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 9FCBDCCD18A for ; Fri, 10 Oct 2025 16:53:47 +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:From:References:Cc:To: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=NrHkIjwbW6MAwNBmCrtoiCycqOn7oq29PvQJ0N98MT0=; b=QVtus7L/qlQRNiBpK4jpcIjGnO uWXWo/+nKg1BNzK0NrdSysSdRhrzAwrPfl8Q/Yr6g9LeFDLRQWiRnVEpZvpJbD7zvZEX481NhM7a3 5Aa8mehCc/kOVevRtYi+2ssVOgFoP74+r+mOz04X8NvpWoy2rXIRqDhSmaanP0e7j7RFynuW+ewJA 9qf2uzn6xcLoPU00EltOwwIAaHsF+0NkhCWBcePsS0e04kk5Fkh/VeKz75qu+2LZkA54WNPsEtf76 lY57uEMed+cO1v/to0VZFQotAdfu6uAQw63QnulnY5Ap8p5Zq4VwA6Tz8LXWaeRhEgG+otp0w0UMK eAKg6YpA==; Received: from localhost ([::1] helo=bombadil.infradead.org) by bombadil.infradead.org with esmtp (Exim 4.98.2 #2 (Red Hat Linux)) id 1v7GNB-00000008zy0-2iNc; Fri, 10 Oct 2025 16:53:41 +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 1v7GN9-00000008zwo-408h for linux-arm-kernel@lists.infradead.org; Fri, 10 Oct 2025 16:53:41 +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 80F9D175D; Fri, 10 Oct 2025 09:53:31 -0700 (PDT) Received: from [10.1.197.69] (eglon.cambridge.arm.com [10.1.197.69]) by usa-sjc-imap-foss1.foss.arm.com (Postfix) with ESMTPSA id 57A743F66E; Fri, 10 Oct 2025 09:53:33 -0700 (PDT) Message-ID: Date: Fri, 10 Oct 2025 17:53:32 +0100 MIME-Version: 1.0 User-Agent: Mozilla Thunderbird Subject: Re: [PATCH v2 27/29] arm_mpam: Add helper to reset saved mbwu state To: Fenghua Yu , 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 , 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> <20250910204309.20751-28-james.morse@arm.com> Content-Language: en-GB From: James Morse In-Reply-To: Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit X-CRM114-Version: 20100106-BlameMichelson ( TRE 0.8.0 (BSD) ) MR-646709E3 X-CRM114-CacheID: sfid-20251010_095340_112706_C678FF00 X-CRM114-Status: GOOD ( 13.52 ) 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 Hi Fenghua, On 26/09/2025 05:11, Fenghua Yu wrote: > On 9/10/25 13:43, James Morse wrote: >> resctrl expects to reset the bandwidth counters when the filesystem >> is mounted. >> >> To allow this, add a helper that clears the saved mbwu state. Instead >> of cross calling to each CPU that can access the component MSC to >> write to the counter, set a flag that causes it to be zero'd on the >> the next read. This is easily done by forcing a configuration update. >> >> Signed-off-by: James Morse > > Other than the following minor change, > > Reviewed-by: Fenghua Yu Thanks! >> diff --git a/drivers/resctrl/mpam_devices.c b/drivers/resctrl/mpam_devices.c >> index 3080a81f0845..8254d6190ca2 100644 >> --- a/drivers/resctrl/mpam_devices.c >> +++ b/drivers/resctrl/mpam_devices.c >>   @@ -1245,6 +1257,37 @@ int mpam_msmon_read(struct mpam_component *comp, struct mon_cfg >> *ctx, >>       return err; >>   } >>   +void mpam_msmon_reset_mbwu(struct mpam_component *comp, struct mon_cfg *ctx) >> +{ >> +    int idx; >> +    struct mpam_msc *msc; >> +    struct mpam_vmsc *vmsc; >> +    struct mpam_msc_ris *ris; >> + >> +    if (!mpam_is_enabled()) >> +        return; >> + >> +    idx = srcu_read_lock(&mpam_srcu); > guard(srcu)(&mpam_srcu); Yeah, Jonathan had already suggested it. >> +    list_for_each_entry_rcu(vmsc, &comp->vmsc, comp_list) { >> +        if (!mpam_has_feature(mpam_feat_msmon_mbwu, &vmsc->props)) >> +            continue; >> + >> +        msc = vmsc->msc; >> +        list_for_each_entry_rcu(ris, &vmsc->ris, vmsc_list) { >> +            if (!mpam_has_feature(mpam_feat_msmon_mbwu, &ris->props)) >> +                continue; >> + >> +            if (WARN_ON_ONCE(!mpam_mon_sel_lock(msc))) >> +                continue; >> + >> +            ris->mbwu_state[ctx->mon].correction = 0; >> +            ris->mbwu_state[ctx->mon].reset_on_next_read = true; >> +            mpam_mon_sel_unlock(msc); >> +        } >> +    } >> +    srcu_read_unlock(&mpam_srcu, idx); >> +} Thanks, James