Received-SPF: pass (google.com: domain of linux-kernel-owner@vger.kernel.org designates 2620:137:e000::1:20 as permitted sender) client-ip=2620:137:e000::1:20;
Message-ID: <b0d9b8ee-d1ac-4580-da97-4d0dcfc10388@intel.com>
Date:   Tue, 13 Jun 2023 09:19:09 -0700
User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:102.0) Gecko/20100101
 Betterbird/102.11.0
Subject: Re: [PATCH v2] base/node / acpi: Change 'node_hmem_attrs' to
 'access_coordinates'
To:     Greg KH <gregkh@linuxfoundation.org>
CC:     <linux-kernel@vger.kernel.org>, <linux-acpi@vger.kernel.org>,
        <linux-cxl@vger.kernel.org>,
        Dan Williams <dan.j.williams@intel.com>, <rafael@kernel.org>,
        <jonathan.cameron@huawei.com>
References: <168660916231.1965241.248859226126456131.stgit@djiang5-mobl3>
 <2023061331-napkin-disburse-915d@gregkh>
Content-Language: en-US
From:   Dave Jiang <dave.jiang@intel.com>
In-Reply-To: <2023061331-napkin-disburse-915d@gregkh>
Content-Type: text/plain; charset="UTF-8"; format=flowed
Content-Transfer-Encoding: 7bit
MIME-Version: 1.0
X-MS-Exchange-AntiSpam-MessageData-ChunkCount: 1
X-MS-Exchange-AntiSpam-MessageData-0: =?utf-8?B?VHY0eU9HeUZOT0RuUUE4OFpBVmxEZDlUT0puei9RNW9FdEpuZStzbGNOeDRi?=
 =?utf-8?B?T0V2dm04cGthRFhRN1Z6aE01NmtvakxXUTdFN2V2OGkyUWZtaU4rWlJWbC9J?=
 =?utf-8?B?akc2eXQ2d0lVWU8vRGVlSytESUw5YjZaTmt1QWJhK0w2ZGE5MHBWNjNGc214?=
 =?utf-8?B?bUVBT093YzVxUjNIV1ZIa2pIUGRVZHkwYUpnWWcyVjVDcHNpdEFRVHA1blFG?=
 =?utf-8?B?dEd0SnMyZ1VMUWcxL0t5TkVXOE5YS3YySlNVSWpvV3B6dHdab0ovcVBPSjZS?=
 =?utf-8?B?NTAvQWJEWHUyNmlJL21hRnFQUHJ3OC84ZHE2cktyYmdUMkpIYUxkU0NSTXBK?=
 =?utf-8?B?bjMwYjN3Q0JqbW1Kc1pwdFBWbmdWYXBobFp2TExJaDdZS0FTYVJOazZkUjQy?=
 =?utf-8?B?d2VGUlcrWkhhejkyWk1HTGdOSnVmUnV2QkdtUktqRUdOaHo2YVlWZnBUWkpK?=
 =?utf-8?B?RFMrZVN2YVNRNWlpelFKSXZxTFdDMjd6cXJRTG4xT1NxWFY1RVlPdGx0bXJN?=
 =?utf-8?B?d2JxQ3NCd1RUOHJuSnJ5RzlldXVqYmhyTzFSVnB0eDlKa1hFaWdNa2hlTFQ3?=
 =?utf-8?B?Vk5rMGRRbGZTVmgrN2N3ZDZWMnhaVmg5aHBmOHRZdmM5NWJKM29SYzEwaXFu?=
 =?utf-8?B?M3R3VVltVDNjUjRTSXZSQ0l3ZVRodEx1dkltc3JnRVRoQ29IVkVHSEI0U0xq?=
 =?utf-8?B?NlZHbWFkQWxEeVNYK2dobEx5NzFmbEVXbVB2WE90eS82RExBQzdJbXZRUkxv?=
 =?utf-8?B?dlFScXZyTEV6SUxNcS9WaTdrdE9UbVdMamVkQ0U1SmpWUUw2S2dMb1pyaHRR?=
 =?utf-8?B?RXlOaFlMZ3JSR3kxSms4QWl2NEZXWVRuRGhjM21CcnFnb3FRTHFEVFNmak9Q?=
 =?utf-8?B?ZmtTS2JZSVVUYnQvVGZ1a1pBdU1Ec2RaSG5oczI2QjkzL1AwaFkyakhnWVAw?=
 =?utf-8?B?ZWFPOSs2a3RDelFOOHNWT2c0WUwxb1RXTGZKMjlmZ1JWSXV6UTZIUmFMdW1U?=
 =?utf-8?B?ZEhnbUFqbjZzeGF6MkplRDJyelV3QzVmOU1LR21aT1lCK0dXd1dacEEyalo4?=
