linux/drivers/base/memory.c
Gary Hade c04fc586c1 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>
2009-01-06 15:59:00 -08:00

483 lines
12 KiB
C

/*
* drivers/base/memory.c - basic Memory class support
*
* Written by Matt Tolentino <matthew.e.tolentino@intel.com>
* Dave Hansen <haveblue@us.ibm.com>
*
* This file provides the necessary infrastructure to represent
* a SPARSEMEM-memory-model system's physical memory in /sysfs.
* All arch-independent code that assumes MEMORY_HOTPLUG requires
* SPARSEMEM should be contained here, or in mm/memory_hotplug.c.
*/
#include <linux/sysdev.h>
#include <linux/module.h>
#include <linux/init.h>
#include <linux/topology.h>
#include <linux/capability.h>
#include <linux/device.h>
#include <linux/memory.h>
#include <linux/kobject.h>
#include <linux/memory_hotplug.h>
#include <linux/mm.h>
#include <linux/mutex.h>
#include <linux/stat.h>
#include <asm/atomic.h>
#include <asm/uaccess.h>
#define MEMORY_CLASS_NAME "memory"
static struct sysdev_class memory_sysdev_class = {
.name = MEMORY_CLASS_NAME,
};
static const char *memory_uevent_name(struct kset *kset, struct kobject *kobj)
{
return MEMORY_CLASS_NAME;
}
static int memory_uevent(struct kset *kset, struct kobject *obj, struct kobj_uevent_env *env)
{
int retval = 0;
return retval;
}
static struct kset_uevent_ops memory_uevent_ops = {
.name = memory_uevent_name,
.uevent = memory_uevent,
};
static BLOCKING_NOTIFIER_HEAD(memory_chain);
int register_memory_notifier(struct notifier_block *nb)
{
return blocking_notifier_chain_register(&memory_chain, nb);
}
EXPORT_SYMBOL(register_memory_notifier);
void unregister_memory_notifier(struct notifier_block *nb)
{
blocking_notifier_chain_unregister(&memory_chain, nb);
}
EXPORT_SYMBOL(unregister_memory_notifier);
/*
* register_memory - Setup a sysfs device for a memory block
*/
static
int register_memory(struct memory_block *memory, struct mem_section *section)
{
int error;
memory->sysdev.cls = &memory_sysdev_class;
memory->sysdev.id = __section_nr(section);
error = sysdev_register(&memory->sysdev);
return error;
}
static void
unregister_memory(struct memory_block *memory, struct mem_section *section)
{
BUG_ON(memory->sysdev.cls != &memory_sysdev_class);
BUG_ON(memory->sysdev.id != __section_nr(section));
/* drop the ref. we got in remove_memory_block() */
kobject_put(&memory->sysdev.kobj);
sysdev_unregister(&memory->sysdev);
}
/*
* use this as the physical section index that this memsection
* uses.
*/
static ssize_t show_mem_phys_index(struct sys_device *dev,
struct sysdev_attribute *attr, char *buf)
{
struct memory_block *mem =
container_of(dev, struct memory_block, sysdev);
return sprintf(buf, "%08lx\n", mem->phys_index);
}
/*
* Show whether the section of memory is likely to be hot-removable
*/
static ssize_t show_mem_removable(struct sys_device *dev,
struct sysdev_attribute *attr, char *buf)
{
unsigned long start_pfn;
int ret;
struct memory_block *mem =
container_of(dev, struct memory_block, sysdev);
start_pfn = section_nr_to_pfn(mem->phys_index);
ret = is_mem_section_removable(start_pfn, PAGES_PER_SECTION);
return sprintf(buf, "%d\n", ret);
}
/*
* online, offline, going offline, etc.
*/
static ssize_t show_mem_state(struct sys_device *dev,
struct sysdev_attribute *attr, char *buf)
{
struct memory_block *mem =
container_of(dev, struct memory_block, sysdev);
ssize_t len = 0;
/*
* We can probably put these states in a nice little array
* so that they're not open-coded
*/
switch (mem->state) {
case MEM_ONLINE:
len = sprintf(buf, "online\n");
break;
case MEM_OFFLINE:
len = sprintf(buf, "offline\n");
break;
case MEM_GOING_OFFLINE:
len = sprintf(buf, "going-offline\n");
break;
default:
len = sprintf(buf, "ERROR-UNKNOWN-%ld\n",
mem->state);
WARN_ON(1);
break;
}
return len;
}
int memory_notify(unsigned long val, void *v)
{
return blocking_notifier_call_chain(&memory_chain, val, v);
}
/*
* MEMORY_HOTPLUG depends on SPARSEMEM in mm/Kconfig, so it is
* OK to have direct references to sparsemem variables in here.
