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mm: show node to memory section relationship with symlinks in sysfs

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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>
This commit is contained in:
Gary Hade 2009-01-06 14:39:14 -08:00 committed by Linus Torvalds
parent ee53a891f4
commit c04fc586c1
14 changed files with 210 additions and 26 deletions
Show stats Download patch file Download diff file Expand all files Collapse all files

53
Documentation/ABI/testing/sysfs-devices-memory
View file

@ -6,7 +6,6 @@ Description:
internal state of the kernel memory blocks. Files could be
added or removed dynamically to represent hot-add/remove
operations.
Users: hotplug memory add/remove tools
https://w3.opensource.ibm.com/projects/powerpc-utils/
@ -19,6 +18,56 @@ Description:
This is useful for a user-level agent to determine
identify removable sections of the memory before attempting
potentially expensive hot-remove memory operation
Users: hotplug memory remove tools
https://w3.opensource.ibm.com/projects/powerpc-utils/
What: /sys/devices/system/memory/memoryX/phys_device
Date: September 2008
Contact: Badari Pulavarty <pbadari@us.ibm.com>
Description:
The file /sys/devices/system/memory/memoryX/phys_device
is read-only and is designed to show the name of physical
memory device. Implementation is currently incomplete.
What: /sys/devices/system/memory/memoryX/phys_index
Date: September 2008
Contact: Badari Pulavarty <pbadari@us.ibm.com>
Description:
The file /sys/devices/system/memory/memoryX/phys_index
is read-only and contains the section ID in hexadecimal
which is equivalent to decimal X contained in the
memory section directory name.
What: /sys/devices/system/memory/memoryX/state
Date: September 2008
Contact: Badari Pulavarty <pbadari@us.ibm.com>
Description:
The file /sys/devices/system/memory/memoryX/state
is read-write. When read, it's contents show the
online/offline state of the memory section. When written,
root can toggle the the online/offline state of a removable
memory section (see removable file description above)
using the following commands.
# echo online > /sys/devices/system/memory/memoryX/state
# echo offline > /sys/devices/system/memory/memoryX/state
For example, if /sys/devices/system/memory/memory22/removable
contains a value of 1 and
/sys/devices/system/memory/memory22/state contains the
string "online" the following command can be executed by
by root to offline that section.
# echo offline > /sys/devices/system/memory/memory22/state
Users: hotplug memory remove tools
https://w3.opensource.ibm.com/projects/powerpc-utils/
What: /sys/devices/system/node/nodeX/memoryY
Date: September 2008
Contact: Gary Hade <garyhade@us.ibm.com>
Description:
When CONFIG_NUMA is enabled
/sys/devices/system/node/nodeX/memoryY is a symbolic link that
points to the corresponding /sys/devices/system/memory/memoryY
memory section directory. For example, the following symbolic
link is created for memory section 9 on node0.
/sys/devices/system/node/node0/memory9 -> ../../memory/memory9

16
Documentation/memory-hotplug.txt
View file

@ -124,7 +124,7 @@ config options.
This option can be kernel module too.
--------------------------------
3 sysfs files for memory hotplug
4 sysfs files for memory hotplug
--------------------------------
All sections have their device information under /sys/devices/system/memory as
@ -138,11 +138,12 @@ For example, assume 1GiB section size. A device for a memory starting at
(0x100000000 / 1Gib = 4)
This device covers address range [0x100000000 ... 0x140000000)
Under each section, you can see 3 files.
Under each section, you can see 4 files.
/sys/devices/system/memory/memoryXXX/phys_index
/sys/devices/system/memory/memoryXXX/phys_device
/sys/devices/system/memory/memoryXXX/state
/sys/devices/system/memory/memoryXXX/removable
'phys_index' : read-only and contains section id, same as XXX.
'state' : read-write
@ -150,10 +151,20 @@ Under each section, you can see 3 files.
at write: user can specify "online", "offline" command
'phys_device': read-only: designed to show the name of physical memory device.
This is not well implemented now.
'removable' : read-only: contains an integer value indicating
whether the memory section is removable or not
removable. A value of 1 indicates that the memory
section is removable and a value of 0 indicates that
it is not removable.
NOTE:
These directories/files appear after physical memory hotplug phase.
If CONFIG_NUMA is enabled the
/sys/devices/system/memory/memoryXXX memory section
directories can also be accessed via symbolic links located in
the /sys/devices/system/node/node* directories. For example:
/sys/devices/system/node/node0/memory9 -> ../../memory/memory9
--------------------------------
4. Physical memory hot-add phase
@ -365,7 +376,6 @@ node if necessary.
- 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.

