linux-kernel - [RFC, 6/7] NUMA hotplug emulator

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Date:	Thu, 13 May 2010 20:00:16 +0800
From:	Shaohui Zheng <shaohui.zheng@...el.com>
To:	akpm@...ux-foundation.org, linux-mm@...ck.org
Cc:	Thomas Gleixner <tglx@...utronix.de>,
	Ingo Molnar <mingo@...hat.com>,
	"H. Peter Anvin" <hpa@...or.com>, x86@...nel.org,
	Andi Kleen <ak@...ux.intel.com>,
	Andrew Morton <akpm@...ux-foundation.org>,
	Hidetoshi Seto <seto.hidetoshi@...fujitsu.com>,
	Greg Kroah-Hartman <gregkh@...e.de>,
	Wu Fengguang <fengguang.wu@...el.com>,
	Heiko Carstens <heiko.carstens@...ibm.com>,
	linux-kernel@...r.kernel.org, haicheng.li@...ux.intel.com,
	shaohui.zheng@...ux.intel.com
Subject: [RFC, 6/7] NUMA hotplug emulator 

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.

Signed-off-by: Shaohui Zheng <shaohui.zheng@...el.com>
Signed-off-by: Haicheng Li <haicheng.li@...el.com>
Signed-off-by: Wu Fengguang <fengguang.wu@...el.com>
---
diff --git a/arch/x86/Kconfig b/arch/x86/Kconfig
index 54ccb0d..787024f 100644
--- a/arch/x86/Kconfig
+++ b/arch/x86/Kconfig
@@ -1239,6 +1239,17 @@ config ARCH_CPU_PROBE_RELEASE
 	  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
+
 config NODES_SHIFT
 	int "Maximum NUMA Nodes (as a power of 2)" if !MAXSMP
 	range 1 10
diff --git a/drivers/base/memory.c b/drivers/base/memory.c
index 933442f..1c2d83d 100644
--- a/drivers/base/memory.c
+++ b/drivers/base/memory.c
@@ -329,6 +329,8 @@ static int block_size_init(void)
  * 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: start_addr, nid
  */
 #ifdef CONFIG_ARCH_MEMORY_PROBE
 static ssize_t
@@ -339,10 +341,26 @@ memory_probe_store(struct class *class, struct class_attribute *attr,
 	int nid;
 	int ret;
 
-	phys_addr = simple_strtoull(buf, NULL, 0);
+	char *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);
+	}
 
-	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);
+	} 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;
-- 
Thanks & Regards,
Shaohui


View attachment "006-hotplug-emulator-extend-memory-probe-interface-to-support-numa.patch" of type "text/x-diff" (2799 bytes)