Date: Mon, 10 Apr 2017 19:08:59 +0200 (CEST)
From: Thomas Gleixner <tglx@linutronix.de>
To: "Luck, Tony" <tony.luck@intel.com>
cc: Vikas Shivappa <vikas.shivappa@linux.intel.com>,
        vikas.shivappa@intel.com, x86@kernel.org, linux-kernel@vger.kernel.org,
        hpa@zytor.com, mingo@kernel.org, peterz@infradead.org,
        ravi.v.shankar@intel.com, fenghua.yu@intel.com,
        h.peter.anvin@intel.com
Subject: Re: [PATCH 1/3] x86/intel_rdt: Fix issue when mkdir uses a freed
 CLOSid
In-Reply-To: <20170405180737.GA4850@intel.com>
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On Wed, 5 Apr 2017, Luck, Tony wrote:
> On Wed, Apr 05, 2017 at 05:20:24PM +0200, Thomas Gleixner wrote:
> > That's just wrong.
> > 
> > The proper behaviour for a new control group is, that at the time when it
> > is created it copies the CBM values of the default group and not claiming
> > access to ALL of the cache by default.
> 
> I don't see that as any more helpful. When you make a new
> control group it is because none of the existing groups
> provides the QoS that you want.  So the first thing the
> user will do is write the schemata file with the values
> they do want.
> 
> So "all access", or "same as default group" are both the
> same to the user ... not what they want.
> 
> We do need to make sure that the schemata matches what is
> in the registers. We need to make sure that changes to the
> schemata file result in the MSRs being written where needed.

That's true today. The MSRs and the schemata file of a newly created group
always match. So there's nothing to fix, right?

Thanks,

	tglx