This set of patches de-couples the idea that there is a single
directory in sysfs for each memory section. The intent of the
patches is to reduce the number of sysfs directories created to
resolve a boot-time performance issue. On very large systems
boot time are getting very long (as seen on powerpc hardware)
due to the enormous number of sysfs directories being created.
On a system with 1 TB of memory we create ~63,000 directories.
For even larger systems boot times are being measured in hours.
This set of patches allows for each directory created in sysfs
to cover more than one memory section. The default behavior for
sysfs directory creation is the same, in that each directory
represents a single memory section. A new file 'end_phys_index'
in each directory contains the physical_id of the last memory
section covered by the directory so that users can easily
determine the memory section range of a directory.
Updates for version 5 of the patchset include the following:
Patch 4/8 Add mutex for add/remove of memory blocks
- Define the mutex using DEFINE_MUTEX macro.
Patch 8/8 Update memory-hotplug documentation
- Add information concerning memory holes in phys_index..end_phys_index.
Thanks,
Nathan Fontenot
Move the find_me mory_block() routine up to avoid needing a forward
declaration in subsequent patches.
Signed-off-by: Nathan Fontenot <[email protected]>
---
drivers/base/memory.c | 62 +++++++++++++++++++++++++-------------------------
1 file changed, 31 insertions(+), 31 deletions(-)
Index: linux-2.6/drivers/base/memory.c
===================================================================
--- linux-2.6.orig/drivers/base/memory.c 2010-08-09 07:36:55.000000000 -0500
+++ linux-2.6/drivers/base/memory.c 2010-08-09 07:44:21.000000000 -0500
@@ -435,6 +435,37 @@ int __weak arch_get_memory_phys_device(u
return 0;
}
+/*
+ * 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;
+}
+
static int add_memory_block(int nid, struct mem_section *section,
unsigned long state, enum mem_add_context context)
{
@@ -468,37 +499,6 @@ static int add_memory_block(int nid, str
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)
{
Update the 'phys_index' properties of a memory block to include a
'start_phys_index' which is the same as the current 'phys_index' property.
The property still appears as 'phys_index' in sysfs but the memory_block
struct name is updated to indicate the start and end values.
This also adds an 'end_phys_index' property to indicate the id of the
last section in th memory block.
Signed-off-by: Nathan Fontenot <[email protected]>
---
drivers/base/memory.c | 28 ++++++++++++++++++++--------
include/linux/memory.h | 3 ++-
2 files changed, 22 insertions(+), 9 deletions(-)
Index: linux-2.6/drivers/base/memory.c
===================================================================
--- linux-2.6.orig/drivers/base/memory.c 2010-08-09 07:44:21.000000000 -0500
+++ linux-2.6/drivers/base/memory.c 2010-08-09 07:44:31.000000000 -0500
@@ -109,12 +109,20 @@ unregister_memory(struct memory_block *m
* uses.
*/
-static ssize_t show_mem_phys_index(struct sys_device *dev,
+static ssize_t show_mem_start_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);
+ return sprintf(buf, "%08lx\n", mem->start_phys_index);
+}
+
+static ssize_t show_mem_end_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->end_phys_index);
}
/*
@@ -128,7 +136,7 @@ static ssize_t show_mem_removable(struct
struct memory_block *mem =
container_of(dev, struct memory_block, sysdev);
- start_pfn = section_nr_to_pfn(mem->phys_index);
+ start_pfn = section_nr_to_pfn(mem->start_phys_index);
ret = is_mem_section_removable(start_pfn, PAGES_PER_SECTION);
return sprintf(buf, "%d\n", ret);
}
@@ -191,7 +199,7 @@ memory_block_action(struct memory_block
int ret;
int old_state = mem->state;
- psection = mem->phys_index;
+ psection = mem->start_phys_index;
first_page = pfn_to_page(psection << PFN_SECTION_SHIFT);
/*
