[PATCH] mm: add node physical memory range to sysfs

[Davidlohr Bueso]

This patch adds a new 'memrange' file that shows the starting and
ending physical addresses that are associated to a node. This is
useful for identifying specific DIMMs within the system.

Signed-off-by: Davidlohr Bueso <davidlohr.bueso@xxxxxx>
---
 drivers/base/node.c | 15 +++++++++++++++
 1 file changed, 15 insertions(+)

diff --git a/drivers/base/node.c b/drivers/base/node.c
index af1a177..f165a0a 100644
--- a/drivers/base/node.c
+++ b/drivers/base/node.c
@@ -211,6 +211,19 @@ static ssize_t node_read_distance(struct device *dev,
 }
 static DEVICE_ATTR(distance, S_IRUGO, node_read_distance, NULL);
 
+static ssize_t node_read_memrange(struct device *dev,
+				  struct device_attribute *attr, char *buf)
+{
+	int nid = dev->id;
+	unsigned long start_pfn = NODE_DATA(nid)->node_start_pfn;
+	unsigned long end_pfn = start_pfn + NODE_DATA(nid)->node_spanned_pages;
+
+	return sprintf(buf, "%#010Lx-%#010Lx\n",
+		       (unsigned long long) start_pfn << PAGE_SHIFT,
+		       (unsigned long long) (end_pfn << PAGE_SHIFT) - 1);
+}
+static DEVICE_ATTR(memrange, S_IRUGO, node_read_memrange, NULL);
+
 #ifdef CONFIG_HUGETLBFS
 /*
  * hugetlbfs per node attributes registration interface:
@@ -274,6 +287,7 @@ int register_node(struct node *node, int num, struct node *parent)
 		device_create_file(&node->dev, &dev_attr_numastat);
 		device_create_file(&node->dev, &dev_attr_distance);
 		device_create_file(&node->dev, &dev_attr_vmstat);
+		device_create_file(&node->dev, &dev_attr_memrange);
 
 		scan_unevictable_register_node(node);
 
@@ -299,6 +313,7 @@ void unregister_node(struct node *node)
 	device_remove_file(&node->dev, &dev_attr_numastat);
 	device_remove_file(&node->dev, &dev_attr_distance);
 	device_remove_file(&node->dev, &dev_attr_vmstat);
+	device_remove_file(&node->dev, &dev_attr_memrange);
 
 	scan_unevictable_unregister_node(node);
 	hugetlb_unregister_node(node);		/* no-op, if memoryless node */
-- 
1.7.11.7



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