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b=F51/FDg+uIp45MA5Pk5Ny+yXxiFF2Tw6bnhlvN7bwRcn5NL7QD/dvCntAL4pZcHQj Clada5Q//btVK1p816mXUNxx7ATviSMgRN39lP3smLyTH4wgC4yfMUzTMZmaA7OJ1v alD6d7lweRLonrmG+L1iywfQ19N21t9cGdBGFOxVaO5HCuloriUsVVS+JP/L1bMT2l Z+IFH4HcpbRSv6nxq3OiYXs2nCIcCUSBKyzKfxwa+3Ssv++h1ujaRdNTm1iJse/Vub jIJRjYCsMS7AwQGf00D4rVFvfJpGt3MT15zq/CZRlhm31UOkjtfbyz0pW/Gkie4Sah inWt/35FUa5tg== From: SeongJae Park To: Cc: SeongJae Park , Andrew Morton , damon@lists.linux.dev, kernel-team@meta.com, linux-kernel@vger.kernel.org, linux-mm@kvack.org Subject: [RFC PATCH 0/2] mm/damon/stat: expose auto-tuned intervals and non-idle ages Date: Tue, 9 Sep 2025 21:00:20 -0700 Message-Id: <20250910040022.168223-1-sj@kernel.org> X-Mailer: git-send-email 2.39.5 MIME-Version: 1.0 Content-Transfer-Encoding: 8bit X-Rspam-User: X-Rspamd-Server: rspam06 X-Rspamd-Queue-Id: A5B4C180002 X-Stat-Signature: ny8y7gsxn7if4xi838i8n8w5k95om19t X-HE-Tag: 1757476827-392571 X-HE-Meta: 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 E/rKXyAp B8J9aUV7L6WyHI8SrJDYlV9yawsha5TTUvgBueEQREqlwOn6o6XADZonO4YlIMhWUNvq2fHdtZzs9M83LPz9qgAnxdO3ABjfjcKb9LraB6bIj3UjuLQT9tLhdAPxNhybD9fz/Di8+zH4PUl+cJedqeUVgVgkEm1JCndrigC3DsdEPay8eJFjOzOgjM2DSubBFiIgqEzRDDArpCso= 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: DAMON_STAT is intentionally providing limited information for easy consumption. From production fleet level usages, below limitations are found, though. The aggregation interval of DAMON_STAT represents the granularity of the memory_idle_ms_percentiles. But it is auto-tuned and not exposed to users, so users cannot know the granularity. All memory regions of non-zero (positive) nr_accesses are treated as having zero idle time. A significant portion of production systems have such zero idle time. Hence breakdown of warm and hot data is impossible. To overcome the limitations, expose the auto-tuned aggregation interval with a new parameter named xxx and the age of non-zero nr_accesses regions as negative idle time, via the existing idle time percentiles parameter. SeongJae Park (2): mm/damon/stat: expose the current tuned aggregation interval mm/damon/stat: expose negative idle time mm/damon/stat.c | 16 +++++++++++----- 1 file changed, 11 insertions(+), 5 deletions(-) base-commit: adc22cc8eb821b7d8274403ad7bdafb411fcc9d7 -- 2.39.5