Commit 3947be19 authored by Dave Hansen's avatar Dave Hansen Committed by Linus Torvalds
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[PATCH] memory hotplug: sysfs and add/remove functions



This adds generic memory add/remove and supporting functions for memory
hotplug into a new file as well as a memory hotplug kernel config option.

Individual architecture patches will follow.

For now, disable memory hotplug when swsusp is enabled.  There's a lot of
churn there right now.  We'll fix it up properly once it calms down.
Signed-off-by: default avatarMatt Tolentino <matthew.e.tolentino@intel.com>
Signed-off-by: default avatarDave Hansen <haveblue@us.ibm.com>
Signed-off-by: default avatarAndrew Morton <akpm@osdl.org>
Signed-off-by: default avatarLinus Torvalds <torvalds@osdl.org>
parent bdc8cb98
......@@ -7,6 +7,7 @@ obj-y := core.o sys.o bus.o dd.o \
obj-y += power/
obj-$(CONFIG_FW_LOADER) += firmware_class.o
obj-$(CONFIG_NUMA) += node.o
obj-$(CONFIG_MEMORY_HOTPLUG) += memory.o
ifeq ($(CONFIG_DEBUG_DRIVER),y)
EXTRA_CFLAGS += -DDEBUG
......
......@@ -9,6 +9,7 @@
#include <linux/device.h>
#include <linux/init.h>
#include <linux/memory.h>
#include "base.h"
......@@ -33,5 +34,6 @@ void __init driver_init(void)
platform_bus_init();
system_bus_init();
cpu_dev_init();
memory_dev_init();
attribute_container_init();
}
/*
* 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/sched.h> /* capable() */
#include <linux/topology.h>
#include <linux/device.h>
#include <linux/memory.h>
#include <linux/kobject.h>
#include <linux/memory_hotplug.h>
#include <linux/mm.h>
#include <asm/atomic.h>
#include <asm/uaccess.h>
#define MEMORY_CLASS_NAME "memory"
static struct sysdev_class memory_sysdev_class = {
set_kset_name(MEMORY_CLASS_NAME),
};
EXPORT_SYMBOL(memory_sysdev_class);
static char *memory_hotplug_name(struct kset *kset, struct kobject *kobj)
{
return MEMORY_CLASS_NAME;
}
static int memory_hotplug(struct kset *kset, struct kobject *kobj, char **envp,
int num_envp, char *buffer, int buffer_size)
{
int retval = 0;
return retval;
}
static struct kset_hotplug_ops memory_hotplug_ops = {
.name = memory_hotplug_name,
.hotplug = memory_hotplug,
};
static struct notifier_block *memory_chain;
static int register_memory_notifier(struct notifier_block *nb)
{
return notifier_chain_register(&memory_chain, nb);
}
static void unregister_memory_notifier(struct notifier_block *nb)
{
notifier_chain_unregister(&memory_chain, nb);
}
/*
* register_memory - Setup a sysfs device for a memory block
*/
static int
register_memory(struct memory_block *memory, struct mem_section *section,
struct node *root)
{
int error;
memory->sysdev.cls = &memory_sysdev_class;
memory->sysdev.id = __section_nr(section);
error = sysdev_register(&memory->sysdev);
if (root && !error)
error = sysfs_create_link(&root->sysdev.kobj,
&memory->sysdev.kobj,
kobject_name(&memory->sysdev.kobj));
return error;
}
static void
unregister_memory(struct memory_block *memory, struct mem_section *section,
struct node *root)
{
BUG_ON(memory->sysdev.cls != &memory_sysdev_class);
BUG_ON(memory->sysdev.id != __section_nr(section));
sysdev_unregister(&memory->sysdev);
if (root)
sysfs_remove_link(&root->sysdev.kobj,
kobject_name(&memory->sysdev.kobj));
}
/*
* use this as the physical section index that this memsection
* uses.
*/
static ssize_t show_mem_phys_index(struct sys_device *dev, char *buf)
{
struct memory_block *mem =
container_of(dev, struct memory_block, sysdev);
return sprintf(buf, "%08lx\n", mem->phys_index);
}
/*
* online, offline, going offline, etc.
