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Subject[7/8,v3] NUMA Hotplug Emulator: extend memory probe interface to support NUMA
Extend memory probe interface to support an extra paramter nid,
the reserved memory can be added into this node if node exists.

Add a memory section(128M) to node 3(boots with mem=1024m)

echo 0x40000000,3 > memory/probe

And more we make it friendly, it is possible to add memory to do

echo 3g > memory/probe
echo 1024m,3 > memory/probe

It maintains backwards compatibility.

Another format suggested by Dave Hansen:

echo physical_address=0x40000000 numa_node=3 > memory/probe

it is more explicit to show meaning of the parameters.

CC: Dave Hansen <dave@linux.vnet.ibm.com>
Signed-off-by: Shaohui Zheng <shaohui.zheng@intel.com>
Signed-off-by: Haicheng Li <haicheng.li@intel.com>
Signed-off-by: Wu Fengguang <fengguang.wu@intel.com>
---
Index: linux-hpe4/Documentation/ABI/testing/sysfs-devices-memory
===================================================================
--- linux-hpe4.orig/Documentation/ABI/testing/sysfs-devices-memory 2010-11-17 09:00:50.653461798 +0800
+++ linux-hpe4/Documentation/ABI/testing/sysfs-devices-memory 2010-11-17 09:01:10.262838849 +0800
@@ -60,6 +60,23 @@
Users: hotplug memory remove tools
http://www.ibm.com/developerworks/wikis/display/LinuxP/powerpc-utils

+What: /sys/devices/system/memory/probe
+Date: Nov 2010
+Contact: Linux Memory Management list <linux-mm@kvack.org>
+Description:
+ memory probe interface is for memory hotplug emulation. it is a software
+ interface to test memory hotplug. We provide the start address and numa
+ nodes id, it will add a memory section to the specified node.
+
+ Add a memory section(128M) to node 3(boots with mem=1024m)
+ echo 0x40000000,3 > memory/probe
+
+ A more friendly method
+ echo 3g > memory/probe
+ echo 1024m,3 > memory/probe
+
+ Another format suggested by Dave Hansen:
+ echo physical_address=0x40000000 numa_node=3 > memory/probe

What: /sys/devices/system/memoryX/nodeY
Date: October 2009
Index: linux-hpe4/arch/x86/Kconfig
===================================================================
--- linux-hpe4.orig/arch/x86/Kconfig 2010-11-17 09:00:50.673463029 +0800
+++ linux-hpe4/arch/x86/Kconfig 2010-11-17 09:01:10.282838829 +0800
@@ -1276,10 +1276,6 @@
def_bool y
depends on ARCH_SPARSEMEM_ENABLE

-config ARCH_MEMORY_PROBE
- def_bool X86_64
- depends on MEMORY_HOTPLUG
-
config ILLEGAL_POINTER_VALUE
hex
default 0 if X86_32
Index: linux-hpe4/drivers/base/memory.c
===================================================================
--- linux-hpe4.orig/drivers/base/memory.c 2010-11-17 09:00:50.673463029 +0800
+++ linux-hpe4/drivers/base/memory.c 2010-11-17 09:01:10.302838792 +0800
@@ -329,6 +329,9 @@
* 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.
+ *
+ * Parameter format 1: physical_address,numa_node
+ * Parameter format 2: physical_address=0x40000000 numa_node=3
*/
#ifdef CONFIG_ARCH_MEMORY_PROBE
static ssize_t
@@ -336,13 +339,53 @@
const char *buf, size_t count)
{
u64 phys_addr;
- int nid;
+ int nid = 0;
int ret;
+ char *p = NULL, *q = NULL;
+ /* format: physical_address=0x40000000 numa_node=3 */
+ p = strchr(buf, '=');
+ if (p != NULL) {
+ *p = '\0';
+ q = strchr(buf, ' ');
+ if (q == NULL) {
+ if (strcmp(buf, "physical_address") != 0)
+ ret = -EPERM;
+ else
+ phys_addr = memparse(p+1, NULL);
+ } else {
+ *q++ = '\0';
+ p = strchr(q, '=');
+ if (strcmp(buf, "physical_address") == 0)
+ phys_addr = memparse(p+1, NULL);
+ if (strcmp(buf, "numa_node") == 0)
+ nid = simple_strtoul(p+1, NULL, 0);
+ if (strcmp(q, "physical_address") == 0)
+ phys_addr = memparse(p+1, NULL);
+ if (strcmp(q, "numa_node") == 0)
+ nid = simple_strtoul(p+1, NULL, 0);
+ }
+ } else { /* physical_address,numa_node */
+ p = strchr(buf, ',');
+ if (p != NULL && strlen(p+1) > 0) {
+ /* nid specified */
+ *p++ = '\0';
+ nid = simple_strtoul(p, NULL, 0);
+ phys_addr = memparse(buf, NULL);
+ } else {
+ phys_addr = memparse(buf, NULL);
+ nid = memory_add_physaddr_to_nid(phys_addr);
+ }
+ }

- phys_addr = simple_strtoull(buf, NULL, 0);
-
- nid = memory_add_physaddr_to_nid(phys_addr);
- ret = add_memory(nid, phys_addr, PAGES_PER_SECTION << PAGE_SHIFT);
+ if (nid < 0 || nid > nr_node_ids - 1) {
+ printk(KERN_ERR "Invalid node id %d(0<=nid<%d).\n", nid, nr_node_ids);
+ ret = -EPERM;
+ } else {
+ printk(KERN_INFO "Add a memory section to node: %d.\n", nid);
+ ret = add_memory(nid, phys_addr, PAGES_PER_SECTION << PAGE_SHIFT);
+ if (ret)
+ count = ret;
+ }

if (ret)
count = ret;
Index: linux-hpe4/mm/Kconfig
===================================================================
--- linux-hpe4.orig/mm/Kconfig 2010-11-17 09:01:10.212839478 +0800
+++ linux-hpe4/mm/Kconfig 2010-11-17 09:01:10.302838792 +0800
@@ -173,6 +173,17 @@
is for cpu hot-add/hot-remove to specified node in software method.
This is for debuging and testing purpose

+config ARCH_MEMORY_PROBE
+ def_bool y
+ bool "Memory hotplug emulation"
+ depends on NUMA_HOTPLUG_EMU
+ ---help---
+ Enable memory hotplug emulation. Reserve memory with grub parameter
+ "mem=N"(such as mem=1024M), where N is the initial memory size, the
+ rest physical memory will be removed from e820 table; the memory probe
+ interface is for memory hot-add to specified node in software method.
+ This is for debuging and testing purpose
+
#
# If we have space for more page flags then we can enable additional
# optimizations and functionality.
--
Thanks & Regards,
Shaohui




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