swh:1:snp:173f8deb0c56c557784b4fd217e7608ac6197844
Tip revision: 6dbe51c251a327e012439c4772097a13df43c5b8 authored by Linus Torvalds on 03 March 2013, 23:11:05 UTC
Linux 3.9-rc1
Linux 3.9-rc1
Tip revision: 6dbe51c
memory.c
/*
* Memory subsystem 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/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 <linux/slab.h>
#include <linux/atomic.h>
#include <asm/uaccess.h>
static DEFINE_MUTEX(mem_sysfs_mutex);
#define MEMORY_CLASS_NAME "memory"
static int sections_per_block;
static inline int base_memory_block_id(int section_nr)
{
return section_nr / sections_per_block;
}
static struct bus_type memory_subsys = {
.name = MEMORY_CLASS_NAME,
.dev_name = MEMORY_CLASS_NAME,
};
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);
static ATOMIC_NOTIFIER_HEAD(memory_isolate_chain);
int register_memory_isolate_notifier(struct notifier_block *nb)
{
return atomic_notifier_chain_register(&memory_isolate_chain, nb);
}
EXPORT_SYMBOL(register_memory_isolate_notifier);
void unregister_memory_isolate_notifier(struct notifier_block *nb)
{
atomic_notifier_chain_unregister(&memory_isolate_chain, nb);
}
EXPORT_SYMBOL(unregister_memory_isolate_notifier);
static void memory_block_release(struct device *dev)
{
struct memory_block *mem = container_of(dev, struct memory_block, dev);
kfree(mem);
}
/*
* register_memory - Setup a sysfs device for a memory block
*/
static
int register_memory(struct memory_block *memory)
{
int error;
memory->dev.bus = &memory_subsys;
memory->dev.id = memory->start_section_nr / sections_per_block;
memory->dev.release = memory_block_release;
error = device_register(&memory->dev);
return error;
}
static void
unregister_memory(struct memory_block *memory)
{
BUG_ON(memory->dev.bus != &memory_subsys);
/* drop the ref. we got in remove_memory_block() */
kobject_put(&memory->dev.kobj);
device_unregister(&memory->dev);
}
unsigned long __weak memory_block_size_bytes(void)
{
return MIN_MEMORY_BLOCK_SIZE;
}
static unsigned long get_memory_block_size(void)
{
unsigned long block_sz;
block_sz = memory_block_size_bytes();
/* Validate blk_sz is a power of 2 and not less than section size */
if ((block_sz & (block_sz - 1)) || (block_sz < MIN_MEMORY_BLOCK_SIZE)) {
WARN_ON(1);
block_sz = MIN_MEMORY_BLOCK_SIZE;
}
return block_sz;
}
/*
* use this as the physical section index that this memsection
* uses.
*/
static ssize_t show_mem_start_phys_index(struct device *dev,
struct device_attribute *attr, char *buf)
{
struct memory_block *mem =
container_of(dev, struct memory_block, dev);
unsigned long phys_index;
phys_index = mem->start_section_nr / sections_per_block;
return sprintf(buf, "%08lx\n", phys_index);
}
static ssize_t show_mem_end_phys_index(struct device *dev,
struct device_attribute *attr, char *buf)
{
struct memory_block *mem =
container_of(dev, struct memory_block, dev);
unsigned long phys_index;
phys_index = mem->end_section_nr / sections_per_block;
return sprintf(buf, "%08lx\n", phys_index);
}
/*
* Show whether the section of memory is likely to be hot-removable
*/
static ssize_t show_mem_removable(struct device *dev,
struct device_attribute *attr, char *buf)
{
unsigned long i, pfn;
int ret = 1;
struct memory_block *mem =
container_of(dev, struct memory_block, dev);
for (i = 0; i < sections_per_block; i++) {
pfn = section_nr_to_pfn(mem->start_section_nr + i);
ret &= is_mem_section_removable(pfn, PAGES_PER_SECTION);
}
return sprintf(buf, "%d\n", ret);
}
/*
* online, offline, going offline, etc.
*/
static ssize_t show_mem_state(struct device *dev,
struct device_attribute *attr, char *buf)
{
struct memory_block *mem =
container_of(dev, struct memory_block, dev);
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);
}
int memory_isolate_notify(unsigned long val, void *v)
{
return atomic_notifier_call_chain(&memory_isolate_chain, val, v);
}
/*
* The probe routines leave the pages reserved, just as the bootmem code does.
