Messages in this thread | | | Date | Mon, 05 Mar 2007 02:50:22 -0500 | From | Andres Salomon <> | Subject | Re: [PATCH] highres: Do not run the TIMER_SOFTIRQ after switching to highres mode |
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Ingo Molnar wrote: > * Andres Salomon <dilinger@debian.org> wrote: > >> Thomas Gleixner wrote: >>>>> The question is, how the tick timer gets enqueued in the softirq queue. >>>>> Can you isolate the codepath, where this happens ? >>> The TIMER_SOFTIRQ runs the hrtimers during bootup until a usable >>> clocksource and clock event sources are registered. The switch to high >>> resolution mode happens inside of the TIMER_SOFTIRQ, but runs the >>> softirq afterwards. That way the tick emulation timer, which was set up >>> in the switch to highres might be executed in the softirq context, which >>> is a BUG. The rbtree has not to be touched by the softirq after the >>> highres switch. >>> >> And an additional request, just to make it explicit that we should not >> have any NO_SOFTIRQ callbacks in the tree; BUG out if we encounter >> such a thing. > > please change it to WARN_ON_ONCE()... > > 'bug out' might mean: 'dead box'/'no resume'/'no bootup'. > > Ingo
Certainly; note that hrtimers.c has quite a few BUG calls which could render a box dead, though.
Patch to follow..
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