Messages in this thread | | | Date | Thu, 28 Jul 2005 11:16:38 +0200 | From | Ingo Molnar <> | Subject | Re: Add prefetch switch stack hook in scheduler function |
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* Nick Piggin <nickpiggin@yahoo.com.au> wrote:
> >>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. > > > >such as? > > Not sure. thread_info? Maybe next->timestamp or some other fields in > next, something in next->mm?
next->thread_info we could and should prefetch - but from the generic scheduler code (see the patch i just sent).
i'm not sure what you mean by prefetching next->timestamp, it's an inline field to 'next', in the first cacheline of it, which we've already used so it's present. (If you mean the value of next->timestamp, that has no address meaning at all so would lead to unpredictable results on some arches.)
next->mm we might want to prefetch, but it's probably not worth it because we are referencing it too soon, in context_switch(). (while the kernel stack itself wont be referenced until the full context-switch is done) But might be worth trying - but even then, it should be done from the generic code, like the thread_info and kernel-stack prefetching.
> I didn't really have a concrete example, but in the interests of being > future proof...
i'd like to keep generic bits in generic code, and only move things to per-arch include files if absolutely necessary. next->mm is generic.
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