From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from foss.arm.com (foss.arm.com [217.140.110.172]) by smtp.subspace.kernel.org (Postfix) with ESMTP id 97F8032ED37; Wed, 18 Feb 2026 16:42:26 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=217.140.110.172 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1771432947; cv=none; b=BYUo1/iqh+kcws14IXfttx07gWAjST/qo+vaVr21DnlNdfbTriCHOA09f+Ecj6d9/QDxpkkFc1LA/J21eJO2oOx9KEAHGJiQudVHoVPPjvTyb3qm8NP1hGw2LJc/0uP4KQQ5x/P5O9lwIPbTBD0jDxQzz++Ddxzy6XfrNtLzvQI= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1771432947; c=relaxed/simple; bh=QFJ80ZejVD3OJcw4POFeYv5atW2IP+NwxY2WLHTmoj8=; h=Message-ID:Date:MIME-Version:Subject:To:Cc:References:From: In-Reply-To:Content-Type; b=d5W6p6fSlwys0H1h1VI67Fp0taoNBrQdNVCMlxDvFbSHTbVRise/WmzkHZDJM5/Dn3xxtEJ9lSy0rGdcOmcuX9v8hFW1xKwsMtN82m69Pk25boQMDvCOPDdSLhPrfMExJOy5eLcsw1rvxJNuKJrHJhiXhe8tEO3xUDMgoNZT5qI= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=arm.com; spf=pass smtp.mailfrom=arm.com; arc=none smtp.client-ip=217.140.110.172 Authentication-Results: smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=arm.com Authentication-Results: smtp.subspace.kernel.org; spf=pass smtp.mailfrom=arm.com Received: from usa-sjc-imap-foss1.foss.arm.com (unknown [10.121.207.14]) by usa-sjc-mx-foss1.foss.arm.com (Postfix) with ESMTP id 961A3339; Wed, 18 Feb 2026 08:42:19 -0800 (PST) Received: from [10.1.196.46] (e134344.arm.com [10.1.196.46]) by usa-sjc-imap-foss1.foss.arm.com (Postfix) with ESMTPSA id C15FF3F62B; Wed, 18 Feb 2026 08:42:20 -0800 (PST) Message-ID: Date: Wed, 18 Feb 2026 16:42:19 +0000 Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 User-Agent: Mozilla Thunderbird Subject: Re: [PATCH v4 26/41] arm_mpam: resctrl: Add support for 'MB' resource To: "Shaopeng Tan (Fujitsu)" Cc: "amitsinght@marvell.com" , "baisheng.gao@unisoc.com" , "baolin.wang@linux.alibaba.com" , "carl@os.amperecomputing.com" , "dave.martin@arm.com" , "david@kernel.org" , "dfustini@baylibre.com" , "fenghuay@nvidia.com" , "gshan@redhat.com" , "james.morse@arm.com" , "jonathan.cameron@huawei.com" , "kobak@nvidia.com" , "lcherian@marvell.com" , "linux-arm-kernel@lists.infradead.org" , "linux-kernel@vger.kernel.org" , "peternewman@google.com" , "punit.agrawal@oss.qualcomm.com" , "quic_jiles@quicinc.com" , "reinette.chatre@intel.com" , "rohit.mathew@arm.com" , "scott@os.amperecomputing.com" , "sdonthineni@nvidia.com" , "xhao@linux.alibaba.com" , "catalin.marinas@arm.com" , "will@kernel.org" , "corbet@lwn.net" , "maz@kernel.org" , "oupton@kernel.org" , "joey.gouly@arm.com" , "suzuki.poulose@arm.com" , "kvmarm@lists.linux.dev" , "zengheng4@huawei.com" , "linux-doc@vger.kernel.org" References: <20260203214342.584712-1-ben.horgan@arm.com> <20260203214342.584712-27-ben.horgan@arm.com> From: Ben Horgan Content-Language: en-US In-Reply-To: Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 7bit Hi Shaopeng, On 2/10/26 06:20, Shaopeng Tan (Fujitsu) wrote: > Hello Ben, > >> From: James Morse >> >> resctrl supports 'MB', as a percentage throttling of traffic from the >> L3. This is the control that mba_sc uses, so ideally the class chosen >> should be as close as possible to the counters used for mbm_total. If >> there is a single L3 and the topology of the memory matches then the >> traffic at the memory controller will be equivalent to that at egress of >> the L3. If these conditions are met allow the memory class to back MB. >> >> MB's percentage control should be backed either with the fixed point >> fraction MBW_MAX or bandwidth portion bitmaps. The bandwidth portion >> bitmaps is not used as its tricky to pick which bits to use to avoid >> contention, and may be possible to expose this as something other than a >> percentage in the future. >> >> CC: Zeng Heng >> Co-developed-by: Dave Martin >> Signed-off-by: Dave Martin >> Signed-off-by: James Morse > >> Signed-off-by: Ben Horgan >> --- >> Changes since v2: >> Code flow change >> Commit message 'or' >> >> Changes since v3: >> initialise tmp_cpumask >> update commit message >> check the traffic matches l3 >> update comment on candidate_class update, only mbm_total >> drop tags due to rework >> --- >> +/* >> + * Test if the traffic for a class matches that at egress from the L3. For >> + * MSC at memory controllers this is only possible if there is a single L3 >> + * as otherwise the counters at the memory can include bandwidth from the >> + * non-local L3. >> + */ >> +static bool traffic_matches_l3(struct mpam_class *class) { > > An error reported by checkpatch.pl is as follows. > > ERROR: open brace '{' following function definitions go on the next line > #826: FILE: drivers/resctrl/mpam_resctrl.c:826: > +static bool traffic_matches_l3(struct mpam_class *class) { Not sure how I let that slip through. Fixed now. > > > Best regards, > Shaopeng TAN Thanks, Ben