From mboxrd@z Thu Jan 1 00:00:00 1970 Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.remote-ip=217.140.110.172 ARC-Seal: i=1; d=subspace.kernel.org; s=arc20261015; a=rsa-sha256; cv=none; t=1793882186; b=aTlh7Yb+SKI2FqjR3EqE93s0jNuMQ0Fv439q6F9U8V1OTeuHQ9q3y8RlI4A7jm1fHyVr QF7Ug+D3oMlytsslVW4rPKISXHALBpR37GV03ngfnZ/46USzYL7G7ZoXVHPKqKJCMA0m6 Qm/mvhI1czIHy2dszeexGjI3H2y4n2/G3HOag9u5nsV/wrVwUb7OUb6AoGoLgX9gYq/uD jQkBUNYxbZYUrME1MP36Rj/ePV708HqJaX2uEOE8G5O9LTyL0kMM13W5Inc2IJ9LG2bl9 fiIMMLyC7kF9Y2EFeW2BHDRM06CmP+QXSseDYbEK9eNBlyBUtXTEKqD2Y+sVssKeREA== ARC-Message-Signature: i=1; d=subspace.kernel.org; s=arc20261015; a=rsa-sha256; c=relaxed/relaxed; t=1793882186; h=DMARC-Filter:Received:Received:DKIM-Signature:Message-ID:Date: MIME-Version:User-Agent:Subject:To:Cc:References:Content-Language: From:In-Reply-To:Content-Type:Content-Transfer-Encoding; bh=/NsG0cyMzXROSstgbjVKXoEsL+g2CwtLRSNxnglyzKA=; b=1Lr6TBvb42pG05pjiBtYrineTt3RlzqGTv/6H3bySHzBaNFeU6ZTwFmhOD5rOWrvshVm NvNLtpX22bxcjf2INMutcaAXVEdcG0YgUi7J6ZdcC6gVo7fuCXTdJ5aZCAdovKIxZBr1p 8lzCvnMEdOfckSweM0ptTSgQWgOeegcFxeBRAtWKpWDsWez6sx7H/Vamh5sxymxWtJPqc pF7IR0FBJZphosah9YgFpXS/OQHTqeNHQaP6SHMAiltLGiXU5s+XTRmy/tjpc6bvejHmV O7KI+rroMUNX25OohqVAXgEKo6Q6pczMVIdR+zsV5WkWTu2fKqb6xLeiYRaqr9LHp8w== ARC-Authentication-Results: i=1; smtp.subspace.kernel.org; dmarc=pass header.from=arm.com; spf=pass smtp.mailfrom=arm.com; dkim=pass header.d=arm.com header.i=@arm.com header.a=rsa-sha256 header.s=foss header.b=jHQeGkBo; arc=none smtp.remote-ip=217.140.110.172 Received: from foss.arm.com (foss.arm.com [217.140.110.172]) by smtp.subspace.kernel.org (Postfix) with ESMTP id E5F21606A326; Thu, 5 Nov 2026 12:36:25 +0000 (UTC) DMARC-Filter: OpenDMARC Filter v1.4.2 smtp.subspace.kernel.org E5F21606A326 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 Authentication-Results: smtp.subspace.kernel.org; dkim=pass (1024-bit key, unprotected) header.d=arm.com header.i=@arm.com header.a=rsa-sha256 header.s=foss header.b=jHQeGkBo 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 BF0331E8D; Thu, 5 Nov 2026 04:36:21 -0800 (PST) Received: from [10.2.212.8] (e134344.arm.com [10.2.212.8]) by usa-sjc-imap-foss1.foss.arm.com (Postfix) with ESMTPSA id 978DF3F673; Thu, 5 Nov 2026 04:36:20 -0800 (PST) DKIM-Signature: v=1; a=rsa-sha256; c=simple/simple; d=arm.com; s=foss; t=1793882184; bh=Xy2a35D5lFs3xumDyQSNHeQOf3ovIJScDgtK1Ak0u04=; h=Date:Subject:To:Cc:References:From:In-Reply-To:From; b=jHQeGkBozT/P4vps+KO9ztDP0/y2NBmMxgQj1XLDVLrgzbghOtq+A4YxSebRD114v RaJDs7jmao2mC0baEwZGDmyQFlADuqFH5RLPwGmr+9yleq0uPMQig6k3EKtZF7sgzh 4hED0g3Z2l1Tf+AlvvQnAw+9ZkTlntjqurTZEDpM= Message-ID: <6fb4ce7c-c173-4e86-8f8b-9bbc53751d8c@arm.com> Date: Thu, 5 Nov 2026 12:36:19 +0000 X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Post: List-Help: List-Subscribe: List-Unsubscribe: List-Owner: Precedence: list MIME-Version: 1.0 User-Agent: Mozilla Thunderbird Subject: Re: [PATCH v6 06/40] arm64: mpam: Context switch the MPAM registers To: Jinjie Ruan 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, tan.shaopeng@fujitsu.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, Shaopeng Tan References: <20260313144617.3420416-1-ben.horgan@arm.com> <20260313144617.3420416-7-ben.horgan@arm.com> <145b3c09-ff33-4fd7-935a-fa4f4c3c07b2@huawei.com> Content-Language: en-US From: Ben Horgan In-Reply-To: <145b3c09-ff33-4fd7-935a-fa4f4c3c07b2@huawei.com> Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit Hi Jinjie, On 05/11/2026 12:20, Jinjie Ruan wrote: > > > 在 2026/3/13 22:45, Ben Horgan 写道: > > Hi, everyone, > > We found a problem as below: > > In an offline/online co-located setup, MPAM gives the offline group a > smaller MBW share, a softirq serving an online service runs with the > PARTID of the throttled offline task it interrupted and is throttled > with it -- a priority inversion. > > Is this a known limitation? Yes. The initial MPAM support was introduced with the userspace and kernel PARTID changing in lockstep so that it matched the standard x86 setup. This left the way open for a generic resctrl way to express that they may be different. > > I see the following patchset uses a separate closid for kernel. > > https://lore.kernel.org/all/cover.1790867441.git.babu.moger@amd.com/ > MPAM should be able to work with that as outlined by Reinette [1]. [1] https://lore.kernel.org/lkml/2ab556af-095b-422b-9396-f845c6fd0342@intel.com/ Thanks, Ben