGtyrgKFn6+pJ2iF6FNrNGjp6s6ssAJMT/ 3BGNqmmZi1GRkrZez393niOPxbbo1IJCQ03qXRBDVdOSWNdHvNvi98cC9RFjZmdGJJ JvDfLvVhQ4LJy9m2EUtUJPtNBgoy3kLAxVHKwcPtlY00r8aDnmS4lbPMUSMyhKsa1g dQT98eXYqp6+A== From: SeongJae Park To: Zhen Ni Cc: SeongJae Park , akpm@linux-foundation.org, vbabka@kernel.org, surenb@google.com, mhocko@suse.com, jackmanb@google.com, hannes@cmpxchg.org, ziy@nvidia.com, linux-mm@kvack.org, linux-kernel@vger.kernel.org Subject: Re: [PATCH v3 4/4] mm/page_owner: document page_owner filter features Date: Tue, 28 Apr 2026 18:35:13 -0700 Message-ID: <20260429013514.88985-1-sj@kernel.org> X-Mailer: git-send-email 2.47.3 In-Reply-To: <20260428071112.1420380-5-zhen.ni@easystack.cn> References: MIME-Version: 1.0 Content-Transfer-Encoding: 8bit X-Rspam-User: X-Rspamd-Queue-Id: DDE0040007 X-Rspamd-Server: rspam06 X-Stat-Signature: 6ygph9zfbgs3wqgp3hit6zxktu7nzmri X-HE-Tag: 1777426518-430931 X-HE-Meta: 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 ISko/BFd KY6ytnozqnocjWMJFxYkf6vb+KzRUw5zHiBSdqXQ966TgW+neZbf9cewU90J7Rumn3kP5TCE9UoA+Vakr7+Jj4akpNkVSWlhWMqPRdSA37zIg3lodK23Wh/pZoGY9o/GWID2AWeZNDIDiat2W7hz9VSCxtHw35ga3cs5VBKpA9uY1yg84P6cLkhmVmkHDy9WjgmJl7W4bfwtoA/JulNs6ep6+7LJgjS7KYqIdjMnZ/7ucwFkGrTGd19TE/gBZaAsu+2Ng Sender: owner-linux-mm@kvack.org Precedence: bulk X-Loop: owner-majordomo@kvack.org List-ID: List-Subscribe: List-Unsubscribe: On Tue, 28 Apr 2026 15:11:12 +0800 Zhen Ni wrote: > 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 Nit. Other parts of the document uses tab for the indentation, while the above new snippet is using four spaces. How about using tab for the consistency? > + > +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 Tab for indentation? > + > +To retrieve the full stack trace for a handle, use:: > + > + cat /sys/kernel/debug/page_owner_stacks/show_stacks_handles Tab? > + > +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 Thanks, SJ