Re: [PATCH] memory hotplug disable boot option

KOSAKI Motohiro
2010-06-29T02:56:23Z

> On Mon, 2010-06-28 at 08:44 -0700, Greg KH wrote:
> > > The directories being created are the standard directories, one for each of the memory
> > > sections present at boot. I think the most used files in each of these directories
> > > is the state and removable file used to do memory hotplug.
> >
> > And perhaps we shouldn't really be creating so many directories? Why
> > not work with the memory hotplug developers to change their interface to
> > not abuse sysfs in such a manner?
>
> Heh, it wasn't abuse until we got this much memory. But, I think this
> one is pretty much 100% my fault.
>
> Nathan, I think the right fix here is probably to untie sysfs from the
> sections a bit. We should be able to have sysfs dirs that represent
> more than one contiguous SECTION_SIZE area of memory.

Why do we need abi breakage? Yourself talked about we guess ppc don't
actually need 16MB section. I think IBM folks have to confirm it.
If our guessing is correct, the firmware fixing is only necessary.

Thats said, I don't 100% refuse your idea. it's interesting. but,
In generical I hate _unncessary_ abi change.

> It will mean re-teaching some of the tools how things work. They'll
> have to know that you can split mem sections, and we'll have to come up
> with a way to do the splitting.
>
> Does ppc *really* remove 16MB sections of RAM these days? It's probably
> worth checking with the firmware folks to see what the limits are in
> practice.
>
> -- Dave
>