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 088D0CF8859 for ; Thu, 20 Nov 2025 13:39:30 +0000 (UTC) Received: by kanga.kvack.org (Postfix) id 503776B008A; Thu, 20 Nov 2025 08:39:30 -0500 (EST) Received: by kanga.kvack.org (Postfix, from userid 40) id 48C356B008C; Thu, 20 Nov 2025 08:39:30 -0500 (EST) X-Delivered-To: int-list-linux-mm@kvack.org Received: by kanga.kvack.org (Postfix, from userid 63042) id 353CF6B0092; Thu, 20 Nov 2025 08:39:30 -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 210BB6B008A for ; Thu, 20 Nov 2025 08:39:30 -0500 (EST) Received: from smtpin25.hostedemail.com (a10.router.float.18 [10.200.18.1]) by unirelay06.hostedemail.com (Postfix) with ESMTP id 748B012A95C for ; Thu, 20 Nov 2025 13:39:27 +0000 (UTC) X-FDA: 84131092374.25.EF7B4FE Received: from out-170.mta1.migadu.com (out-170.mta1.migadu.com [95.215.58.170]) by imf06.hostedemail.com (Postfix) with ESMTP id 8666B180008 for ; Thu, 20 Nov 2025 13:39:25 +0000 (UTC) Authentication-Results: imf06.hostedemail.com; dkim=pass header.d=linux.dev header.s=key1 header.b=A4d9y4YW; dmarc=pass (policy=none) header.from=linux.dev; spf=pass (imf06.hostedemail.com: domain of qi.zheng@linux.dev designates 95.215.58.170 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=1763645965; 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=4VBW5d85HPNjGo5XvcopxN5QwpZOcDhSseUA2IDtV6A=; b=Cp6Fp5Usc2SH5h6ZPpppZ7nxHXyfidw0VCvbN9SbkyeK1LV84Ib/oJBUQmkSwUnoemGVaC hzpCZYUNOxFKMAcsslGDmmgDbOo8lvSzDCOYfrLLbdDcQSz+aZe75MdKtHal7TB+gJgdyk Wa8bDYdaK+w0/GSgWK4/K/YYOlfGtq4= ARC-Seal: i=1; s=arc-20220608; d=hostedemail.com; t=1763645965; a=rsa-sha256; cv=none; b=31oFDTdXxwgxiq8NqteccSZI/pNLYZYTQ7ReLitQnU0O0raByOwa0oxEkc1U4K6H+Wg2YE Bl1LYaHhZQ3/cYTmaz3Lz/KAZTw9E3Q8Zg+XUYZIXhfzrVpccc/b03YwtYhr/FhFshzoCC M0ZhbiO+6h5cXUjG4BcTDciFn9cuOxk= ARC-Authentication-Results: i=1; imf06.hostedemail.com; dkim=pass header.d=linux.dev header.s=key1 header.b=A4d9y4YW; dmarc=pass (policy=none) header.from=linux.dev; spf=pass (imf06.hostedemail.com: domain of qi.zheng@linux.dev designates 95.215.58.170 as permitted sender) smtp.mailfrom=qi.zheng@linux.dev Message-ID: <82a16330-f801-46f9-bc4d-b10ae9e1472a@linux.dev> DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=linux.dev; s=key1; t=1763645963; 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=4VBW5d85HPNjGo5XvcopxN5QwpZOcDhSseUA2IDtV6A=; b=A4d9y4YWBMIDtkYVklUQaOQptNvSdxm1jgBqV92EzXwKqRp6kfKDevWnXtE/QsdXN65gi5 n9IUhTH1NvnYDMs2/WbW/QyCefvwAe0xMwYh2pih3XH9sj9UJqFaEJEbaNa6MWWuRZsXvl azBSwSk/aVFUYrpaIUusu5PJC937F6A= Date: Thu, 20 Nov 2025 21:39:11 +0800 MIME-Version: 1.0 Subject: Re: [PATCH v1 13/26] mm: mglru: prevent memory cgroup release in mglru To: Harry Yoo Cc: hannes@cmpxchg.org, hughd@google.com, mhocko@suse.com, roman.gushchin@linux.dev, shakeel.butt@linux.dev, muchun.song@linux.dev, david@redhat.com, lorenzo.stoakes@oracle.com, ziy@nvidia.com, imran.f.khan@oracle.com, kamalesh.babulal@oracle.com, axelrasmussen@google.com, yuanchu@google.com, weixugc@google.com, akpm@linux-foundation.org, linux-mm@kvack.org, linux-kernel@vger.kernel.org, cgroups@vger.kernel.org, Muchun Song , Qi Zheng References: 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-Stat-Signature: nueu1nqgcyxuczwugpauz9wiy3y5bp15 X-Rspam-User: X-Rspamd-Queue-Id: 8666B180008 X-Rspamd-Server: rspam10 X-HE-Tag: 1763645965-893205 X-HE-Meta: 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 83Ssn4mu PBcEUNNFrJqSfbVW7NCgTswX6AY06r5gjbxqiAXQfKL6iWwIOMwyhnghSEv6t/k/l36sdYRgcn6CM8TftbeWXGPl79+vaMutDVnIvq/sYvHgyOpv1QI3jFIGjtW8Dj9nm1zEBXy9ug3mL//P8Ex6JN6yo+bojeqffr7yTojYe8AdviwQHS4E3hk5zJqSc50HxQTRIkWbm+mQP3saTfmCtzhZOU7Xnc15hIuEFW9Lnb+oCL78DTAdRgs+OU73y94968lnEatDLdJjSAeo= 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 11/19/25 6:13 PM, Harry Yoo wrote: > On Tue, Oct 28, 2025 at 09:58:26PM +0800, Qi Zheng wrote: >> From: Muchun Song >> >> In the near future, a folio will no longer pin its corresponding >> memory cgroup. To ensure safety, it will only be appropriate to >> hold the rcu read lock or acquire a reference to the memory cgroup >> returned by folio_memcg(), thereby preventing it from being released. >> >> In the current patch, the rcu read lock is employed to safeguard >> against the release of the memory cgroup in mglru. >> >> This serves as a preparatory measure for the reparenting of the >> LRU pages. >> >> Signed-off-by: Muchun Song >> Signed-off-by: Qi Zheng >> --- >> mm/vmscan.c | 23 +++++++++++++++++------ >> 1 file changed, 17 insertions(+), 6 deletions(-) >> >> diff --git a/mm/vmscan.c b/mm/vmscan.c >> index 660cd40cfddd4..676e6270e5b45 100644 >> --- a/mm/vmscan.c >> +++ b/mm/vmscan.c >> @@ -4279,6 +4288,8 @@ bool lru_gen_look_around(struct page_vma_mapped_walk *pvmw) >> >> arch_leave_lazy_mmu_mode(); >> >> + rcu_read_unlock(); >> + >> /* feedback from rmap walkers to page table walkers */ >> if (mm_state && suitable_to_scan(i, young)) >> update_bloom_filter(mm_state, max_seq, pvmw->pmd); > > mm_state has the same life cycle as mem_cgroup. So it should be > protected by rcu read lock? You are right. The mm_state is defined as follows: struct lruvec { struct lru_gen_mm_state mm_state; }; will fix it in the next version. Thanks, Qi >