Commit c04fc586 authored by Gary Hade's avatar Gary Hade Committed by Linus Torvalds

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: default avatarGary Hade <garyhade@us.ibm.com>
Signed-off-by: default avatarBadari Pulavarty <pbadari@us.ibm.com>
Acked-by: default avatarIngo Molnar <mingo@elte.hu>
Signed-off-by: default avatarAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: default avatarLinus Torvalds <torvalds@linux-foundation.org>
parent ee53a891
......@@ -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
......@@ -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.
......
......@@ -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",
......
......@@ -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 */
......
......@@ -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;
......
......@@ -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);
......
......@@ -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
......
......@@ -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;
......
......@@ -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;
}
......
......@@ -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;
......
......@@ -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
......
......@@ -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);
......
......@@ -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)
......
......@@ -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
......
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