linux-kernel - Re: [RFC PATCH 03/10] arch/x86: Re-arrange RDT init code

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Date:   Wed, 3 Oct 2018 11:54:49 -0700
From:   Reinette Chatre <reinette.chatre@...el.com>
To:     "Moger, Babu" <Babu.Moger@....com>,
        "tglx@...utronix.de" <tglx@...utronix.de>,
        "mingo@...hat.com" <mingo@...hat.com>,
        "hpa@...or.com" <hpa@...or.com>,
        "fenghua.yu@...el.com" <fenghua.yu@...el.com>,
        "vikas.shivappa@...ux.intel.com" <vikas.shivappa@...ux.intel.com>,
        "tony.luck@...el.com" <tony.luck@...el.com>
Cc:     "x86@...nel.org" <x86@...nel.org>,
        "peterz@...radead.org" <peterz@...radead.org>,
        "pombredanne@...b.com" <pombredanne@...b.com>,
        "gregkh@...uxfoundation.org" <gregkh@...uxfoundation.org>,
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        "bp@...e.de" <bp@...e.de>,
        "rafael.j.wysocki@...el.com" <rafael.j.wysocki@...el.com>,
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        "linux-kernel@...r.kernel.org" <linux-kernel@...r.kernel.org>
Subject: Re: [RFC PATCH 03/10] arch/x86: Re-arrange RDT init code

Hi Babu,

On 10/2/2018 4:41 PM, Moger, Babu wrote:
> On 10/02/2018 02:21 PM, Reinette Chatre wrote:
>> On 9/24/2018 12:19 PM, Moger, Babu wrote:
>>>  static enum cpuhp_state rdt_online;
>>> @@ -866,8 +872,22 @@ static int __init rdt_late_init(void)
>>>  	struct rdt_resource *r;
>>>  	int state, ret;
>>>  
>>> -	if (!get_rdt_resources())
>>> +	/* Run quirks first */
>>> +	rdt_quirks();
>>> +
>>> +	rdt_alloc_capable = get_rdt_alloc_resources();
>>> +	rdt_mon_capable = get_rdt_mon_resources();
>>> +
>>> +	if (!(rdt_alloc_capable || rdt_mon_capable)) {
>>> +		pr_info("RDT allocation or monitoring not detected\n");
>>
>> This function ends with a log entry for every resource discovered. Is
>> this new log entry needed to indicate that such resources have not been
>> found? Could it not just be the absence of the other message?
> 
> As this is relatively new feature, so I added this info message. It helped
> me debug what went wrong. Otherwise, I don't see anything. I can remove it
> if the message is too annoying to the user.

This log entry is made after detection of resources/features supported
by the system. A user would find more information in the
presence/absence of the relevant CPU feature flags in /proc/cpuinfo.

Reinette