@@ -264,7 +272,7 @@ store_mem_state(struct sys_device *dev,
int ret = -EINVAL;
mem = container_of(dev, struct memory_block, sysdev);
- phys_section_nr = mem->phys_index;
+ phys_section_nr = mem->start_phys_index;
if (!present_section_nr(phys_section_nr))
goto out;
@@ -296,7 +304,8 @@ static ssize_t show_phys_device(struct s
return sprintf(buf, "%d\n", mem->phys_device);
}
-static SYSDEV_ATTR(phys_index, 0444, show_mem_phys_index, NULL);
+static SYSDEV_ATTR(phys_index, 0444, show_mem_start_phys_index, NULL);
+static SYSDEV_ATTR(end_phys_index, 0444, show_mem_end_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);
@@ -476,16 +485,18 @@ static int add_memory_block(int nid, str
if (!mem)
return -ENOMEM;
- mem->phys_index = __section_nr(section);
+ mem->start_phys_index = __section_nr(section);
mem->state = state;
mutex_init(&mem->state_mutex);
- start_pfn = section_nr_to_pfn(mem->phys_index);
+ start_pfn = section_nr_to_pfn(mem->start_phys_index);
mem->phys_device = arch_get_memory_phys_device(start_pfn);
ret = register_memory(mem, section);
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);
@@ -507,6 +518,7 @@ int remove_memory_block(unsigned long no
mem = find_memory_block(section);
unregister_mem_sect_under_nodes(mem);
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);
Index: linux-2.6/include/linux/memory.h
===================================================================
--- linux-2.6.orig/include/linux/memory.h 2010-08-09 07:36:55.000000000 -0500
+++ linux-2.6/include/linux/memory.h 2010-08-09 07:44:31.000000000 -0500
@@ -21,7 +21,8 @@
#include <linux/mutex.h>
struct memory_block {
- unsigned long phys_index;
+ unsigned long start_phys_index;
+ unsigned long end_phys_index;
unsigned long state;
/*
* This serializes all state change requests. It isn't
Add a section count property to the memory_block struct to track the number
of memory sections that have been added/removed from a memory block. This
alolws us to know when the lasat memory section of a memory block has been
removed so we can remove the memory block.
Signed-off-by: Nathan Fontenot <[email protected]>
---
drivers/base/memory.c | 18 +++++++++++-------
include/linux/memory.h | 2 ++
2 files changed, 13 insertions(+), 7 deletions(-)
Index: linux-2.6/drivers/base/memory.c
===================================================================
--- linux-2.6.orig/drivers/base/memory.c 2010-08-09 07:44:31.000000000 -0500
+++ linux-2.6/drivers/base/memory.c 2010-08-09 07:49:04.000000000 -0500
@@ -487,6 +487,7 @@ static int add_memory_block(int nid, str
mem->start_phys_index = __section_nr(section);
mem->state = state;
+ atomic_inc(&mem->section_count);
mutex_init(&mem->state_mutex);
start_pfn = section_nr_to_pfn(mem->start_phys_index);
mem->phys_device = arch_get_memory_phys_device(start_pfn);
@@ -516,13 +517,16 @@ int remove_memory_block(unsigned long no
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, 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, section);
+
+ if (atomic_dec_and_test(&mem->section_count)) {
+ unregister_mem_sect_under_nodes(mem);
+ 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, section);
+ }
return 0;
}
Index: linux-2.6/include/linux/memory.h
===================================================================
--- linux-2.6.orig/include/linux/memory.h 2010-08-09 07:44:31.000000000 -0500
+++ linux-2.6/include/linux/memory.h 2010-08-09 07:49:04.000000000 -0500
@@ -19,11 +19,13 @@
#include <linux/node.h>
#include <linux/compiler.h>
#include <linux/mutex.h>
+#include <asm/atomic.h>
struct memory_block {
unsigned long start_phys_index;
unsigned long end_phys_index;
unsigned long state;
+ atomic_t section_count;
/*
* This serializes all state change requests. It isn't
* held during creation because the control files are
Add a new mutex for use in adding and removing of memory blocks. This
is needed to avoid any race conditions in which the same memory block could
be added and removed at the same time.