 =?utf-8?B?VTdZd3p1WDBWWEdIbkE3aTZxemRva2VLNzVlbWdaRDJiZzFoYTN6aHo1L3lH?=
 =?utf-8?B?OTcxZFl5L09heW9PZHVsWG1VeVJacEl3Nk9KeFF1aDdjdURmSTVWQmpxM2RC?=
 =?utf-8?B?c0ZRSG5xck9UR3ExMVdBNjVRRmdFWmxiSTNBWHZCVFJsYmNDSnlkS1BhT040?=
 =?utf-8?B?WTMrVk5nRXlMYm1tQkZBQ0p4alJ2YzRlQnVmb1B6S0Y2RHF4ZThMb2RLSi9M?=
 =?utf-8?B?YXRzNmxBMWpITW5HS2VsenpGc3QydFlQNVhLbDhnMG5wTlpCOFhSd0krV2tK?=
 =?utf-8?B?WFJoYUhNT0dodGRGbnh4Ly9uRjVSU1pCYkw3M0lrbUlodEdtUTNSVFVwQUxm?=
 =?utf-8?B?TmpLcUp4RVJzSUppQ3FXTEpKOFV3NDdzMHFWNFNTN21nYWF3Z3djWFRNYVFy?=
 =?utf-8?B?aW9QeHU3WDdNYURzeVlYekhLbmVES0Q1MHByeUZUMzZrSUdJUHhRL3dMZEg5?=
 =?utf-8?B?UWowZmZOMDY5UGhCa0k0L29QMDc0WUsxZS83MnI5WTdxZXhFVmlLQk5MdWln?=
 =?utf-8?B?SjFpSFhHRTZNbkRTbWQxeVlxbytQL0lOY3ZVT2FaTVgvSnVJbkRiNTB4RzJJ?=
 =?utf-8?B?MVZ6aCt0d3FOa1EvWDNZMTYvTXc3VlNxMWVZUHhzU2FWNERhaEpNcHRSb2Jj?=
 =?utf-8?B?eEtpL1cveXZETTMreFpVNngvd0MyVlVuSWxsSGg5R0ZzOTNPeG1PSkpYRlhR?=
 =?utf-8?B?d0cwWTNFNTZLdUp6RCtYL2NHUkVRdTdjNU9TN1BJYk1COStQVmxCWTkrekxT?=
 =?utf-8?B?MURWMW84QlZuMEVIb2RINjlOTHV3ZkRMWVplbG04QjdxcUF6cHA4aWMxckxB?=
 =?utf-8?B?T3VIT2VNbVRlM1BXOXYveHMxdGk4N0VPVmZZWkFZMkpmcmxBVHVkOTVORDIw?=
 =?utf-8?B?TDVrNTFWaDFkVFVJczkwWFZTT1ZLMDh4VnQ0TFZ0am5YdlAzNlF0YkdnaTRN?=
 =?utf-8?B?S0dYM3g0Tzgxak5uUVlTZ01mRXVHbDNxcnBvR0tmY0VJVGtIaUwvcktBSjFt?=
 =?utf-8?Q?owMsLEbWMRFIhkWNyIhGN7VNd?=
X-MS-Exchange-CrossTenant-Network-Message-Id: 4171b236-0831-4902-cfaf-08db6c29ecb0
X-MS-Exchange-CrossTenant-AuthSource: PH7PR11MB5984.namprd11.prod.outlook.com
X-MS-Exchange-CrossTenant-AuthAs: Internal
X-MS-Exchange-CrossTenant-OriginalArrivalTime: 13 Jun 2023 16:19:12.6229
 (UTC)
X-MS-Exchange-CrossTenant-FromEntityHeader: Hosted
X-MS-Exchange-CrossTenant-Id: 46c98d88-e344-4ed4-8496-4ed7712e255d
X-MS-Exchange-CrossTenant-MailboxType: HOSTED
X-MS-Exchange-CrossTenant-UserPrincipalName: 4evmXgaSNOUyOxIZJWNQEz5YuzRC/jfhHj3WMV3nhaN1v0TzflxwZYUyUAQ5QBdnqFvkWThPsG4BWBzg5J7siQ==
X-MS-Exchange-Transport-CrossTenantHeadersStamped: PH8PR11MB8039
X-OriginatorOrg: intel.com
X-Spam-Status: No, score=-4.5 required=5.0 tests=BAYES_00,DKIMWL_WL_HIGH,
        DKIM_SIGNED,DKIM_VALID,DKIM_VALID_AU,DKIM_VALID_EF,NICE_REPLY_A,
        RCVD_IN_DNSWL_MED,SPF_HELO_NONE,SPF_NONE,T_SCC_BODY_TEXT_LINE,
        URIBL_BLOCKED autolearn=ham autolearn_force=no version=3.4.6
X-Spam-Checker-Version: SpamAssassin 3.4.6 (2021-04-09) on
        lindbergh.monkeyblade.net
Precedence: bulk
List-ID: <linux-kernel.vger.kernel.org>
X-Mailing-List: linux-kernel@vger.kernel.org


On 6/13/23 00:57, Greg KH wrote:
