base/node / acpi: Change 'node_hmem_attrs' to 'access_coordinates'
authorDave Jiang <dave.jiang@intel.com>
Thu, 21 Dec 2023 22:02:37 +0000 (15:02 -0700)
committerDan Williams <dan.j.williams@intel.com>
Fri, 22 Dec 2023 22:23:13 +0000 (14:23 -0800)
commit6a954e94d038f41d79c4e04348c95774d1c9337d
tree336fd69c7a9954edb78f976052e9ea548146f060
parent60e43fe5285e2077ce9904d78cd42a230d03b788
base/node / acpi: Change 'node_hmem_attrs' to 'access_coordinates'

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 exercise 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>
Reviewed-by: Jonathan Cameron <Jonathan.Cameron@huawei.com>
Signed-off-by: Dave Jiang <dave.jiang@intel.com>
Acked-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Link: https://lore.kernel.org/r/170319615734.2212653.15319394025985499185.stgit@djiang5-mobl3
Signed-off-by: Dan Williams <dan.j.williams@intel.com>
drivers/acpi/numa/hmat.c
drivers/base/node.c
include/linux/memory-tiers.h
include/linux/node.h
mm/memory-tiers.c