* Make sure they're still that way.
*/
static bool pages_correctly_reserved(unsigned long start_pfn,
unsigned long nr_pages)
{
int i, j;
struct page *page;
unsigned long pfn = start_pfn;
/*
* memmap between sections is not contiguous except with
* SPARSEMEM_VMEMMAP. We lookup the page once per section
* and assume memmap is contiguous within each section
*/
for (i = 0; i < sections_per_block; i++, pfn += PAGES_PER_SECTION) {
if (WARN_ON_ONCE(!pfn_valid(pfn)))
return false;
page = pfn_to_page(pfn);
for (j = 0; j < PAGES_PER_SECTION; j++) {
if (PageReserved(page + j))
continue;
printk(KERN_WARNING "section number %ld page number %d "
"not reserved, was it already online?\n",
pfn_to_section_nr(pfn), j);
return false;
}
}
return true;
}
/*
* 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(unsigned long phys_index, unsigned long action, int online_type)
{
unsigned long start_pfn;
unsigned long nr_pages = PAGES_PER_SECTION * sections_per_block;
struct page *first_page;
int ret;
first_page = pfn_to_page(phys_index << PFN_SECTION_SHIFT);
start_pfn = page_to_pfn(first_page);
switch (action) {
case MEM_ONLINE:
if (!pages_correctly_reserved(start_pfn, nr_pages))
return -EBUSY;
ret = online_pages(start_pfn, nr_pages, online_type);
break;
case MEM_OFFLINE:
ret = offline_pages(start_pfn, nr_pages);
break;
default:
WARN(1, KERN_WARNING "%s(%ld, %ld) unknown action: "
"%ld\n", __func__, phys_index, 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 online_type)
{
int ret = 0;
if (mem->state != from_state_req) {
ret = -EINVAL;
goto out;
}
if (to_state == MEM_OFFLINE)
mem->state = MEM_GOING_OFFLINE;
ret = memory_block_action(mem->start_section_nr, to_state, online_type);
if (ret) {
mem->state = from_state_req;
goto out;
}
mem->state = to_state;
switch (mem->state) {
case MEM_OFFLINE:
kobject_uevent(&mem->dev.kobj, KOBJ_OFFLINE);
break;
case MEM_ONLINE:
kobject_uevent(&mem->dev.kobj, KOBJ_ONLINE);
break;
default:
break;
}
out:
return ret;
}
static int memory_block_change_state(struct memory_block *mem,
unsigned long to_state, unsigned long from_state_req,
int online_type)
{
int ret;
mutex_lock(&mem->state_mutex);
ret = __memory_block_change_state(mem, to_state, from_state_req,
online_type);
mutex_unlock(&mem->state_mutex);
return ret;
}
static ssize_t
store_mem_state(struct device *dev,
struct device_attribute *attr, const char *buf, size_t count)
{
struct memory_block *mem;
int ret = -EINVAL;
mem = container_of(dev, struct memory_block, dev);
if (!strncmp(buf, "online_kernel", min_t(int, count, 13)))
ret = memory_block_change_state(mem, MEM_ONLINE,
MEM_OFFLINE, ONLINE_KERNEL);
else if (!strncmp(buf, "online_movable", min_t(int, count, 14)))
ret = memory_block_change_state(mem, MEM_ONLINE,
MEM_OFFLINE, ONLINE_MOVABLE);
else if (!strncmp(buf, "online", min_t(int, count, 6)))
ret = memory_block_change_state(mem, MEM_ONLINE,
MEM_OFFLINE, ONLINE_KEEP);
else if(!strncmp(buf, "offline", min_t(int, count, 7)))
ret = memory_block_change_state(mem, MEM_OFFLINE,
MEM_ONLINE, -1);
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 device *dev,
struct device_attribute *attr, char *buf)
{
struct memory_block *mem =
container_of(dev, struct memory_block, dev);
return sprintf(buf, "%d\n", mem->phys_device);
}
static DEVICE_ATTR(phys_index, 0444, show_mem_start_phys_index, NULL);
static DEVICE_ATTR(end_phys_index, 0444, show_mem_end_phys_index, NULL);
static DEVICE_ATTR(state, 0644, show_mem_state, store_mem_state);
static DEVICE_ATTR(phys_device, 0444, show_phys_device, NULL);
