Messages in this thread | | | From | Linus Torvalds <> | Date | Tue, 29 Nov 2011 12:12:44 -0800 | Subject | Re: Perhaps a side effect regarding NMI returns |
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On Tue, Nov 29, 2011 at 12:09 PM, Andi Kleen <andi@firstfloor.org> wrote: > > Not sure what problem Steven thinks is there. Once you > switched the stack any nesting is fine.
The problem is that NMI's are blocked!
We're potentially switching to another process, there is no guarantee there will be an "iret" *anywhere* in any patch for a long time. So any subsequent NMI's will not be able to come in.
> The reason I added them originally is to prevent the race of remote > kernel events being delayed for a long time. With Frederic's nohz work > this will be more important in the future. Today it would be eventually > picked up by the regular timer interrupts.
You're just delaying another kind of event: the next NMI.
And NMI's really shouldn't be triggering any scheduling-related events afaik.
Linus
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