2
arch/ia64/mm/init.c
View file

@ -692,7 +692,7 @@ int arch_add_memory(int nid, u64 start, u64 size)
pgdat = NODE_DATA(nid);
zone = pgdat->node_zones + ZONE_NORMAL;
ret = __add_pages(zone, start_pfn, nr_pages);
ret = __add_pages(nid, zone, start_pfn, nr_pages);
if (ret)
printk("%s: Problem encountered in __add_pages() as ret=%d\n",

2
arch/powerpc/mm/mem.c
View file

@ -132,7 +132,7 @@ int arch_add_memory(int nid, u64 start, u64 size)
/* this should work for most non-highmem platforms */
zone = pgdata->node_zones;
return __add_pages(zone, start_pfn, nr_pages);
return __add_pages(nid, zone, start_pfn, nr_pages);
}
#endif /* CONFIG_MEMORY_HOTPLUG */

2
arch/s390/mm/init.c
View file

@ -183,7 +183,7 @@ int arch_add_memory(int nid, u64 start, u64 size)
rc = vmem_add_mapping(start, size);
if (rc)
return rc;
rc = __add_pages(zone, PFN_DOWN(start), PFN_DOWN(size));
rc = __add_pages(nid, zone, PFN_DOWN(start), PFN_DOWN(size));
if (rc)
vmem_remove_mapping(start, size);
return rc;

3
arch/sh/mm/init.c
View file

@ -311,7 +311,8 @@ int arch_add_memory(int nid, u64 start, u64 size)
pgdat = NODE_DATA(nid);
/* We only have ZONE_NORMAL, so this is easy.. */
ret = __add_pages(pgdat->node_zones + ZONE_NORMAL, start_pfn, nr_pages);
ret = __add_pages(nid, pgdat->node_zones + ZONE_NORMAL,
start_pfn, nr_pages);
if (unlikely(ret))
printk("%s: Failed, __add_pages() == %d\n", __func__, ret);

2
arch/x86/mm/init_32.c
View file

@ -1079,7 +1079,7 @@ int arch_add_memory(int nid, u64 start, u64 size)
unsigned long start_pfn = start >> PAGE_SHIFT;
unsigned long nr_pages = size >> PAGE_SHIFT;
return __add_pages(zone, start_pfn, nr_pages);
return __add_pages(nid, zone, start_pfn, nr_pages);
}
#endif

2
arch/x86/mm/init_64.c
View file

@ -857,7 +857,7 @@ int arch_add_memory(int nid, u64 start, u64 size)
if (last_mapped_pfn > max_pfn_mapped)
max_pfn_mapped = last_mapped_pfn;
ret = __add_pages(zone, start_pfn, nr_pages);
ret = __add_pages(nid, zone, start_pfn, nr_pages);
WARN_ON_ONCE(ret);
return ret;