static DEVICE_ATTR(removable, 0444, show_mem_removable, NULL);
#define mem_create_simple_file(mem, attr_name) \
device_create_file(&mem->dev, &dev_attr_##attr_name)
#define mem_remove_simple_file(mem, attr_name) \
device_remove_file(&mem->dev, &dev_attr_##attr_name)
/*
* Block size attribute stuff
*/
static ssize_t
print_block_size(struct device *dev, struct device_attribute *attr,
char *buf)
{
return sprintf(buf, "%lx\n", get_memory_block_size());
}
static DEVICE_ATTR(block_size_bytes, 0444, print_block_size, NULL);
static int block_size_init(void)
{
return device_create_file(memory_subsys.dev_root,
&dev_attr_block_size_bytes);
}
/*
* 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 device *dev, struct device_attribute *attr,
const char *buf, size_t count)
{
u64 phys_addr;
int nid;
int i, ret;
unsigned long pages_per_block = PAGES_PER_SECTION * sections_per_block;
phys_addr = simple_strtoull(buf, NULL, 0);
if (phys_addr & ((pages_per_block << PAGE_SHIFT) - 1))
return -EINVAL;
for (i = 0; i < sections_per_block; i++) {
nid = memory_add_physaddr_to_nid(phys_addr);
ret = add_memory(nid, phys_addr,
PAGES_PER_SECTION << PAGE_SHIFT);
if (ret)
goto out;
phys_addr += MIN_MEMORY_BLOCK_SIZE;
}
ret = count;
out:
return ret;
}
static DEVICE_ATTR(probe, S_IWUSR, NULL, memory_probe_store);
static int memory_probe_init(void)
{
return device_create_file(memory_subsys.dev_root, &dev_attr_probe);
}
#else
static inline int memory_probe_init(void)
{
return 0;
}
#endif
#ifdef CONFIG_MEMORY_FAILURE
/*
* Support for offlining pages of memory
*/
/* Soft offline a page */
static ssize_t
store_soft_offline_page(struct device *dev,
struct device_attribute *attr,
const char *buf, size_t count)
{
int ret;
u64 pfn;
if (!capable(CAP_SYS_ADMIN))
return -EPERM;
if (strict_strtoull(buf, 0, &pfn) < 0)
return -EINVAL;
pfn >>= PAGE_SHIFT;
if (!pfn_valid(pfn))
return -ENXIO;
ret = soft_offline_page(pfn_to_page(pfn), 0);
return ret == 0 ? count : ret;
}
/* Forcibly offline a page, including killing processes. */
static ssize_t
store_hard_offline_page(struct device *dev,
struct device_attribute *attr,
const char *buf, size_t count)
{
int ret;
u64 pfn;
if (!capable(CAP_SYS_ADMIN))
return -EPERM;
if (strict_strtoull(buf, 0, &pfn) < 0)
return -EINVAL;
pfn >>= PAGE_SHIFT;
ret = memory_failure(pfn, 0, 0);
return ret ? ret : count;
}
static DEVICE_ATTR(soft_offline_page, S_IWUSR, NULL, store_soft_offline_page);
static DEVICE_ATTR(hard_offline_page, S_IWUSR, NULL, store_hard_offline_page);
static __init int memory_fail_init(void)
{
int err;
err = device_create_file(memory_subsys.dev_root,
&dev_attr_soft_offline_page);
if (!err)
err = device_create_file(memory_subsys.dev_root,
&dev_attr_hard_offline_page);
return err;
}
#else
static inline int memory_fail_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...
*/
int __weak arch_get_memory_phys_device(unsigned long start_pfn)
{
return 0;
}
/*
* A reference for the returned object is held and the reference for the
* hinted object is released.
*/
struct memory_block *find_memory_block_hinted(struct mem_section *section,
struct memory_block *hint)
{
int block_id = base_memory_block_id(__section_nr(section));
struct device *hintdev = hint ? &hint->dev : NULL;
struct device *dev;
dev = subsys_find_device_by_id(&memory_subsys, block_id, hintdev);
if (hint)
put_device(&hint->dev);
if (!dev)
return NULL;
return container_of(dev, struct memory_block, dev);
}
/*
* 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 device subsystems.