Signed-off-by: Nathan Fontenot <[email protected]>
---
drivers/base/memory.c | 7 +++++++
1 file changed, 7 insertions(+)
Index: linux-2.6/drivers/base/memory.c
===================================================================
--- linux-2.6.orig/drivers/base/memory.c 2010-08-09 07:49:04.000000000 -0500
+++ linux-2.6/drivers/base/memory.c 2010-08-09 07:50:20.000000000 -0500
@@ -27,6 +27,8 @@
#include <asm/atomic.h>
#include <asm/uaccess.h>
+static DEFINE_MUTEX(mem_sysfs_mutex);
+
#define MEMORY_CLASS_NAME "memory"
static struct sysdev_class memory_sysdev_class = {
@@ -485,6 +487,8 @@ static int add_memory_block(int nid, str
if (!mem)
return -ENOMEM;
+ mutex_lock(&mem_sysfs_mutex);
+
mem->start_phys_index = __section_nr(section);
mem->state = state;
atomic_inc(&mem->section_count);
@@ -508,6 +512,7 @@ static int add_memory_block(int nid, str
ret = register_mem_sect_under_node(mem, nid);
}
+ mutex_unlock(&mem_sysfs_mutex);
return ret;
}
@@ -516,6 +521,7 @@ int remove_memory_block(unsigned long no
{
struct memory_block *mem;
+ mutex_lock(&mem_sysfs_mutex);
mem = find_memory_block(section);
if (atomic_dec_and_test(&mem->section_count)) {
@@ -528,6 +534,7 @@ int remove_memory_block(unsigned long no
unregister_memory(mem, section);
}
+ mutex_unlock(&mem_sysfs_mutex);
return 0;
}
Update the memory sysfs code that each sysfs memory directory is now
considered a memory block that can contain multiple memory sections per
memory block. The default size of each memory block is SECTION_SIZE_BITS
to maintain the current behavior of having a single memory section per
memory block (i.e. one sysfs directory per memory section).
For architectures that want to have memory blocks span multiple
memory sections they need only define their own memory_block_size_bytes()
routine.
Signed-off-by: Nathan Fontenot <[email protected]>
---
drivers/base/memory.c | 148 ++++++++++++++++++++++++++++++++++----------------
1 file changed, 103 insertions(+), 45 deletions(-)
Index: linux-2.6/drivers/base/memory.c
===================================================================
--- linux-2.6.orig/drivers/base/memory.c 2010-08-09 07:50:20.000000000 -0500
+++ linux-2.6/drivers/base/memory.c 2010-08-09 07:50:28.000000000 -0500
@@ -30,6 +30,14 @@
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) * sections_per_block;
+}
static struct sysdev_class memory_sysdev_class = {
.name = MEMORY_CLASS_NAME,
@@ -84,22 +92,21 @@ EXPORT_SYMBOL(unregister_memory_isolate_
* 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->start_phys_index;
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);
@@ -133,13 +140,16 @@ static ssize_t show_mem_end_phys_index(s
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->start_phys_index);
- ret = is_mem_section_removable(start_pfn, PAGES_PER_SECTION);
+ for (i = mem->start_phys_index; i <= mem->end_phys_index; i++) {
+ pfn = section_nr_to_pfn(i);
+ ret &= is_mem_section_removable(pfn, PAGES_PER_SECTION);
+ }
+
return sprintf(buf, "%d\n", ret);
}
@@ -192,17 +202,14 @@ int memory_isolate_notify(unsigned long
* 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->start_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
@@ -215,8 +222,8 @@ memory_block_action(struct memory_block
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;
}
}
@@ -227,18 +234,13 @@ memory_block_action(struct memory_block
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;
}
@@ -248,7 +250,7 @@ memory_block_action(struct memory_block
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) {
@@ -256,8 +258,21 @@ static int memory_block_change_state(str
goto out;
}
- ret = memory_block_action(mem, to_state);
- if (!ret)
+ if (to_state == MEM_OFFLINE)
+ mem->state = MEM_GOING_OFFLINE;
+
+ for (i = mem->start_phys_index; i <= mem->end_phys_index; i++) {
+ ret = memory_section_action(i, to_state);
+ if (ret)
+ break;
+ }
+
+ if (ret) {
+ for (i = mem->start_phys_index; i <= mem->end_phys_index; i++)
+ memory_section_action(i, from_state_req);
+
+ mem->state = from_state_req;
+ } else
mem->state = to_state;
out:
@@ -270,20 +285,15 @@ 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->start_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;
