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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 4 of the patchset includes an additional patch [4/9] that introduces a new mutex to be taken for any add or remove (not hotplug) of memory. The following updates are also included. Patch 2/9 Add new phys_index properties - The start_phys_index property was reverted to the original phys_index name. Patch 3/9 Add section count to memory_block - Use atomic_dec_and_test() Patch 7/9 Update the node sysfs code - Update the inline definition of unregister_mem_sects_under_nodes for !CONFIG_NUMA builds. Patch 8/9 Define memory_block_size_bytes() for ppc/pseries - Use an unsigned long for getting property value. Patch 9/9 Update memory-hotplug documentation - Minor updates for reversion of phys_index property name. Thanks, Nathan Fontenot --
Move the find_memory_block() routine up to avoid needing a forward
declaration in subsequent patches.
Signed-off-by: Nathan Fontenot <nfont@austin.ibm.com>
---
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 2010-08-02 13:23:51.000000000 -0500
+++ linux-2.6/drivers/base/memory.c 2010-08-02 13:32:21.000000000 -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 ...On Tue, 03 Aug 2010 08:36:39 -0500 Acked-by: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com> --
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 <nfont@austin.ibm.com>
---
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 2010-08-02 13:32:21.000000000 -0500
+++ linux-2.6/drivers/base/memory.c 2010-08-02 13:33:27.000000000 -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 = ...On Tue, 03 Aug 2010 08:37:31 -0500 Acked-by: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com> nitpick. After this patch, end_phys_index is added but contains 0. It's better to contain the same value with phys_index.. But, ok. Following patch will fix it. Thanks, --
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
allows us to know when the last memory section of a memory block has been
removed so we can remove the memory block.
Signed-off-by: Nathan Fontenot <nfont@austin.ibm.com>
---
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 2010-08-02 13:33:27.000000000 -0500
+++ linux-2.6/drivers/base/memory.c 2010-08-02 13:35:00.000000000 -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 2010-08-02 ...On Tue, 03 Aug 2010 08:38:37 -0500 Acked-by: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com> --
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 <nfont@austin.ibm.com>
---
drivers/base/memory.c | 9 +++++++++
1 file changed, 9 insertions(+)
Index: linux-2.6/drivers/base/memory.c
===================================================================
--- linux-2.6.orig/drivers/base/memory.c 2010-08-02 13:35:00.000000000 -0500
+++ linux-2.6/drivers/base/memory.c 2010-08-02 13:45:34.000000000 -0500
@@ -27,6 +27,8 @@
#include <asm/atomic.h>
#include <asm/uaccess.h>
+static struct 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;
}
@@ -562,6 +569,8 @@ int __init memory_dev_init(void)
if (ret)
goto out;
+ mutex_init(&mem_sysfs_mutex);
+
/*
* Create entries for memory sections that were found
* during boot and have been initialized
--
On Tue, 03 Aug 2010 08:39:50 -0500 Acked-by: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com> For static symbol of mutex, we usually do static DEFINE_MUTEX(mem_sysfs_mutex); Then, extra calls of mutex_init() is not required. --
ok, fixed in the next version of the patches. -Nathan --
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 <nfont@austin.ibm.com>
---
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 2010-08-02 13:45:34.000000000 -0500
+++ linux-2.6/drivers/base/memory.c 2010-08-02 14:01:04.000000000 -0500
@@ -30,6 +30,14 @@
static struct 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)
{
...On Tue, 03 Aug 2010 08:40:49 -0500 Acked-by: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com> (But maybe it's better to get ppc guy's Ack.) --
Update the find_memory_block declaration to to take a struct mem_section *
so that it matches the definition.
Signed-off-by: Nathan Fontenot <nfont@austin.ibm.com>
---
include/linux/memory.h | 2 +-
1 file changed, 1 insertion(+), 1 deletion(-)
Index: linux-2.6/include/linux/memory.h
===================================================================
--- linux-2.6.orig/include/linux/memory.h 2010-08-02 13:58:41.000000000 -0500
+++ linux-2.6/include/linux/memory.h 2010-08-02 14:01:15.000000000 -0500
@@ -116,7 +116,7 @@ extern int memory_dev_init(void);
extern int remove_memory_block(unsigned long, struct mem_section *, int);
extern int memory_notify(unsigned long val, void *v);
extern int memory_isolate_notify(unsigned long val, void *v);
-extern struct memory_block *find_memory_block(unsigned long);
+extern struct memory_block *find_memory_block(struct mem_section *);
extern int memory_is_hidden(struct mem_section *);
#define CONFIG_MEM_BLOCK_SIZE (PAGES_PER_SECTION<<PAGE_SHIFT)
enum mem_add_context { BOOT, HOTPLUG };
--
On Tue, 03 Aug 2010 08:41:45 -0500 Acked-by: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com> Hmm...my mmotm-0727 has this definition in memory.h... extern struct memory_block *find_memory_block(struct mem_section *); What patch makes it unsigned long ? --
I was basing the patches on the latest mainline tree. Looks like can drop this patch in the next version of the patchset. -Nathan --
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 <nfont@austin.ibm.com>
---
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 2010-08-02 13:57:20.000000000 -0500
+++ linux-2.6/drivers/base/node.c 2010-08-02 14:01:58.000000000 -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 ...On Tue, 03 Aug 2010 08:42:35 -0500 Acked-by: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com> --
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 <nfont@austin.ibm.com>
---
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 2010-08-02 13:57:03.000000000 -0500
+++ linux-2.6/arch/powerpc/platforms/pseries/hotplug-memory.c 2010-08-02 14:09:52.000000000 -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 ...Update the memory hotplug documentation to reflect the new behaviors of memory blocks reflected in sysfs. Signed-off-by: Nathan Fontenot <nfont@austin.ibm.com> --- Documentation/memory-hotplug.txt | 40 +++++++++++++++++++++++---------------- 1 file changed, 24 insertions(+), 16 deletions(-) Index: linux-2.6/Documentation/memory-hotplug.txt =================================================================== --- linux-2.6.orig/Documentation/memory-hotplug.txt 2010-08-02 14:09:28.000000000 -0500 +++ linux-2.6/Documentation/memory-hotplug.txt 2010-08-02 14:10:36.000000000 -0500 @@ -126,36 +126,44 @@ 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. 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 ...
On Tue, 03 Aug 2010 08:44:16 -0500 Acked-by: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com> A request from me: Could you clarify what happens if there are memory hole in [start end)_phys_index. in Documentation ? (Or add TODO list.) Thanks, --
