--------------------------------
4 sysfs files for memory hotplug
--------------------------------
-All sections have their device information under /sys/devices/system/memory as
+All sections have their device information in sysfs. Each section is part of
+a memory block under /sys/devices/system/memory as
/sys/devices/system/memory/memoryXXX
-(XXX is section id.)
+(XXX is the section id.)
-Now, XXX is defined as start_address_of_section / section_size.
+Now, XXX is defined as (start_address_of_section / section_size) of the first
+section contained in the memory block. The files 'phys_index' and
+'end_phys_index' under each directory report the beginning and end section id's
+for the memory block covered by the sysfs directory. It is expected that all
+memory sections in this range are present and no memory holes exist in the
+range. Currently there is no way to determine if there is a memory hole, but
+the existence of one should not affect the hotplug capabilities of the memory
+block.
For example, assume 1GiB section size. A device for a memory starting at
0x100000000 is /sys/device/system/memory/memory4
(0x100000000 / 1Gib = 4)
This device covers address range [0x100000000 ... 0x140000000)
-Under each section, you can see 4 files.
+Under each section, you can see 4 or 5 files, the end_phys_index file being
+a recent addition and not present on older kernels.
-/sys/devices/system/memory/memoryXXX/phys_index
+/sys/devices/system/memory/memoryXXX/start_phys_index
+/sys/devices/system/memory/memoryXXX/end_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
- at read: contains online/offline state of memory.
- 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.
+'phys_index' : read-only and contains section id of the first section
+ in the memory block, same as XXX.
+'end_phys_index' : read-only and contains section id of the last section
+ in the memory block.
+'state' : read-write
+ at read: contains online/offline state of memory.
+ at write: user can specify "online", "offline" command
+ which will be performed on al sections in the block.
+'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 block is removable or not
+ removable. A value of 1 indicates that the memory
+ block is removable and a value of 0 indicates that
+ it is not removable. A memory block is removable only if
+ every section in the block is removable.
NOTE:
These directories/files appear after physical memory hotplug phase.
static DEFINE_MUTEX(mem_sysfs_mutex);
#define MEMORY_CLASS_NAME "memory"
+#define MIN_MEMORY_BLOCK_SIZE (1 << SECTION_SIZE_BITS)
+
+static int sections_per_block;
+
+static inline int base_memory_block_id(int section_nr)
+{
+ return section_nr / sections_per_block;
+}
static struct sysdev_class memory_sysdev_class = {
.name = MEMORY_CLASS_NAME,
* register_memory - Setup a sysfs device for a memory block
*/
static
-int register_memory(struct memory_block *memory, struct mem_section *section)
+int register_memory(struct memory_block *memory)
{
int error;
memory->sysdev.cls = &memory_sysdev_class;
- memory->sysdev.id = __section_nr(section);
+ memory->sysdev.id = memory->phys_index / sections_per_block;
error = sysdev_register(&memory->sysdev);
return error;
}
static void
-unregister_memory(struct memory_block *memory, struct mem_section *section)
+unregister_memory(struct memory_block *memory)
{
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);
}
+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.
{
struct memory_block *mem =
container_of(dev, struct memory_block, sysdev);
- return sprintf(buf, "%08lx\n", mem->phys_index);
+ return sprintf(buf, "%08lx\n", mem->phys_index / sections_per_block);
}
/*
static ssize_t show_mem_removable(struct sys_device *dev,
struct sysdev_attribute *attr, char *buf)
{
- unsigned long start_pfn;
- int ret;
+ unsigned long i, pfn;
+ int ret = 1;
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);
+ for (i = 0; i < sections_per_block; i++) {
+ pfn = section_nr_to_pfn(mem->phys_index + i);
+ ret &= is_mem_section_removable(pfn, PAGES_PER_SECTION);
+ }
+
return sprintf(buf, "%d\n", ret);
}
* OK to have direct references to sparsemem variables in here.
