Re: [PATCH] memory hotplug disable boot option

KAMEZAWA Hiroyuki
2010-06-30T00:37:30Z

On Tue, 29 Jun 2010 11:04:15 -0700
Greg KH <gregkh@suse.de> wrote:

> On Tue, Jun 29, 2010 at 09:03:04AM -0700, Dave Hansen wrote:
> > On Tue, 2010-06-29 at 11:56 +0900, KOSAKI Motohiro wrote:
> > > > 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.
> >
> > >From the mouth of the kernel dumbass who coded this up: it's not the
> > firmware's fault. We shouldn't punt this to them, and the proper fix
> > _isn't_ in the firmware, plus they may have other more fundamental
> > reasons to keep the LMB sizes what they are.
>
> I agree, this should be fixed in the api to userspace, having this many
> sysfs directories and/or files is just looney.
>
> thanks,
>

Hmm, adding
CONFIG_NEW_MEMORY_SYSFS_LAYOUT or
memory_sysfs_layout=small boot option
and adding a scalable interface for large scale machines ?
I'd like to consider something..

Thanks,
-Kame