NUMA hotplug emulator

RFC Superseded Shaohui Zheng 6 participants 16 messages May 13, 2010 – May 24, 2010

Subsystems (3)

Memory management x86 Driver core

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Shaohui Zheng

author

2010-05-13 11:52 UTC #0 lore raw

RFC 3/7 NUMA 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 <[email protected]>

Signed-off-by Shaohui Zheng <[email protected]>

---

arch/x86/Kconfig +14 -0

index 9458685..2c078c8 100644
@@ -1214,6 +1214,20 @@ config NUMA_EMU
 	  into virtual nodes when booted with "numa=fake=N", where N is the
 	  number of nodes. This is only useful for debugging.
 
+config NUMA_HOTPLUG_EMU
+	bool "NUMA hotplug emulator"
+	depends on X86_64 && NUMA && 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.
+
 config NODES_SHIFT
 	int "Maximum NUMA Nodes (as a power of 2)" if !MAXSMP
 	range 1 10

drivers/base/node.c +40 ~~-11~~

72 lines not on this page · raw message

Signature · 2 lines

Thanks & Regards,
Shaohui

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 <[email protected]>

Signed-off-by Shaohui Zheng <[email protected]>

---

arch/x86/Kconfig +14 -0

index 9458685..2c078c8 100644
@@ -1214,6 +1214,20 @@ config NUMA_EMU
 	  into virtual nodes when booted with "numa=fake=N", where N is the
 	  number of nodes. This is only useful for debugging.
 
+config NUMA_HOTPLUG_EMU
+	bool "NUMA hotplug emulator"
+	depends on X86_64 && NUMA && 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.
+
 config NODES_SHIFT
 	int "Maximum NUMA Nodes (as a power of 2)" if !MAXSMP
 	range 1 10

drivers/base/node.c +40 ~~-11~~

72 lines not on this page · raw message

Greg KH

2010-05-13 16:59 UTC #1 lore raw

Quoted 1 line · Shaohui Zheng

Userland interface to hotplug-add fake offlined nodes.

Why include 2 copies of the patch in one email?

Quoted 7 lines

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

As you are trying to add a new sysfs file, please create the matching Documentation/ABI/ file as well.

Also note that sysfs files are "one value per file", which I don't think this file follows, right?

thanks,

greg k-h

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Dave Hansen

2010-05-13 17:55 UTC #2 lore raw

Quoted 5 lines · Greg KH

Quoted 5 lines
Add a sysfs entry "probe" under /sys/devices/system/node/:
- to show all fake offlined nodes:
    $ cat /sys/devices/system/node/probe

Quoted 8 lines

Quoted 2 lines
- to hotadd a fake offlined node, e.g. nodeid is N:
    $ echo N > /sys/devices/system/node/probe
As you are trying to add a new sysfs file, please create the matching Documentation/ABI/ file as well.
Also note that sysfs files are "one value per file", which I don't think this file follows, right?

I think in this case, it was meant to be a list of acceptable parameters rather than a set of values, kinda like /sys/power/state. Instead, I guess we could have:

	/sys/devices/system/node/probeable/3
	/sys/devices/system/node/probeable/43
	/sys/devices/system/node/probeable/65
	/sys/devices/system/node/probeable/5145

and the knowledge that you need to pick one of those to echo into /sys/devices/system/node/probe. But, it's a lot more self explanatory if you 'cat /sys/devices/system/node/probe', and then pick one of those to echo back into the file.

