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 8362E2FBE12; Fri, 10 Oct 2025 16:53:40 +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=1760115222; cv=none; b=lvwJWyRLwi/4ebQSxZNwlGH/SNdW9iIHP105O7WUiYPsgRD6AVRabsTrUfLxDsmwC4jBDD5sKbMGGfiuk0fh+a4r+5ev63901y1Jgdc28DrqG7ptbswIEaBmHV8bVc53FX8uM6ziM5/z1OtQFKu80j4gODq6hs4E6KL3FIOMR/4= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1760115222; c=relaxed/simple; bh=WYmRoI4S9GFrm7QXAvKGxioni4+4DNuDA6TyvB1V6tU=; h=Message-ID:Date:MIME-Version:Subject:To:Cc:References:From: In-Reply-To:Content-Type; b=t77LXaWvLt7hz4LJOQX7TwIY0YQUx+jJjw/diDBLDr+UY5yMoOjI6wbefhZ7H/FFn5G7aoyDl1EFHz4Wdjbt/hqiRWf2t8R1ZszCcY+nDjyHKCjYv7fSgmrrqj8JathEtyqo18yYdkpC80c0vxsdMXJ5027+9tKAIwMDCwzwvEA= 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 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 Precedence: bulk X-Mailing-List: linux-acpi@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: 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 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