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 DF92B1A9FBA; Thu, 5 Feb 2026 16:20:42 +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=1770308443; cv=none; b=QfCkxE2aiZsBVOPaI37NjnEoa2I0ZaC65uEfm+mHWzuipQbfRa9vgRHg76g6EdfIBG+i6LgVmgje71rh9WD178d9wt22sEgKdplKMHVIMuam+PrXM57YEsxLRQk6aAzfB2/P8iai55IA/qxvUJiIrrHytJVkfuST7gtWSuDzzx4= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1770308443; c=relaxed/simple; bh=3j9lC1ezcq1o4I4TKi+RkA8i98PkQhrH+eBR1wizp9M=; h=Date:From:To:Cc:Subject:Message-ID:References:MIME-Version: Content-Type:Content-Disposition:In-Reply-To; b=N41WkGFs9T8lvhq0fxqnDr2FbFvnUzZWzi6TECjDclFgPi3YMsGM6hBv+YnxDQtF/xOdwSgocGG8rFX8rAfGXgsUjQQf8sZIYubBo6z0tH9cr8ltLNrX1yUTP83g6fqgC2DSkK2JpnPgWGexpMu6qOru2tM0UgpVEfzaYS1rIRc= 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 EC098339; Thu, 5 Feb 2026 08:20:35 -0800 (PST) Received: from arm.com (arrakis.cambridge.arm.com [10.1.197.46]) by usa-sjc-imap-foss1.foss.arm.com (Postfix) with ESMTPSA id 85D6C3F632; Thu, 5 Feb 2026 08:20:36 -0800 (PST) Date: Thu, 5 Feb 2026 16:20:33 +0000 From: Catalin Marinas To: Ben Horgan 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, 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 Subject: Re: [PATCH v4 05/41] arm64: mpam: Re-initialise MPAM regs when CPU comes online Message-ID: References: <20260203214342.584712-1-ben.horgan@arm.com> <20260203214342.584712-6-ben.horgan@arm.com> Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20260203214342.584712-6-ben.horgan@arm.com> On Tue, Feb 03, 2026 at 09:43:06PM +0000, Ben Horgan wrote: > From: James Morse > > Now that the MPAM system registers are expected to have values that change, > reprogram them based on the previous value when a CPU is brought online. > > Previously MPAM's 'default PARTID' of 0 was always used for MPAM in > kernel-space as this is the PARTID that hardware guarantees to > reset. Because there are a limited number of PARTID, this value is exposed > to user-space, meaning resctrl changes to the resctrl default group would > also affect kernel threads. Instead, use the task's PARTID value for > kernel work on behalf of user-space too. The default of 0 is kept for both > user-space and kernel-space when MPAM is not enabled. > > Tested-by: Gavin Shan > Tested-by: Shaopeng Tan > Tested-by: Peter Newman > Reviewed-by: Jonathan Cameron > Signed-off-by: James Morse > Reviewed-by: Gavin Shan > Signed-off-by: Ben Horgan Reviewed-by: Catalin Marinas