From mboxrd@z Thu Jan  1 00:00:00 1970
Return-Path: <linux-kernel-owner@vger.kernel.org>
Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand
	id S1752649AbbJWNha (ORCPT <rfc822;w@1wt.eu>);
	Fri, 23 Oct 2015 09:37:30 -0400
Received: from bh-25.webhostbox.net ([208.91.199.152]:40274 "EHLO
	bh-25.webhostbox.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org
	with ESMTP id S1751074AbbJWNh2 (ORCPT
	<rfc822;linux-kernel@vger.kernel.org>);
	Fri, 23 Oct 2015 09:37:28 -0400
Subject: Re: [PATCH v2 05/10] hwmon: (fam15h_power) Add compute unit
 accumulated power
To: Borislav Petkov <bp@suse.de>, Huang Rui <ray.huang@amd.com>
References: <1445308109-17970-1-git-send-email-ray.huang@amd.com>
 <1445308109-17970-6-git-send-email-ray.huang@amd.com>
 <20151023132702.GC2844@pd.tnic>
Cc: Peter Zijlstra <peterz@infradead.org>, Jean Delvare <jdelvare@suse.de>,
        Andy Lutomirski <luto@amacapital.net>,
        Andreas Herrmann <herrmann.der.user@gmail.com>,
        Thomas Gleixner <tglx@linutronix.de>, Ingo Molnar <mingo@kernel.org>,
        "Rafael J. Wysocki" <rjw@rjwysocki.net>, Len Brown <lenb@kernel.org>,
        John Stultz <john.stultz@linaro.org>,
        =?UTF-8?B?RnLDqWTDqXJpYyBXZWlzYmVja2Vy?= <fweisbec@gmail.com>,
        lm-sensors@lm-sensors.org, linux-kernel@vger.kernel.org,
        x86@kernel.org, Andreas Herrmann <herrmann.der.user@googlemail.com>,
        Aravind Gopalakrishnan <Aravind.Gopalakrishnan@amd.com>,
        Fengguang Wu <fengguang.wu@intel.com>, Aaron Lu <aaron.lu@intel.com>,
        Tony Li <tony.li@amd.com>
From: Guenter Roeck <linux@roeck-us.net>
Message-ID: <562A3812.6060805@roeck-us.net>
Date: Fri, 23 Oct 2015 06:37:22 -0700
User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:38.0) Gecko/20100101
 Thunderbird/38.3.0
MIME-Version: 1.0
In-Reply-To: <20151023132702.GC2844@pd.tnic>
Content-Type: text/plain; charset=utf-8; format=flowed
Content-Transfer-Encoding: 7bit
X-Authenticated_sender: linux@roeck-us.net
X-OutGoing-Spam-Status: No, score=-1.0
X-AntiAbuse: This header was added to track abuse, please include it with any abuse report
X-AntiAbuse: Primary Hostname - bh-25.webhostbox.net
X-AntiAbuse: Original Domain - vger.kernel.org
X-AntiAbuse: Originator/Caller UID/GID - [47 12] / [47 12]
X-AntiAbuse: Sender Address Domain - roeck-us.net
X-Get-Message-Sender-Via: bh-25.webhostbox.net: authenticated_id: linux@roeck-us.net
X-Source: 
X-Source-Args: 
X-Source-Dir: 
Sender: linux-kernel-owner@vger.kernel.org
List-ID: <linux-kernel.vger.kernel.org>
X-Mailing-List: linux-kernel@vger.kernel.org

On 10/23/2015 06:27 AM, Borislav Petkov wrote:
> On Tue, Oct 20, 2015 at 10:28:24AM +0800, Huang Rui wrote:
>> This patch adds a member in fam15h_power_data which specifies the
>> compute unit accumulated power. It adds do_read_registers_on_cu to do
>> all the read to all MSRs and run it on one of the online cores on each
>> compute unit with smp_call_function_many(). This behavior can decrease
>> IPI numbers.
>>
>> Suggested-by: Borislav Petkov <bp@alien8.de>
>> Signed-off-by: Huang Rui <ray.huang@amd.com>
>> Cc: Guenter Roeck <linux@roeck-us.net>
>> Cc: Peter Zijlstra <peterz@infradead.org>
>> Cc: Ingo Molnar <mingo@kernel.org>
>> ---
>>   drivers/hwmon/fam15h_power.c | 68 +++++++++++++++++++++++++++++++++++++++++++-
>>   1 file changed, 67 insertions(+), 1 deletion(-)
>>

[ ... ]

>> +static void do_read_registers_on_cu(void *_data)
>> +{
>> +	struct fam15h_power_data *data = _data;
>> +	int cpu, cu, cores_per_cu;
>> +
>> +	cpu = smp_processor_id();
>> +
>> +	cores_per_cu = amd_get_cores_per_cu();
>> +	cu = cpu / cores_per_cu;
>> +
>> +	WARN_ON(rdmsrl_safe(MSR_F15H_CU_PWR_ACCUMULATOR,
>> +			    &data->cu_acc_power[cu]));
>
> I guess the WARN_ON's here should be WARN_ON_ONCE() - otherwise dmesg is
> filling up very quickly.
>
I don't really understand why WARN_ON (or WARN_ON_ONCE)
would be warranted here in the first place.

Guenter