Re: [PATCH] [4/4] SLAB: Fix node add timer race in cache_reap

KAMEZAWA Hiroyuki
2010-03-01T02:03:14Z

On Fri, 26 Feb 2010 18:31:15 +0100
Andi Kleen <andi@firstfloor.org> wrote:

> On Fri, Feb 26, 2010 at 11:24:50AM -0600, Christoph Lameter wrote:
> > On Fri, 26 Feb 2010, Andi Kleen wrote:
> >
> > > > > Memory hotplug with node add never quite worked on x86 before,
> > > > > for various reasons not related to slab.
> > > >
> > > > Ok but why did things break in such a big way?
> > >
> > > 1) numa memory hotadd never worked
> >
> > Well Kamesan indicated that this worked if a cpu became online.
>
> I mean in the general case. There were tons of problems all over.
>
Then, it's cpu hotplug matter, not memory hotplug.
cpu hotplug callback should prepaare

l3 = searchp->nodelists[node];
BUG_ON(!l3);

before onlined. Rather than taking care of races.

Thanks,
-Kame