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Received: from 30.74.144.121(mailfrom:baolin.wang@linux.alibaba.com fp:SMTPD_---0X9U07yk_1787556133 cluster:ay36) by smtp.aliyun-inc.com; Mon, 24 Aug 2026 15:22:14 +0800 Message-ID: <7e897a4e-2075-485a-8cc5-5bb928fba437@linux.alibaba.com> Date: Mon, 24 Aug 2026 15:22:13 +0800 MIME-Version: 1.0 User-Agent: Mozilla Thunderbird Subject: Re: [PATCH 0/3] mm/mglru: clean up isolate_folios and scan_folios for readability and clarity To: "Barry Song (Xiaomi)" , akpm@linux-foundation.org, linux-mm@kvack.org Cc: axelrasmussen@google.com, 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, 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, yuanchu@google.com References: <20260820045603.68809-1-baohua@kernel.org> From: Baolin Wang In-Reply-To: <20260820045603.68809-1-baohua@kernel.org> Content-Type: text/plain; charset=UTF-8; format=flowed Content-Transfer-Encoding: 7bit X-Rspamd-Server: rspam05 X-Rspamd-Queue-Id: E04841C0006 X-Stat-Signature: ou5ctc5k816imfqydosjk3c3pt3315r4 X-Rspam-User: X-HE-Tag: 1787556140-852452 X-HE-Meta: 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 rE3FhrbH 9fvNDpPHv15Y2E8h62dOwv5SahO1Z6pagS5gRHjWq4LyXoB9e4SsZ+TSTHpvC6sw5wS4Stl99vaP9/e4pMyU/gIXNvtHMFJr96RddxEm0zJjWuzqiKXxyuF4xEymYIEV2VL7aXwGIBWIh823eQ9Y2yyuTHQoHUgO51n2D5TvW7gVzONwEzfTTuNbD5wqOJm9wViWx/s1bmydIKmnfIpyVpGE/7vicBa1n9gsEbjf1FrkfjdXKEAHoj+j5c9KGvAGZJEty8yE2GdAUPyyqSWLseL8dwfpS9hm9OvxNG2PFl0kl0HOMROlJn84cCZLoveSYOFRxy/0Ep/XvX5OHa/NrIo8/wt4aoIMxDcfWDGrMk3XQtUCXS0iNIuianGJo4M7x7V+6eMzktJz4eYEKLuil3+kT3nGrD35CbNnT4kZYqSBiPxNcWN7NtmyOOkZIKLPIIvy5w7KoivdHc4M= Sender: owner-linux-mm@kvack.org Precedence: bulk X-Loop: owner-majordomo@kvack.org List-ID: List-Subscribe: List-Unsubscribe: On 8/20/26 12:56 PM, Barry Song (Xiaomi) wrote: > This is a cleanup series split out from the MGLRU swappiness series [1], > with the cleanup changes separated to make them easier to review. > > Right now, isolate_folios() is quite difficult to follow: > > 1. It uses for_each_evictable_type(i, swappiness) to iterate over the > types, but i is not actually used as the type within the loop body. > > 2. It uses scanned == 0 to detect whether the current reclaim type is > exhausted, but this is not an accurate indication. > > 3. It has an internal retry when no folios can be isolated after scanning > some folios, but the retry is implemented in a way nobody can understand. > > This patchset makes these behaviors explicit and much easier to follow. > > Run kernel builds for several rounds in a 1 GB memcg and take the > average build time. The patchset shows almost no performance impact, > with a very small improvement that could simply be noise: Just FYI: I tested this patchset with a 3G memcg limit and a 10G zram device, running 'make -j32' to build kernel on my 32-core Arm machines, and got some performance improvement for ths sys time: w/o patch w/patch sys 1845s 1570s > w/o patch w/patch Delta > > real 109.149 108.990 -0.15% > sys 223.213 222.592 -0.28% > > pgscan_file 498,208 486,994 -2.25% > refault_file 262,696 254,688 -3.05% > > Thanks very much to Baolin and Lian for their previous reviews of the > original RFC patchset for this part. > > [1] https://lore.kernel.org/linux-mm/20260812121658.69965-1-baohua@kernel.org/ > > Barry Song (Xiaomi) (2): > mm/mglru: improve scan_folios() exhaustion detection > mm/mglru: retry the same type once if isolation fails due to races > > Ridong Chen (1): > mm/mglru: improve readability of isolate_folios() > > mm/vmscan.c | 78 ++++++++++++++++++++++++++++++++++++----------------- > 1 file changed, 54 insertions(+), 24 deletions(-) >