Re: build error: sparsemem + SLOB

Hugh Dickins
2006-11-21T13:31:24Z

On Mon, 20 Nov 2006, Christoph Lameter wrote:
> On Mon, 20 Nov 2006, Hugh Dickins wrote:
>
> > Lucky so far. Well, we'd actually have to be quite unlucky to ever
> > see what page_lock_anon_vma/SLAB_DESTROY_BY_RCU are guarding against.
>
> Hmmm... I had to repeatedly fix my new slab code when I broke
> DESTROY_BY_RCU. The machine wont even boot if that is not done right.

I'm intrigued, and a little worried: won't even boot! Do you have some
particular SGI monster in mind when you say "The machine"? Why was such a
narrow (preemption disabled) window in page_lock_anon_vma so vulnerable?
Swamped with many or slow-to-handle interrupts? Or was your slab code
grossly over-eager in trying to free pages?

Hugh