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Date:   Tue, 13 Jun 2023 09:57:05 +0200
From:   Greg KH <gregkh@linuxfoundation.org>
To:     Dave Jiang <dave.jiang@intel.com>
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
Subject: Re: [PATCH v2] base/node / acpi: Change 'node_hmem_attrs' to
 'access_coordinates'
Message-ID: <2023061331-napkin-disburse-915d@gregkh>
References: <168660916231.1965241.248859226126456131.stgit@djiang5-mobl3>
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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?

thanks,

greg k-h