From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from smtp.kernel.org (aws-us-west-2-korg-mail-1.web.codeaurora.org [10.30.226.201]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id 8570B15A864; Sat, 7 Mar 2026 00:21:15 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=10.30.226.201 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1772842875; cv=none; b=a27WtZwVLEAO0n8Bn2t/E4QmFFmMSZ7K7CNDqygLvXdPnFx6Vrw+bF+Iw/edG0vJrLoGKlumZUVbmYpbqKkKeOoJkFYzlXRdfDfQcOub+vsyamqHGPLNaVXCAajDKqYL6W2UsyAFV0yoaGIx8AmF24kTIqm88n3UilN/tJx/9C4= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1772842875; c=relaxed/simple; bh=uqHdwNgwIWQfBSHknp0uLe4ul6M3Tot+WSbz66G0te4=; h=From:To:Cc:Subject:Date:Message-ID:In-Reply-To:References: MIME-Version; b=RWgOKMnaKSHpLbrqae6jxRMsiIglv8jV4kOQXEDRN3KWvXXP3qZxoxEjlNZLERv/TLr/OFwPYDhjvwa0hqJlDwx+lAWwHexoH4c4QwbW72d9Xb1sF9QsNa3ZPEbm5fhH/bfCOqTB04AKKEKqenCMenWQ/SvDT1CqPpIykHMVuFI= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b=WmwAfEbn; arc=none smtp.client-ip=10.30.226.201 Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b="WmwAfEbn" Received: by smtp.kernel.org (Postfix) with ESMTPSA id 6E9CDC4CEF7; Sat, 7 Mar 2026 00:20:59 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1772842875; bh=uqHdwNgwIWQfBSHknp0uLe4ul6M3Tot+WSbz66G0te4=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; 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: Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Transfer-Encoding: 8bit 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 [...]