Ping!
On Fri, Aug 14, 2015 at 03:46:14AM +0200, Frederic Weisbecker wrote: > From: Vatika Harlalka <vatikaharla...@gmail.com> > > The problem addressed in this patch is about affining unpinned timers. > Adaptive or Full Dynticks CPUs are currently disturbed by unnecessary > jitter due to firing of such timers on them. > > This patch will affine timers to online CPUs which are not full dynticks > in NOHZ_FULL configured systems. It should not introduce overhead in > nohz full off case due to static keys. > > Reviewed-by: Preeti U Murthy <pre...@linux.vnet.ibm.com> > Signed-off by: Vatika Harlalka <vatikaharla...@gmail.com> > Cc: Ingo Molnar <mi...@kernel.org> > Cc: Peter Zijlstra <pet...@infradead.org> > Cc: Christoph Lameter <c...@linux.com> > Cc: Thomas Gleixner <t...@linutronix.de> > Cc: Paul E. McKenney <paul...@linux.vnet.ibm.com> > Cc: Chris Metcalf <cmetc...@ezchip.com> > Signed-off-by: Frederic Weisbecker <fweis...@gmail.com> > --- > include/linux/tick.h | 9 ++++++++- > kernel/sched/core.c | 7 +++++-- > 2 files changed, 13 insertions(+), 3 deletions(-) > > diff --git a/include/linux/tick.h b/include/linux/tick.h > index 3741ba1..51e6493 100644 > --- a/include/linux/tick.h > +++ b/include/linux/tick.h > @@ -143,13 +143,20 @@ static inline void tick_nohz_full_add_cpus_to(struct > cpumask *mask) > if (tick_nohz_full_enabled()) > cpumask_or(mask, mask, tick_nohz_full_mask); > } > - > +static inline int housekeeping_any_cpu(void) > +{ > + return cpumask_any_and(housekeeping_mask, cpu_online_mask); > +} > extern void __tick_nohz_full_check(void); > extern void tick_nohz_full_kick(void); > extern void tick_nohz_full_kick_cpu(int cpu); > extern void tick_nohz_full_kick_all(void); > extern void __tick_nohz_task_switch(struct task_struct *tsk); > #else > +static inline int housekeeping_any_cpu(void) > +{ > + return smp_processor_id(); > +} > static inline bool tick_nohz_full_enabled(void) { return false; } > static inline bool tick_nohz_full_cpu(int cpu) { return false; } > static inline void tick_nohz_full_add_cpus_to(struct cpumask *mask) { } > diff --git a/kernel/sched/core.c b/kernel/sched/core.c > index 9917c96..4fd42e4 100644 > --- a/kernel/sched/core.c > +++ b/kernel/sched/core.c > @@ -623,18 +623,21 @@ int get_nohz_timer_target(void) > int i, cpu = smp_processor_id(); > struct sched_domain *sd; > > - if (!idle_cpu(cpu)) > + if (!idle_cpu(cpu) && is_housekeeping_cpu(cpu)) > return cpu; > > rcu_read_lock(); > for_each_domain(cpu, sd) { > for_each_cpu(i, sched_domain_span(sd)) { > - if (!idle_cpu(i)) { > + if (!idle_cpu(i) && is_housekeeping_cpu(cpu)) { > cpu = i; > goto unlock; > } > } > } > + > + if (!is_housekeeping_cpu(cpu)) > + cpu = housekeeping_any_cpu(); > unlock: > rcu_read_unlock(); > return cpu; > -- > 2.1.4 > -- 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/