19
drivers/base/memory.c
View file

@ -347,8 +347,9 @@ static inline int memory_probe_init(void)
* section belongs to...
*/
static int add_memory_block(unsigned long node_id, struct mem_section *section,
unsigned long state, int phys_device)
static int add_memory_block(int nid, struct mem_section *section,
unsigned long state, int phys_device,
enum mem_add_context context)
{
struct memory_block *mem = kzalloc(sizeof(*mem), GFP_KERNEL);
int ret = 0;
@ -370,6 +371,10 @@ static int add_memory_block(unsigned long node_id, struct mem_section *section,
ret = mem_create_simple_file(mem, phys_device);
if (!ret)
ret = mem_create_simple_file(mem, removable);
if (!ret) {
if (context == HOTPLUG)
ret = register_mem_sect_under_node(mem, nid);
}
return ret;
}
@ -382,7 +387,7 @@ static int add_memory_block(unsigned long node_id, struct mem_section *section,
*
* This could be made generic for all sysdev classes.
*/
static struct memory_block *find_memory_block(struct mem_section *section)
struct memory_block *find_memory_block(struct mem_section *section)
{
struct kobject *kobj;
struct sys_device *sysdev;
@ -411,6 +416,7 @@ int remove_memory_block(unsigned long node_id, struct mem_section *section,
struct memory_block *mem;
mem = find_memory_block(section);
unregister_mem_sect_under_nodes(mem);
mem_remove_simple_file(mem, phys_index);
mem_remove_simple_file(mem, state);
mem_remove_simple_file(mem, phys_device);
@ -424,9 +430,9 @@ int remove_memory_block(unsigned long node_id, struct mem_section *section,
* need an interface for the VM to add new memory regions,
* but without onlining it.
*/
int register_new_memory(struct mem_section *section)
int register_new_memory(int nid, struct mem_section *section)
{
return add_memory_block(0, section, MEM_OFFLINE, 0);
return add_memory_block(nid, section, MEM_OFFLINE, 0, HOTPLUG);
}
int unregister_memory_section(struct mem_section *section)
@ -458,7 +464,8 @@ int __init memory_dev_init(void)
for (i = 0; i < NR_MEM_SECTIONS; i++) {
if (!present_section_nr(i))
continue;
err = add_memory_block(0, __nr_to_section(i), MEM_ONLINE, 0);
err = add_memory_block(0, __nr_to_section(i), MEM_ONLINE,
0, BOOT);
if (!ret)
ret = err;
}

103
drivers/base/node.c
View file

@ -6,6 +6,7 @@
#include <linux/module.h>
#include <linux/init.h>
#include <linux/mm.h>
#include <linux/memory.h>
#include <linux/node.h>
#include <linux/hugetlb.h>
#include <linux/cpumask.h>
@ -248,6 +249,105 @@ int unregister_cpu_under_node(unsigned int cpu, unsigned int nid)
return 0;
}
#ifdef CONFIG_MEMORY_HOTPLUG_SPARSE
#define page_initialized(page) (page->lru.next)
static int get_nid_for_pfn(unsigned long pfn)
{
struct page *page;
if (!pfn_valid_within(pfn))
return -1;
page = pfn_to_page(pfn);
if (!page_initialized(page))
return -1;
return pfn_to_nid(pfn);
}
/* register memory section under specified node if it spans that node */
int register_mem_sect_under_node(struct memory_block *mem_blk, int nid)
{
unsigned long pfn, sect_start_pfn, sect_end_pfn;
if (!mem_blk)
return -EFAULT;
if (!node_online(nid))
return 0;
sect_start_pfn = section_nr_to_pfn(mem_blk->phys_index);
sect_end_pfn = sect_start_pfn + PAGES_PER_SECTION - 1;
for (pfn = sect_start_pfn; pfn <= sect_end_pfn; pfn++) {
int page_nid;
page_nid = get_nid_for_pfn(pfn);
if (page_nid < 0)
continue;
if (page_nid != nid)
continue;
return sysfs_create_link_nowarn(&node_devices[nid].sysdev.kobj,
&mem_blk->sysdev.kobj,
kobject_name(&mem_blk->sysdev.kobj));
}
/* mem section does not span the specified node */
return 0;
}
/* unregister memory section under all nodes that it spans */
int unregister_mem_sect_under_nodes(struct memory_block *mem_blk)
{
nodemask_t unlinked_nodes;
unsigned long pfn, sect_start_pfn, sect_end_pfn;
if (!mem_blk)
return -EFAULT;
nodes_clear(unlinked_nodes);
sect_start_pfn = section_nr_to_pfn(mem_blk->phys_index);
sect_end_pfn = sect_start_pfn + PAGES_PER_SECTION - 1;
for (pfn = sect_start_pfn; pfn <= sect_end_pfn; pfn++) {
unsigned int nid;
nid = get_nid_for_pfn(pfn);
if (nid < 0)
continue;
if (!node_online(nid))
continue;
if (node_test_and_set(nid, unlinked_nodes))
continue;
sysfs_remove_link(&node_devices[nid].sysdev.kobj,
kobject_name(&mem_blk->sysdev.kobj));
}
return 0;
}
static int link_mem_sections(int nid)
{
unsigned long start_pfn = NODE_DATA(nid)->node_start_pfn;
unsigned long end_pfn = start_pfn + NODE_DATA(nid)->node_spanned_pages;
unsigned long pfn;
int err = 0;
for (pfn = start_pfn; pfn < end_pfn; pfn += PAGES_PER_SECTION) {
unsigned long section_nr = pfn_to_section_nr(pfn);
struct mem_section *mem_sect;
struct memory_block *mem_blk;
int ret;
if (!present_section_nr(section_nr))
continue;
mem_sect = __nr_to_section(section_nr);
mem_blk = find_memory_block(mem_sect);
ret = register_mem_sect_under_node(mem_blk, nid);
if (!err)
err = ret;
/* discard ref obtained in find_memory_block() */
kobject_put(&mem_blk->sysdev.kobj);
}
return err;
}
#else
static int link_mem_sections(int nid) { return 0; }
#endif /* CONFIG_MEMORY_HOTPLUG_SPARSE */
int register_one_node(int nid)
{
int error = 0;
@ -267,6 +367,9 @@ int register_one_node(int nid)
if (cpu_to_node(cpu) == nid)
register_cpu_under_node(cpu, nid);
}
/* link memory sections under this node */
error = link_mem_sections(nid);
}
return error;

