Messages in this thread | | | Date | Sat, 11 Dec 2004 17:32:08 +0100 | From | Manfred Spraul <> | Subject | Re: RCU question |
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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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