Re: [Patch](memory hotplug) Hot-add with sparsemem-vmemmap

[Yasunori Goto <y-goto@jp.fujitsu.com>]

> On Fri, 17 Aug 2007, Yasunori Goto wrote:
> 
> > Todo: # Even if this patch is applied, the message "[xxxx-xxxx] potential
> >         offnode page_structs" is displayed. To allocate memmap on its node,
> >         memmap (and pgdat) must be initialized itself like chicken and
> >         egg relationship.
> 
> Hmmmm.... You need to create something like the bootmem allocator?

Right. I suppose it may be better.

> 
> Or relocate the memory map later.

I suppose relocation will be messy way.....

> 
> Or just add a small piece of memory first so that only one memmap block is 
> placed off line?

I'm not sure what you mean about "add small piece".
Do you mean reservation for memmap/pgdat block first?
Then this is second choice.

Even if either is chosen, kernel must remember memmap's place until
unplug. I'll try easier way.

>  
> >       # vmemmap_unpopulate will be necessary for followings.
> >          - For cancel hot-add due to error.
> >          - For unplug.
> > 
> > Please comment.
> 
> Looks fine to me.

Thanks :-)


-- 
Yasunori Goto 


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