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b=WmwAfEbnQ1wSHbjNfaEJ42F5hwBgvwXS9sSph+A3kiUEaK/gwfCSZPcoDL5GCMrBi g9yT+7VCQHdc8qDDa3N9PxpUUdxOJXLgg+rRf1boS4RH5hWsgTP07I0EFhm2h5ql0w ghYrCGf5xMPPQe118CxJrclLXDvTq3hMfGreNsFJf95ekOjLYtaTlsbp5FwD5KhIJm +rx7ZJRmCSrcdr1NrdNVLk8d8Yt70bW+onIGK0U1U6tNcrdzLc2KaUMKI42bDbNIom dGDPDpmup4NuO3YcDgpyXzBIcVanBUng7QTL0GU7SS14S9E+DvbihG7eqg7MroKz+x RfQdsChtexJ7A== From: SeongJae Park To: SeongJae Park Cc: Andrew Morton , damon@lists.linux.dev, linux-kernel@vger.kernel.org, linux-mm@kvack.org Subject: Re: [RFC PATCH v2 01/10] mm/damon/core: introduce damos_quota_goal_tuner Date: Fri, 6 Mar 2026 16:20:46 -0800 Message-ID: <20260307002046.98992-1-sj@kernel.org> X-Mailer: git-send-email 2.47.3 In-Reply-To: <20260304044122.79394-2-sj@kernel.org> References: MIME-Version: 1.0 Content-Transfer-Encoding: 8bit X-Rspam-User: X-Rspamd-Server: rspam11 X-Rspamd-Queue-Id: 76C90A0007 X-Stat-Signature: mn8rft4ub7zjkzy4ifybz7j33cyazweh X-HE-Tag: 1772842876-432085 X-HE-Meta: U2FsdGVkX1/UaWUZsGoU0qBZAdUavx1oSDi1f+JwTmue23nTSlIYxNUuhJnMJ9iWDwjTQUoDJuQ/GV68o9FBGCQRbUb2x4B1KessaDNvV5/auxkt/nVHlpdNroWyMN7oIafzYDcFnV3Om29v5kXf9wO8HLnyFuVjZGykJmmGa+iNdmY8iXKpRmBWZEfGSkARR2//r0GDWAourU9drPD4L4u3eNN8WUKjqgDcMW7JOOZjO8Cif0C8HqPQ4qPgN14axisQOxA4S1x8tz7lwUCoYbMgXl16QjL5yRefR4ihdvHn6PdQt6N64ubt8uHuLfxjdBJq3Yu9bMIWcYxMjkMFLNYp03rRjkT14NsTrju/onJ+BzZTH1vDgm5ZD/gWT08dmzZfqmVZq60R3wBXqOWRB9gHuqo0pPU2obqtriVXcEUNpUMEe3hApawFl9J+li9yDynKq2EPDTykuNfPBmDYD3UTAf5PqCu4bl3fVLgaooL+NJAwNsMjnLnfCXdlkHQQrG0fK4n+MNlY5CNhBFabbS9ZAneZ7Nwuhe2hQ+0xNWao6hdsbNAXa5RO44eAUGut5hRg2cE4vEdjYuuY7t9Lu731fdY3b8JessvTbbLnwJQX9ZbFuRUjoxL6jxtaF1vqwq4yL9lu/ahp1d3msDJDCCVDaf0eq6P7hbdOzTN4hN2n+nuLyMgCAVSK432iEQmUeOK3hK+GxES5JCRHDJDdoO+mfeLub4Nb1A9xfq2/p5Qjttrh4q6qNwb3Shy50XE+sNvAhDxtvFBKT5m+z3eHlpHaZSmpzEjQSWLh6fvdSTcuWl8J58eIjXdSW99JeD4FOhJuckd2lxBaAFJXWoCGIfcm6PHwkSiLkZABJDno5qEMyW9SSguB08FSZEtrLEEusiCL9DnTz4/ysMwlwcRelBka+JmvhniadTC3Zpt2nhjhvTQ/nF7BM1b+Zd5c48oAi2CPpgQe9UiMqzp4k5p ghJ0cxxd rJSRzwLMo4jp7xU03gcsYveO7bmI7eN2c565ijWdzS9bEgO3iBfgDDOyvO0UbOHAxShwANj+QfN8UR34c3CsTph8FODZCLqM/pL0Z2XZu0ybOvc2etN5aSWuLg7VLKPT+brniEkChoHKCcHwYJc+XoXKIC96PjdaTcma/Jn3iNAxea6Uoi5JYYCo854HjDzmI2w0UYa88NXlet1CCctmNr45eP8hN/vdCm4ydOh5UEnR41n2SCJnKqZOicD73iInzV94Uk2mYDMnh5wugbrLiMV3hl/XxshSLQ5sH/4vcuVtucMVSYZbgDqiT2O4uAFECpzh270TerfaY2SHHljxaYK3bsuyFN0oq8AeKL1/KTF2ZNr4= Sender: owner-linux-mm@kvack.org Precedence: bulk X-Loop: owner-majordomo@kvack.org List-ID: List-Subscribe: List-Unsubscribe: On Tue, 3 Mar 2026 20:41:10 -0800 SeongJae Park wrote: > Currently DAMOS quota goal feature utilizes a single feedback loop based > algorithm for automatic tuning of the effective quota. It is useful in > dynamic environments that operate systems with only kernels in the long > term. But, no one fits all. It is not very easy to control in > environments having more controlled characteristics and user-space > control towers. We actually got multiple reports [1,2] of use cases > that the algorithm is not optimal. > > Introduce a new field of 'struct damos_quotas', namely 'goal_tuner'. It > specifies what tuning algorithm the given scheme should use, and allows > DAMON API callers to set it as they want. Nonetheless, this commit > introduces no new tuning algorithm but only the interface. This commit > hence makes no behavioral change. A new algorithm will be added by the > following commit. > > [1] https://lore.kernel.org/CALa+Y17__d=ZsM1yX+MXx0ozVdsXnFqF4p0g+kATEitrWyZFfg@mail.gmail.com > [2] https://lore.kernel.org/20260204022537.814-1-yunjeong.mun@sk.com > > Signed-off-by: SeongJae Park > --- [...] > diff --git a/mm/damon/core.c b/mm/damon/core.c > index e8c44541754f7..c5503fdb10bb7 100644 > --- a/mm/damon/core.c > +++ b/mm/damon/core.c > @@ -432,6 +432,7 @@ struct damos *damon_new_scheme(struct damos_access_pattern *pattern, > scheme->quota = *(damos_quota_init(quota)); > /* quota.goals should be separately set by caller */ > INIT_LIST_HEAD(&scheme->quota.goals); > + scheme->quota.goal_tuner = quota->goal_tuner; Because scheme->quota is overwrote with *quota above, the above goal_tuner set is unnecessary. I'll drop this in the next spin. Thanks, SJ [...]