Re: RCU question

From: Manfred Spraul
Date: Sun Dec 12 2004 - 17:43:16 EST


George Anzinger wrote:


The "normal" idle loop just looks at the need_resched flag and goes right back to the hlt,

That's the problem: If a the tasklet does a wakeup then the reschedule is delayed until the next interrupt. Testing need_resched and executing hlt must be atomic, but it isn't - NMIs break the atomicity.
Not a big deal, except if someone implements a tickless kernel. I think we can ignore it for now [or was the thread started by someone who want's to disable the hardware timer when the system is really idle?]

--
Manfred
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