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Wed, 02 Jul 2025 19:44:21 -0700 (PDT) Message-ID: <7f747869-dc37-64f3-127a-0b61a9d069dc@gmail.com> Date: Thu, 3 Jul 2025 10:44:13 +0800 Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 User-Agent: Mozilla/5.0 (Macintosh; Intel Mac OS X 10.15; rv:102.0) Gecko/20100101 Thunderbird/102.15.0 Subject: Re: [PATCH] mm/mglru: Stop try_to_inc_min_seq() if the oldest generation LRU lists are not empty To: Yuanchu Xie Cc: akpm@linux-foundation.org, hannes@cmpxchg.org, yuzhao@google.com, kinseyho@google.com, david@redhat.com, mhocko@kernel.org, zhengqi.arch@bytedance.com, shakeel.butt@linux.dev, lorenzo.stoakes@oracle.com, linux-mm@kvack.org, linux-kernel@vger.kernel.org, Hao Jia References: <20250630080603.36171-1-jiahao.kernel@gmail.com> From: Hao Jia In-Reply-To: Content-Type: text/plain; charset=UTF-8; format=flowed Content-Transfer-Encoding: 8bit On 2025/7/3 03:22, Yuanchu Xie wrote: > On Tue, Jul 1, 2025 at 10:45 PM Hao Jia wrote: >> >> Perhaps another way to explain it is clearer. >> >> It is known that min_seq[type] has not increased, that is, min_seq[type] >> is equal to lrugen->min_seq[type], then the following: >> >> case 1: min_seq[type] has not been reassigned and changed before >> judgment min_seq[type] <= lrugen->min_seq[type]. >> >> Then the subsequent min_seq[type] <= lrugen->min_seq[type] judgment will >> always be true. >> >> >> case 2: min_seq[type] is reassigned to seq, before judgment >> min_seq[type] <= lrugen->min_seq[type]. >> >> Then at least the condition of min_seq[type] > seq must be met before >> min_seq[type] will be reassigned to seq. >> That is to say, before the reassignment, lrugen->min_seq[type] > seq is >> met, and then min_seq[type] = seq. >> >> Then the following min_seq[type]（seq） <= lrugen->min_seq[type] judgment >> is always true. > > This sounds good to me. Can you change the code to use one bool to > detect any increments in `min_seq[type]`? You don't need `int > seq_inc_flags[ANON_AND_FILE] = {0};` > > Also update the commit message with what you have here. IMO much more clear. > Thanks for your review, I have done it in patch v2. Link to v2: https://lore.kernel.org/all/20250703023946.65315-1-jiahao.kernel@gmail.com/ Thanks, Hao