From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org Received: from bombadil.infradead.org (bombadil.infradead.org [198.137.202.133]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.lore.kernel.org (Postfix) with ESMTPS id 401F5CAC582 for ; Fri, 12 Sep 2025 14:52:17 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; d=lists.infradead.org; s=bombadil.20210309; h=Sender:List-Subscribe:List-Help :List-Post:List-Archive:List-Unsubscribe:List-Id:Content-Transfer-Encoding: Content-Type:In-Reply-To:References:Cc:To:From:Subject:MIME-Version:Date: Message-ID:Reply-To:Content-ID:Content-Description:Resent-Date:Resent-From: Resent-Sender:Resent-To:Resent-Cc:Resent-Message-ID:List-Owner; bh=TXUmKbbNO3lTdF+TIniCzMR+B5Zi1zCZ7HmxRzVH2iA=; b=jZcYfs+Ak5KSkDS1ntj1f4AziS gxzXoBB5gdBrrimVbuwsM/nWYN7Gmma2YXhuV4ZPSp8GY5TDEKusc0ajBG4MKkDRczbGivTkeYSxa CToN6i5B8quPhyIPYZMmxAA48ZBQdrrxIUz/hl3VtARm8DAS6k1NfvOnP2BGJMEnAcEvQfeadcIPa vBq6yE9AxKuFJkkxAt26RG0EEBu3KxlVraCJeWcAaB8mJ4j4RlKdGVDw7Q0CgHtbmUkgl2JVy1/Sw 84XvYFQWyW7WPYQZLFwbKlKWx5Qa01AQj/vNApO7OXeFeBwGmC8aL0VvqhJAfPqVwp+H39G4ffwLD aoWQVV3w==; Received: from localhost ([::1] helo=bombadil.infradead.org) by bombadil.infradead.org with esmtp (Exim 4.98.2 #2 (Red Hat Linux)) id 1ux58G-0000000A2gJ-2N0L; Fri, 12 Sep 2025 14:52:12 +0000 Received: from foss.arm.com ([217.140.110.172]) by bombadil.infradead.org with esmtp (Exim 4.98.2 #2 (Red Hat Linux)) id 1ux58E-0000000A2eT-0g8q for linux-arm-kernel@lists.infradead.org; Fri, 12 Sep 2025 14:52:11 +0000 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 93B2616A3; Fri, 12 Sep 2025 07:52:00 -0700 (PDT) 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 4F0013F694; Fri, 12 Sep 2025 07:52:04 -0700 (PDT) Message-ID: <52b6bd30-55af-4916-89c0-f87446689fbe@arm.com> Date: Fri, 12 Sep 2025 15:52:03 +0100 MIME-Version: 1.0 User-Agent: Mozilla Thunderbird Subject: Re: [PATCH v2 15/29] arm_mpam: Reset MSC controls from cpu hp callbacks From: Ben Horgan To: James Morse , linux-kernel@vger.kernel.org, linux-arm-kernel@lists.infradead.org, linux-acpi@vger.kernel.org Cc: D Scott Phillips OS , carl@os.amperecomputing.com, lcherian@marvell.com, bobo.shaobowang@huawei.com, tan.shaopeng@fujitsu.com, baolin.wang@linux.alibaba.com, Jamie Iles , Xin Hao , peternewman@google.com, dfustini@baylibre.com, amitsinght@marvell.com, David Hildenbrand , Dave Martin , Koba Ko , Shanker Donthineni , fenghuay@nvidia.com, baisheng.gao@unisoc.com, Jonathan Cameron , Rob Herring , Rohit Mathew , Rafael Wysocki , Len Brown , Lorenzo Pieralisi , Hanjun Guo , Sudeep Holla , Catalin Marinas , Will Deacon , Greg Kroah-Hartman , Danilo Krummrich References: <20250910204309.20751-1-james.morse@arm.com> <20250910204309.20751-16-james.morse@arm.com> Content-Language: en-US In-Reply-To: Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 7bit X-CRM114-Version: 20100106-BlameMichelson ( TRE 0.8.0 (BSD) ) MR-646709E3 X-CRM114-CacheID: sfid-20250912_075210_245084_86D542FC X-CRM114-Status: GOOD ( 17.01 ) X-BeenThere: linux-arm-kernel@lists.infradead.org X-Mailman-Version: 2.1.34 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Sender: "linux-arm-kernel" Errors-To: linux-arm-kernel-bounces+linux-arm-kernel=archiver.kernel.org@lists.infradead.org On 9/12/25 12:25, Ben Horgan wrote: > Hi James, > > On 9/10/25 21:42, James Morse wrote: >> When a CPU comes online, it may bring a newly accessible MSC with >> it. Only the default partid has its value reset by hardware, and >> even then the MSC might not have been reset since its config was >> previously dirtyied. e.g. Kexec. >> >> Any in-use partid must have its configuration restored, or reset. >> In-use partids may be held in caches and evicted later. >> >> MSC are also reset when CPUs are taken offline to cover cases where >> firmware doesn't reset the MSC over reboot using UEFI, or kexec >> where there is no firmware involvement. >> >> If the configuration for a RIS has not been touched since it was >> brought online, it does not need resetting again. >> >> To reset, write the maximum values for all discovered controls. >> >> CC: Rohit Mathew >> Signed-off-by: James Morse >> --- >> Changes since RFC: >> * Last bitmap write will always be non-zero. >> * Dropped READ_ONCE() - teh value can no longer change. >> * Write 0 to proporitional stride, remove the bwa_fract variable. >> * Removed nested srcu lock, the assert should cover it. >> --- >> drivers/resctrl/mpam_devices.c | 117 ++++++++++++++++++++++++++++++++ >> drivers/resctrl/mpam_internal.h | 8 +++ >> 2 files changed, 125 insertions(+) >> >> + >> +static void mpam_reset_msc(struct mpam_msc *msc, bool online) >> +{ >> + struct mpam_msc_ris *ris; >> + >> + mpam_assert_srcu_read_lock_held(); > > Unneeded? Checked in list_for_each_entry_srcu().> + If you do get rid of this then that leaves one use of the helper, mpam_assert_srcu_read_lock_held(), and so the helper could go. > Thanks, > > Ben > > Thanks, Ben