6
include/linux/memory.h
View file

@ -79,14 +79,14 @@ static inline int memory_notify(unsigned long val, void *v)
#else
extern int register_memory_notifier(struct notifier_block *nb);
extern void unregister_memory_notifier(struct notifier_block *nb);
extern int register_new_memory(struct mem_section *);
extern int register_new_memory(int, struct mem_section *);
extern int unregister_memory_section(struct mem_section *);
extern int memory_dev_init(void);
extern int remove_memory_block(unsigned long, struct mem_section *, int);
extern int memory_notify(unsigned long val, void *v);
extern struct memory_block *find_memory_block(struct mem_section *);
#define CONFIG_MEM_BLOCK_SIZE (PAGES_PER_SECTION<<PAGE_SHIFT)
enum mem_add_context { BOOT, HOTPLUG };
#endif /* CONFIG_MEMORY_HOTPLUG_SPARSE */
#ifdef CONFIG_MEMORY_HOTPLUG

2
include/linux/memory_hotplug.h
View file

@ -72,7 +72,7 @@ extern void __offline_isolated_pages(unsigned long, unsigned long);
extern int offline_pages(unsigned long, unsigned long, unsigned long);
/* reasonably generic interface to expand the physical pages in a zone */
extern int __add_pages(struct zone *zone, unsigned long start_pfn,
extern int __add_pages(int nid, struct zone *zone, unsigned long start_pfn,
unsigned long nr_pages);
extern int __remove_pages(struct zone *zone, unsigned long start_pfn,
unsigned long nr_pages);

13
include/linux/node.h
View file

@ -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)

11
mm/memory_hotplug.c
View file

@ -216,7 +216,8 @@ static int __meminit __add_zone(struct zone *zone, unsigned long phys_start_pfn)
return 0;
}
static int __meminit __add_section(struct zone *zone, unsigned long phys_start_pfn)
static int __meminit __add_section(int nid, struct zone *zone,
unsigned long phys_start_pfn)
{
int nr_pages = PAGES_PER_SECTION;
int ret;
@ -234,7 +235,7 @@ static int __meminit __add_section(struct zone *zone, unsigned long phys_start_p
if (ret < 0)
return ret;
return register_new_memory(__pfn_to_section(phys_start_pfn));
return register_new_memory(nid, __pfn_to_section(phys_start_pfn));
}
#ifdef CONFIG_SPARSEMEM_VMEMMAP
@ -273,8 +274,8 @@ static int __remove_section(struct zone *zone, struct mem_section *ms)
* call this function after deciding the zone to which to
* add the new pages.
*/
int __ref __add_pages(struct zone *zone, unsigned long phys_start_pfn,
unsigned long nr_pages)
int __ref __add_pages(int nid, struct zone *zone, unsigned long phys_start_pfn,
unsigned long nr_pages)
{
unsigned long i;
int err = 0;
@ -284,7 +285,7 @@ int __ref __add_pages(struct zone *zone, unsigned long phys_start_pfn,
end_sec = pfn_to_section_nr(phys_start_pfn + nr_pages - 1);
for (i = start_sec; i <= end_sec; i++) {
err = __add_section(zone, i << PFN_SECTION_SHIFT);
err = __add_section(nid, zone, i << PFN_SECTION_SHIFT);
/*
* EEXIST is finally dealt with by ioresource collision