Seems like a decent place to violate the "rule". :)

-- Dave

Greg KH

2010-05-13 18:45 UTC #3 lore raw

Quoted 24 lines · Dave Hansen

Quoted 5 lines · Greg KH
Quoted 5 lines
Add a sysfs entry "probe" under /sys/devices/system/node/:
- to show all fake offlined nodes:
    $ cat /sys/devices/system/node/probe
Quoted 8 lines
Quoted 2 lines
- to hotadd a fake offlined node, e.g. nodeid is N:
    $ echo N > /sys/devices/system/node/probe
As you are trying to add a new sysfs file, please create the matching Documentation/ABI/ file as well.
Also note that sysfs files are "one value per file", which I don't think this file follows, right?
I think in this case, it was meant to be a list of acceptable parameters rather than a set of values, kinda like /sys/power/state. Instead, I guess we could have:
	/sys/devices/system/node/probeable/3
	/sys/devices/system/node/probeable/43
	/sys/devices/system/node/probeable/65
	/sys/devices/system/node/probeable/5145

Quoted 6 lines

and the knowledge that you need to pick one of those to echo into /sys/devices/system/node/probe. But, it's a lot more self explanatory if you 'cat /sys/devices/system/node/probe', and then pick one of those to echo back into the file.
Seems like a decent place to violate the "rule". :)

How big would this "list" be? What will it look like exactly?

thanks,

greg k-h

Haicheng Li

2010-05-14 02:13 UTC #4 lore raw

In reply to Dave Hansen

Quoted 8 lines · Dave Hansen

Quoted 7 lines · Greg KH
Quoted 7 lines
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

Quoted 8 lines

Quoted 5 lines
As you are trying to add a new sysfs file, please create the matching Documentation/ABI/ file as well.
Also note that sysfs files are "one value per file", which I don't think this file follows, right?
I think in this case, it was meant to be a list of acceptable parameters rather than a set of values, kinda like /sys/power/state.

Right.

Quoted 9 lines

Instead, I guess we could have:
	/sys/devices/system/node/probeable/3
	/sys/devices/system/node/probeable/43
	/sys/devices/system/node/probeable/65
	/sys/devices/system/node/probeable/5145
and the knowledge that you need to pick one of those to echo into /sys/devices/system/node/probe.

I think this way would make things complex if we just want to show user which node could be hotadded.

Quoted 3 lines

But, it's a lot more self
explanatory if you 'cat /sys/devices/system/node/probe', and then pick one of those to echo back into the file.

agreed.

Quoted 1 line

Seems like a decent place to violate the "rule". :)

Shaohui Zheng

author

2010-05-14 01:49 UTC #5 lore raw

In reply to Greg KH

Quoted 4 lines · Greg KH

Quoted 1 line · Shaohui Zheng
Userland interface to hotplug-add fake offlined nodes.
Why include 2 copies of the patch in one email?

I always try to attach the patch as attachment, it is the same with the mail content, I guess it should take convenience when you need to save the patch to local, it might be a bad habbit, I will be careful when I send patch next time. thanks for the reminding.

Quoted 11 lines

Quoted 8 lines
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
As you are trying to add a new sysfs file, please create the matching Documentation/ABI/ file as well.

Agree, We will document it in.

Quoted 3 lines

Also note that sysfs files are "one value per file", which I don't think this file follows, right?

Agree, the cpu/probe interface should write only, and we should create another file to indicate the hidden nodes, such as cpu/hidden. We will follow this rule when we send the formal patch.

Thanks greg's comments so much, have a nice day.

Quoted 4 lines

thanks,
greg k-h

Signature · 2 lines

Thanks & Regards,
Shaohui

Wu Fengguang

2010-05-14 02:01 UTC #6 lore raw

Quoted 9 lines · Shaohui

Quoted 4 lines · Greg KH
Quoted 1 line · Shaohui Zheng
Userland interface to hotplug-add fake offlined nodes.
Why include 2 copies of the patch in one email?
I always try to attach the patch as attachment, it is the same with the mail content, I guess it should take convenience when you need to save the patch to local, it might be a bad habbit, I will be careful when I send patch next time. thanks for the reminding.

Shaohui, git/quilt are great tools for submitting patch series.

