From: Haicheng Li <haicheng.li@xxxxxxxxxxxxxxx>
Subject: hotplug emulator: Userland interface to hotplug-add fake offlined nodes.
Add a sysfs entry "probe" under /sys/devices/system/node/:
- to show all fake offlined nodes:
$ cat /sys/devices/system/node/probe
- to hotadd a fake offlined node, e.g. nodeid is N:
$ echo N > /sys/devices/system/node/probe
Signed-off-by: Haicheng Li <haicheng.li@xxxxxxxxxxxxxxx>
Signed-off-by: Shaohui Zheng <shaohui.zheng@xxxxxxxxx>
---
diff --git a/drivers/base/node.c b/drivers/base/node.c
index 2872e86..d21bea2 100644
--- a/drivers/base/node.c
+++ b/drivers/base/node.c
@@ -538,6 +538,25 @@ void unregister_one_node(int nid)
unregister_node(&node_devices[nid]);
}
+#ifdef CONFIG_NODE_HOTPLUG_EMU
+static ssize_t store_nodes_probe(struct sysdev_class *class,
+ struct sysdev_class_attribute *attr,
+ const char *buf, size_t count)
+{
+ long nid;
+
+ strict_strtol(buf, 0, &nid);
+ if (nid < 0 || nid > nr_node_ids - 1) {
+ printk(KERN_ERR "Invalid NUMA node id: %ld (0 <= nid < %d).\n",
+ nid, nr_node_ids);
+ return -EPERM;
+ }
+ hotadd_hidden_nodes(nid);
+
+ return count;
+}
+#endif
+
/*
* node states attributes
*/
@@ -566,26 +585,35 @@ static ssize_t show_node_state(struct sysdev_class *class,
return print_nodes_state(na->state, buf);
}
-#define _NODE_ATTR(name, state) \
+#define _NODE_ATTR_RO(name, state) \
{ _SYSDEV_CLASS_ATTR(name, 0444, show_node_state, NULL), state }
+#define _NODE_ATTR_RW(name, store_func, state) \
+ { _SYSDEV_CLASS_ATTR(name, 0644, show_node_state, store_func), state }
+
static struct node_attr node_state_attr[] = {
- _NODE_ATTR(possible, N_POSSIBLE),
- _NODE_ATTR(online, N_ONLINE),
- _NODE_ATTR(has_normal_memory, N_NORMAL_MEMORY),
- _NODE_ATTR(has_cpu, N_CPU),
+ [N_POSSIBLE] = _NODE_ATTR_RO(possible, N_POSSIBLE),
+#ifdef CONFIG_NODE_HOTPLUG_EMU
+ [N_HIDDEN] = _NODE_ATTR_RW(probe, store_nodes_probe, N_HIDDEN),
+#endif
+ [N_ONLINE] = _NODE_ATTR_RO(online, N_ONLINE),
+ [N_NORMAL_MEMORY] = _NODE_ATTR_RO(has_normal_memory, N_NORMAL_MEMORY),
#ifdef CONFIG_HIGHMEM
- _NODE_ATTR(has_high_memory, N_HIGH_MEMORY),
+ [N_HIGH_MEMORY] = _NODE_ATTR_RO(has_high_memory, N_HIGH_MEMORY),
#endif
+ [N_CPU] = _NODE_ATTR_RO(has_cpu, N_CPU),
};
static struct sysdev_class_attribute *node_state_attrs[] = {
- &node_state_attr[0].attr,
- &node_state_attr[1].attr,
- &node_state_attr[2].attr,
- &node_state_attr[3].attr,
+ &node_state_attr[N_POSSIBLE].attr,
+#ifdef CONFIG_NODE_HOTPLUG_EMU
+ &node_state_attr[N_HIDDEN].attr,
+#endif
+ &node_state_attr[N_ONLINE].attr,
+ &node_state_attr[N_NORMAL_MEMORY].attr,
+ &node_state_attr[N_CPU].attr,
#ifdef CONFIG_HIGHMEM
- &node_state_attr[4].attr,
+ &node_state_attr[N_HIGH_MEMORY].attr,
#endif
NULL
};
diff --git a/mm/Kconfig b/mm/Kconfig
index f0fb912..a01a679 100644
--- a/mm/Kconfig
+++ b/mm/Kconfig
@@ -147,6 +147,21 @@ config MEMORY_HOTREMOVE
depends on MEMORY_HOTPLUG && ARCH_ENABLE_MEMORY_HOTREMOVE
depends on MIGRATION
+config NUMA_HOTPLUG_EMU
+ bool "NUMA hotplug emulator"
+ depends on X86_64 && NUMA && MEMORY_HOTPLUG
+
+ ---help---
+
+config NODE_HOTPLUG_EMU
+ bool "Node hotplug emulation"
+ depends on NUMA_HOTPLUG_EMU && MEMORY_HOTPLUG
+ ---help---
+ Enable Node hotplug emulation. The machine will be setup with
+ hidden virtual nodes when booted with "numa=hide=N*size", where
+ N is the number of hidden nodes, size is the memory size per
+ hidden node. This is only useful for debugging.
+
#
# If we have space for more page flags then we can enable additional
# optimizations and functionality.
--
Thanks & Regards,
Shaohui
--
To unsubscribe from this list: send the line "unsubscribe linux-hotplug" in
the body of a message to majordomo@xxxxxxxxxxxxxxx
More majordomo info at http://vger.kernel.org/majordomo-info.html
