From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org Received: from kanga.kvack.org (kanga.kvack.org [205.233.56.17]) (using TLSv1 with cipher DHE-RSA-AES256-SHA (256/256 bits)) (No client certificate requested) by smtp.lore.kernel.org (Postfix) with ESMTPS id D7F77D68BDD for ; Thu, 18 Dec 2025 06:26:31 +0000 (UTC) Received: by kanga.kvack.org (Postfix) id 117246B0088; Thu, 18 Dec 2025 01:26:31 -0500 (EST) Received: by kanga.kvack.org (Postfix, from userid 40) id 09B026B0089; Thu, 18 Dec 2025 01:26:31 -0500 (EST) X-Delivered-To: int-list-linux-mm@kvack.org Received: by kanga.kvack.org (Postfix, from userid 63042) id EDED26B008A; Thu, 18 Dec 2025 01:26:30 -0500 (EST) X-Delivered-To: linux-mm@kvack.org Received: from relay.hostedemail.com (smtprelay0014.hostedemail.com [216.40.44.14]) by kanga.kvack.org (Postfix) with ESMTP id DD52E6B0088 for ; Thu, 18 Dec 2025 01:26:30 -0500 (EST) Received: from smtpin18.hostedemail.com (a10.router.float.18 [10.200.18.1]) by unirelay02.hostedemail.com (Postfix) with ESMTP id 4949213C228 for ; Thu, 18 Dec 2025 06:26:30 +0000 (UTC) X-FDA: 84231607740.18.EAAD73E Received: from out-182.mta0.migadu.com (out-182.mta0.migadu.com [91.218.175.182]) by imf17.hostedemail.com (Postfix) with ESMTP id 2947440004 for ; Thu, 18 Dec 2025 06:26:27 +0000 (UTC) Authentication-Results: imf17.hostedemail.com; dkim=pass header.d=linux.dev header.s=key1 header.b="FuYlSs/7"; dmarc=pass (policy=none) header.from=linux.dev; spf=pass (imf17.hostedemail.com: domain of qi.zheng@linux.dev designates 91.218.175.182 as permitted sender) smtp.mailfrom=qi.zheng@linux.dev ARC-Seal: i=1; s=arc-20220608; d=hostedemail.com; t=1766039188; a=rsa-sha256; cv=none; b=1EHk2Eg0IjHUnpE2Ujq+NjoLPA5TJSuqRHR1EJncZAyIjbNRYsY9XecXPx4+SjbTcHwvO0 Hi+hs5O7oow0f6yXMSL7B4RQvcP0X4/KtTnOPPxQUEnUdLTAjTLCslfNiHCUGeRVFFsjC0 Bs2xifUVE2FEN6pVvhWJVS2VBB78lJU= ARC-Authentication-Results: i=1; imf17.hostedemail.com; dkim=pass header.d=linux.dev header.s=key1 header.b="FuYlSs/7"; dmarc=pass (policy=none) header.from=linux.dev; spf=pass (imf17.hostedemail.com: domain of qi.zheng@linux.dev designates 91.218.175.182 as permitted sender) smtp.mailfrom=qi.zheng@linux.dev ARC-Message-Signature: i=1; a=rsa-sha256; c=relaxed/relaxed; d=hostedemail.com; s=arc-20220608; t=1766039188; h=from:from:sender:reply-to:subject:subject:date:date: message-id:message-id:to:to:cc:cc:mime-version:mime-version: content-type:content-type: content-transfer-encoding:content-transfer-encoding: in-reply-to:in-reply-to:references:references:dkim-signature; bh=JQrjMLHrieslIFKAFZlyBoYqknDz5bzEWuLKkBRkaL0=; b=pRSMsFpfjqKlgozRNZ2Uk8CxGrsRfPPTBpmsc8KbZMQtbOSt1TvB700UjSJFTnwmexVPHp d6T3Gv392qphi4oP8/AhXEwHztzYl92ykCMucncMDS0nvC0XOF/HzIRd5su3S1V1SJ84tk 6JsSNqOLqEsYStfwScozriDZWT9jQsQ= Message-ID: <0088cfa4-7a60-4a44-afbf-7ee0b6ebb2c4@linux.dev> DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=linux.dev; s=key1; t=1766039185; h=from:from:reply-to:subject:subject:date:date:message-id:message-id: to:to:cc:cc:mime-version:mime-version:content-type:content-type: content-transfer-encoding:content-transfer-encoding: in-reply-to:in-reply-to:references:references; bh=JQrjMLHrieslIFKAFZlyBoYqknDz5bzEWuLKkBRkaL0=; b=FuYlSs/7qmGAWTBWBQxbkrQbCqmEgMoaZbgNCMzzBh2YuxnQ4ybZRmxxhOsEvYhEP/oLbi kCd5PStGxyUh0c2Z4AaMItHC8yCAjs4pfvMkkqPWpkdLoA07BFunegRu9McSC8iyvdBI9U kiSb3lXDFNSP9K+oqxxW3hL4HtTI+TQ= Date: Thu, 18 Dec 2025 14:25:26 +0800 MIME-Version: 1.0 Subject: Re: [PATCH v2 06/28] mm: memcontrol: allocate object cgroup for non-kmem case To: Johannes Weiner Cc: