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Received: from 30.246.177.19(mailfrom:baolin.wang@linux.alibaba.com fp:SMTPD_---0X8VCyTA_1786068232 cluster:ay36) by smtp.aliyun-inc.com; Fri, 07 Aug 2026 10:03:53 +0800 Message-ID: <06cd88f2-8e2a-490f-804c-93c200bd294a@linux.alibaba.com> Date: Fri, 7 Aug 2026 10:03:51 +0800 MIME-Version: 1.0 User-Agent: Mozilla Thunderbird Subject: Re: [RFC PATCH v5 3/4] mm/vmscan: avoid pointless large folio splits without swap To: Xueyuan Chen , akpm@linux-foundation.org, linux-mm@kvack.org Cc: linux-kernel@vger.kernel.org, cgroups@vger.kernel.org, zhaonanzhe@xiaomi.com, baohua@kernel.org, hannes@cmpxchg.org, youngjun.park@lge.com, hughd@google.com, chrisl@kernel.org, kasong@tencent.com, shikemeng@huaweicloud.com, nphamcs@gmail.com, baoquan.he@linux.dev, mhocko@kernel.org, roman.gushchin@linux.dev, shakeel.butt@linux.dev, muchun.song@linux.dev, david@kernel.org, ljs@kernel.org, liam@infradead.org, vbabka@kernel.org, rppt@kernel.org, surenb@google.com, qi.zheng@linux.dev, axelrasmussen@google.com, yuanchu@google.com, weixugc@google.com References: <20260730122304.2496440-1-xueyuan.chen21@gmail.com> <20260730122304.2496440-4-xueyuan.chen21@gmail.com> From: Baolin Wang In-Reply-To: <20260730122304.2496440-4-xueyuan.chen21@gmail.com> Content-Type: text/plain; charset=UTF-8; format=flowed Content-Transfer-Encoding: 7bit X-Rspamd-Server: rspam01 X-Rspamd-Queue-Id: EB07520002 X-Stat-Signature: 6orcef5wsrtrayyf1pfn9oqrpnrznhd5 X-Rspam-User: X-HE-Tag: 1786068237-377480 X-HE-Meta: U2FsdGVkX19ty8C+si+IBvMJ5l/7ERoB5dtF9Il06MO+U0oC/tQGeXklIEoVWw2x9OBrEk5DstBRU0j4rZd1IKXzRf8ZH7NgeXeEpnk3FoYir9qCiClhm6nGr258//hdSkACWnEusAr381SbSR0/umt+XeJyKvqvYUtkUm3LTfg3jGI5XSCf5oZEr7pi0MB7X+G/q1erRx594Ho2wLt5DfD1uKfJdgU9VSvUNsxYYCigFZeKMc8k+KGjFt4dBt/DEYxwtjxXDHL/OiQ1PZDAyc1lt3q2Q1oG5Y+hX4xm0vQ+qB8GmrNNeGq7a/l92V7rvEiAsGwlcas/83hikMKswVnPC2Js3wCMGU7PGwsTg9S5m43uYbTc3zlYgu8Mu+C9EHu5G7lHzr/iiPFWUKmuCRGMBJIp7Vr4eGJM8FQHM07HfNjaXjQyCHCJPgzLg8/zYZfTTRo8lo0t6Pqk8PMUoM6pY4fo53/SizOK/WT9wQ0ldaC62ZxV+NEvW9btD4q/0Wyibj+IL+VXLEzIEXW/T4XnTprM8JLu32oOjjiBmuU6yoUyDsZ0p+YJY9Zm34aoy8ZYa0IHkJYL0L6RYc/Mf4r7BZoYvxggHrDBwXB4/FkFA89hxe7uJOYLY87EaMEbVWwcodBqsdZ4BDCWLTfnDya6NQgIKXIiwePGgC6FD+caJm9XChfnORygkla0VfvHTnrVxxDnCswFMpYZHT90tgfNVHYpKnNKFB5ayyvMTHslySvR2Womb9n/RMRjYZ3gJUsPGqud9Zx5JHeZ1hpPYNrJuRmrjDQhxVgrW4Bumwm5Dv8htmFUMgdMgYlHUpN61UaKFMG6IYkxvZ7JOZcN5dt/uOjy0gm73uMvPn06GVVMEhp9SLjY6OBAS/gvwCgWRhkjgiWYNfqPZ/bgRLePe55T1hSfsh9Sr+7g9DZFcgTvk8+t4ujbewmSYSY2gJBbqdQbKr2v8RTHgGIH8YO 6+I87XHi faUgS3afwMlH9GydWZA99Oc85sGe/82Vky3N/TAIncHyRDM9gX62RpGfhCui109Ca1E9EUWIEIJ4k2CUC2jUVB/Jlv/kJnO5RnOnLxkA8GKQbEyOHGKUkL59ZjkOjPbvMQSGnEu8nCSNVUsvZVpF9Tp1LcV05GV1h1QV/q4ItQozjaZJVUeHNMtdyLIoy5wGPVstQZi4G5NUih6dPcVvyL4FMgnfz8zjEaoCTIHdd54EXAPTowFQW4OzwT7dLLz5x2FSt3WmiwUorzu6IVfXvY65wukgzrN6ePdU2yFyhROxAaYtmNuCdVAc/mjQcxmIdwBOJ5b2VhybVOm+TrPOINZQqcMdq3WkPk3E/69P3nxVKmEHWrjtBCeEFZNKo0jXtTNNqvl9GU7ZlVRFVYcNIYTadiP1TQzQ0Tl/8SbF/QXex+D7yuaUcc0V4Jh0XGbyoOtOfyGIOa168PvJxgNXU3kerNA== Sender: owner-linux-mm@kvack.org Precedence: bulk X-Loop: owner-majordomo@kvack.org List-ID: List-Subscribe: List-Unsubscribe: On 7/30/26 8:23 PM, Xueyuan Chen wrote: > From: "Barry Song (Xiaomi)" > > When swap is disabled, exhausted, or unavailable due to memcg swap > limits, splitting a large anonymous folio cannot make swapout progress. > The fallback only destroys the large folio and inflates split statistics. > > Use -E2BIG from folio_alloc_swap() as the explicit signal that splitting > the folio might allow swapout of smaller pieces. For other allocation > failures, keep the existing activation path and avoid the split. > > This preserves the split fallback for fragmented or partially available > swap, while avoiding it when there is no backing space for any part of the > folio. > > Reported-by: Nanzhe Zhao > Signed-off-by: Barry Song (Xiaomi) > Signed-off-by: Xueyuan Chen > --- LGTM. Feel free to add: Reviewed-by: Baolin Wang