*/
static int
-memory_block_action(struct memory_block *mem, unsigned long action)
+memory_section_action(unsigned long phys_index, 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);
+ first_page = pfn_to_page(phys_index << PFN_SECTION_SHIFT);
/*
* The probe routines leave the pages reserved, just
continue;
printk(KERN_WARNING "section number %ld page number %d "
- "not reserved, was it already online? \n",
- psection, i);
+ "not reserved, was it already online?\n",
+ phys_index, i);
return -EBUSY;
}
}
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);
+ WARN(1, KERN_WARNING "%s(%ld, %ld) unknown action: "
+ "%ld\n", __func__, phys_index, action, action);
ret = -EINVAL;
}
static int memory_block_change_state(struct memory_block *mem,
unsigned long to_state, unsigned long from_state_req)
{
- int ret = 0;
+ int i, ret = 0;
+
mutex_lock(&mem->state_mutex);
if (mem->state != from_state_req) {
goto out;
}
- ret = memory_block_action(mem, to_state);
- if (!ret)
+ if (to_state == MEM_OFFLINE)
+ mem->state = MEM_GOING_OFFLINE;
+
+ for (i = 0; i < sections_per_block; i++) {
+ ret = memory_section_action(mem->phys_index + i, to_state);
+ if (ret)
+ break;
+ }
+
+ if (ret) {
+ for (i = 0; i < sections_per_block; i++)
+ memory_section_action(mem->phys_index + i,
+ from_state_req);
+
+ mem->state = from_state_req;
+ } else
mem->state = to_state;
out:
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;
print_block_size(struct sysdev_class *class, struct sysdev_class_attribute *attr,
char *buf)
{
- return sprintf(buf, "%lx\n", (unsigned long)PAGES_PER_SECTION * PAGE_SIZE);
+ return sprintf(buf, "%lx\n", get_memory_block_size());
}
static SYSDEV_CLASS_ATTR(block_size_bytes, 0444, print_block_size, NULL);
struct sys_device *sysdev;
struct memory_block *mem;
char name[sizeof(MEMORY_CLASS_NAME) + 9 + 1];
+ int block_id = base_memory_block_id(__section_nr(section));
kobj = hint ? &hint->sysdev.kobj : NULL;
* 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));
+ sprintf(&name[0], "%s%d", MEMORY_CLASS_NAME, block_id);
kobj = kset_find_obj_hinted(&memory_sysdev_class.kset, name, kobj);
if (!kobj)
return find_memory_block_hinted(section, NULL);
}
-static int add_memory_block(int nid, struct mem_section *section,
- unsigned long state, enum mem_add_context context)
+static int init_memory_block(struct memory_block **memory,
+ struct mem_section *section, unsigned long state)
{
- struct memory_block *mem = kzalloc(sizeof(*mem), GFP_KERNEL);
+ struct memory_block *mem;
unsigned long start_pfn;
+ int scn_nr;
int ret = 0;
+ mem = kzalloc(sizeof(*mem), GFP_KERNEL);
if (!mem)
return -ENOMEM;
- mutex_lock(&mem_sysfs_mutex);
-
- mem->phys_index = __section_nr(section);
+ scn_nr = __section_nr(section);
+ mem->phys_index = base_memory_block_id(scn_nr) * sections_per_block;
mem->state = state;
mem->section_count++;
mutex_init(&mem->state_mutex);
start_pfn = section_nr_to_pfn(mem->phys_index);
mem->phys_device = arch_get_memory_phys_device(start_pfn);
- ret = register_memory(mem, section);
+ ret = register_memory(mem);
if (!ret)
ret = mem_create_simple_file(mem, phys_index);
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,
+ unsigned long state, enum mem_add_context context)
+{
+ struct memory_block *mem;
+ int ret = 0;
+
+ mutex_lock(&mem_sysfs_mutex);
+
+ mem = find_memory_block(section);
+ if (mem) {
+ mem->section_count++;
+ kobject_put(&mem->sysdev.kobj);
+ } else
+ ret = init_memory_block(&mem, section, state);
+
if (!ret) {
- if (context == HOTPLUG)
+ if (context == HOTPLUG &&
+ mem->section_count == sections_per_block)
ret = register_mem_sect_under_node(mem, nid);
}
mem_remove_simple_file(mem, state);
mem_remove_simple_file(mem, phys_device);
mem_remove_simple_file(mem, removable);
- unregister_memory(mem, section);
- }
+ unregister_memory(mem);
+ kfree(mem);
+ } else
+ kobject_put(&mem->sysdev.kobj);
mutex_unlock(&mem_sysfs_mutex);
return 0;
*/
int register_new_memory(int nid, struct mem_section *section)
{
- return add_memory_block(nid, section, MEM_OFFLINE, HOTPLUG);
+ return add_memory_section(nid, section, MEM_OFFLINE, HOTPLUG);
}
int unregister_memory_section(struct mem_section *section)
unsigned int i;
int ret;
int err;
+ unsigned long block_sz;
memory_sysdev_class.kset.uevent_ops = &memory_uevent_ops;
ret = sysdev_class_register(&memory_sysdev_class);
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;
- err = add_memory_block(0, __nr_to_section(i), MEM_ONLINE,
- BOOT);
+ err = add_memory_section(0, __nr_to_section(i), MEM_ONLINE,
+ BOOT);
if (!ret)
ret = err;
}
projects / GitHub / moto-9609 / android_kernel_motorola_exynos9610.git / commitdiff