*/
static int
memory_block_action(struct memory_block *mem, unsigned long action)
{
int i;
unsigned long psection;
unsigned long start_pfn, start_paddr;
struct page *first_page;
int ret;
int old_state = mem->state;
psection = mem->phys_index;
first_page = pfn_to_page(psection << PFN_SECTION_SHIFT);
/*
* The probe routines leave the pages reserved, just
* as the bootmem code does. Make sure they're still
* that way.
*/
if (action == MEM_ONLINE) {
for (i = 0; i < PAGES_PER_SECTION; i++) {
if (PageReserved(first_page+i))
continue;
printk(KERN_WARNING "section number %ld page number %d "
"not reserved, was it already online? \n",
psection, i);
return -EBUSY;
}
}
switch (action) {
case MEM_ONLINE:
start_pfn = page_to_pfn(first_page);
ret = online_pages(start_pfn, PAGES_PER_SECTION);
break;
case MEM_OFFLINE:
mem->state = MEM_GOING_OFFLINE;
start_paddr = page_to_pfn(first_page) << PAGE_SHIFT;
ret = remove_memory(start_paddr,
PAGES_PER_SECTION << PAGE_SHIFT);
if (ret) {
mem->state = old_state;
break;
}
break;
default:
WARN(1, KERN_WARNING "%s(%p, %ld) unknown action: %ld\n",
__func__, mem, action, action);
ret = -EINVAL;
}
return ret;
}
static int memory_block_change_state(struct memory_block *mem,
unsigned long to_state, unsigned long from_state_req)
{
int ret = 0;
mutex_lock(&mem->state_mutex);
if (mem->state != from_state_req) {
ret = -EINVAL;
goto out;
}
ret = memory_block_action(mem, to_state);
if (!ret)
mem->state = to_state;
out:
mutex_unlock(&mem->state_mutex);
return ret;
}
static ssize_t
store_mem_state(struct sys_device *dev,
struct sysdev_attribute *attr, const char *buf, size_t count)
{
struct memory_block *mem;
unsigned int phys_section_nr;
int ret = -EINVAL;
mem = container_of(dev, struct memory_block, sysdev);
phys_section_nr = mem->phys_index;
if (!present_section_nr(phys_section_nr))
goto out;
if (!strncmp(buf, "online", min((int)count, 6)))
ret = memory_block_change_state(mem, MEM_ONLINE, MEM_OFFLINE);
else if(!strncmp(buf, "offline", min((int)count, 7)))
ret = memory_block_change_state(mem, MEM_OFFLINE, MEM_ONLINE);
out:
if (ret)
return ret;
return count;
}
/*
* phys_device is a bad name for this. What I really want
* is a way to differentiate between memory ranges that
* are part of physical devices that constitute
* a complete removable unit or fru.
* i.e. do these ranges belong to the same physical device,
* s.t. if I offline all of these sections I can then
* remove the physical device?
*/
static ssize_t show_phys_device(struct sys_device *dev,
struct sysdev_attribute *attr, char *buf)
{
struct memory_block *mem =
container_of(dev, struct memory_block, sysdev);
return sprintf(buf, "%d\n", mem->phys_device);
}
static SYSDEV_ATTR(phys_index, 0444, show_mem_phys_index, NULL);
static SYSDEV_ATTR(state, 0644, show_mem_state, store_mem_state);
static SYSDEV_ATTR(phys_device, 0444, show_phys_device, NULL);
static SYSDEV_ATTR(removable, 0444, show_mem_removable, NULL);
#define mem_create_simple_file(mem, attr_name) \
sysdev_create_file(&mem->sysdev, &attr_##attr_name)
#define mem_remove_simple_file(mem, attr_name) \
sysdev_remove_file(&mem->sysdev, &attr_##attr_name)
/*
* Block size attribute stuff
*/
static ssize_t
print_block_size(struct class *class, char *buf)
{
return sprintf(buf, "%lx\n", (unsigned long)PAGES_PER_SECTION * PAGE_SIZE);
}
static CLASS_ATTR(block_size_bytes, 0444, print_block_size, NULL);
static int block_size_init(void)
{
return sysfs_create_file(&memory_sysdev_class.kset.kobj,
&class_attr_block_size_bytes.attr);
}
/*
* Some architectures will have custom drivers to do this, and
* will not need to do it from userspace. The fake hot-add code
* as well as ppc64 will do all of their discovery in userspace
* and will require this interface.