@@ -460,12 +470,13 @@ struct memory_block *find_memory_block(s
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));
/*
* 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(&memory_sysdev_class.kset, name);
if (!kobj)
@@ -477,26 +488,26 @@ struct memory_block *find_memory_block(s
return mem;
}
-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 ret = 0;
+ mem = kzalloc(sizeof(*mem), GFP_KERNEL);
if (!mem)
return -ENOMEM;
- mutex_lock(&mem_sysfs_mutex);
-
- mem->start_phys_index = __section_nr(section);
+ mem->start_phys_index = base_memory_block_id(__section_nr(section));
+ mem->end_phys_index = mem->start_phys_index + sections_per_block - 1;
mem->state = state;
atomic_inc(&mem->section_count);
mutex_init(&mem->state_mutex);
start_pfn = section_nr_to_pfn(mem->start_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)
@@ -507,8 +518,29 @@ static int add_memory_block(int nid, str
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) {
+ atomic_inc(&mem->section_count);
+ kobject_put(&mem->sysdev.kobj);
+ } else
+ ret = init_memory_block(&mem, section, state);
+
if (!ret) {
- if (context == HOTPLUG)
+ if (context == HOTPLUG &&
+ atomic_read(&mem->section_count) == sections_per_block)
ret = register_mem_sect_under_node(mem, nid);
}
@@ -531,8 +563,10 @@ int remove_memory_block(unsigned long no
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;
@@ -544,7 +578,7 @@ int remove_memory_block(unsigned long no
*/
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)
@@ -555,6 +589,26 @@ int unregister_memory_section(struct mem
return remove_memory_block(0, section, 0);
}
+u32 __weak memory_block_size_bytes(void)
+{
+ return MIN_MEMORY_BLOCK_SIZE;
+}
+
+static u32 get_memory_block_size(void)
+{
+ u32 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;
+}
+
/*
* Initialize the sysfs support for memory devices...
*/
@@ -563,12 +617,16 @@ int __init memory_dev_init(void)
unsigned int i;
int ret;
int err;
+ int 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
@@ -576,8 +634,8 @@ 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,
- BOOT);
+ err = add_memory_section(0, __nr_to_section(i), MEM_ONLINE,
+ BOOT);
if (!ret)
ret = err;
}
Update the node sysfs code to be aware of the new capability for a memory
block to contain multiple memory sections. This requires an additional
parameter to unregister_mem_sect_under_nodes so that we know which memory
section of the memory block to unregister.
Signed-off-by: Nathan Fontenot <[email protected]>
---
drivers/base/memory.c | 2 +-
drivers/base/node.c | 12 ++++++++----
include/linux/node.h | 6 ++++--
3 files changed, 13 insertions(+), 7 deletions(-)
Index: linux-2.6/drivers/base/node.c
===================================================================
--- linux-2.6.orig/drivers/base/node.c 2010-08-09 07:36:50.000000000 -0500
+++ linux-2.6/drivers/base/node.c 2010-08-09 07:53:30.000000000 -0500
@@ -346,8 +346,10 @@ int register_mem_sect_under_node(struct
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;
+
+ sect_start_pfn = section_nr_to_pfn(mem_blk->start_phys_index);
+ sect_end_pfn = section_nr_to_pfn(mem_blk->end_phys_index);
+ sect_end_pfn += PAGES_PER_SECTION - 1;
for (pfn = sect_start_pfn; pfn <= sect_end_pfn; pfn++) {
int page_nid;
@@ -371,7 +373,8 @@ int register_mem_sect_under_node(struct
}
/* unregister memory section under all nodes that it spans */
-int unregister_mem_sect_under_nodes(struct memory_block *mem_blk)
+int unregister_mem_sect_under_nodes(struct memory_block *mem_blk,
+ unsigned long phys_index)
{
NODEMASK_ALLOC(nodemask_t, unlinked_nodes, GFP_KERNEL);
unsigned long pfn, sect_start_pfn, sect_end_pfn;
@@ -383,7 +386,8 @@ int unregister_mem_sect_under_nodes(stru
if (!unlinked_nodes)
return -ENOMEM;
nodes_clear(*unlinked_nodes);
- sect_start_pfn = section_nr_to_pfn(mem_blk->phys_index);
+
+ sect_start_pfn = section_nr_to_pfn(phys_index);
sect_end_pfn = sect_start_pfn + PAGES_PER_SECTION - 1;
for (pfn = sect_start_pfn; pfn <= sect_end_pfn; pfn++) {
int nid;
Index: linux-2.6/drivers/base/memory.c
===================================================================
