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b=LRkCWV+6NtfpT16NZsCqsUyUufxp/ReZ/SfZzFG5LRFFwLcBW0ZGleb+KyBuaCONJ IwH/dXNWfqxbGsaAiRA3Qbq7FTxOQOEhi068OI91SOuJEcrmMLRqA9A3TqzY6LYJ3J A+y5I4Th7POhVnistBnvsfAMKV+R5XlfOXZi6UfDisd153oPhz5CW9GewwvzoBaCKv o4iCfmIErROPPcLPrb9NmDk4y3kuov+RflqMe7SL9zgcqa+dHJNBZqB0ZX4Dk6C7py XpVQayPMRLKp99j+Tz/3xTOQhlG6+mAXVtwFeXdvmcrRJXWlkk3L5L03oflglAoaH4 512yHMXAyyGZQ== From: SJ Park To: Ravi Jonnalagadda Cc: SJ Park , akinobu.mita@gmail.com, damon@lists.linux.dev, linux-mm@kvack.org, linux-kernel@vger.kernel.org, linux-doc@vger.kernel.org, akpm@linux-foundation.org, corbet@lwn.net, bijan311@gmail.com, ajayjoshi@micron.com, honggyu.kim@sk.com, yunjeong.mun@sk.com, rientjes@google.com, weixugc@google.com, jic23@kernel.org, gourry@gourry.net Subject: Re: [RFC PATCH v2 0/9] mm/damon: hardware-sampled access reports Date: Thu, 10 Sep 2026 17:34:01 -0700 Message-ID: <20260911003402.90722-1-sj@kernel.org> X-Mailer: git-send-email 2.47.3 In-Reply-To: <20260910171623.6638-1-ravis.opensrc@gmail.com> References: MIME-Version: 1.0 Content-Transfer-Encoding: 8bit X-Rspam-User: X-Rspamd-Server: rspam09 X-Rspamd-Queue-Id: 64C6520002 X-Stat-Signature: 7ohemdba3pbur7gqnr91u41fagjxok4g X-HE-Tag: 1789086850-994727 X-HE-Meta: U2FsdGVkX18iGa2FX52Mqw+k0oNQTFcQUUXwCbUCk8Vinp0C54bFHwtf7H9sWSWVEkzpLW5Fx+UFEN+STDRDkvfddU5UZ1Queh1eDfa2POROja9yTWZxgzbacsQdPA0dhU9WfgzsfPk5IMDL/f6Ubb/dNod5jAvVE+3/zGYF+TOApTWHZdZ4tc2wmNpw652KNwNwpR3VIDVmn8KKIhKNYOB2lUyQxVfzwxrFrVKjLTdOZ6RGry0bZDVSrvZUv5M83TzAz/w1brEhNHxVUx5h82wY3uI/7HTfunKrWFTRP97zxMNyCLoBbJoyuUnwskwwxpWvtoGUb9ghcLrKuGwJc6yY6V6T5kx/a2zJNsBhxF65wSxfb7Pb4JqnI3UXfoAZITB6PnU2rY7sINi/PXL6UP5m2/i4Pep3EbX54XMUpGbaE+/1/MJlh/ij/byFNYYbikf64Z1QnT049LE/PxPJPer2fhz/4PinuomxwesOEIioM+wbCWqwWVbSFT0yd1q5BmK7Tj8LcbP8ic73s0vFy3CcFq2hDmSMxFB0w2mZyxW1CeAAtIEMvQDxI5syzJY6K7lx9HxnW6z/80exrMGyB5JmKsrDgQLk9hEkRPjWXiUSxFhD4wSIzp4NP5KTAKpNwWPBo49xXqdoNTTQ5WEq75rgo8GCqOBVGcMVMuFqxaFxw6jcIV+qCJhMSDS3ck5SEe5HUqFKUMvg7tOzBTYoiXLlEEahUEAaLG4+FjvCK8clObZZh78PElW33yv3p1RvchoQpQToLK76MaMn26pGwiACJDUKMMTv3cPgN7Rx45G2/e6B5b7BrM3/MPwvNXXLIfft8/yUTA5X5UgrfnF8aRIgs8N0kze1br13Gpg2Us2QSRqMoWJJNjA94WXCsyrxzNbuV9RTqyFKkhvzrmGfWYNnmi8jxLIiV9B+ECvyKArbW/spb9xKtYozNe/Yx8LDggqLLsFbO1z90q5ap+l oScrMx8V Ouk/QzoFzhf5uARWKhboiKcnUXIsRvaIZzcJfQSEKE8oYwWoKoIIgzUkaJtqJ4HzWF6aRAmdA1vqM+/YpxdIpLvMS2eIP2ojMYP1Z+go7K+m2nsgiyQCOhCeHfT7VI1OL/o277cQf0p/n/sQ2CQYPbY6om2DP0NiNVjrYrAShsCtBYy1xtMJVYGigSfGG/Iu5LrXle3niHzJPXRxN/Ldyl6+EiFvVQHGvE7CNVVMOSUJ6tn9BLTG84KsuLQrqkJ3/MR6mMdL3AkcPIdcE9rVyWYcy8EmusdFwQ7kFLqDV7mk2HvaJjBe2iIWWpq8+SKrTJtZeCA0dfA6T8v4= Sender: owner-linux-mm@kvack.org Precedence: bulk X-Loop: owner-majordomo@kvack.org List-ID: List-Subscribe: List-Unsubscribe: On Thu, 10 Sep 2026 10:16:14 -0700 Ravi Jonnalagadda wrote: > This series lets DAMON take its access information from a hardware sampler > instead of from a page-table scan, and lets a scheme's score be weighted by what > that sampler reported. > > The change from v1 [1] is that it is now built on the data attribute probe > infrastructure that has since landed in mm-new: a PMU is expressed as one more > probe on a context, with its own weight and probe hits, rather than as a > mechanism of its own beside the ops set. The rest of this posting is the same > substrate reworked onto that, plus two consumers. > > This is not a merge request. The series is based on damon/next at the > base-commit below, which moves, so the tree it was built and tested from is also > on > > https://github.com/ravis-opensrc/linux/tree/damon/perf-rfc-v2-09-06-26 > > It is posted for design feedback, on the substrate and on where it belongs in > the roadmap for extending DAMON beyond the pte-accessed bit [2]. That roadmap's > second milestone, now open, is a first data attribute monitored through > `damon_report_access()`, and that is what a sampling PMU is here. So this > series keeps that function and its callers and replaces its body: the reporting > path a hardware sampler needs cannot take a mutex, and the drain has to reach a > virtual-address context as well as a physical one. The shape of the ring, the > drain and the sysfs surface are what is most useful to review. Thank you for this series, Ravi! I will take time to thoughly read and reply this series by the end of this weekend. Thanks, SJ [...]