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Howlett" , Nico Pache , Ryan Roberts , Dev Jain , Barry Song , Lance Yang , Mike Rapoport , Suren Baghdasaryan , Michal Hocko , Kairui Song , Qi Zheng , Shakeel Butt , Axel Rasmussen , Yuanchu Xie , Wei Xu , Rik van Riel , Harry Yoo , Jann Horn , Johannes Weiner , linux-kernel@vger.kernel.org, Luka Bai Subject: Re: [PATCH 2/5] mm/khugepaged: use slab cache instead of normal kmalloc Message-ID: References: <20260531-thp_collapse_hint-v1-0-e7f8c2035621@tencent.com> <20260531-thp_collapse_hint-v1-2-e7f8c2035621@tencent.com> MIME-Version: 1.0 Content-Type: text/plain; charset=utf-8 Content-Disposition: inline Content-Transfer-Encoding: 8bit In-Reply-To: X-Proofpoint-ORIG-GUID: t5BKz75ZnySRwTvBBiKMnByvzccKJ5w6 X-Authority-Info-Out: v=2.4 cv=EKwLElZC c=1 sm=1 tr=0 ts=6a2a288f cx=c_apl:c_pps:t_out a=bsP7O+dXZ5uKcj+dsLqiMw==:117 a=bsP7O+dXZ5uKcj+dsLqiMw==:17 a=IkcTkHD0fZMA:10 a=FelO9ux0wxsA:10 a=x7bEGLp0ZPQA:10 a=UaoJkeuwEpQA:10 a=VkNPw1HP01LnGYTKEx00:22 a=GvQkQWPkAAAA:8 a=m7Ui_3NsPc4YXKPq_aYA:9 a=3ZKOabzyN94A:10 a=QEXdDO2ut3YA:10 X-Proofpoint-Spam-Details-Enc: AW1haW4tMjYwNjExMDAyOSBTYWx0ZWRfX4l+a9oFbl2ox b88Qc2+ZGmKn++3zFz882O+a9KPxBFQ3YHYIW46q+0JhG5h8r6Cx4c4h+SI6IZZdxv/+q3g+SeO wv2x6YY9/NY2v+vQqPborxdmenjriyGjiocUi5Zxr+9TwwASzEM7VZ9S+MCiELPuXRgG+jESZQN TEDibLodPu3OcTE3eXqkm6g948PJrjS+LD3Hzmv8alpc+qN86XQjW8Q1qAbP5PlE/p2W1O+dV0P Qf+zUZsMtD0GuzpQmoaOMsE3ljscNkv3IVl7TdUeIAZXee/MG+iQmxktBk3EjGPjS0gA44vmOhv hr7Qmd04d43M164WJ89sTL0Mlg6bFR9IuYBxsdwsySpR/Qiheq2RvXwxkAA1Ww= X-Proofpoint-GUID: t5BKz75ZnySRwTvBBiKMnByvzccKJ5w6 X-Rspamd-Queue-Id: DB5374000B X-Stat-Signature: o1mwsk3b8zsdssdgiaey83rgksecryy5 X-Rspam-User: X-Rspamd-Server: rspam12 X-HE-Tag: 1781147792-998890 X-HE-Meta: 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 UOG15+BT 1qOH9dVtjclpgqF2GNSL9Inbaq+hDjaSxIaFsHzWHMAQxhkNIzEn8Xa5Ei2wefdvQ4YubnDe2B/7/Fqkxhwi/81tnjpI9LU1k1ctoOdt/HsqQgLTsdOUbvkaQNWyOwB3ners4q/LriR556kabBcOdfBYPicH6EtIrPayNWYgZI3Y1vDKXV7K3ZMJu8qzskknnYm+eRnHq76gP6Gsoh8MEbikenj+4jCLofT1scJiuDVyvwGX/GobDUki+NoDDKqpNkAmlGPpYRS1ZiyJHpRg7AZvfcmkxYEkvyX4gBgGI/y0kqD5TlE5Pkm4YMumK0qEhibMgkYoV+xDFKvVn+wIVDMw7o5kEPoVauDG0nCtLxABV/snjU3C2RuvdOlkIxcfe4rbTWKZNkTV6BkH+GKQnrmaWmTDYYmGuXbKyJKv5EWmdYkObPUCkJSUs7w== Sender: owner-linux-mm@kvack.org Precedence: bulk X-Loop: owner-majordomo@kvack.org List-ID: List-Subscribe: List-Unsubscribe: 在 Tue, Jun 09, 2026 at 12:26:18PM +0200，Vlastimil Babka (SUSE) 写道： > On 5/31/26 06:23, Luka Bai wrote: > > From: Luka Bai > > > > We added a kmem slab cached called collapse_hint_cache for > > khugepaged collapse hint, to improve the performance in allocation > > and freeing for the hint structs. > > > > Signed-off-by: Luka Bai > > Khugepaged isn't exactly a hotpath? Adding own cache comes with memory > overhead, so this doesn't seem like a sufficient reason to do that. > Hi Vlastimil, Thanks for the review :). Yeah Khugepaged is not a hotpath. But in my implementation we will allocate those khugepaged collapse hint structs in other paths like walk_mm() and lru_gen_look_around(), which may be called more frequently under memory pressure. I'm a little afraid that directly using kmalloc may compromise the performance of reclaimation... What do you think? Thanks. :) Best regards, Luka