On Tue, Jun 03, 2014 at 05:00:08PM +0200, Peter Zijlstra wrote: > On Tue, Jun 03, 2014 at 04:40:18PM +0200, Frederic Weisbecker wrote: > > irq work currently only supports local callbacks. However its code > > is mostly ready to run remote callbacks and we have some potential user. > > > > The full nohz subsystem currently open codes its own remote irq work > > on top of the scheduler ipi when it wants a CPU to reevaluate its next > > tick. However this ad hoc solution bloats the scheduler IPI. > > > > Lets just extend the irq work subsystem to support remote queuing on top > > of the generic SMP IPI to handle this kind of user. This shouldn't add > > noticeable overhead. > > > > Suggested-by: Peter Zijlstra <pet...@infradead.org> > > Cc: Andrew Morton <a...@linux-foundation.org> > > Cc: Ingo Molnar <mi...@kernel.org> > > Cc: Kevin Hilman <khil...@linaro.org> > > Cc: Paul E. McKenney <paul...@linux.vnet.ibm.com> > > Acked-by: Peter Zijlstra <pet...@infradead.org> > > > Cc: Thomas Gleixner <t...@linutronix.de> > > Cc: Viresh Kumar <viresh.ku...@linaro.org> > > Signed-off-by: Frederic Weisbecker <fweis...@gmail.com> > > --- > > include/linux/irq_work.h | 2 ++ > > kernel/irq_work.c | 22 +++++++++++++++++++++- > > kernel/smp.c | 4 ++++ > > 3 files changed, 27 insertions(+), 1 deletion(-) > > > @@ -198,6 +199,9 @@ void generic_smp_call_function_single_interrupt(void) > > csd->func(csd->info); > > csd_unlock(csd); > > } > > + > > + /* Handle irq works queued remotely by irq_work_queue_on() */ > > + irq_work_run(); > > } > > One could possibly extend that comment by stating that we explicitly run > the irq_work bits after the function bits, because the function bits are > typically synchronous and have people waiting on them, while not so for > the irq_works. >
Good point! I'll expand the comment. -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majord...@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