*/
static ssize_t show_mem_state(struct sys_device *dev, 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;
}
static inline int memory_notify(unsigned long val, void *v)
{
return 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;
memory_notify(MEM_GOING_OFFLINE, NULL);
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;
}
memory_notify(MEM_MAPPING_INVALID, NULL);
break;
default:
printk(KERN_WARNING "%s(%p, %ld) unknown action: %ld\n",
__FUNCTION__, mem, action, action);
WARN_ON(1);
ret = -EINVAL;
}
/*
* For now, only notify on successful memory operations
*/
if (!ret)
memory_notify(action, NULL);
return ret;
}
static int memory_block_change_state(struct memory_block *mem,
unsigned long to_state, unsigned long from_state_req)
{
int ret = 0;
down(&mem->state_sem);
if (mem->state != from_state_req) {
ret = -EINVAL;
goto out;
}
ret = memory_block_action(mem, to_state);
if (!ret)
mem->state = to_state;
out:
up(&mem->state_sem);
return ret;
}
static ssize_t
store_mem_state(struct sys_device *dev, 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 (!valid_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, 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);
#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)
{
sysfs_create_file(&memory_sysdev_class.kset.kobj,
&class_attr_block_size_bytes.attr);
return 0;
}
/*
* 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 __user *buf, size_t count)
{
u64 phys_addr;
int ret;
phys_addr = simple_strtoull(buf, NULL, 0);
ret = add_memory(phys_addr, PAGES_PER_SECTION << PAGE_SHIFT);
if (ret)
count = ret;
return count;
}
static CLASS_ATTR(probe, 0700, NULL, memory_probe_store);
static int memory_probe_init(void)
{
sysfs_create_file(&memory_sysdev_class.kset.kobj,
&class_attr_probe.attr);
return 0;
}
#else
#define memory_probe_init(...) do {} while (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(unsigned long node_id, struct mem_section *section,
unsigned long state, int phys_device)
{
size_t size = sizeof(struct memory_block);
struct memory_block *mem = kmalloc(size, GFP_KERNEL);
int ret = 0;
if (!mem)
return -ENOMEM;
memset(mem, 0, size);
mem->phys_index = __section_nr(section);
mem->state = state;
init_MUTEX(&mem->state_sem);
mem->phys_device = phys_device;
ret = register_memory(mem, section, NULL);
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);
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.
*/
static 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);
mem_remove_simple_file(mem, phys_index);
mem_remove_simple_file(mem, state);
mem_remove_simple_file(mem, phys_device);
unregister_memory(mem, section, NULL);
return 0;
}
/*
* need an interface for the VM to add new memory regions,
* but without onlining it.
*/
int register_new_memory(struct mem_section *section)
{
return add_memory_block(0, section, MEM_OFFLINE, 0);
}
int unregister_memory_section(struct mem_section *section)
{
if (!valid_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;
memory_sysdev_class.kset.hotplug_ops = &memory_hotplug_ops;
ret = sysdev_class_register(&memory_sysdev_class);
/*
* Create entries for memory sections that were found
* during boot and have been initialized
*/
for (i = 0; i < NR_MEM_SECTIONS; i++) {
if (!valid_section_nr(i))
continue;
add_memory_block(0, __nr_to_section(i), MEM_ONLINE, 0);
}
memory_probe_init();
block_size_init();
return ret;
}
/*
* include/linux/memory.h - generic memory definition
*
* This is mainly for topological representation. We define the
* basic "struct memory_block" here, which can be embedded in per-arch
* definitions or NUMA information.
*
* Basic handling of the devices is done in drivers/base/memory.c
* and system devices are handled in drivers/base/sys.c.
*
* Memory block are exported via sysfs in the class/memory/devices/
* directory.
*
*/
#ifndef _LINUX_MEMORY_H_
#define _LINUX_MEMORY_H_
#include <linux/sysdev.h>
#include <linux/node.h>
#include <linux/compiler.h>
#include <asm/semaphore.h>
struct memory_block {
unsigned long phys_index;
unsigned long state;
/*
* This serializes all state change requests. It isn't
* held during creation because the control files are
* created long after the critical areas during
* initialization.