> On Mon, Jun 12, 2023 at 03:32:42PM -0700, Dave Jiang wrote:
>> Dan Williams suggested changing the struct 'node_hmem_attrs' to
>> 'access_coordinates' [1]. The struct is a container of r/w-latency and
>> r/w-bandwidth numbers. Moving forward, this container will also be used by
>> CXL to store the performance characteristics of each link hop in
>> the PCIE/CXL topology. So, where node_hmem_attrs is just the access
>> parameters of a memory-node, access_coordinates applies more broadly
>> to hardware topology characteristics. The observation is that seemed like
>> an excercise in having the application identify "where" it falls on a
>> spectrum of bandwidth and latency needs. For the tuple of read/write-latency
>> and read/write-bandwidth, "coordinates" is not a perfect fit. Sometimes it
>> is just conveying values in isolation and not a "location" relative to
>> other performance points, but in the end this data is used to identify the
>> performance operation point of a given memory-node. [2]
>>
>> Link: http://lore.kernel.org/r/64471313421f7_1b66294d5@dwillia2-xfh.jf.intel.com.notmuch/
>> Link: https://lore.kernel.org/linux-cxl/645e6215ee0de_1e6f2945e@dwillia2-xfh.jf.intel.com.notmuch/
>> Suggested-by: Dan Williams <dan.j.williams@intel.com>
>> Reviewed-by: Dan Williams <dan.j.williams@intel.com>
>> Signed-off-by: Dave Jiang <dave.jiang@intel.com>
>>
>> ---
>>
>> Hi Greg and Rafael,
>> please consider ACK this patch and Dan can take it through the
>> CXL upstream tree. The remaining ACPI [1] and CXL [2] patches for enabling
>> CXL QoS class data have dependency on this patch. Thank you!
>>
>> [1]: https://lore.kernel.org/linux-cxl/168333141100.2290593.16294670316057617744.stgit@djiang5-mobl3/T/#t
>> [2]: https://lore.kernel.org/linux-cxl/168451588868.3470703.3527256859632103687.stgit@djiang5-mobl3/T/#t
> Isn't this going to conflict with the version that I have in the
> driver-core-next tree as commit 7810f4dc8795 ("base/node: Use 'property'
> to identify an access parameter")?
>
> Or was that a different thing?

Yes this is a different thing and should not conflict. But a small 
dependency on the mentioned commit above however:

@@ -168,7 +168,7 @@ static ssize_t property##_show(struct device *dev,			\
  			   char *buf)					\
  {									\
  	return sysfs_emit(buf, "%u\n",					\
-			  to_access_nodes(dev)->hmem_attrs.property);	\
+			  to_access_nodes(dev)->coord.property);	\
  }									\
  static DEVICE_ATTR_RO(property)
  

>
> thanks,
>
> greg k-h