Date: Sat, 5 Jun 2004 04:18:13 +0200
From: Andi Kleen <ak@suse.de>
To: Manfred Spraul <manfred@colorfullife.com>
Cc: akpm@osdl.org, linux-kernel@vger.kernel.org
Subject: Re: [PATCH] Use numa policy API for boot time policy
Message-Id: <20040605041813.75e2d22d.ak@suse.de>
In-Reply-To: <40C12865.9050803@colorfullife.com>
References: <20040605034356.1037d299.ak@suse.de>
	<40C12865.9050803@colorfullife.com>
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On Sat, 05 Jun 2004 03:56:53 +0200
Manfred Spraul <manfred@colorfullife.com> wrote:

> Andi Kleen wrote:
> 
> >Suggested by Manfred Spraul.
> >
> >__get_free_pages had a hack to do node interleaving allocation at boot time.
> >This patch sets an interleave process policy using the NUMA API for init
> >and the idle threads instead. Before entering the user space init the policy
> >is reset to default again. Result is the same.
> >
> >Advantage is less code and removing of a check from a fast path.
> >
> >Removes more code than it adds.
> >
> >I verified that the memory distribution after boot is roughly the same.
> >
> >  
> >
> 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.

But it sounds quite bogus anyways to move the complete hash tables
to another node anyways. It would probably be better to use vmalloc() 
and a interleaving mapping for it. Then you would get the NUMA bandwidth 
benefit even for accessing single tables.

-Andi
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