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authorKeith Busch <keith.busch@intel.com>2019-03-11 14:56:01 -0600
committerGreg Kroah-Hartman <gregkh@linuxfoundation.org>2019-04-04 18:41:21 +0200
commite1cf33aafb8462c7d0a0e6349925870316f040ee (patch)
treea45159a6e1d29d976957ec619c57ee296c421a3a /drivers/base/node.c
parent08d9dbe72b1f899468b2b34f9309e88a84f440f2 (diff)
downloadlinux-e1cf33aafb8462c7d0a0e6349925870316f040ee.tar.bz2
node: Add heterogenous memory access attributes
Heterogeneous memory systems provide memory nodes with different latency and bandwidth performance attributes. Provide a new kernel interface for subsystems to register the attributes under the memory target node's initiator access class. If the system provides this information, applications may query these attributes when deciding which node to request memory. The following example shows the new sysfs hierarchy for a node exporting performance attributes: # tree -P "read*|write*"/sys/devices/system/node/nodeY/accessZ/initiators/ /sys/devices/system/node/nodeY/accessZ/initiators/ |-- read_bandwidth |-- read_latency |-- write_bandwidth `-- write_latency The bandwidth is exported as MB/s and latency is reported in nanoseconds. The values are taken from the platform as reported by the manufacturer. Memory accesses from an initiator node that is not one of the memory's access "Z" initiator nodes linked in the same directory may observe different performance than reported here. When a subsystem makes use of this interface, initiators of a different access number may not have the same performance relative to initiators in other access numbers, or omitted from the any access class' initiators. Descriptions for memory access initiator performance access attributes are added to sysfs stable documentation. Acked-by: Jonathan Cameron <Jonathan.Cameron@huawei.com> Tested-by: Jonathan Cameron <Jonathan.Cameron@huawei.com> Signed-off-by: Keith Busch <keith.busch@intel.com> Reviewed-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com> Tested-by: Brice Goglin <Brice.Goglin@inria.fr> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Diffstat (limited to 'drivers/base/node.c')
-rw-r--r--drivers/base/node.c59
1 files changed, 59 insertions, 0 deletions
diff --git a/drivers/base/node.c b/drivers/base/node.c
index 6f4097680580..2de546a040a5 100644
--- a/drivers/base/node.c
+++ b/drivers/base/node.c
@@ -71,6 +71,9 @@ struct node_access_nodes {
struct device dev;
struct list_head list_node;
unsigned access;
+#ifdef CONFIG_HMEM_REPORTING
+ struct node_hmem_attrs hmem_attrs;
+#endif
};
#define to_access_nodes(dev) container_of(dev, struct node_access_nodes, dev)
@@ -148,6 +151,62 @@ free:
return NULL;
}
+#ifdef CONFIG_HMEM_REPORTING
+#define ACCESS_ATTR(name) \
+static ssize_t name##_show(struct device *dev, \
+ struct device_attribute *attr, \
+ char *buf) \
+{ \
+ return sprintf(buf, "%u\n", to_access_nodes(dev)->hmem_attrs.name); \
+} \
+static DEVICE_ATTR_RO(name);
+
+ACCESS_ATTR(read_bandwidth)
+ACCESS_ATTR(read_latency)
+ACCESS_ATTR(write_bandwidth)
+ACCESS_ATTR(write_latency)
+
+static struct attribute *access_attrs[] = {
+ &dev_attr_read_bandwidth.attr,
+ &dev_attr_read_latency.attr,
+ &dev_attr_write_bandwidth.attr,
+ &dev_attr_write_latency.attr,
+ NULL,
+};
+
+/**
+ * node_set_perf_attrs - Set the performance values for given access class
+ * @nid: Node identifier to be set
+ * @hmem_attrs: Heterogeneous memory performance attributes
+ * @access: The access class the for the given attributes
+ */
+void node_set_perf_attrs(unsigned int nid, struct node_hmem_attrs *hmem_attrs,
+ unsigned access)
+{
+ struct node_access_nodes *c;
+ struct node *node;
+ int i;
+
+ if (WARN_ON_ONCE(!node_online(nid)))
+ return;
+
+ node = node_devices[nid];
+ c = node_init_node_access(node, access);
+ if (!c)
+ return;
+
+ c->hmem_attrs = *hmem_attrs;
+ for (i = 0; access_attrs[i] != NULL; i++) {
+ if (sysfs_add_file_to_group(&c->dev.kobj, access_attrs[i],
+ "initiators")) {
+ pr_info("failed to add performance attribute to node %d\n",
+ nid);
+ break;
+ }
+ }
+}
+#endif
+
#define K(x) ((x) << (PAGE_SHIFT - 10))
static ssize_t node_read_meminfo(struct device *dev,
struct device_attribute *attr, char *buf)