On Wed, Apr 17, 2013 at 06:24:49PM +0200, Frederic Weisbecker wrote: > Provide a new kernel config that defaults all CPUs to be part > of the full dynticks range, except the boot one for timekeeping. > > This default setting is overriden by the nohz_full= boot option > if passed by the user. > > This is helpful for those who don't need a finegrained range > of full dynticks CPU and also for automated testing. > > Suggested-by: Ingo Molnar <[email protected]> > Signed-off-by: Frederic Weisbecker <[email protected]> > Cc: Andrew Morton <[email protected]> > Cc: Chris Metcalf <[email protected]> > Cc: Christoph Lameter <[email protected]> > Cc: Geoff Levand <[email protected]> > Cc: Gilad Ben Yossef <[email protected]> > Cc: Hakan Akkan <[email protected]> > Cc: Ingo Molnar <[email protected]> > Cc: Kevin Hilman <[email protected]> > Cc: Li Zhong <[email protected]> > Cc: Paul E. McKenney <[email protected]> > Cc: Paul Gortmaker <[email protected]> > Cc: Peter Zijlstra <[email protected]> > Cc: Steven Rostedt <[email protected]> > Cc: Thomas Gleixner <[email protected]>
Reviewed-by: Paul E. McKenney <[email protected]> > --- > kernel/time/Kconfig | 10 ++++++++++ > kernel/time/tick-sched.c | 23 +++++++++++++++++++++-- > 2 files changed, 31 insertions(+), 2 deletions(-) > > diff --git a/kernel/time/Kconfig b/kernel/time/Kconfig > index 358d601..99c3f13 100644 > --- a/kernel/time/Kconfig > +++ b/kernel/time/Kconfig > @@ -128,6 +128,16 @@ config NO_HZ_FULL > > endchoice > > +config NO_HZ_FULL_ALL > + bool "Full dynticks system on all CPUs by default" > + depends on NO_HZ_FULL > + help > + If the user doesn't pass the nohz_full boot option to > + define the range of full dynticks CPUs, consider that all > + CPUs in the system are full dynticks by default. > + Note the boot CPU will still be kept outside the range to > + handle the timekeeping duty. > + > config NO_HZ > bool "Old Idle dynticks config" > depends on !ARCH_USES_GETTIMEOFFSET && GENERIC_CLOCKEVENTS > diff --git a/kernel/time/tick-sched.c b/kernel/time/tick-sched.c > index d71a5f2..a76e090 100644 > --- a/kernel/time/tick-sched.c > +++ b/kernel/time/tick-sched.c > @@ -203,12 +203,31 @@ static int __cpuinit tick_nohz_cpu_down_callback(struct > notifier_block *nfb, > */ > static char __initdata nohz_full_buf[NR_CPUS + 1]; > > +static int tick_nohz_init_all(void) > +{ > + int err = -1; > + > +#ifdef CONFIG_NO_HZ_FULL_ALL > + if (!alloc_cpumask_var(&nohz_full_mask, GFP_KERNEL)) { > + pr_err("NO_HZ: Can't allocate full dynticks cpumask\n"); > + return err; > + } > + err = 0; > + cpumask_setall(nohz_full_mask); > + cpumask_clear_cpu(smp_processor_id(), nohz_full_mask); > + have_nohz_full_mask = true; > +#endif > + return err; > +} > + > void __init tick_nohz_init(void) > { > int cpu; > > - if (!have_nohz_full_mask) > - return; > + if (!have_nohz_full_mask) { > + if (tick_nohz_init_all() < 0) > + return; > + } > > cpu_notifier(tick_nohz_cpu_down_callback, 0); > > -- > 1.7.5.4 > -- 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/