Quoted 15 lines

Quoted 11 lines
Quoted 8 lines
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
As you are trying to add a new sysfs file, please create the matching Documentation/ABI/ file as well.
Agree, We will document it in.
Quoted 1 line

Quoted 6 lines

Quoted 2 lines
Also note that sysfs files are "one value per file", which I don't think this file follows, right?
Agree, the cpu/probe interface should write only, and we should create another file to indicate the hidden nodes, such as cpu/hidden. We will follow this rule when we send the formal patch.

I'd prefer to avoid new interfaces if not absolutely necessary.

Thanks,
Fengguang

Shaohui Zheng

author

2010-05-14 02:15 UTC #7 lore raw

Quoted 5 lines · Wu Fengguang

Quoted 4 lines · Shaohui
Quoted 3 lines · Greg KH
Quoted 1 line · Shaohui Zheng
Userland interface to hotplug-add fake offlined nodes.

Quoted 7 lines

Quoted 5 lines
Quoted 1 line
Why include 2 copies of the patch in one email?
I always try to attach the patch as attachment, it is the same with the mail content, I guess it should take convenience when you need to save the patch to local, it might be a bad habbit, I will be careful when I send patch next time. thanks for the reminding.
Shaohui, git/quilt are great tools for submitting patch series.

Thanks fengguang, I am the new fish in LKML, so I send the patches manually one by one, I will try this tool next time.

Quoted 27 lines

Quoted 16 lines
Quoted 4 lines
Quoted 4 lines
Add a sysfs entry "probe" under /sys/devices/system/node/:
Quoted 8 lines
Quoted 5 lines
- 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
As you are trying to add a new sysfs file, please create the matching Documentation/ABI/ file as well.
Agree, We will document it in.
Quoted 1 line
Quoted 6 lines
Quoted 2 lines
Also note that sysfs files are "one value per file", which I don't think this file follows, right?
Agree, the cpu/probe interface should write only, and we should create another file to indicate the hidden nodes, such as cpu/hidden. We will follow this rule when we send the formal patch.
I'd prefer to avoid new interfaces if not absolutely necessary.
Thanks,
Fengguang

Signature · 8 lines

Thanks & Regards,
Shaohui

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Haicheng Li

2010-05-14 02:01 UTC #8 lore raw

In reply to Greg KH

Quoted 10 lines · Greg KH

Quoted 7 lines
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
As you are trying to add a new sysfs file, please create the matching Documentation/ABI/ file as well.

Yes, we missed it. thank you.

Quoted 2 lines

Also note that sysfs files are "one value per file", which I don't think this file follows, right?

Sorry, we didn't make the descriptions clear enough.
It should follow "one value per file". It intends to show acceptable parameters.

For example, if we have 4 fake offlined nodes, like node 2-5, then:

  $ cat /sys/devices/system/node/probe
    2-5

Then user hotadds node3 to system:

  $ echo 3 > /sys/devices/system/node/probe
  $ cat /sys/devices/system/node/probe
    2,4-5

-haicheng

Haicheng Li

2010-05-14 03:31 UTC #9 lore raw

In reply to Shaohui Zheng

Quoted 21 lines · Shaohui Zheng

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 <[email protected]>
Signed-off-by Shaohui Zheng <[email protected]>
---
drivers/base/node.c +0 -0
index 057979a..a0be257 100644
@@ -535,6 +535,26 @@ void unregister_one_node(int nid)
 	unregister_node(&node_devices[nid]);
 }
 

drivers/base/node.c void unregister_one_node(int nid) · line 547

Quoted 10 lines

drivers/base/node.c +10 -0

+#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;
+	int ret;
+
+	strict_strtol(buf, 0, &nid);
+	if (nid < 0 || nid > nr_node_ids - 1) {

Shaohui,

In fact, no need to do such check here, hotadd_hidden_nodes() can handle such invalid parameter by itself.

drivers/base/node.c void unregister_one_node(int nid) · line 550

Quoted 3 lines

drivers/base/node.c +3 -0

+		printk(KERN_ERR "Invalid NUMA node id: %d (0 <= nid < %d).\n",
+			nid, nr_node_ids);
+		return -EPERM;

