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authorGary Hade <garyhade@us.ibm.com>2009-01-06 14:39:14 -0800
committerLinus Torvalds <torvalds@linux-foundation.org>2009-01-06 15:59:00 -0800
commitc04fc586c1a480ba198f03ae7b6cbd7b57380b91 (patch)
tree9d6544a3b62cc01dbcbb1e315b84378b45ba86d2 /include/linux/node.h
parentee53a891f47444c53318b98dac947ede963db400 (diff)
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mm: show node to memory section relationship with symlinks in sysfs
Show node to memory section relationship with symlinks in sysfs Add /sys/devices/system/node/nodeX/memoryY symlinks for all the memory sections located on nodeX. For example: /sys/devices/system/node/node1/memory135 -> ../../memory/memory135 indicates that memory section 135 resides on node1. Also revises documentation to cover this change as well as updating Documentation/ABI/testing/sysfs-devices-memory to include descriptions of memory hotremove files 'phys_device', 'phys_index', and 'state' that were previously not described there. In addition to it always being a good policy to provide users with the maximum possible amount of physical location information for resources that can be hot-added and/or hot-removed, the following are some (but likely not all) of the user benefits provided by this change. Immediate: - Provides information needed to determine the specific node on which a defective DIMM is located. This will reduce system downtime when the node or defective DIMM is swapped out. - Prevents unintended onlining of a memory section that was previously offlined due to a defective DIMM. This could happen during node hot-add when the user or node hot-add assist script onlines _all_ offlined sections due to user or script inability to identify the specific memory sections located on the hot-added node. The consequences of reintroducing the defective memory could be ugly. - Provides information needed to vary the amount and distribution of memory on specific nodes for testing or debugging purposes. Future: - Will provide information needed to identify the memory sections that need to be offlined prior to physical removal of a specific node. Symlink creation during boot was tested on 2-node x86_64, 2-node ppc64, and 2-node ia64 systems. Symlink creation during physical memory hot-add tested on a 2-node x86_64 system. Signed-off-by: Gary Hade <garyhade@us.ibm.com> Signed-off-by: Badari Pulavarty <pbadari@us.ibm.com> Acked-by: Ingo Molnar <mingo@elte.hu> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Diffstat (limited to 'include/linux/node.h')
-rw-r--r--include/linux/node.h13
1 files changed, 13 insertions, 0 deletions
diff --git a/include/linux/node.h b/include/linux/node.h
index bc001bc..681a697 100644
--- a/include/linux/node.h
+++ b/include/linux/node.h
@@ -26,6 +26,7 @@ struct node {
struct sys_device sysdev;
};
+struct memory_block;
extern struct node node_devices[];
extern int register_node(struct node *, int, struct node *);
@@ -35,6 +36,9 @@ extern int register_one_node(int nid);
extern void unregister_one_node(int nid);
extern int register_cpu_under_node(unsigned int cpu, unsigned int nid);
extern int unregister_cpu_under_node(unsigned int cpu, unsigned int nid);
+extern int register_mem_sect_under_node(struct memory_block *mem_blk,
+ int nid);
+extern int unregister_mem_sect_under_nodes(struct memory_block *mem_blk);
#else
static inline int register_one_node(int nid)
{
@@ -52,6 +56,15 @@ static inline int unregister_cpu_under_node(unsigned int cpu, unsigned int nid)
{
return 0;
}
+static inline int register_mem_sect_under_node(struct memory_block *mem_blk,
+ int nid)
+{
+ return 0;
+}
+static inline int unregister_mem_sect_under_nodes(struct memory_block *mem_blk)
+{
+ return 0;
+}
#endif
#define to_node(sys_device) container_of(sys_device, struct node, sysdev)
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