--- linux-2.6.orig/drivers/base/memory.c 2010-08-09 07:50:28.000000000 -0500
+++ linux-2.6/drivers/base/memory.c 2010-08-09 07:53:30.000000000 -0500
@@ -555,9 +555,9 @@ int remove_memory_block(unsigned long no
mutex_lock(&mem_sysfs_mutex);
mem = find_memory_block(section);
+ unregister_mem_sect_under_nodes(mem, __section_nr(section));
if (atomic_dec_and_test(&mem->section_count)) {
- unregister_mem_sect_under_nodes(mem);
mem_remove_simple_file(mem, phys_index);
mem_remove_simple_file(mem, end_phys_index);
mem_remove_simple_file(mem, state);
Index: linux-2.6/include/linux/node.h
===================================================================
--- linux-2.6.orig/include/linux/node.h 2010-08-09 07:36:50.000000000 -0500
+++ linux-2.6/include/linux/node.h 2010-08-09 07:53:30.000000000 -0500
@@ -44,7 +44,8 @@ extern int register_cpu_under_node(unsig
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);
+extern int unregister_mem_sect_under_nodes(struct memory_block *mem_blk,
+ unsigned long phys_index);
#ifdef CONFIG_HUGETLBFS
extern void register_hugetlbfs_with_node(node_registration_func_t doregister,
@@ -72,7 +73,8 @@ static inline int register_mem_sect_unde
{
return 0;
}
-static inline int unregister_mem_sect_under_nodes(struct memory_block *mem_blk)
+static inline int unregister_mem_sect_under_nodes(struct memory_block *mem_blk,
+ unsigned long phys_index)
{
return 0;
}
Define a version of memory_block_size_bytes() for powerpc/pseries such that
a memory block spans an entire lmb.
Signed-off-by: Nathan Fontenot <[email protected]>
---
arch/powerpc/platforms/pseries/hotplug-memory.c | 66 +++++++++++++++++++-----
1 file changed, 53 insertions(+), 13 deletions(-)
Index: linux-2.6/arch/powerpc/platforms/pseries/hotplug-memory.c
===================================================================
--- linux-2.6.orig/arch/powerpc/platforms/pseries/hotplug-memory.c 2010-08-09 07:36:49.000000000 -0500
+++ linux-2.6/arch/powerpc/platforms/pseries/hotplug-memory.c 2010-08-09 07:54:00.000000000 -0500
@@ -17,6 +17,54 @@
#include <asm/pSeries_reconfig.h>
#include <asm/sparsemem.h>
+static u32 get_memblock_size(void)
+{
+ struct device_node *np;
+ unsigned int memblock_size = 0;
+
+ np = of_find_node_by_path("/ibm,dynamic-reconfiguration-memory");
+ if (np) {
+ const unsigned long *size;
+
+ size = of_get_property(np, "ibm,lmb-size", NULL);
+ memblock_size = size ? *size : 0;
+
+ of_node_put(np);
+ } else {
+ unsigned int memzero_size = 0;
+ const unsigned int *regs;
+
+ np = of_find_node_by_path("/memory@0");
+ if (np) {
+ regs = of_get_property(np, "reg", NULL);
+ memzero_size = regs ? regs[3] : 0;
+ of_node_put(np);
+ }
+
+ if (memzero_size) {
+ /* We now know the size of memory@0, use this to find
+ * the first memoryblock and get its size.
+ */
+ char buf[64];
+
+ sprintf(buf, "/memory@%x", memzero_size);
+ np = of_find_node_by_path(buf);
+ if (np) {
+ regs = of_get_property(np, "reg", NULL);
+ memblock_size = regs ? regs[3] : 0;
+ of_node_put(np);
+ }
+ }
+ }
+
+ return memblock_size;
+}
+
+u32 memory_block_size_bytes(void)
+{
+ return get_memblock_size();
+}
+
static int pseries_remove_memblock(unsigned long base, unsigned int memblock_size)
{
unsigned long start, start_pfn;
@@ -127,30 +175,22 @@ static int pseries_add_memory(struct dev
static int pseries_drconf_memory(unsigned long *base, unsigned int action)
{
- struct device_node *np;
- const unsigned long *lmb_size;
+ unsigned long memblock_size;
int rc;
- np = of_find_node_by_path("/ibm,dynamic-reconfiguration-memory");
- if (!np)
+ memblock_size = get_memblock_size();
+ if (!memblock_size)
return -EINVAL;
- lmb_size = of_get_property(np, "ibm,lmb-size", NULL);
- if (!lmb_size) {
- of_node_put(np);
- return -EINVAL;
- }
-
if (action == PSERIES_DRCONF_MEM_ADD) {
- rc = memblock_add(*base, *lmb_size);
+ rc = memblock_add(*base, memblock_size);
rc = (rc < 0) ? -EINVAL : 0;
} else if (action == PSERIES_DRCONF_MEM_REMOVE) {
- rc = pseries_remove_memblock(*base, *lmb_size);
+ rc = pseries_remove_memblock(*base, memblock_size);
} else {
rc = -EINVAL;
}
- of_node_put(np);
return rc;
}
Update the memory hotplug documentation to reflect the new behaviors of
memory blocks reflected in sysfs.
