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 B346B4F6479; Wed, 9 Sep 2026 10:28:43 +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=1788949724; cv=none; b=PEFg4gcpCFTFjQTFpFyqBdxpVMfzvVGOsEGNgA/dzcvjkTz+jnVkTD2rJykcFJKh05CKRVKctr6saOBUKcwS7GaF/iRUiTna04k6TT0UPg5hDdB20V8/Xn0A7wbdL67zCWm3HElFCGojmMLlR5Zk5l4FBHg7zbhTMq8QbGoSAAA= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1788949724; c=relaxed/simple; bh=BLrTYCgmHQIfCZpgff2lne/0urPO9bDrVp1IxaP6rSA=; h=Message-ID:Date:MIME-Version:Subject:To:Cc:References:From: In-Reply-To:Content-Type; b=kGw67RSL3BHmCC0Twjf3PzWU0QJQ/dcOXXbKoGcVXiQk69nNDvq9MhdoTx5Qs6q8ZWbAepbkfOas7HGL5ZM2MhCDRdCz+9zI9IP9GbgmnnhoWO84tHIcvuIO2/qtqOrCxGGBjuR3Yfa6OsJdk/yQvhEU/bpLgu6MNwUEyJmwF5I= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b=kleZA+60; arc=none smtp.client-ip=100.103.45.18 Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b="kleZA+60" Received: by smtp.kernel.org (Postfix) with ESMTPSA id 4EB001F00A3A; Wed, 9 Sep 2026 10:28:39 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=kernel.org; s=k20260515; t=1788949723; bh=60Fn9vMhQz6j6ntR/n7XOI7vJwXbXBwP3B0Uhh6u4UA=; h=Date:Subject:To:Cc:References:From:In-Reply-To; b=kleZA+60Lv1tfMbYFJryHNYaxLvlrFE2+5CgNbMl9BGqJAtpLWeJK14WrfabM7HgB jKR3YR2lUmigxbTGGVo+xzupsc0LiNpO/q7mJuTEfPnt290ils3CF9HVcMeoXTYNdx XnjfsTVL4mxfeUk9lFPmSVOzUeOMbaFWdj4Q7Dco5LVTWtutGUKyYWuSKUX5IcSHXk 1ziRbbjHSpqnDANaIwOf3/jrb8hP42S+t0OCol2OoLhW9VdnwLTYliwoInXkCavkJU 9XndRQymonbcrswFomGGDHqDGULXj/10mx5rDVkKq4WvbRk9cDqmNb1xe7VGxJb68n xrVrMzli4FCcg== Message-ID: Date: Wed, 9 Sep 2026 12:28:37 +0200 Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 User-Agent: Mozilla Thunderbird Subject: Re: [PATCH v3 0/8] mm/page_owner: Add PID/TGID/COMM and cgroup filtering To: "zhen.ni" , Andrew Morton Cc: Lorenzo Stoakes , "Liam R . 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> <6e8bfb0d-d595-4e6b-9536-0323ada57e25@easystack.cn> From: "David Hildenbrand (Arm)" Content-Language: en-US Autocrypt: addr=david@kernel.org; keydata= xsFNBFXLn5EBEAC+zYvAFJxCBY9Tr1xZgcESmxVNI/0ffzE/ZQOiHJl6mGkmA1R7/uUpiCjJ dBrn+lhhOYjjNefFQou6478faXE6o2AhmebqT4KiQoUQFV4R7y1KMEKoSyy8hQaK1umALTdL QZLQMzNE74ap+GDK0wnacPQFpcG1AE9RMq3aeErY5tujekBS32jfC/7AnH7I0v1v1TbbK3Gp XNeiN4QroO+5qaSr0ID2sz5jtBLRb15RMre27E1ImpaIv2Jw8NJgW0k/D1RyKCwaTsgRdwuK Kx/Y91XuSBdz0uOyU/S8kM1+ag0wvsGlpBVxRR/xw/E8M7TEwuCZQArqqTCmkG6HGcXFT0V9 PXFNNgV5jXMQRwU0O/ztJIQqsE5LsUomE//bLwzj9IVsaQpKDqW6TAPjcdBDPLHvriq7kGjt WhVhdl0qEYB8lkBEU7V2Yb+SYhmhpDrti9Fq1EsmhiHSkxJcGREoMK/63r9WLZYI3+4W2rAc UucZa4OT27U5ZISjNg3Ev0rxU5UH2/pT4wJCfxwocmqaRr6UYmrtZmND89X0KigoFD/XSeVv jwBRNjPAubK9/k5NoRrYqztM9W6sJqrH8+UWZ1Idd/DdmogJh0gNC0+N42Za9yBRURfIdKSb