Re: [PATCH] Register sysfs file for hotpluged new node

From: Yasunori Goto
Date: Wed May 17 2006 - 01:56:56 EST

> On Tue, 2006-05-16 at 21:23 +0900, Yasunori Goto wrote:
> > + /*
> > + * register this node to sysfs.
> > + * this is depends on topology. So each arch has its own.
> > + */
> > + if (new_pgdat){
> > + ret = arch_register_node(nid);
> > + BUG_ON(ret);
> > + }
> Please don't do BUG_ON()s for things like this. Memory hotplug _should_
> handle failures from top to bottom and not screw you over. It isn't a
> crime or a bug to be out of memory.

Basically, I would like to agree.
But, there is no way to roll back from here now.
If online_node_map is set once, then new pgdat might be touched.
There is no way to disable them.

And I suppose it is not good thing that creating sysfs file of new node
before setting online_node_map. It means user interface is shown
before system initialization completion.

(In addition, remove_memory() is not yet....)

If return code of arch_register_node is ignored,
cpu hotplug will work without new node's file.
When we tried cpu hotplug on it, it was cause of stack dump at last.

> Have you run this past the ppc maintainers?

Nope. I just tried cross compile.
I want powerpc box for test....


Yasunori Goto

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