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b=gasBn2fWJ//NUxKL9tbdOzF2iOSzTNPiq5/m0pGiDe93U97Scwv8eD+9RETnfvY0O iuBi3UjXjvaEtfc63eKCkUcmLedLEFvXR5LG9JqmtusXEVqSiqbiKljn4YEjktnb6t 5gFWJ0txmmGVWitITkJJcCtmyqMDf56SELo8VTG8U0qqOVk39cnPO+MzCTb51nFEQD HikzV64qn7+vpXjI9Oj2oQAgiQj9mrA9+qa9MDmHNpTUdaZQo7JcfizQP0ov3cC7cP FKFM4sXj8GwVPFb7bKU/JpBr2Uju+jdPO2Mik+ceDzAhnUw84MhboGKReIV5liJ+x0 dH7xIrExMdh+w== From: SeongJae Park To: Asier Gutierrez Cc: SeongJae Park , akpm@linux-foundation.org, damon@lists.linux.dev, linux-mm@kvack.org, linux-kernel@vger.kernel.org, wangkefeng.wang@huawei.com, artem.kuzin@huawei.com, stepanov.anatoly@huawei.com Subject: Re: [RFC PATCH v1] mm: improve call_controls_lock Date: Mon, 29 Dec 2025 07:22:49 -0800 Message-ID: <20251229152250.78975-1-sj@kernel.org> X-Mailer: git-send-email 2.47.3 In-Reply-To: <20251229145533.2437293-1-gutierrez.asier@huawei-partners.com> References: MIME-Version: 1.0 Content-Transfer-Encoding: 8bit X-Rspamd-Server: rspam01 X-Rspamd-Queue-Id: C93B1C0011 X-Stat-Signature: j31fjqepsah1o3jh9j31fhdy93a6dyr8 X-Rspam-User: X-HE-Tag: 1767021783-568731 X-HE-Meta: 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 Z48ZBpgp NsLj2MRG7uLfp1373HrptSJqG/qzfgU7VksxQ4kA9tSsKN5VKEtGAXxdYKmX6j8vFIe+HS0s8RUFCR0h7oYnLBfJ4uhCjT1OfibNrPqYom4EOenWm5Vrez6FYDNapxlXcdAmICaIgqZvUnN0PJ05jsNEIxpG/0d6oHxWCBi+yFrUfZYNLzkzfFt4V+0kSpsRzp1qtA43jJAe0f+t2p0J0LgH9vIXbf8NdlJRieJbKm8Yv2n6MWk/OJWYOovAI47b9OQKKj9nrqjQIlj+4QNsvkPz5aw== X-Bogosity: Ham, tests=bogofilter, spamicity=0.000000, version=1.2.4 Sender: owner-linux-mm@kvack.org Precedence: bulk X-Loop: owner-majordomo@kvack.org List-ID: List-Subscribe: List-Unsubscribe: Hello Asier, Thank you for sending this patch! On Mon, 29 Dec 2025 14:55:32 +0000 Asier Gutierrez wrote: > This is a minor patch set for a call_controls_lock synchronization improvement. Please break description lines to not exceed 75 characters per line. > > Spinlocks are faster than mutexes, even when the mutex takes the fast > path. Hence, this patch replaces the mutex call_controls_lock with a spinlock. But call_controls_lock is not being used on performance critical part. Actually, most of DAMON code is not performance critical. I really appreciate your patch, but I have to say I don't think this change is really needed now. Please let me know if I'm missing something. > > Initial benchmarking shows the following results > > > # bpftrace -e 'kprobe:kdamond_call { @start[tid] = nsecs; } Commit log shouldn't start with '#'. Please consider indenting the above command and below outputs of it. Thanks, SJ [...]