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 E4E3CFC9ED3 for ; Sat, 7 Mar 2026 08:53:13 +0000 (UTC) Received: by kanga.kvack.org (Postfix) id D932F6B0005; Sat, 7 Mar 2026 03:53:12 -0500 (EST) Received: by kanga.kvack.org (Postfix, from userid 40) id D40A46B0089; Sat, 7 Mar 2026 03:53:12 -0500 (EST) X-Delivered-To: int-list-linux-mm@kvack.org Received: by kanga.kvack.org (Postfix, from userid 63042) id C4C866B008A; Sat, 7 Mar 2026 03:53:12 -0500 (EST) X-Delivered-To: linux-mm@kvack.org Received: from relay.hostedemail.com (smtprelay0010.hostedemail.com [216.40.44.10]) by kanga.kvack.org (Postfix) with ESMTP id 9DDB86B0005 for ; Sat, 7 Mar 2026 03:53:12 -0500 (EST) Received: from smtpin15.hostedemail.com (a10.router.float.18 [10.200.18.1]) by unirelay03.hostedemail.com (Postfix) with ESMTP id 06DDDBC2A0 for ; Sat, 7 Mar 2026 08:53:12 +0000 (UTC) X-FDA: 84518652624.15.380A4EA Received: from out-177.mta1.migadu.com (out-177.mta1.migadu.com [95.215.58.177]) by imf22.hostedemail.com (Postfix) with ESMTP id 03385C000A for ; Sat, 7 Mar 2026 08:53:09 +0000 (UTC) Authentication-Results: imf22.hostedemail.com; dkim=pass header.d=linux.dev header.s=key1 header.b=CawqzaEc; spf=pass (imf22.hostedemail.com: domain of qi.zheng@linux.dev designates 95.215.58.177 as permitted sender) smtp.mailfrom=qi.zheng@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=1772873590; 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=BTpdDjrX0wTiL0fAhrePIJwxDS9K/k1k3ZXc5DUWgFA=; b=gJ+dXAM4xgBywbaMUSAzN5oz5QiDJ/u3zFbjqSRdcJh84oybGjmQk2ntnd9FlbsMHs5pj/ hZNKhlf/WoVTKTP6p10+WrJRj6bUzK1KqByPyyhST3Id8dcBcHhWzXn+76QBmz4C4z9cV2 qaOg2kmtWUoswOpGiLWR6ieke4MiunY= ARC-Authentication-Results: i=1; imf22.hostedemail.com; dkim=pass header.d=linux.dev header.s=key1 header.b=CawqzaEc; spf=pass (imf22.hostedemail.com: domain of qi.zheng@linux.dev designates 95.215.58.177 as permitted sender) smtp.mailfrom=qi.zheng@linux.dev; dmarc=pass (policy=none) header.from=linux.dev ARC-Seal: i=1; s=arc-20220608; d=hostedemail.com; t=1772873590; a=rsa-sha256; cv=none; b=EDfLqCEHCYs09+ZVRAW+vsBf1LmA+zI/F8sSn6v043GpPe+QhH3Qph30NctcLJ8iwwaULL O2UU56JsZpQIhM9uv5hTep6hUAK10DXvitCxxnjJQS7sGjYnWUGb0d7vt1wqQO7eyarqSz TWm3ER/C+Dr/py7X34SHe6T1XHbAL+o= Message-ID: DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=linux.dev; s=key1; t=1772873587; 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=BTpdDjrX0wTiL0fAhrePIJwxDS9K/k1k3ZXc5DUWgFA=; b=CawqzaEcU9hO9vJW+5g8ONlJ2RUwoSXjBsrHnHWghOAHhDNG5ovYnEL5GkizH5j+vQLW/u Smfzz/V5alCB0t6HJYZvtsS7YbVIFnMwRLlmk2UdFl5qh6hb18+cZxpoAZZ6kVemODYg/j 1uIpWYQGZmSj/3ji+7RQAzkA8EgqoCY= Date: Sat, 7 Mar 2026 16:51:58 +0800 MIME-Version: 1.0 Subject: Re: [PATCH v6 31/33] mm: memcontrol: convert objcg to be per-memcg per-node type To: Usama Arif Cc: hannes@cmpxchg.org, 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, yosry.ahmed@linux.dev, 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, bhe@redhat.com, usamaarif642@gmail.com, linux-mm@kvack.org, linux-kernel@vger.kernel.org, cgroups@vger.kernel.org, Qi Zheng