B3JfpUqcWwE7vUaYrHG1nw54pLUoPG6sAA7Mehl3nd4pZUALHwARAQABzS5EYXZpZCBIaWxk ZW5icmFuZCAoQ3VycmVudCkgPGRhdmlkQGtlcm5lbC5vcmc+wsGQBBMBCAA6AhsDBQkmWAik AgsJBBUKCQgCFgICHgUCF4AWIQQb2cqtc1xMOkYN/MpN3hD3AP+DWgUCaYJt/AIZAQAKCRBN 3hD3AP+DWriiD/9BLGEKG+N8L2AXhikJg6YmXom9ytRwPqDgpHpVg2xdhopoWdMRXjzOrIKD g4LSnFaKneQD0hZhoArEeamG5tyo32xoRsPwkbpIzL0OKSZ8G6mVbFGpjmyDLQCAxteXCLXz ZI0VbsuJKelYnKcXWOIndOrNRvE5eoOfTt2XfBnAapxMYY2IsV+qaUXlO63GgfIOg8RBaj7x 3NxkI3rV0SHhI4GU9K6jCvGghxeS1QX6L/XI9mfAYaIwGy5B68kF26piAVYv/QZDEVIpo3t7 /fjSpxKT8plJH6rhhR0epy8dWRHk3qT5tk2P85twasdloWtkMZ7FsCJRKWscm1BLpsDn6EQ4 jeMHECiY9kGKKi8dQpv3FRyo2QApZ49NNDbwcR0ZndK0XFo15iH708H5Qja/8TuXCwnPWAcJ DQoNIDFyaxe26Rx3ZwUkRALa3iPcVjE0//TrQ4KnFf+lMBSrS33xDDBfevW9+Dk6IISmDH1R HFq2jpkN+FX/PE8eVhV68B2DsAPZ5rUwyCKUXPTJ/irrCCmAAb5Jpv11S7hUSpqtM/6oVESC 3z/7CzrVtRODzLtNgV4r5EI+wAv/3PgJLlMwgJM90Fb3CB2IgbxhjvmB1WNdvXACVydx55V7 LPPKodSTF29rlnQAf9HLgCphuuSrrPn5VQDaYZl4N/7zc2wcWM7BTQRVy5+RARAA59fefSDR 9nMGCb9LbMX+TFAoIQo/wgP5XPyzLYakO+94GrgfZjfhdaxPXMsl2+o8jhp/hlIzG56taNdt VZtPp3ih1AgbR8rHgXw1xwOpuAd5lE1qNd54ndHuADO9a9A0vPimIes78Hi1/yy+ZEEvRkHk /kDa6F3AtTc1m4rbbOk2fiKzzsE9YXweFjQvl9p+AMw6qd/iC4lUk9g0+FQXNdRs+o4o6Qvy iOQJfGQ4UcBuOy1IrkJrd8qq5jet1fcM2j4QvsW8CLDWZS1L7kZ5gT5EycMKxUWb8LuRjxzZ 3QY1aQH2kkzn6acigU3HLtgFyV1gBNV44ehjgvJpRY2cC8VhanTx0dZ9mj1YKIky5N+C0f21 zvntBqcxV0+3p8MrxRRcgEtDZNav+xAoT3G0W4SahAaUTWXpsZoOecwtxi74CyneQNPTDjNg azHmvpdBVEfj7k3p4dmJp5i0U66Onmf6mMFpArvBRSMOKU9DlAzMi4IvhiNWjKVaIE2Se9BY FdKVAJaZq85P2y20ZBd08ILnKcj7XKZkLU5FkoA0udEBvQ0f9QLNyyy3DZMCQWcwRuj1m73D sq8DEFBdZ5eEkj1dCyx+t/ga6x2rHyc8Sl86oK1tvAkwBNsfKou3v+jP/l14a7DGBvrmlYjO 59o3t6inu6H7pt7OL6u6BQj7DoMAEQEAAcLBfAQYAQgAJgIbDBYhBBvZyq1zXEw6Rg38yk3e EPcA/4NaBQJonNqrBQkmWAihAAoJEE3eEPcA/4NaKtMQALAJ8PzprBEXbXcEXwDKQu+P/vts IfUb1UNMfMV76BicGa5NCZnJNQASDP/+bFg6O3gx5NbhHHPeaWz/VxlOmYHokHodOvtL0WCC 8A5PEP8tOk6029Z+J+xUcMrJClNVFpzVvOpb1lCbhjwAV465Hy+NUSbbUiRxdzNQtLtgZzOV Zw7jxUCs4UUZLQTCuBpFgb15bBxYZ/BL9MbzxPxvfUQIPbnzQMcqtpUs21CMK2PdfCh5c4gS sDci6D5/ZIBw94UQWmGpM/O1ilGXde2ZzzGYl64glmccD8e87OnEgKnH3FbnJnT4iJchtSvx yJNi1+t0+qDti4m88+/9IuPqCKb6Stl+s2dnLtJNrjXBGJtsQG/sRpqsJz5x1/2nPJSRMsx9 5YfqbdrJSOFXDzZ8/r82HgQEtUvlSXNaXCa95ez0UkOG7+bDm2b3s0XahBQeLVCH0mw3RAQg r7xDAYKIrAwfHHmMTnBQDPJwVqxJjVNr7yBic4yfzVWGCGNE4DnOW0vcIeoyhy9vnIa3w1uZ 3iyY2Nsd7JxfKu1PRhCGwXzRw5TlfEsoRI7V9A8isUCoqE2Dzh3FvYHVeX4Us+bRL/oqareJ CIFqgYMyvHj7Q06kTKmauOe4Nf0l0qEkIuIzfoLJ3qr5UyXc2hLtWyT9Ir+lYlX9efqh7mOY qIws/H2t In-Reply-To: <6e8bfb0d-d595-4e6b-9536-0323ada57e25@easystack.cn> Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit On 9/9/26 04:35, zhen.ni wrote: > > > 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. Because it results in less kernel code :) And less kernel code is good. Unless unavoidable. -- Cheers, David