device-dax: Add a 'target_node' attribute (21c75763) · Commits · 戴 / test

The target-node attribute is the Linux numa-node that a device-dax instance may create when it is online. Prior to being online the device's 'numa_node' property reflects the closest online cpu node which is the typical expectation of a device 'numa_node'. Once it is online it becomes its own distinct numa node, i.e. 'target_node'. Export the 'target_node' property to give userspace tooling the ability to predict the effective numa-node from a device-dax instance configured to provide 'System RAM' capacity. Cc: Vishal Verma <vishal.l.verma@intel.com> Reported-by:

Dave Hansen <dave.hansen@linux.intel.com> Signed-off-by:

Dan Williams <dan.j.williams@intel.com>

drivers/dax/bus.c

+28 −0

Original line number	Diff line number	Diff line
		@@ -279,13 +279,41 @@ static ssize_t size_show(struct device *dev,
		}
		static DEVICE_ATTR_RO(size);

		static int dev_dax_target_node(struct dev_dax *dev_dax)
		{
		struct dax_region *dax_region = dev_dax->region;

		return dax_region->target_node;
		}

		static ssize_t target_node_show(struct device *dev,
		struct device_attribute attr, char buf)
		{
		struct dev_dax *dev_dax = to_dev_dax(dev);

		return sprintf(buf, "%d\n", dev_dax_target_node(dev_dax));
		}
		static DEVICE_ATTR_RO(target_node);

		static umode_t dev_dax_visible(struct kobject kobj, struct attribute a, int n)
		{
		struct device *dev = container_of(kobj, struct device, kobj);
		struct dev_dax *dev_dax = to_dev_dax(dev);

		if (a == &dev_attr_target_node.attr && dev_dax_target_node(dev_dax) < 0)
		return 0;
		return a->mode;
		}

		static struct attribute *dev_dax_attributes[] = {
		&dev_attr_size.attr,
		&dev_attr_target_node.attr,
		NULL,
		};

		static const struct attribute_group dev_dax_attribute_group = {
		.attrs = dev_dax_attributes,
		.is_visible = dev_dax_visible,
		};

		static const struct attribute_group *dax_attribute_groups[] = {

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