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c04fc586c1
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>
103 lines
3.0 KiB
C
103 lines
3.0 KiB
C
/*
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* include/linux/memory.h - generic memory definition
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*
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* This is mainly for topological representation. We define the
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* basic "struct memory_block" here, which can be embedded in per-arch
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* definitions or NUMA information.
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*
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* Basic handling of the devices is done in drivers/base/memory.c
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* and system devices are handled in drivers/base/sys.c.
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*
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* Memory block are exported via sysfs in the class/memory/devices/
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* directory.
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*
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*/
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#ifndef _LINUX_MEMORY_H_
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#define _LINUX_MEMORY_H_
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#include <linux/sysdev.h>
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#include <linux/node.h>
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#include <linux/compiler.h>
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#include <linux/mutex.h>
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struct memory_block {
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unsigned long phys_index;
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unsigned long state;
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/*
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* This serializes all state change requests. It isn't
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* held during creation because the control files are
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* created long after the critical areas during
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* initialization.
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*/
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struct mutex state_mutex;
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int phys_device; /* to which fru does this belong? */
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void *hw; /* optional pointer to fw/hw data */
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int (*phys_callback)(struct memory_block *);
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struct sys_device sysdev;
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};
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/* These states are exposed to userspace as text strings in sysfs */
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#define MEM_ONLINE (1<<0) /* exposed to userspace */
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#define MEM_GOING_OFFLINE (1<<1) /* exposed to userspace */
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#define MEM_OFFLINE (1<<2) /* exposed to userspace */
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#define MEM_GOING_ONLINE (1<<3)
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#define MEM_CANCEL_ONLINE (1<<4)
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#define MEM_CANCEL_OFFLINE (1<<5)
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struct memory_notify {
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unsigned long start_pfn;
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unsigned long nr_pages;
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int status_change_nid;
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};
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struct notifier_block;
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struct mem_section;
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/*
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* Priorities for the hotplug memory callback routines (stored in decreasing
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* order in the callback chain)
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*/
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#define SLAB_CALLBACK_PRI 1
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#define IPC_CALLBACK_PRI 10
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#ifndef CONFIG_MEMORY_HOTPLUG_SPARSE
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static inline int memory_dev_init(void)
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{
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return 0;
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}
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static inline int register_memory_notifier(struct notifier_block *nb)
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{
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return 0;
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}
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static inline void unregister_memory_notifier(struct notifier_block *nb)
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{
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}
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static inline int memory_notify(unsigned long val, void *v)
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{
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return 0;
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}
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#else
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extern int register_memory_notifier(struct notifier_block *nb);
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extern void unregister_memory_notifier(struct notifier_block *nb);
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extern int register_new_memory(int, struct mem_section *);
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extern int unregister_memory_section(struct mem_section *);
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extern int memory_dev_init(void);
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extern int remove_memory_block(unsigned long, struct mem_section *, int);
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extern int memory_notify(unsigned long val, void *v);
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extern struct memory_block *find_memory_block(struct mem_section *);
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#define CONFIG_MEM_BLOCK_SIZE (PAGES_PER_SECTION<<PAGE_SHIFT)
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enum mem_add_context { BOOT, HOTPLUG };
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#endif /* CONFIG_MEMORY_HOTPLUG_SPARSE */
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#ifdef CONFIG_MEMORY_HOTPLUG
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#define hotplug_memory_notifier(fn, pri) { \
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static __meminitdata struct notifier_block fn##_mem_nb =\
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{ .notifier_call = fn, .priority = pri }; \
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register_memory_notifier(&fn##_mem_nb); \
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}
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#else
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#define hotplug_memory_notifier(fn, pri) do { } while (0)
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#endif
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#endif /* _LINUX_MEMORY_H_ */
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