Re: Add prefetch switch stack hook in scheduler function

From: Nick Piggin
Date: Thu Jul 28 2005 - 03:35:53 EST


Keith Owens wrote:
On Thu, 28 Jul 2005 09:41:18 +0200,
Ingo Molnar <mingo@xxxxxxx> 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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