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 60286D711CF for ; Fri, 19 Dec 2025 00:24:05 +0000 (UTC) Received: by kanga.kvack.org (Postfix) id 847016B008C; Thu, 18 Dec 2025 19:24:04 -0500 (EST) Received: by kanga.kvack.org (Postfix, from userid 40) id 7998C6B0092; Thu, 18 Dec 2025 19:24:04 -0500 (EST) X-Delivered-To: int-list-linux-mm@kvack.org Received: by kanga.kvack.org (Postfix, from userid 63042) id 65DFC6B0093; Thu, 18 Dec 2025 19:24:04 -0500 (EST) X-Delivered-To: linux-mm@kvack.org Received: from relay.hostedemail.com (smtprelay0017.hostedemail.com [216.40.44.17]) by kanga.kvack.org (Postfix) with ESMTP id 5182E6B008C for ; Thu, 18 Dec 2025 19:24:04 -0500 (EST) Received: from smtpin05.hostedemail.com (a10.router.float.18 [10.200.18.1]) by unirelay02.hostedemail.com (Postfix) with ESMTP id 0B34D13AB1A for ; Fri, 19 Dec 2025 00:24:04 +0000 (UTC) X-FDA: 84234323208.05.FF9F797 Received: from out-188.mta0.migadu.com (out-188.mta0.migadu.com [91.218.175.188]) by imf26.hostedemail.com (Postfix) with ESMTP id 39B8F140013 for ; Fri, 19 Dec 2025 00:24:02 +0000 (UTC) Authentication-Results: imf26.hostedemail.com; dkim=pass header.d=linux.dev header.s=key1 header.b=RZLJt1u5; spf=pass (imf26.hostedemail.com: domain of shakeel.butt@linux.dev designates 91.218.175.188 as permitted sender) smtp.mailfrom=shakeel.butt@linux.dev; dmarc=pass (policy=none) header.from=linux.dev ARC-Message-Signature: i=1; a=rsa-sha256; c=relaxed/relaxed; d=hostedemail.com; s=arc-20220608; t=1766103842; 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: in-reply-to:in-reply-to:references:references:dkim-signature; bh=e0+oX+rExeXmom0V9N+9NGQb1ojEVAyEotZoi27S/X8=; b=OKFQEd07D+HeaVt3oVjPQ/l6mCKPMu8J4yK9zUNwH9Td8IBrIUH9c5Poi5XK68tI0BP2f7 m8ZQap279kFf7ORnR9jKKVQkJzpWGs9o+bYI85MLdTBJqC1wmNdFdNcIkZ7hEK+vhNpLT4 lUVUWQMZdZVI7aehY798kDgdRvFbNbk= ARC-Authentication-Results: i=1; imf26.hostedemail.com; dkim=pass header.d=linux.dev header.s=key1 header.b=RZLJt1u5; spf=pass (imf26.hostedemail.com: domain of shakeel.butt@linux.dev designates 91.218.175.188 as permitted sender) smtp.mailfrom=shakeel.butt@linux.dev; dmarc=pass (policy=none) header.from=linux.dev ARC-Seal: i=1; s=arc-20220608; d=hostedemail.com; t=1766103842; a=rsa-sha256; cv=none; b=ZaxyOcA0Kf7yvGiwskOc6/ODlFUIEP8yrtCak2E3M+FxCrAXmwMeXmrvCZzQzg7nakpF61 tIE24ylgpJEcArhctQqa4P2nKJwk9k4wJUMln/OcoqqVveehaHsPnMZ/4CbGJ3CcBvFzHR zrWUZTrXsX0DlA6d17CaBoRajOqFNws= Date: Thu, 18 Dec 2025 16:23:48 -0800 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=linux.dev; s=key1; t=1766103835; 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: in-reply-to:in-reply-to:references:references; bh=e0+oX+rExeXmom0V9N+9NGQb1ojEVAyEotZoi27S/X8=; b=RZLJt1u5LXNALiyxSmprVDFAeGIC8zaGmEKBAXGhMBXumB2jhDT9m3Pk3Lz9HhjTREr/Yo c2X0SVlJ3bCSJ/afGcgX87ZYT8QZyUalb/341yZwsC7GC1bCHFc6AHuhiul32xy/6y9QkT 4hPhtTx8JW6Rth5C++VhaPwaCc0lHD4= X-Report-Abuse: Please report any abuse attempt to abuse@migadu.com and include these headers. From: Shakeel Butt To: Qi Zheng Cc: hannes@cmpxchg.org, hughd@google.com, mhocko@suse.com, roman.gushchin@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 Subject: Re: [PATCH v2 06/28] mm: memcontrol: allocate object cgroup for non-kmem case Message-ID: References: <897be76398cb2027d08d1bcda05260ede54dc134.1765956025.git.zhengqi.arch@bytedance.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <897be76398cb2027d08d1bcda05260ede54dc134.1765956025.git.zhengqi.arch@bytedance.com> X-Migadu-Flow: FLOW_OUT X-Rspamd-Server: rspam02 X-Stat-Signature: zs5p9h8d17p7qysc6wrbyrp7ibn7eajr X-Rspam-User: X-Rspamd-Queue-Id: 39B8F140013 X-HE-Tag: 1766103841-362548 X-HE-Meta: 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 K20Jmv9p bCrnrm+j0OwEiPLa6qNm4vt9NsVwot9PQvQ4x1KHYYulVMS4zqZpz7bO+GZ+S/a6WM7rLUa3aVR7wKIyRmz2LI0z508Ww2YeY9qd3Z7L6Na6EHsptNNpoUKzz8bBxkItCn6IE136UH0sJqfBvJn4+H7Oouqdx4JS+BZGlQN5OzXUOLJdMYQfxuiRZwCMbvvsErnymJmpZXgiYT+CgOFCpwABWerkr/WiHDsQB1dLBJwHcjP7COS0bE9v+MY8IJEeyEkrH 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 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. > > 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. > > 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 Acked-by: Shakeel Butt