Re: [PATCH] Use numa policy API for boot time policy

[Andi Kleen <ak@suse.de>]

On Sat, 05 Jun 2004 12:20:53 +0200
Manfred Spraul <manfred@colorfullife.com> wrote:

> Andi Kleen wrote:
> 
> >On Sat, 05 Jun 2004 03:56:53 +0200
> >Manfred Spraul <manfred@colorfullife.com> wrote:
> >  
> >
> >>Does it work for order != 0 allocations? It's important that the big 
> >>hash tables do not end up all in node 0. AFAICS alloc_pages_current() 
> >>calls interleave_nodes() only for order==0 allocs.
> >>    
> >>
> >
> >That's correct. It will only work for order 0 allocations.
> >
> >  
> >
> What's the purpose of the "&& order == 0)" test for MPOL_INTERLEAVE in 
> alloc_pages_current?
> What would break if it's removed?

Nothing. Just the interleaving will not be very good.
Just the vma interleaving relies on order 0 right now.

But I would really try to use vmalloc() for this. In fact you don't
even need vmalloc_interleaved(), because the normal vmalloc allocation
together with the interleave policy should do the right thing.

> 
> And what about in_interrupt() allocations? During boot everything should 
> be interleaved - I'd modify default_policy to MPOL_INTERLEAVE instead of 
> setting process affinity.

Better don't do that. It may break some subtle assumptions.

I guess the in_interrupt() allocations will have to live with that.
They should be relatively rare.

In theory you could add a system_state == SYSTEM_BOOTING check again,
but polluting the fast path for this would be imho overkill.

-Andi