Messages in this thread | | | Date | Tue, 29 Jul 2014 14:07:39 +0200 | From | Peter Zijlstra <> | Subject | Re: [PATCH 05/10] smp: Fast path check on IPI list |
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On Mon, Jul 28, 2014 at 07:37:31PM +0200, Frederic Weisbecker wrote: > When we enqueue a remote irq work, we trigger the same IPI as those > raised by smp_call_function_*() family. > > So when we receive such IPI, we check both irq_work and smp_call_function > queues. Thus if we trigger a remote irq work, we'll likely find the > smp_call_function queue empty unless we collide with concurrent enqueuers > but the probability is low. > > Meanwhile, checking the smp_call_function queue can be costly because > we use llist_del_all() which relies on cmpxchg().
xchg()
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