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Date:   Tue, 30 Aug 2022 15:23:17 -0700
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Subject: Re: [PATCH v3 02/10] x86/cpufeatures: Add Slow Memory Bandwidth
 Allocation feature flag
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To:     <babu.moger@amd.com>
CC:     <bagasdotme@gmail.com>, <bp@alien8.de>, <corbet@lwn.net>,
        <dave.hansen@linux.intel.com>, <eranian@google.com>,
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References: <9965edff-c558-2962-4aad-3342480026bc@intel.com>
 <20220829232554.53763-1-babu.moger@amd.com>
 <59259155-6c51-a750-216a-ebbb0702d200@intel.com>
 <3aa991a8-ac08-297d-8328-5380897f6dd9@amd.com>
From:   Reinette Chatre <reinette.chatre@intel.com>
In-Reply-To: <3aa991a8-ac08-297d-8328-5380897f6dd9@amd.com>
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Hi Babu,

On 8/30/2022 3:10 PM, Moger, Babu wrote:
> On 8/30/2022 11:39 AM, Reinette Chatre wrote:

>> Would the "SMBA" resource be available only when CXL.mem devices are present
>> on the system? Since this is a CPU feature it is unclear to me whether
>> presence of CXL.mem devices would be known at the time "SMBA" is enumerated.
>> Could the "SMBA" resource thus exist without memory to throttle?
> 
> Yes.The presence of the SMBA feature(with CXL.mem) is independent of whether slow memory is actually present in the system.If there is no slow memory, then setting a SMBA limit will have no impact on the performance of the system.
> 

I think this is significant and should also be documented.

Reinette