hughd@google.com, mhocko@suse.com, roman.gushchin@linux.dev, shakeel.butt@linux.dev, muchun.song@linux.dev, david@kernel.org, lorenzo.stoakes@oracle.com, ziy@nvidia.com, harry.yoo@oracle.com, imran.f.khan@oracle.com, kamalesh.babulal@oracle.com, axelrasmussen@google.com, yuanchu@google.com, weixugc@google.com, chenridong@huaweicloud.com, mkoutny@suse.com, akpm@linux-foundation.org, hamzamahfooz@linux.microsoft.com, apais@linux.microsoft.com, lance.yang@linux.dev, linux-mm@kvack.org, linux-kernel@vger.kernel.org, cgroups@vger.kernel.org, Muchun Song , Qi Zheng References: <897be76398cb2027d08d1bcda05260ede54dc134.1765956025.git.zhengqi.arch@bytedance.com> X-Report-Abuse: Please report any abuse attempt to abuse@migadu.com and include these headers. From: Qi Zheng In-Reply-To: Content-Type: text/plain; charset=UTF-8; format=flowed Content-Transfer-Encoding: 7bit X-Migadu-Flow: FLOW_OUT X-Rspam-User: X-Rspamd-Queue-Id: 2947440004 X-Rspamd-Server: rspam10 X-Stat-Signature: u68zyuz8qi46qqj7eqxwttqwwewxg8yq X-HE-Tag: 1766039187-743000 X-HE-Meta: U2FsdGVkX1+Ciw7MXbIBZjlyDLrfJvEb3m+NI62wJRk5YTso6a/Q6A1ilASC9e5INi3ZOCYYD3m1UHROTmniO48Ms4me3wKP7BpVolXq1CsgOIgERJYpD4f7AJSNGVIEz+k5CPkDnDVaBSJkxSBp28r4i3+SqPLAM28y4ekPd7O3PUdMHyGk1VE0OFdZ4VZuipzBgKdsHh88Hb3A1WW8r1mQ1VPVmgYhLjdJ6b0Q8M26S2sNb7qLK13EOOvQvMOenLCr1GxP0puin3Iv3+K6bRvoVYYFZCoHmT8Aty02EfIziK2Y/oQxdx7u5NitY2UxQefKlwkEmAwZnLDS3WQ5k6mdQ7xff+Lvk3cOl5k1+R/uDS3cAUopT2pnjsRmaiXmAbOeewES/yplXQXrdh5x4a2Qz2Eelw4slLFZSvErh709DJJrIbTj2DL43+fyzK1kacA9uZGMbKb+7Uo5HPyce9plsKGP/cexIG/rbHHfcR9eM6ZgYC4+N7kXN91c5LtcS8KrcuoBi8zPKMGo8FsVsL4gRIV0bGnC4kbwhm0HkiiUcp7oM873qGDAlWjpoSx7l/rbPX4juvdkWRVyP2ScYnYDg+fSP0LQNBo/BsKQZuTlJNua3Mrxq/2TfspTHA6I3r7Rqzf6+GuSraCE19jMRHtfZso5UcM4CLHulivEtcjW76zyBpzHI36GsxgZDs95aONY1dS/lssR2OblTCmnjQPk8phHBHNORHHBkfEXcX+Gl/Qc3GK+6+FB7M43TWUiHvCYn0dqv1XdMEfN+MospooQvQG4kqudpcokGkD9Iv2dqD1wNm/8/IdPN4zId+8HWpqU1LP5q+riWkKezyzoBsK6D1HHGDbY/N6HwJNMRcnrp0djvewVVEUIPw4UurUfwSYqcxYjUrMjwSg1J7cZ/IqczIoH+X69pSqQJdVbmlRy0mLAiiuOgiJpdXcRWjsRqHW4jHvpqBwLaPRP8HV pqF+S7xJ 68bRKjgEUvKuUKFr3J/ffabwTCXAgyzreFquCh/bQgfW5NmUiOwJvjsueCwDg1ZNh7OBmf0H3wUgEgTAwcrUCaIS1cpaQeGsFi9r9GiCj8Jcmjswn24sfnZwypgUpvX++DwX5nTJX1E4oXQ4vwgv97kksaZrYsytIpRV13VxNCrAaxOmEVvOwF3Z1o2tr8qvnQCCADGl0dSwmcdKHZkwh9cqS0tfZm+g6TtgoyIMCeYHaI61GaJKjUPzaAxX8w43Y1l01/deJ+cBtz9PUjGUiLbijF33DLWXgOcNj2w55E78OJBexMepk2OF5ZkmPhee6IlER 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: On 12/18/25 5:22 AM, Johannes Weiner wrote: > On Wed, Dec 17, 2025 at 03:27:30PM +0800, Qi Zheng wrote: >> From: Muchun Song >> >> Pagecache pages are charged at allocation time and hold a reference >> to the original memory cgroup until reclaimed. Depending on memory >> pressure, page sharing patterns between different cgroups and cgroup >> creation/destruction rates, many dying memory cgroups can be pinned >> by pagecache pages, reducing page reclaim efficiency and wasting >> memory. Converting LRU folios and most other raw memory cgroup pins >> to the object cgroup direction can fix this long-living problem. > > Not a big deal, but since the coverletter will be preserved in git, I > don't think you need to repeat the full thesis. Got it. > >> As a result, the objcg infrastructure is no longer solely applicable >> to the kmem case. In this patch, we extend the scope of the objcg >> infrastructure beyond the kmem case, enabling LRU folios to reuse >> it for folio charging purposes. > > "To allow LRU page reparenting, the objcg infrastructure [...]" OK, will do. > >> It should be noted that LRU folios are not accounted for at the root >> level, yet the folio->memcg_data points to the root_mem_cgroup. Hence, >> the folio->memcg_data of LRU folios always points to a valid pointer. >> However, the root_mem_cgroup does not possess an object cgroup. >> Therefore, we also allocate an object cgroup for the root_mem_cgroup. >> >> Signed-off-by: Muchun Song >> Signed-off-by: Qi Zheng >> Reviewed-by: Harry Yoo > > Looks good to me. > > Acked-by: Johannes Weiner Thanks!