Re: lowlatency-2.2.13-A1 questions

Ingo Molnar (mingo@chiara.csoma.elte.hu)
Thu, 2 Dec 1999 21:28:51 +0100 (CET)


On Thu, 2 Dec 1999, William Montgomery wrote:

> An interrupt can occur during the kernel schedule function
> just prior to the "__switch_to" function and the interrupt handler
> may add a new task to the run-queue and set current->need_resched.
> Then the current task gets switched out immediately and the need_resched
> flag is lost. Should the new task inherit need_resched in this
> case? Is this an oversight or is this intentional?

hm, this shouldnt happen, because it's not current->need_resched that gets
set, but cpu_curr(cpu)->need_resched. cpu_curr gets set atomically and
takes the value of the next process already before doing the switch_to().
So any new wakeup and potential ->need_resched setting should go to the
next process.

-- mingo

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