[PATCH] [RESEND] mm: show memory section to node relationship in sysfs

[Gary Hade <garyhade@us.ibm.com>]

Resending with linux-kernel@vger.kernel.org copied this time.  No changes
other than this and the Subject line.  Based on linux-mm discussion
yesterday I will be revising this patch to include proper documentation
and symlinks instead of node number containing files.  If there are any
other comments please fire away.


Show memory section to node relationship in sysfs

Add /sys/devices/system/memory/memoryX/node files to show
the node on which each memory section resides.

Signed-off-by: Gary Hade <garyhade@us.ibm.com>

---
 Documentation/memory-hotplug.txt |    1 -
 drivers/base/memory.c            |   20 ++++++++++++++++++++
 2 files changed, 20 insertions(+), 1 deletion(-)

Index: linux-2.6.27-rc5/drivers/base/memory.c
===================================================================
--- linux-2.6.27-rc5.orig/drivers/base/memory.c	2008-09-03 14:24:54.000000000 -0700
+++ linux-2.6.27-rc5/drivers/base/memory.c	2008-09-03 14:25:14.000000000 -0700
@@ -150,6 +150,22 @@
 	return len;
 }

+/*
+ * node on which memory section resides
+ */
+static ssize_t show_mem_node(struct sys_device *dev,
+			struct sysdev_attribute *attr, char *buf)
+{
+	unsigned long start_pfn;
+	int ret;
+	struct memory_block *mem =
+		container_of(dev, struct memory_block, sysdev);
+
+	start_pfn = section_nr_to_pfn(mem->phys_index);
+	ret = pfn_to_nid(start_pfn);
+	return sprintf(buf, "%d\n", ret);
+}
+
 int memory_notify(unsigned long val, void *v)
 {
 	return blocking_notifier_call_chain(&memory_chain, val, v);
@@ -278,6 +294,7 @@
 static SYSDEV_ATTR(state, 0644, show_mem_state, store_mem_state);
 static SYSDEV_ATTR(phys_device, 0444, show_phys_device, NULL);
 static SYSDEV_ATTR(removable, 0444, show_mem_removable, NULL);
+static SYSDEV_ATTR(node, 0444, show_mem_node, NULL);

 #define mem_create_simple_file(mem, attr_name)	\
 	sysdev_create_file(&mem->sysdev, &attr_##attr_name)
@@ -368,6 +385,8 @@
 		ret = mem_create_simple_file(mem, phys_device);
 	if (!ret)
 		ret = mem_create_simple_file(mem, removable);
+	if (!ret)
+		ret = mem_create_simple_file(mem, node);

 	return ret;
 }
@@ -413,6 +432,7 @@
 	mem_remove_simple_file(mem, state);
 	mem_remove_simple_file(mem, phys_device);
 	mem_remove_simple_file(mem, removable);
+	mem_remove_simple_file(mem, node);
 	unregister_memory(mem, section);

 	return 0;
Index: linux-2.6.27-rc5/Documentation/memory-hotplug.txt
===================================================================
--- linux-2.6.27-rc5.orig/Documentation/memory-hotplug.txt	2008-09-03 14:25:54.000000000 -0700
+++ linux-2.6.27-rc5/Documentation/memory-hotplug.txt	2008-09-03 14:26:15.000000000 -0700
@@ -365,7 +365,6 @@
   - allowing memory hot-add to ZONE_MOVABLE. maybe we need some switch like
     sysctl or new control file.
   - showing memory section and physical device relationship.
-  - showing memory section and node relationship (maybe good for NUMA)
   - showing memory section is under ZONE_MOVABLE or not
   - test and make it better memory offlining.
   - support HugeTLB page migration and offlining.

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