Signed-off-by: Nathan Fontent <[email protected]>
---
Documentation/memory-hotplug.txt | 46 +++++++++++++++++++++++++--------------
1 file changed, 30 insertions(+), 16 deletions(-)
Index: linux-2.6/Documentation/memory-hotplug.txt
===================================================================
--- linux-2.6.orig/Documentation/memory-hotplug.txt 2010-08-09 07:36:48.000000000 -0500
+++ linux-2.6/Documentation/memory-hotplug.txt 2010-08-09 07:59:54.000000000 -0500
@@ -126,36 +126,50 @@ config options.
--------------------------------
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 5 files.
-/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.
On Monday, August 09, 2010 11:43:46 am Nathan Fontenot wrote:
> Update the memory hotplug documentation to reflect the new behaviors of
> memory blocks reflected in sysfs.
<snip>
> Index: linux-2.6/Documentation/memory-hotplug.txt
> ===================================================================
> --- linux-2.6.orig/Documentation/memory-hotplug.txt 2010-08-09 07:36:48.000000000 -0500
> +++ linux-2.6/Documentation/memory-hotplug.txt 2010-08-09 07:59:54.000000000 -0500
<snip>
> -/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.
<snip>
> +'phys_index' : read-only and contains section id of the first section
Shouldn't this be "start_phys_index"?
Thanks,
Nish
--
Nishanth Aravamudan <[email protected]>
Linux Technology Center
On Monday, August 09, 2010 01:44:37 pm Nishanth Aravamudan wrote:
> On Monday, August 09, 2010 11:43:46 am Nathan Fontenot wrote:
> > Update the memory hotplug documentation to reflect the new behaviors of
> > memory blocks reflected in sysfs.
>
> <snip>
>
> > Index: linux-2.6/Documentation/memory-hotplug.txt
> > ===================================================================
> > --- linux-2.6.orig/Documentation/memory-hotplug.txt 2010-08-09 07:36:48.000000000 -0500
> > +++ linux-2.6/Documentation/memory-hotplug.txt 2010-08-09 07:59:54.000000000 -0500
>
> <snip>
>
> > -/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.
>
> <snip>
>
> > +'phys_index' : read-only and contains section id of the first section
>
> Shouldn't this be "start_phys_index"?
Ah, actually it's that the Documentation change doesn't seem to agree with
patch 2/8 ? That is, 2/8 leaves phys_index in place, but changes several
variables, while this patch indicates its removal?
Thanks,
Nish
--
Nishanth Aravamudan <[email protected]>
Linux Technology Center
On 08/09/2010 03:44 PM, Nishanth Aravamudan wrote:
> On Monday, August 09, 2010 11:43:46 am Nathan Fontenot wrote:
>> Update the memory hotplug documentation to reflect the new behaviors of
>> memory blocks reflected in sysfs.
>
> <snip>
>
>> Index: linux-2.6/Documentation/memory-hotplug.txt
>> ===================================================================
>> --- linux-2.6.orig/Documentation/memory-hotplug.txt 2010-08-09 07:36:48.000000000 -0500
>> +++ linux-2.6/Documentation/memory-hotplug.txt 2010-08-09 07:59:54.000000000 -0500
>
> <snip>
>
>> -/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.
>
> <snip>
>
>> +'phys_index' : read-only and contains section id of the first section
>
> Shouldn't this be "start_phys_index"?
Hmmm... looks like I missed something in the documentation.