Per Andi's earlier review comments, -EPERM is odd, we'd fix it.

drivers/base/node.c void unregister_one_node(int nid) · line 556

Quoted 6 lines

drivers/base/node.c +6 -0

+	}
+	hotadd_hidden_nodes(nid);
+
+	return count;
+}
+#endif

Pls. replace it with following code:

+#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;
+ int ret;
+
+ ret = strict_strtol(buf, 0, &nid);
+ if (ret == -EINVAL)
+ return ret;
+
+ ret = hotadd_hidden_nodes(nid);
+ if (!ret)
+ return count;
+ else
+ return -EIO;
+}
+#endif

-haicheng

Wu Fengguang

2010-05-14 04:11 UTC #10 lore raw

Quoted 11 lines

Pls. replace it with following code:

drivers/base/node.c +9 -0

+#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;
+       int ret;
+
+       ret = strict_strtol(buf, 0, &nid);

drivers/base/node.c void unregister_one_node(int nid) · line 556

Quoted 10 lines

drivers/base/node.c +10 -0

+       if (ret == -EINVAL)
+               return ret;
+
+       ret = hotadd_hidden_nodes(nid);
+       if (!ret)
+               return count;
+       else
+               return -EIO;
+}
+#endif

How about this?

       err = strict_strtol(buf, 0, &nid);
       if (err < 0)
               return err;

       err = hotadd_hidden_nodes(nid);
       if (err < 0)
               return err;

       return count;

Thanks,
Fengguang

Shaohui Zheng

author

2010-05-14 05:24 UTC #11 lore raw

Quoted 34 lines · Wu Fengguang

Quoted 11 lines

Pls. replace it with following code:

drivers/base/node.c +9 -0

+#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;
+       int ret;
+
+       ret = strict_strtol(buf, 0, &nid);

drivers/base/node.c void unregister_one_node(int nid) · line 556

Quoted 10 lines

drivers/base/node.c +10 -0

+       if (ret == -EINVAL)
+               return ret;
+
+       ret = hotadd_hidden_nodes(nid);
+       if (!ret)
+               return count;
+       else
+               return -EIO;
+}
+#endif

How about this?

       err = strict_strtol(buf, 0, &nid);
       if (err < 0)
               return err;

       err = hotadd_hidden_nodes(nid);
       if (err < 0)
               return err;

       return count;

Quoted 2 lines

Thanks,
Fengguang

Both seems good.

Haicheng's code is prefered, since it was already reviewed.

Signature · 8 lines

Thanks & Regards,
Shaohui

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Haicheng Li

2010-05-14 05:32 UTC #12 lore raw

In reply to Wu Fengguang

Quoted 24 lines · Wu Fengguang

Quoted 11 lines

Pls. replace it with following code:

drivers/base/node.c +9 -0

+#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;
+       int ret;
+
+       ret = strict_strtol(buf, 0, &nid);

drivers/base/node.c void unregister_one_node(int nid) · line 556

Quoted 10 lines

drivers/base/node.c +10 -0

+       if (ret == -EINVAL)
+               return ret;
+
+       ret = hotadd_hidden_nodes(nid);
+       if (!ret)
+               return count;
+       else
+               return -EIO;
+}
+#endif

How about this?

Quoted 3 lines

       err = strict_strtol(buf, 0, &nid);
       if (err < 0)
               return err;

other negative value would be odd here.

Quoted 3 lines

       err = hotadd_hidden_nodes(nid);
       if (err < 0)
               return err;

hotadd_hidden_nodes could return -EEXIST, which is also odd here, right?

