From c04fc586c1a480ba198f03ae7b6cbd7b57380b91 Mon Sep 17 00:00:00 2001 From: Gary Hade Date: Tue, 6 Jan 2009 14:39:14 -0800 Subject: 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 Signed-off-by: Badari Pulavarty Acked-by: Ingo Molnar Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds --- include/linux/node.h | 13 +++++++++++++ 1 file changed, 13 insertions(+) (limited to 'include/linux/node.h') diff --git a/include/linux/node.h b/include/linux/node.h index bc001bc225c3..681a697b9a86 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) -- cgit v1.2.3-59-g8ed1b