Re: [PATCH] [1/4] SLAB: Handle node-not-up case in fallback_alloc() v2

Nick Piggin
2010-02-15T10:22:28Z

On Mon, Feb 15, 2010 at 11:07:12AM +0100, Andi Kleen wrote:
> > This is a better way to go anyway because it really is a proper
> > "fallback" alloc. I think that possibly used to work (ie. kmem_getpages
> > would be able to pass -1 for the node there) but got broken along the
> > line.
>
> Thanks for the review.
>
> I should add there's still one open problem: in some cases
> the oom killer kicks in on hotadd. Still working on that one.
>
> In general hotadd was mighty bitrotted :/

Yes, that doesn't surprise me. I'm sure you can handle it, but send
some traces if you have problems.

> > Although it's not such a hot path to begin with, care to put a branch
> > annotation there?
>
> pointer == NULL is already default unlikely in gcc
>
> /* Pointers are usually not NULL. */
> DEF_PREDICTOR (PRED_POINTER, "pointer", HITRATE (85), 0)
> DEF_PREDICTOR (PRED_TREE_POINTER, "pointer (on trees)", HITRATE (85), 0)

Well I still prefer to annotate it. I think builtin expect is 99%.