Quoted 4 lines

       return count;
Thanks,
Fengguang

Wu Fengguang

2010-05-14 05:52 UTC #13 lore raw

Quoted 25 lines · Haicheng Li

Quoted 24 lines · Wu Fengguang

Quoted 11 lines

Pls. replace it with following code:

drivers/base/node.c +9 -0

+#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;
+       int ret;
+
+       ret = strict_strtol(buf, 0, &nid);

drivers/base/node.c void unregister_one_node(int nid) · line 556

Quoted 10 lines

drivers/base/node.c +10 -0

+       if (ret == -EINVAL)
+               return ret;
+
+       ret = hotadd_hidden_nodes(nid);
+       if (!ret)
+               return count;
+       else
+               return -EIO;
+}
+#endif

How about this?

Quoted 5 lines

Quoted 3 lines
       err = strict_strtol(buf, 0, &nid);
       if (err < 0)
               return err;
other negative value would be odd here.

Yes, strict_strtoul() will be better.

Quoted 5 lines

Quoted 3 lines
       err = hotadd_hidden_nodes(nid);
       if (err < 0)
               return err;
hotadd_hidden_nodes could return -EEXIST, which is also odd here, right?

Why not? write(2) says "Other errors may occur, depending on the object connected to fd."

Thanks,
Fengguang

Ankita Garg

2010-05-21 10:11 UTC #14 lore raw

In reply to Shaohui Zheng

Hi,

Quoted 25 lines · Shaohui Zheng

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 <[email protected]>
Signed-off-by Shaohui Zheng <[email protected]>
---
arch/x86/Kconfig +4 -0
index 9458685..2c078c8 100644
@@ -1214,6 +1214,20 @@ config NUMA_EMU
 	  into virtual nodes when booted with "numa=fake=N", where N is the
 	  number of nodes. This is only useful for debugging.
 
+config NUMA_HOTPLUG_EMU
+	bool "NUMA hotplug emulator"
+	depends on X86_64 && NUMA && HOTPLUG
+	---help---

arch/x86/Kconfig config NUMA_EMU · line 1230

Quoted 10 lines

arch/x86/Kconfig +10 -0

+
+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.
+

The above dependencies do not work as expected. I could configure NUMA_HOTPLUG_EMU & NODE_HOTPLUG_EMU without having MEMORY_HOTPLUG turned on. By pushing the above definition below SPARSEMEM and memory hot add and remove, the dependencies could be sorted out.

Signature · 5 lines

Regards,                                                                        
Ankita Garg ([email protected])                                                 
Linux Technology Center                                                         
IBM India Systems & Technology Labs,                                            
Bangalore, India

Shaohui Zheng

author

2010-05-24 01:58 UTC #15 lore raw

Quoted 35 lines · Ankita Garg

Hi,
Quoted 32 lines · Shaohui Zheng
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 <[email protected]>
Signed-off-by Shaohui Zheng <[email protected]>
---
arch/x86/Kconfig +11 -0
index 9458685..2c078c8 100644
@@ -1214,6 +1214,20 @@ config NUMA_EMU
 	  into virtual nodes when booted with "numa=fake=N", where N is the
 	  number of nodes. This is only useful for debugging.
 
+config NUMA_HOTPLUG_EMU
+	bool "NUMA hotplug emulator"
+	depends on X86_64 && NUMA && 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

Quoted 8 lines

arch/x86/Kconfig config NUMA_EMU · line 1230
Quoted 3 lines
arch/x86/Kconfig +3 -0
+	  N is the number of hidden nodes, size is the memory size per
+	  hidden node. This is only useful for debugging.
+
The above dependencies do not work as expected. I could configure NUMA_HOTPLUG_EMU & NODE_HOTPLUG_EMU without having MEMORY_HOTPLUG turned on. By pushing the above definition below SPARSEMEM and memory hot add and remove, the dependencies could be sorted out.

Ankita,
The emulation code was tested by many times, but we did not try each
combination for the new options, good catching.
We will includes your suggestion in the formal patch. thanks so much.

Quoted 7 lines

Signature · 6 lines

-- 
Regards,                                                                        
Ankita Garg ([email protected])                                                 
Linux Technology Center                                                         
IBM India Systems & Technology Labs,                                            
Bangalore, India

Signature · 8 lines

Thanks & Regards,
Shaohui

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