On Thu, 10 Apr 2014, Naoya Horiguchi wrote:
> Yes, that's right, but it seems to me that just node_start_pfn and node_end_pfn
> is not enough because there can be holes (without any page struct backed) inside
> [node_start_pfn, node_end_pfn), and it's not aware of memory hotplug.
>
So? Who cares if there are non-addressable holes in part of the span?
Ulrich, correct me if I'm wrong, but it seems you're looking for just a
address-to-nodeid mapping (or pfn-to-nodeid mapping) and aren't actually
expecting that there are no holes in a node for things like acpi or I/O or
reserved memory.
The node spans a contiguous length of memory, there's no consideration for
addresses that aren't actually backed by physical memory. We are just
representing proximity domains that have a base address and length in the
acpi world.
Memory hotplug is already taken care of because onlining and offlining
nodes already add these node classes and {start,end}_phys_addr would
show up automatically. If you use node_start_pfn(nid) and
node_end_pfn(nid) as suggested, there's no futher consideration needed for
hotplug.
I think trying to represent holes and handling different memory models and
hotplug in special ways is complete overkill.
Ulrich, can I have your ack?
---
Documentation/ABI/stable/sysfs-devices-node | 12 ++++++++++++
drivers/base/node.c | 18 ++++++++++++++++++
2 files changed, 30 insertions(+)
diff --git a/Documentation/ABI/stable/sysfs-devices-node b/Documentation/ABI/stable/sysfs-devices-node
--- a/Documentation/ABI/stable/sysfs-devices-node
+++ b/Documentation/ABI/stable/sysfs-devices-node
@@ -63,6 +63,18 @@ Description:
The node's hit/miss statistics, in units of pages.
See Documentation/numastat.txt
+What: /sys/devices/system/node/nodeX/start_phys_addr
+Date: April 2014
+Contact: David Rientjes <rientjes@xxxxxxxxxx>
+Description:
+ The physical base address of this node.
+
+What: /sys/devices/system/node/nodeX/end_phys_addr
+Date: April 2014
+Contact: David Rientjes <rientjes@xxxxxxxxxx>
+Description:
+ The physical base + length address of this node.
+
What: /sys/devices/system/node/nodeX/distance
Date: October 2002
Contact: Linux Memory Management list <linux-mm@xxxxxxxxx>
diff --git a/drivers/base/node.c b/drivers/base/node.c
--- a/drivers/base/node.c
+++ b/drivers/base/node.c
@@ -170,6 +170,20 @@ static ssize_t node_read_numastat(struct device *dev,
}
static DEVICE_ATTR(numastat, S_IRUGO, node_read_numastat, NULL);
+static ssize_t node_read_start_phys_addr(struct device *dev,
+ struct device_attribute *attr, char *buf)
+{
+ return sprintf(buf, "0x%lx\n", node_start_pfn(dev->id) << PAGE_SHIFT);
+}
+static DEVICE_ATTR(start_phys_addr, S_IRUGO, node_read_start_phys_addr, NULL);
+
+static ssize_t node_read_end_phys_addr(struct device *dev,
+ struct device_attribute *attr, char *buf)
+{
+ return sprintf(buf, "0x%lx\n", node_end_pfn(dev->id) << PAGE_SHIFT);
+}
+static DEVICE_ATTR(end_phys_addr, S_IRUGO, node_read_end_phys_addr, NULL);
+
static ssize_t node_read_vmstat(struct device *dev,
struct device_attribute *attr, char *buf)
{
@@ -286,6 +300,8 @@ static int register_node(struct node *node, int num, struct node *parent)
device_create_file(&node->dev, &dev_attr_cpulist);
device_create_file(&node->dev, &dev_attr_meminfo);
device_create_file(&node->dev, &dev_attr_numastat);
+ device_create_file(&node->dev, &dev_attr_start_phys_addr);
+ device_create_file(&node->dev, &dev_attr_end_phys_addr);
device_create_file(&node->dev, &dev_attr_distance);
device_create_file(&node->dev, &dev_attr_vmstat);
@@ -311,6 +327,8 @@ void unregister_node(struct node *node)
device_remove_file(&node->dev, &dev_attr_cpulist);
device_remove_file(&node->dev, &dev_attr_meminfo);
device_remove_file(&node->dev, &dev_attr_numastat);
+ device_remove_file(&node->dev, &dev_attr_start_phys_addr);
+ device_remove_file(&node->dev, &dev_attr_end_phys_addr);
device_remove_file(&node->dev, &dev_attr_distance);
device_remove_file(&node->dev, &dev_attr_vmstat);
--
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