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s=arc-20220608; d=hostedemail.com; t=1766450749; a=rsa-sha256; cv=none; b=sRS6e2FAKT1rjYrX4IcLc6VvgfmJJjMAZYuOaUmNJo0CrLmcpp4kjlrWDEpqEHLZgGngYI yZKsSoUHqMxeD1NY7fcrOBUZ93vbz6UGrIsFZvCc4dfUzyz0mfTQFxv/Tm8vFbrjyIeGWT 8d+ME0f4TWgI2ChRohLMlYcD1HcbPg8= ARC-Authentication-Results: i=1; imf03.hostedemail.com; dkim=none; spf=pass (imf03.hostedemail.com: domain of chenridong@huaweicloud.com designates 45.249.212.51 as permitted sender) smtp.mailfrom=chenridong@huaweicloud.com; dmarc=none Received: from mail.maildlp.com (unknown [172.19.163.198]) by dggsgout11.his.huawei.com (SkyGuard) with ESMTPS id 4dZx9q4cH0zYQtGk for ; Tue, 23 Dec 2025 08:45:03 +0800 (CST) Received: from mail02.huawei.com (unknown [10.116.40.128]) by mail.maildlp.com (Postfix) with ESMTP id C0C264056B for ; Tue, 23 Dec 2025 08:45:39 +0800 (CST) Received: from [10.67.111.176] (unknown [10.67.111.176]) by APP4 (Coremail) with SMTP id gCh0CgB31_cy5klp8wiXBA--.20992S2; Tue, 23 Dec 2025 08:45:39 +0800 (CST) Message-ID: <8aff3f15-79d6-48a0-a63d-735fabf6759d@huaweicloud.com> Date: Tue, 23 Dec 2025 08:45:38 +0800 MIME-Version: 1.0 User-Agent: Mozilla Thunderbird Subject: Re: [PATCH -next 1/5] mm/mglru: use mem_cgroup_iter for global reclaim To: Shakeel Butt Cc: akpm@linux-foundation.org, axelrasmussen@google.com, yuanchu@google.com, weixugc@google.com, david@kernel.org, lorenzo.stoakes@oracle.com, Liam.Howlett@oracle.com, vbabka@suse.cz, rppt@kernel.org, surenb@google.com, mhocko@suse.com, corbet@lwn.net, hannes@cmpxchg.org, roman.gushchin@linux.dev, muchun.song@linux.dev, zhengqi.arch@bytedance.com, linux-mm@kvack.org, linux-doc@vger.kernel.org, linux-kernel@vger.kernel.org, cgroups@vger.kernel.org, lujialin4@huawei.com, zhongjinji@honor.com References: <20251209012557.1949239-1-chenridong@huaweicloud.com> <20251209012557.1949239-2-chenridong@huaweicloud.com> <702b6c0b-5e65-4f55-9a2f-4d07c3a84e39@huaweicloud.com> Content-Language: en-US From: Chen Ridong In-Reply-To: Content-Type: text/plain; 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>>>> break; >>> >>> This seems buggy as we may break the loop without calling >>> mem_cgroup_iter_break(). I think for kswapd the cookie will be NULL and >>> if should_abort_scan() returns true, we will break the loop without >>> calling mem_cgroup_iter_break() and will leak a reference to memcg. >>> >> >> Thank you for catching that—my mistake. >> >> This also brings up another point: In kswapd, the traditional LRU iterates through all memcgs, but >> stops for the generational LRU (GENLRU) when should_abort_scan is met (i.e., enough pages are >> reclaimed or the watermark is satisfied). Shouldn't both behave consistently? >> >> Perhaps we should add should_abort_scan(lruvec, sc) in shrink_node_memcgs for the traditional LRU as >> well? > > We definitely should discuss about should_abort_scan() for traditional > reclaim but to keep things simple, let's do that after this series. For > now, follow Johannes' suggestion of lru_gen_should_abort_scan(). > Okey, understood. -- Best regards, Ridong