References: <20260306202931.3878822-1-usama.arif@linux.dev> X-Report-Abuse: Please report any abuse attempt to abuse@migadu.com and include these headers. From: Qi Zheng In-Reply-To: <20260306202931.3878822-1-usama.arif@linux.dev> Content-Type: text/plain; charset=UTF-8; format=flowed Content-Transfer-Encoding: 7bit X-Migadu-Flow: FLOW_OUT X-Rspamd-Queue-Id: 03385C000A X-Stat-Signature: jg6ngwy1g1jmuydeqiok8g4ejkqswqqq X-Rspam-User: X-Rspamd-Server: rspam06 X-HE-Tag: 1772873589-293301 X-HE-Meta: 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 6XFFWo1C 04xZSl1yv1bL04jZSHlv/50lgqKkNlCuca5Q5nYtnqdb23UlBsDoWiXawqmst7Rk+3zvTtPyQkE/w5Vb2YcTYivVP3Gr3VGw125brVaNAafLH84ghRotRoNbBrc4MGUPHVF0FXqW/yhcNUlbfL/eGf7PljLa5EBy/+sxsNq03Rq+m0hsT/zxracx5ShZrxxdOhBOeAjw7PLAysXKQJssQa2mMqXIdCsyrtTea5I0XjnbUn89XdXwnY7WZ9gWKeySZsy+dRsFcJUC2sYc= Sender: owner-linux-mm@kvack.org Precedence: bulk X-Loop: owner-majordomo@kvack.org List-ID: List-Subscribe: List-Unsubscribe: Hi Usama, On 3/7/26 4:29 AM, Usama Arif wrote: > On Thu, 5 Mar 2026 19:52:49 +0800 Qi Zheng wrote: > >> From: Qi Zheng >> >> Convert objcg to be per-memcg per-node type, so that when reparent LRU >> folios later, we can hold the lru lock at the node level, thus avoiding >> holding too many lru locks at once. >> >> Signed-off-by: Qi Zheng >> Acked-by: Shakeel Butt >> --- >> include/linux/memcontrol.h | 23 +++++------ >> include/linux/sched.h | 2 +- >> mm/memcontrol.c | 79 +++++++++++++++++++++++--------------- >> 3 files changed, 62 insertions(+), 42 deletions(-) >> > > [...] > >> @@ -4087,7 +4100,13 @@ static int mem_cgroup_css_online(struct cgroup_subsys_state *css) >> xa_store(&mem_cgroup_private_ids, memcg->id.id, memcg, GFP_KERNEL); >> >> return 0; >> -free_shrinker: >> +free_objcg: >> + for_each_node(nid) { >> + struct mem_cgroup_per_node *pn = memcg->nodeinfo[nid]; >> + >> + if (pn && pn->orig_objcg) >> + obj_cgroup_put(pn->orig_objcg); > > Is it possible that you might call obj_cgroup_put twice on the same cgroup? Oh, I think you are right. Here pn->orig_objcg was not reset to NULL, so obj_cgroup_put() will be called in __mem_cgroup_free() again. > > If css_create fails, css_free_rwork_fn is queued, which ends up calling > mem_cgroup_css_free which calls obj_cgroup_put again? > > Maybe adding pn->orig_objcg = NULL overhere after obj_cgroup_put > is enough to prevent the double put from causing issues? Agree. Like this? diff --git a/mm/memcontrol.c b/mm/memcontrol.c index 992a3f5caa62b..e0795aec4356b 100644 --- a/mm/memcontrol.c +++ b/mm/memcontrol.c @@ -4140,8 +4140,10 @@ static int mem_cgroup_css_online(struct cgroup_subsys_state *css) for_each_node(nid) { struct mem_cgroup_per_node *pn = memcg->nodeinfo[nid]; - if (pn && pn->orig_objcg) + if (pn && pn->orig_objcg) { obj_cgroup_put(pn->orig_objcg); + pn->orig_objcg = NULL; + } } free_shrinker_info(memcg); offline_kmem: If there are no problems, I will send a fix patch later. Thanks, Qi > >> + } >> free_shrinker_info(memcg); >> offline_kmem: >> memcg_offline_kmem(memcg); >> -- >> 2.20.1 >> >>