The property should be 'phys_index'. I thought about changing it to
'start_phys_index' but that was rejected. The listing of the files
above is wrong in this patch, it should be
+/sys/devices/system/memory/memoryXXX/phys_index
+/sys/devices/system/memory/memoryXXX/end_phys_index
Thanks,
Nathan
On Mon, 2010-08-09 at 12:53 -0500, Nathan Fontenot wrote:
> This set of patches de-couples the idea that there is a single
> directory in sysfs for each memory section. The intent of the
> patches is to reduce the number of sysfs directories created to
> resolve a boot-time performance issue. On very large systems
> boot time are getting very long (as seen on powerpc hardware)
> due to the enormous number of sysfs directories being created.
> On a system with 1 TB of memory we create ~63,000 directories.
> For even larger systems boot times are being measured in hours.
Hi Nathan,
The set is looking pretty good to me. We _might_ want to up the ante in
the future and allow it to be even more dynamic than this, but this
looks like a good start to me.
BTW, have you taken a look at what the hotplug events look like if only
a single section (not filling up a whole block) is added?
Feel free to add my:
Acked-by: Dave Hansen <[email protected]>
-- Dave
On Mon, 09 Aug 2010 12:53:00 -0500
Nathan Fontenot <[email protected]> wrote:
> This set of patches de-couples the idea that there is a single
> directory in sysfs for each memory section. The intent of the
> patches is to reduce the number of sysfs directories created to
> resolve a boot-time performance issue. On very large systems
> boot time are getting very long (as seen on powerpc hardware)
> due to the enormous number of sysfs directories being created.
> On a system with 1 TB of memory we create ~63,000 directories.
> For even larger systems boot times are being measured in hours.
And those "hours" are mainly due to this problem, I assume.
> This set of patches allows for each directory created in sysfs
> to cover more than one memory section. The default behavior for
> sysfs directory creation is the same, in that each directory
> represents a single memory section. A new file 'end_phys_index'
> in each directory contains the physical_id of the last memory
> section covered by the directory so that users can easily
> determine the memory section range of a directory.
What you're proposing appears to be a non-back-compatible
userspace-visible change. This is a big issue!
It's not an unresolvable issue, as this is a must-fix problem. But you
should tell us what your proposal is to prevent breakage of existing
installations. A Kconfig option would be good, but a boot-time kernel
command line option which selects the new format would be much better.
However you didn't mention this issue at all, and it's the most
important one.
> Updates for version 5 of the patchset include the following:
>
> Patch 4/8 Add mutex for add/remove of memory blocks
> - Define the mutex using DEFINE_MUTEX macro.
>
> Patch 8/8 Update memory-hotplug documentation
> - Add information concerning memory holes in phys_index..end_phys_index.
And you forgot to tell us how long those machines boot with the
patchset applied, which is the entire point of the patchset!
On Thu, 2010-08-12 at 12:08 -0700, Andrew Morton wrote:
> > This set of patches allows for each directory created in sysfs
> > to cover more than one memory section. The default behavior for
> > sysfs directory creation is the same, in that each directory
> > represents a single memory section. A new file 'end_phys_index'
> > in each directory contains the physical_id of the last memory
> > section covered by the directory so that users can easily
> > determine the memory section range of a directory.
>
> What you're proposing appears to be a non-back-compatible
> userspace-visible change. This is a big issue!
Nathan, one thought to get around this at the moment would be to bump up
the size that we export in /sys/devices/system/memory/block_size_bytes.
I think you have already done most of the hard work to accomplish
this.
You can still add the end_phys_index stuff. But, for now, it would
always be equal to start_phys_index.
-- Dave
On 08/12/2010 02:08 PM, Andrew Morton wrote:
> On Mon, 09 Aug 2010 12:53:00 -0500
> Nathan Fontenot <[email protected]> wrote:
>
>> This set of patches de-couples the idea that there is a single
>> directory in sysfs for each memory section. The intent of the
>> patches is to reduce the number of sysfs directories created to
>> resolve a boot-time performance issue. On very large systems
>> boot time are getting very long (as seen on powerpc hardware)
>> due to the enormous number of sysfs directories being created.
>> On a system with 1 TB of memory we create ~63,000 directories.
>> For even larger systems boot times are being measured in hours.
>
> And those "hours" are mainly due to this problem, I assume.
Yes, those hours are spent creating the sysfs directories for each
of the memory sections.
