Re: timer_bh behaviour incorrect for 2.2.13?

Andrea Arcangeli (andrea@suse.de)
Fri, 10 Dec 1999 16:37:51 +0100 (CET)


On Fri, 10 Dec 1999, Ingo Molnar wrote:

>what i ment was that i think that this is physically impossible. Since
>local interrupts are disabled, even with the worst cache-miss and TLB-miss
>scenario possible, it's impossible for the above big chunk of code to
>execute just inbetween those two others.

What about your NMI in 2.3.x?

I agree that looks physically impossible in 2.2.x IA32 but it doesn't look
impossible in 2.3.x IA32 without disabling the NMI watchdog.

More in general I don't write SMP code assuming that both cpus runs at the
same speed. I assume that every CPU can stop for some time at any time for
any reason. I consdier depending on the timings as a race. The common code
doesn't run only IA32. Of course I agree that the single __cli is fine for
testing in 2.2.13.

Andrea

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