*/
struct semaphore state_sem;
int phys_device; /* to which fru does this belong? */
void *hw; /* optional pointer to fw/hw data */
int (*phys_callback)(struct memory_block *);
struct sys_device sysdev;
};
/* These states are exposed to userspace as text strings in sysfs */
#define MEM_ONLINE (1<<0) /* exposed to userspace */
#define MEM_GOING_OFFLINE (1<<1) /* exposed to userspace */
#define MEM_OFFLINE (1<<2) /* exposed to userspace */
/*
* All of these states are currently kernel-internal for notifying
* kernel components and architectures.
*
* For MEM_MAPPING_INVALID, all notifier chains with priority >0
* are called before pfn_to_page() becomes invalid. The priority=0
* entry is reserved for the function that actually makes
* pfn_to_page() stop working. Any notifiers that want to be called
* after that should have priority <0.
*/
#define MEM_MAPPING_INVALID (1<<3)
#ifndef CONFIG_MEMORY_HOTPLUG
static inline int memory_dev_init(void)
{
return 0;
}
static inline int register_memory_notifier(struct notifier_block *nb)
{
return 0;
}
static inline void unregister_memory_notifier(struct notifier_block *nb)
{
}
#else
extern int register_memory(struct memory_block *, struct mem_section *section, struct node *);
extern int register_new_memory(struct mem_section *);
extern int unregister_memory_section(struct mem_section *);
extern int memory_dev_init(void);
extern int register_memory_notifier(struct notifier_block *nb);
extern void unregister_memory_notifier(struct notifier_block *nb);
#define CONFIG_MEM_BLOCK_SIZE (PAGES_PER_SECTION<<PAGE_SHIFT)
extern int invalidate_phys_mapping(unsigned long, unsigned long);
struct notifier_block;
extern int register_memory_notifier(struct notifier_block *nb);
extern void unregister_memory_notifier(struct notifier_block *nb);
extern struct sysdev_class memory_sysdev_class;
#endif /* CONFIG_MEMORY_HOTPLUG */
#define hotplug_memory_notifier(fn, pri) { \
static struct notifier_block fn##_mem_nb = \
{ .notifier_call = fn, .priority = pri }; \
register_memory_notifier(&fn##_mem_nb); \
}
#endif /* _LINUX_MEMORY_H_ */
......@@ -3,6 +3,8 @@
#include <linux/mmzone.h>
#include <linux/spinlock.h>
#include <linux/mmzone.h>
#include <linux/notifier.h>
#ifdef CONFIG_MEMORY_HOTPLUG
/*
......@@ -46,6 +48,19 @@ static inline void zone_seqlock_init(struct zone *zone)
{
seqlock_init(&zone->span_seqlock);
}
extern int zone_grow_free_lists(struct zone *zone, unsigned long new_nr_pages);
extern int zone_grow_waitqueues(struct zone *zone, unsigned long nr_pages);
extern int add_one_highpage(struct page *page, int pfn, int bad_ppro);
/* need some defines for these for archs that don't support it */
extern void online_page(struct page *page);
/* VM interface that may be used by firmware interface */
extern int add_memory(u64 start, u64 size);
extern int remove_memory(u64 start, u64 size);
extern int online_pages(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,
unsigned long nr_pages);
#else /* ! CONFIG_MEMORY_HOTPLUG */
/*
* Stub functions for when hotplug is off
......@@ -65,5 +80,25 @@ static inline int zone_span_seqretry(struct zone *zone, unsigned iv)
static inline void zone_span_writelock(struct zone *zone) {}
static inline void zone_span_writeunlock(struct zone *zone) {}
static inline void zone_seqlock_init(struct zone *zone) {}
static inline int mhp_notimplemented(const char *func)
{
printk(KERN_WARNING "%s() called, with CONFIG_MEMORY_HOTPLUG disabled\n", func);
dump_stack();
return -ENOSYS;
}
static inline int __add_pages(struct zone *zone, unsigned long start_pfn,
unsigned long nr_pages)
{
return mhp_notimplemented(__FUNCTION__);
}
#endif /* ! CONFIG_MEMORY_HOTPLUG */
static inline int __remove_pages(struct zone *zone, unsigned long start_pfn,
unsigned long nr_pages)
{
printk(KERN_WARNING "%s() called, not yet supported\n", __FUNCTION__);
dump_stack();
return -ENOSYS;
}
#endif /* __LINUX_MEMORY_HOTPLUG_H */