*/
struct memory_block *find_memory_block(struct mem_section *section)
{
return find_memory_block_hinted(section, NULL);
}
static int init_memory_block(struct memory_block **memory,
struct mem_section *section, unsigned long state)
{
struct memory_block *mem;
unsigned long start_pfn;
int scn_nr;
int ret = 0;
mem = kzalloc(sizeof(*mem), GFP_KERNEL);
if (!mem)
return -ENOMEM;
scn_nr = __section_nr(section);
mem->start_section_nr =
base_memory_block_id(scn_nr) * sections_per_block;
mem->end_section_nr = mem->start_section_nr + sections_per_block - 1;
mem->state = state;
mem->section_count++;
mutex_init(&mem->state_mutex);
start_pfn = section_nr_to_pfn(mem->start_section_nr);
mem->phys_device = arch_get_memory_phys_device(start_pfn);
ret = register_memory(mem);
if (!ret)
ret = mem_create_simple_file(mem, phys_index);
if (!ret)
ret = mem_create_simple_file(mem, end_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);
*memory = mem;
return ret;
}
static int add_memory_section(int nid, struct mem_section *section,
struct memory_block **mem_p,
unsigned long state, enum mem_add_context context)
{
struct memory_block *mem = NULL;
int scn_nr = __section_nr(section);
int ret = 0;
mutex_lock(&mem_sysfs_mutex);
if (context == BOOT) {
/* same memory block ? */
if (mem_p && *mem_p)
if (scn_nr >= (*mem_p)->start_section_nr &&
scn_nr <= (*mem_p)->end_section_nr) {
mem = *mem_p;
kobject_get(&mem->dev.kobj);
}
} else
mem = find_memory_block(section);
if (mem) {
mem->section_count++;
kobject_put(&mem->dev.kobj);
} else {
ret = init_memory_block(&mem, section, state);
/* store memory_block pointer for next loop */
if (!ret && context == BOOT)
if (mem_p)
*mem_p = mem;
}
if (!ret) {
if (context == HOTPLUG &&
mem->section_count == sections_per_block)
ret = register_mem_sect_under_node(mem, nid);
}
mutex_unlock(&mem_sysfs_mutex);
return ret;
}
int remove_memory_block(unsigned long node_id, struct mem_section *section,
int phys_device)
{
struct memory_block *mem;
mutex_lock(&mem_sysfs_mutex);
mem = find_memory_block(section);
unregister_mem_sect_under_nodes(mem, __section_nr(section));
mem->section_count--;
if (mem->section_count == 0) {
mem_remove_simple_file(mem, phys_index);
mem_remove_simple_file(mem, end_phys_index);
mem_remove_simple_file(mem, state);
mem_remove_simple_file(mem, phys_device);
mem_remove_simple_file(mem, removable);
unregister_memory(mem);
} else
kobject_put(&mem->dev.kobj);
mutex_unlock(&mem_sysfs_mutex);
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_section(nid, section, NULL, MEM_OFFLINE, HOTPLUG);
}
int unregister_memory_section(struct mem_section *section)
{
if (!present_section(section))
return -EINVAL;
return remove_memory_block(0, section, 0);
}
/*
* offline one memory block. If the memory block has been offlined, do nothing.
*/
int offline_memory_block(struct memory_block *mem)
{
int ret = 0;
mutex_lock(&mem->state_mutex);
if (mem->state != MEM_OFFLINE)
ret = __memory_block_change_state(mem, MEM_OFFLINE, MEM_ONLINE, -1);
mutex_unlock(&mem->state_mutex);
return ret;
}
/* return true if the memory block is offlined, otherwise, return false */
bool is_memblock_offlined(struct memory_block *mem)
{
return mem->state == MEM_OFFLINE;
}
/*
* Initialize the sysfs support for memory devices...
*/
int __init memory_dev_init(void)
{
unsigned int i;
int ret;
int err;
unsigned long block_sz;
struct memory_block *mem = NULL;
ret = subsys_system_register(&memory_subsys, NULL);
if (ret)
goto out;
block_sz = get_memory_block_size();
sections_per_block = block_sz / MIN_MEMORY_BLOCK_SIZE;
/*
* 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;
/* don't need to reuse memory_block if only one per block */
err = add_memory_section(0, __nr_to_section(i),
(sections_per_block == 1) ? NULL : &mem,
MEM_ONLINE,
BOOT);
if (!ret)
ret = err;
}
err = memory_probe_init();
if (!ret)
ret = err;
err = memory_fail_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;
}