Commit-ID: 6833dbedc680daac32418f919e675d208eb45fa9 Gitweb: http://git.kernel.org/tip/6833dbedc680daac32418f919e675d208eb45fa9 Author: Mike Galbraith <mgalbra...@suse.de> AuthorDate: Mon, 5 Dec 2011 10:01:47 +0100 Committer: Thomas Gleixner <t...@linutronix.de> CommitDate: Fri, 21 Feb 2014 21:43:21 +0100
sched, nohz: Isolated cores do not load balance The user explicitly disabled load balancing, else this core would not be disconnected. Don't add these to nohz.idle_cpus_mask. Cc: Lei Wen <lei...@marvell.com> Signed-off-by: Mike Galbraith <mgalbra...@suse.de> Signed-off-by: Peter Zijlstra <pet...@infradead.org> Link: http://lkml.kernel.org/n/tip-vmme4f49psirp966pklm5...@git.kernel.org Signed-off-by: Thomas Gleixner <t...@linutronix.de> --- kernel/sched/fair.c | 25 ++++++++++++++++++------- 1 file changed, 18 insertions(+), 7 deletions(-) diff --git a/kernel/sched/fair.c b/kernel/sched/fair.c index 37ee473..9ca5d57 100644 --- a/kernel/sched/fair.c +++ b/kernel/sched/fair.c @@ -6802,6 +6802,11 @@ out_unlock: return 0; } +static inline int on_null_domain(struct rq *rq) +{ + return unlikely(!rcu_dereference_sched(rq->sd)); +} + #ifdef CONFIG_NO_HZ_COMMON /* * idle load balancing details @@ -6856,8 +6861,13 @@ static void nohz_balancer_kick(void) static inline void nohz_balance_exit_idle(int cpu) { if (unlikely(test_bit(NOHZ_TICK_STOPPED, nohz_flags(cpu)))) { - cpumask_clear_cpu(cpu, nohz.idle_cpus_mask); - atomic_dec(&nohz.nr_cpus); + /* + * Completely isolated CPUs don't ever set, so we must test. + */ + if (likely(cpumask_test_cpu(cpu, nohz.idle_cpus_mask))) { + cpumask_clear_cpu(cpu, nohz.idle_cpus_mask); + atomic_dec(&nohz.nr_cpus); + } clear_bit(NOHZ_TICK_STOPPED, nohz_flags(cpu)); } } @@ -6911,6 +6921,12 @@ void nohz_balance_enter_idle(int cpu) if (test_bit(NOHZ_TICK_STOPPED, nohz_flags(cpu))) return; + /* + * If we're a completely isolated CPU, we don't play. + */ + if (on_null_domain(cpu_rq(cpu))) + return; + cpumask_set_cpu(cpu, nohz.idle_cpus_mask); atomic_inc(&nohz.nr_cpus); set_bit(NOHZ_TICK_STOPPED, nohz_flags(cpu)); @@ -7173,11 +7189,6 @@ static void run_rebalance_domains(struct softirq_action *h) nohz_idle_balance(this_rq, idle); } -static inline int on_null_domain(struct rq *rq) -{ - return !rcu_dereference_sched(rq->sd); -} - /* * Trigger the SCHED_SOFTIRQ if it is time to do periodic load balancing. */ -- 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/
