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Zwane Mwaikambo wrote:
>On Fri, 10 Dec 2004, George Anzinger wrote:
>
>
>
>>That is ok. Either we have interrupts off and no softirqs are pending and we
>>proceed to the "hlt" (where the interrupt will be taken), or softirqs are
>>pending, we turn interrupts on, do the softirq, turn interrupts off and try
>>again. Unless some tasklet (RCU?) never "gives up" or we will exit the while
>>with interrupts off and move on to the "hlt". Or did I miss something?
>>
>>
>
>But the point is that you cannot execute hlt with interrupts disabled.
>
>
The trick is the sti instruction: It enables interrupt processing after
the following instruction.
Thus
sti
hlt
cannot race - it atomically enables interrupts and waits.
--
Manfred
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