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Date: Thu, 28 Jul 2005 18:31:57 +1000
From: Nick Piggin <nickpiggin@yahoo.com.au>
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To: Keith Owens <kaos@ocs.com.au>
CC: Ingo Molnar <mingo@elte.hu>, David.Mosberger@acm.org,
       Andrew Morton <akpm@osdl.org>,
       "Chen, Kenneth W" <kenneth.w.chen@intel.com>,
       linux-kernel@vger.kernel.org, linux-ia64@vger.kernel.org
Subject: Re: Add prefetch switch stack hook in scheduler function
References: <10613.1122538148@kao2.melbourne.sgi.com>
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Keith Owens wrote:
> On Thu, 28 Jul 2005 09:41:18 +0200,
> Ingo Molnar <mingo@elte.hu> wrote:

>>i'm wondering, is the switch_stack at the same/similar place as
>>next->thread_info? If yes then we could simply do a
>>prefetch(next->thread_info).
> 
> 
> No, they can be up to 30K apart.  See include/asm-ia64/ptrace.h.
> thread_info is at ~0xda0, depending on the config.  The switch_stack
> can be as high as 0x7bd0 in the kernel stack, depending on why the task
> is sleeping.
> 

Just a minor point, I agree with David: I'd like it to be called
prefetch_task(), because some architecture may want to prefetch other
memory.

-- 
SUSE Labs, Novell Inc.

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