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b=PdGiT0CuPwQbG7gpnwF2wu669kC1UAzW8GO4geRORQE0qSbP4ixBfL0PHSiQCsGRn ZIVRqTqDeINniv6qDdu1ce5ZHYAbn53uHjcWWbqrsFieDgIyxyliRaSY9PM0F0t6+o qCtD+9qN4iV+el0CYwQbFjuhTSMKeEZWzORDeQydnniS9d4oQfCnwl6mcBiERmb3W+ mhUr4sACuzrGSuAp9qJavKJuWoVhFuZJr/FhsdOlmUbhqnHAsTtnMJrWSP943NpM0L JXRaHqQIVrgTCoxODhGEHuNbnXs1ZR8tlaqbKxYmiw/G5C4T4LH7uLwed+rz32prBu azyrNI47fDITA== From: "Barry Song (Xiaomi)" To: baolin.wang@linux.alibaba.com, akpm@linux-foundation.org Cc: axelrasmussen@google.com, baohua@kernel.org, baoquan.he@linux.dev, chenridong@xiaomi.com, david@kernel.org, hannes@cmpxchg.org, kasong@tencent.com, lianux.mm@gmail.com, linux-kernel@vger.kernel.org, linux-mm@kvack.org, ljs@kernel.org, lyugaofei@xiaomi.com, mhocko@kernel.org, qi.zheng@linux.dev, shakeel.butt@linux.dev, stevensd@chromium.org, wangzicheng@honor.com, weixugc@google.com, xueyuan.chen21@gmail.com, yuanchu@google.com, zhangbo56@xiaomi.com Subject: Re: [PATCH v3 6/7] mm/mglru: move folios from oldest gen to second-oldest gen from head to tail Date: Fri, 4 Sep 2026 11:27:48 +0800 Message-Id: <20260904032748.210-1-baohua@kernel.org> X-Mailer: git-send-email 2.39.3 (Apple Git-146) In-Reply-To: <129ecc53-f96e-4a5d-a79c-c05293d815d3@linux.alibaba.com> References: <129ecc53-f96e-4a5d-a79c-c05293d815d3@linux.alibaba.com> MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit X-Stat-Signature: k4nouoi5kdcexowcm4x7rnuig3xq4mz6 X-Rspamd-Server: rspam12 X-Rspamd-Queue-Id: 313AF40005 X-Rspam-User: X-HE-Tag: 1788492476-375658 X-HE-Meta: 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 NhVoWBKK akF/EpLBOyHvdQwkULZU+gesOqN4ImWRGYrveWz0Qge63rOEv/eEabn2eEwZDOy8mRULMlHP3fwCWkV/NbUDnc/EjU8M+ywOohnwxJbbr0qCBeyIZP6PO7RvfEg7qg03nfOsYNvxugiEFeFt3aaOA7gU+JUppJu/iN0Udltl0xBlLj2Oy0mRaNzXDPA74fh7ISLtlsuWrE2Pq8W9Q/xf4g30K+COzAFpV11yawstJ3jaXbk1RbWS5Dwd+AQNgg6VpyxQk8rhSBBsn1ykvfVRwBMDQSGnzkv5iGFod1QXgFWnWP+mV3H3+njdTGQDYzRc9g+2R7ozMG5hCE5Mv80UY5DTMhQ== Sender: owner-linux-mm@kvack.org Precedence: bulk X-Loop: owner-majordomo@kvack.org List-ID: List-Subscribe: List-Unsubscribe: On Fri, Sep 4, 2026 at 10:47 AM Baolin Wang wrote: [...] > > Could you add this info to the commit message? (IIUC, someone tried to > remove the prefetch in MM, since they found that prefetch doesn't seem > to help much on modern CPUs.) Sure. I guess we could ask Andrew for his kind help in adding the following to the Changelog of this patch. Hi Andrew, Could you please update the changelog and add the description below at the end? Hopefully, this would be easier for you than handling a new version. If you would prefer a new version instead, please let me know. The impact of the added prefetching might be arch-dependent. Some architectures could benefit more from prefetching, while others might see little to no impact. In my x86 test, it shows a very slight improvement: ***** no-prefetch: agetest: ... gen 100:    2.421 ms gen 101:    2.424 ms gen 102:    2.420 ms gen 103:    2.413 ms Total:   248.418 ms Average: 2.460 ms agetest: ... gen 100:    2.393 ms gen 101:    2.396 ms gen 102:    2.395 ms gen 103:    2.392 ms Total:   245.627 ms Average: 2.432 ms agetest: ... gen 100:    2.433 ms gen 101:    2.427 ms gen 102:    2.432 ms gen 103:    2.450 ms Total:   249.186 ms Average: 2.467 ms **** has-prefetch: agetest: .... gen 100:    2.314 ms gen 101:    2.310 ms gen 102:    2.321 ms gen 103:    2.303 ms Total:   237.619 ms Average: 2.353 ms agetest: gen 100:    2.342 ms gen 101:    2.343 ms gen 102:    2.339 ms gen 103:    2.335 ms Total:   239.929 ms Average: 2.376 ms agetest: gen 100:    2.344 ms gen 101:    2.347 ms gen 102:    2.352 ms gen 103:    2.348 ms Total:   241.188 ms Average: 2.388 ms Basically, it’s 2.3xx vs. 2.4xx, lower is better.