>
>> This set of patches allows for each directory created in sysfs
>> to cover more than one memory section. The default behavior for
>> sysfs directory creation is the same, in that each directory
>> represents a single memory section. A new file 'end_phys_index'
>> in each directory contains the physical_id of the last memory
>> section covered by the directory so that users can easily
>> determine the memory section range of a directory.
>
> What you're proposing appears to be a non-back-compatible
> userspace-visible change. This is a big issue!
>
> It's not an unresolvable issue, as this is a must-fix problem. But you
> should tell us what your proposal is to prevent breakage of existing
> installations. A Kconfig option would be good, but a boot-time kernel
> command line option which selects the new format would be much better.
This shouldn't break existing installations, unless an architecture chooses
to do so. With my patch only the powerpc/pseries arch is updated such that
what is seen in userspace is different.
The default behavior is maintained for all architectures unless they define
their own version of memory_block_size_bytes(). The default definition of
this routine (defined as __weak in Patch 5/8) sets the memory block size
to the same size it currently is, and thus preserving the exisitng 1 sysfs
directory per memory section. The only change that will be seen is a new
propery for memory section, end_phys_addr, which will have the same value
as the existing 'phys_addr' property.
>
> However you didn't mention this issue at all, and it's the most
> important one.
>
>
>> Updates for version 5 of the patchset include the following:
>>
>> Patch 4/8 Add mutex for add/remove of memory blocks
>> - Define the mutex using DEFINE_MUTEX macro.
>>
>> Patch 8/8 Update memory-hotplug documentation
>> - Add information concerning memory holes in phys_index..end_phys_index.
>
> And you forgot to tell us how long those machines boot with the
> patchset applied, which is the entire point of the patchset!
Yes, I am working on getting more time on our large systems to get
performance numbers with this patch. I'll post them when I get them.
-Nathan
On Mon, 2010-08-16 at 09:34 -0500, Nathan Fontenot wrote:
> > It's not an unresolvable issue, as this is a must-fix problem. But you
> > should tell us what your proposal is to prevent breakage of existing
> > installations. A Kconfig option would be good, but a boot-time kernel
> > command line option which selects the new format would be much better.
>
> This shouldn't break existing installations, unless an architecture chooses
> to do so. With my patch only the powerpc/pseries arch is updated such that
> what is seen in userspace is different.
Even if an arch defines the override for the sysfs dir size, I still
don't think this breaks anything (it shouldn't). We move _all_ of the
directories over, all at once, to a single, uniform size. The only
apparent change to a user moving kernels would be a larger
block_size_bytes (which is certainly not changing the ABI) and a new
sysfs file for the end of the section. The new sysfs file is
_completely_ redundant at this point.
The architecture is only supposed to bump up the directory size when it
*KNOWS* that all operations will be done at the larger section size,
such as if the specific hardware has physical DIMMs which are much
larger than SECTION_SIZE.
Let's say we have a system with 20MB of memory, SECTION_SIZE of 1MB and
a sysfs dir size of 4MB.
Before the patch, we have 20 directories: one for each section. After
this patch, we have 5 directories.
The thing that I think is the next step, but that we _will_ probably
need eventually is this, take the 5 sysfs dirs in the above case:
0->3, 4->7, 8->11, 12->15, 16->19
and turn that into a single one:
0->19
*That* will require changing the ABI, but we could certainly have some
bloated and slow, but backward-compatible mode.
-- Dave
Hi Nathan,
> This set of patches de-couples the idea that there is a single
> directory in sysfs for each memory section. The intent of the
> patches is to reduce the number of sysfs directories created to
> resolve a boot-time performance issue. On very large systems
> boot time are getting very long (as seen on powerpc hardware)
> due to the enormous number of sysfs directories being created.
> On a system with 1 TB of memory we create ~63,000 directories.
> For even larger systems boot times are being measured in hours.
>
> This set of patches allows for each directory created in sysfs
> to cover more than one memory section. The default behavior for
> sysfs directory creation is the same, in that each directory
> represents a single memory section. A new file 'end_phys_index'
> in each directory contains the physical_id of the last memory
> section covered by the directory so that users can easily
> determine the memory section range of a directory.
I tested this on a POWER7 with 2TB memory and the boot time improved from
greater than 6 hours (I gave up), to under 5 minutes. Nice!
Tested-by: Anton Blanchard <[email protected]>
Anton