*/
#ifdef CONFIG_ARCH_MEMORY_PROBE
static ssize_t
memory_probe_store(struct class *class, const char *buf, size_t count)
{
u64 phys_addr;
int nid;
int ret;
phys_addr = simple_strtoull(buf, NULL, 0);
nid = memory_add_physaddr_to_nid(phys_addr);
ret = add_memory(nid, phys_addr, PAGES_PER_SECTION << PAGE_SHIFT);
if (ret)
count = ret;
return count;
}
static CLASS_ATTR(probe, S_IWUSR, NULL, memory_probe_store);
static int memory_probe_init(void)
{
return sysfs_create_file(&memory_sysdev_class.kset.kobj,
&class_attr_probe.attr);
}
#else
static inline int memory_probe_init(void)
{
return 0;
}
#endif
/*
* Note that phys_device is optional. It is here to allow for
* differentiation between which *physical* devices each
* section belongs to...
*/
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;
if (!mem)
return -ENOMEM;
mem->phys_index = __section_nr(section);
mem->state = state;
mutex_init(&mem->state_mutex);
mem->phys_device = phys_device;
ret = register_memory(mem, section);
if (!ret)
ret = mem_create_simple_file(mem, phys_index);
if (!ret)
ret = mem_create_simple_file(mem, state);
if (!ret)
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;
}
/*
* For now, we have a linear search to go find the appropriate
* memory_block corresponding to a particular phys_index. If
* this gets to be a real problem, we can always use a radix
* tree or something here.
*
* This could be made generic for all sysdev classes.
*/
struct memory_block *find_memory_block(struct mem_section *section)
{
struct kobject *kobj;
struct sys_device *sysdev;
struct memory_block *mem;
char name[sizeof(MEMORY_CLASS_NAME) + 9 + 1];
/*
* This only works because we know that section == sysdev->id
* slightly redundant with sysdev_register()
*/
sprintf(&name[0], "%s%d", MEMORY_CLASS_NAME, __section_nr(section));
kobj = kset_find_obj(&memory_sysdev_class.kset, name);
if (!kobj)
return NULL;
sysdev = container_of(kobj, struct sys_device, kobj);
mem = container_of(sysdev, struct memory_block, sysdev);
return mem;
}
int remove_memory_block(unsigned long node_id, struct mem_section *section,
int phys_device)
{
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);
mem_remove_simple_file(mem, removable);
unregister_memory(mem, section);
return 0;
}
/*
* need an interface for the VM to add new memory regions,
* but without onlining it.
*/
int register_new_memory(int nid, struct mem_section *section)
{
return add_memory_block(nid, section, MEM_OFFLINE, 0, HOTPLUG);
}
int unregister_memory_section(struct mem_section *section)
{
if (!present_section(section))
return -EINVAL;
return remove_memory_block(0, section, 0);
}
/*
* Initialize the sysfs support for memory devices...
*/
int __init memory_dev_init(void)
{
unsigned int i;
int ret;
int err;
memory_sysdev_class.kset.uevent_ops = &memory_uevent_ops;
ret = sysdev_class_register(&memory_sysdev_class);
if (ret)
goto out;
/*
* Create entries for memory sections that were found
* during boot and have been initialized
*/
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, BOOT);
if (!ret)
ret = err;
}
err = memory_probe_init();
if (!ret)
ret = err;
err = block_size_init();
if (!ret)
ret = err;
out:
if (ret)
printk(KERN_ERR "%s() failed: %d\n", __func__, ret);
return ret;
}