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Howlett" , Vlastimil Babka , Mike Rapoport , Suren Baghdasaryan , Michal Hocko , Jonathan Corbet , Shuah Khan , Randy Dunlap , Brendan Jackman , Johannes Weiner , Zi Yan , linux-mm@kvack.org, linux-doc@vger.kernel.org, linux-kernel@vger.kernel.org References: <20260907082620.2083838-1-zhen.ni@easystack.cn> <79548641-25f3-4ec3-a549-782fad168962@kernel.org> From: "zhen.ni" In-Reply-To: <79548641-25f3-4ec3-a549-782fad168962@kernel.org> Content-Type: text/plain; charset=UTF-8; format=flowed Content-Transfer-Encoding: 8bit X-HM-Tid: 0aa084054d8e0229kunm29073d571f33c1 X-HM-MType: 1 X-HM-Spam-Status: e1kfGhgUHx5ZQUpXWQgPGg8OCBgUHx5ZQUlOS1dZFg8aDwILHllBWSg2Ly tZV1koWUFJQjdXWRgWCB1ZQUpXWS1ZQUlXWQ8JGhUIEh9ZQVlDGk5CVh0eTUNKGElMTExKHlYVFA kWGhdVGRETFhoSFyQUDg9ZV1kYEgtZQVlJSkNVQk9VSkpDVUJLWVdZFhoPEhUdFFlBWU9LSFVCQk lOS1VKS0tVSkJLQlkG X-Rspam-User: X-Rspamd-Server: rspam09 X-Rspamd-Queue-Id: 223A31A0003 X-Stat-Signature: o8x8mrci14bghtubhwkbw7rwscuk9x6m X-HE-Tag: 1788921342-28371 X-HE-Meta: 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 puNchhmY fbbK14pyUxzNEonoiJYyfr3Rzbfrcm86yfG/Y/4IqTSmSBoZSB+CDWvc/nJ5/QB320p8bqPMDeqzGbj7PkkbJcFRThgKqNGo+Kz3HH3KDUJpj4dpeFS4gsL3d9wdZCzhTmTIowspOARvxwUgc9OFZ1l+X4u2HON5AjFOnjQhyUxvn/+cV/qjDPa2zB7t9g+g5CWoRb16+w+qhOeFor/p4gmp6OYCj/8BIt++RJRxIVTtGdrZZX+f0Nv1FVH9ZGRzAO6uLxT0OxQwE+aQXH8oVvTrCd9OxmxQFFwwouECTQ3XsETE4LpAOJzeEDAAHmLFzf9Aq/Z9qOa5UQWg= Sender: owner-linux-mm@kvack.org Precedence: bulk X-Loop: owner-majordomo@kvack.org List-ID: List-Subscribe: List-Unsubscribe: 在 2026/9/8 22:30, David Hildenbrand (Arm) 写道: > On 9/7/26 10:26, Zhen Ni wrote: >> This patch series adds process and memory cgroup filtering support to >> page_owner. Following the previous series that introduced print_mode and >> NUMA node filters: >> https://lore.kernel.org/linux-mm/20260707115411.1714314-1-zhen.ni@easystack.cn/ >> >> This series adds filtering capabilities to page_owner, allowing users to >> filter output by specific processes and memory cgroups. Users can now >> filter page_owner output by PID, TGID, COMM (with wildcard support), and >> memory cgroup path. This makes page_owner debugging more focused and >> efficient for tracking memory allocations in specific contexts. >> >> Targeted filtering provides significant performance benefits on large memory >> servers by reducing both execution time and output size. By filtering at the >> kernel level before reading, only relevant page allocations are processed, >> dramatically reducing the amount of data that needs to be handled in userspace. > > page_owner is used for debugging. Why do we have to add kernel code to make it > faster? > > How much faster are we talking about? On my VM with just 2GB of RAM, the raw page_owner output takes real 0m6.178s. Filter it down to PID 1, and it drops to real 0m0.286s. Handle mode takes real 0m0.938s — roughly an 85% speedup. I've also tried this on a 1TB server, and it's very slow. The numbers would look even more extreme. You're right that execution time isn't the main concern for a debug tool. But that's kind of the point — I'm trying to optimize the current execution flow of page_owner, reduce unnecessary overhead, and make the tool more user-friendly (especially for servers with 1TB+ of memory).If the user only cares about a specific slice of memory, why dump everything from the kernel side and then filter it all over again in userspace? Might as well filter at the source. > > Or are there other limits to actually implementing it without kernel pre-filtering? >