Messages in this thread | | | Date | Tue, 13 May 2014 21:33:29 +0200 | From | Frederic Weisbecker <> | Subject | Re: [PATCH 1/5] irq_work: Let arch tell us if it can raise irq work |
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On Tue, May 13, 2014 at 07:09:42PM +0200, Peter Zijlstra wrote: > On Tue, May 13, 2014 at 04:38:37PM +0200, Frederic Weisbecker wrote: > > We prepare for executing the full nohz kick through an irq work. But > > if we do this as is, we'll run into conflicting tick locking: the tick > > holds the hrtimer lock and the nohz kick may do so too. > > It does? How does the tick end up holding that lock? > > Normal hrtimer callbacks run without holding the hrtimer lock -- I made > it so. > > This means tick_sched_timer() is called without hrtimer lock, and I > don't see it taking it anywhere in tick_sched_do_timer() or > tick_sched_handle().
Check hrtimer_interrupt(), it takes the per cpu base->lock.
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