On 10/28, Kevin Hilman wrote: > Stephen Boyd <[email protected]> writes: > > > This will allow the scheduler tick to be restarted if we're in > > full NOHZ mode. > > > > Cc: Kevin Hilman <[email protected]> > > Cc: Frederic Weisbecker <[email protected]> > > Signed-off-by: Stephen Boyd <[email protected]> > > Minor nit, but I'd prefer a more verbose changelog (I forget things > quickly and like to rely on changelogs for my memory.) Probably worth > adding something like: "By default, irq_work is tied to the tick > processing (update_process_times()) but in full NOHZ mode, no tick means > no IRQ work. In order for IRQ work to be done in full NOHZ mode, a > self-IPI is used to process IRQ work." > > Other than the changelog nit, patch looks good, feel free to add > > Reviewed-by: Kevin Hilman <[email protected]> > > If Russell is OK with this, it can go to his patch system. >
Fair enough. This is what I came up with. I'll send it off to the patch tracker in about 12 hours if nobody else has anymore comments. ----8<----- ARM: Support arch_irq_work_raise() via self IPIs By default, IRQ work is run from the tick interrupt (see irq_work_run() in update_process_times()). When we're in full NOHZ mode, restarting the tick requires the use of IRQ work and if the only place we run IRQ work is in the tick interrupt we have an unbreakable cycle. Implement arch_irq_work_raise() via self IPIs to break this cycle and get the tick started again. Note that we implement this via IPIs which are only available on SMP builds. This shouldn't be a problem because full NOHZ is only supported on SMP builds anyway. Signed-off-by: Stephen Boyd <[email protected]> Reviewed-by: Kevin Hilman <[email protected]> Cc: Frederic Weisbecker <[email protected]> -- Qualcomm Innovation Center, Inc. is a member of Code Aurora Forum, hosted by The Linux Foundation -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to [email protected] More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
