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SubjectRe: [patch] sched: unlocked context-switches
>>>>> On Tue, 12 Apr 2005 08:42:53 +0200, Ingo Molnar <mingo@elte.hu> said:

Ingo> * David Mosberger <davidm@napali.hpl.hp.com> wrote:

>> Now, Ingo says that the order is reversed with his patch, i.e.,
>> switch_mm() happens after switch_to(). That means flush_tlb_mm()
>> may now see a current->active_mm which hasn't really been
>> activated yet. That should be OK since it would just mean that
>> we'd do an early (and duplicate) activate_context(). While it
>> does not give me a warm and fuzzy feeling to have this
>> inconsistent state be observable by interrupt-handlers (and, in
>> particular, IPI-handlers), I don't see any problem with it off
>> hand.

Ingo> thanks for the analysis. I fundamentally dont have any fuzzy
Ingo> feeling from having _any_ portion of the context-switch path
Ingo> nonatomic, but with more complex hardware it's just not
Ingo> possible it seems.

No kidding! ;-)

I _think_ the change is OK. I'll need testing, of course.
Sure would be nice to have 2.7.xx...

Thanks,

--david
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