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Thu, 17 Sep 2026 11:00:19 -0700 (PDT) Received: from LAPTOP-97G9G880.domain.name ([106.222.202.182]) by smtp.gmail.com with ESMTPSA id 5a478bee46e88-33bf5b1d335sm18580264eec.28.2026.09.17.11.00.16 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Thu, 17 Sep 2026 11:00:19 -0700 (PDT) From: Karthikeyan KS To: Sang-Heon Jeon Cc: SJ Park , Andrew Morton , damon@lists.linux.dev, linux-mm@kvack.org, linux-kernel@vger.kernel.org Subject: Re: [PATCH] mm/damon: reject zero sampling interval Date: Thu, 17 Sep 2026 18:00:13 +0000 Message-ID: <20260917180013.1279018-1-karthiproffesional@gmail.com> X-Mailer: git-send-email 2.43.0 In-Reply-To: References: Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Transfer-Encoding: 8bit Hi Sang-Heon, Hi SJ, > I think SJ already commented on a similar patch. please refer to [1] > > [1] https://lore.kernel.org/all/20260722094304.3132750-1-dayou5941@163.com/ Thanks, missed that thread. Same objection applies to mine. > Can't we keep supporting zero sample interval and fix the warning > or the real bug instead? I measured a few floors for kdamond_usleep(): floor kdamond CPU (3s) vs sample_us=5000 1us 84% 28x 100us 42% 14x 1000us 12% ~3x 5000us ~2% 1x (matches control) 5000us is damon_new_ctx()'s own default, and at that floor the spin is just gone. Would you rather we just document sample_us=0 as accepted/expected behavior, or clamp it to that default inside damon_set_attrs()? Thanks, Karthikeyan KS