From: Shaohui Zheng <shaohui.zheng@xxxxxxxxx>
Add mem_hotplug/add_memory interface to support to memory hotplug emulation.
the reserved memory can be added into desired node with this interface.
Add a memory section(128M) to node 3(boots with mem=1024m)
echo 0x40000000,3 > mem_hotplug/add_memory
And more we make it friendly, it is possible to add memory to do
echo 3g > mem_hotplug/add_memory
echo 1024m,3 > mem_hotplug/add_memory
Another format suggested by Dave Hansen:
echo physical_address=0x40000000 numa_node=3 > mem_hotplug/add_memory
it is more explicit to show meaning of the parameters.
CC: David Rientjes <rientjes@xxxxxxxxxx>
CC: Dave Hansen <dave@xxxxxxxxxxxxxxxxxx>
Signed-off-by: Shaohui Zheng <shaohui.zheng@xxxxxxxxx>
Signed-off-by: Haicheng Li <haicheng.li@xxxxxxxxx>
Signed-off-by: Shaohui Zheng <shaohui.zheng@xxxxxxxxx>
---
Index: linux-hpe4/mm/memory_hotplug.c
===================================================================
--- linux-hpe4.orig/mm/memory_hotplug.c 2010-12-02 12:17:58.267622002 +0800
+++ linux-hpe4/mm/memory_hotplug.c 2010-12-02 12:18:02.507622002 +0800
@@ -983,4 +983,87 @@
}
module_init(node_debug_init);
+
+#ifdef CONFIG_ARCH_MEMORY_PROBE
+
+static ssize_t add_memory_store(struct file *file, const char __user *buf,
+ size_t count, loff_t *ppos)
+{
+ u64 phys_addr = 0;
+ 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);
+ }
+ }
+
+ 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;
+
+ return count;
+}
+
+static const struct file_operations add_memory_file_ops = {
+ .write = add_memory_store,
+ .llseek = generic_file_llseek,
+};
+
+static int __init memory_debug_init(void)
+{
+ if (!memhp_debug_root)
+ memhp_debug_root = debugfs_create_dir("mem_hotplug", NULL);
+ if (!memhp_debug_root)
+ return -ENOMEM;
+
+ if (!debugfs_create_file("add_memory", S_IWUSR, memhp_debug_root,
+ NULL, &add_memory_file_ops))
+ return -ENOMEM;
+
+ return 0;
+}
+
+module_init(memory_debug_init);
+
+#endif /* CONFIG_ARCH_MEMORY_PROBE */
#endif /* CONFIG_DEBUG_FS */
Index: linux-hpe4/Documentation/memory-hotplug.txt
===================================================================
--- linux-hpe4.orig/Documentation/memory-hotplug.txt 2010-12-02 12:18:17.387622002 +0800
+++ linux-hpe4/Documentation/memory-hotplug.txt 2010-12-02 12:30:51.717622000 +0800
@@ -19,6 +19,7 @@
4.1 Hardware(Firmware) Support
4.2 Notify memory hot-add event by hand
4.3 Node hotplug emulation
+ 4.4 Memory hotplug emulation
5. Logical Memory hot-add phase
5.1. State of memory
5.2. How to online memory
@@ -239,6 +240,30 @@
Once the new node has been added, it is possible to online the memory by
toggling the "state" of its memory section(s) as described in section 5.1.
+4.4 Memory hotplug emulation
+------------
+With debugfs, it is possible to test memory hotplug with software method, we
+can add memory section to desired node with add_memory interface. It is a much
+more powerful interface than "probe" described in section 4.2.
+
+The add_memory interface is located at "mem_hotplug/add_memory" at the debugfs
+mount point.
+
+Add a memory section(128M) to node 3(boots with mem=1024m)
+
+ echo 0x40000000,3 > mem_hotplug/add_memory
+
+And more we make it friendly, it is possible to add memory to do
+
+ echo 3g > mem_hotplug/add_memory
+ echo 1024m,3 > mem_hotplug/add_memory
+
+Another format suggested by Dave Hansen:
+
+ echo physical_address=0x40000000 numa_node=3 > mem_hotplug/add_memory
+
+Once the new memory section has been added, it is possible to online the memory
+by toggling the "state" described in section 5.1.
------------------------------
5. Logical Memory hot-add phase
--
Thanks & Regards,
Shaohui
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