diff options
| author | Suresh Siddha <suresh.b.siddha@intel.com> | 2011-12-01 17:07:35 -0800 |
|---|---|---|
| committer | Ingo Molnar <mingo@elte.hu> | 2011-12-06 09:06:36 +0100 |
| commit | 786d6dc7aeb2bfbfe417507b7beb83919f319db3 (patch) | |
| tree | b2190cc2e926b2ce27918525443810e1c6a5416f /kernel/sched | |
| parent | 0b005cf54eac170a8f22540ab096a6e07bf49e7c (diff) | |
sched, nohz: Clean up the find_new_ilb() using sched groups nr_busy_cpus
nr_busy_cpus in the sched_group_power indicates whether the group
is semi idle or not. This helps remove the is_semi_idle_group() and simplify
the find_new_ilb() in the context of finding an optimal cpu that can do
idle load balancing.
Signed-off-by: Suresh Siddha <suresh.b.siddha@intel.com>
Signed-off-by: Peter Zijlstra <a.p.zijlstra@chello.nl>
Cc: Thomas Gleixner <tglx@linutronix.de>
Link: http://lkml.kernel.org/r/20111202010832.656983582@sbsiddha-desk.sc.intel.com
Signed-off-by: Ingo Molnar <mingo@elte.hu>
Diffstat (limited to 'kernel/sched')
| -rw-r--r-- | kernel/sched/fair.c | 48 |
1 files changed, 12 insertions, 36 deletions
diff --git a/kernel/sched/fair.c b/kernel/sched/fair.c index 821af14335f..65a6f8b1bf1 100644 --- a/kernel/sched/fair.c +++ b/kernel/sched/fair.c @@ -4733,7 +4733,6 @@ out_unlock: */ static struct { cpumask_var_t idle_cpus_mask; - cpumask_var_t grp_idle_mask; atomic_t nr_cpus; unsigned long next_balance; /* in jiffy units */ } nohz ____cacheline_aligned; @@ -4774,33 +4773,6 @@ static inline struct sched_domain *lowest_flag_domain(int cpu, int flag) (sd && (sd->flags & flag)); sd = sd->parent) /** - * is_semi_idle_group - Checks if the given sched_group is semi-idle. - * @ilb_group: group to be checked for semi-idleness - * - * Returns: 1 if the group is semi-idle. 0 otherwise. - * - * We define a sched_group to be semi idle if it has atleast one idle-CPU - * and atleast one non-idle CPU. This helper function checks if the given - * sched_group is semi-idle or not. - */ -static inline int is_semi_idle_group(struct sched_group *ilb_group) -{ - cpumask_and(nohz.grp_idle_mask, nohz.idle_cpus_mask, - sched_group_cpus(ilb_group)); - - /* - * A sched_group is semi-idle when it has atleast one busy cpu - * and atleast one idle cpu. - */ - if (cpumask_empty(nohz.grp_idle_mask)) - return 0; - - if (cpumask_equal(nohz.grp_idle_mask, sched_group_cpus(ilb_group))) - return 0; - - return 1; -} -/** * find_new_ilb - Finds the optimum idle load balancer for nomination. * @cpu: The cpu which is nominating a new idle_load_balancer. * @@ -4815,8 +4787,8 @@ static inline int is_semi_idle_group(struct sched_group *ilb_group) static int find_new_ilb(int cpu) { int ilb = cpumask_first(nohz.idle_cpus_mask); + struct sched_group *ilbg; struct sched_domain *sd; - struct sched_group *ilb_group; /* * Have idle load balancer selection from semi-idle packages only @@ -4834,23 +4806,28 @@ static int find_new_ilb(int cpu) rcu_read_lock(); for_each_flag_domain(cpu, sd, SD_POWERSAVINGS_BALANCE) { - ilb_group = sd->groups; + ilbg = sd->groups; do { - if (is_semi_idle_group(ilb_group)) { - ilb = cpumask_first(nohz.grp_idle_mask); + if (ilbg->group_weight != + atomic_read(&ilbg->sgp->nr_busy_cpus)) { + ilb = cpumask_first_and(nohz.idle_cpus_mask, + sched_group_cpus(ilbg)); goto unlock; } - ilb_group = ilb_group->next; + ilbg = ilbg->next; - } while (ilb_group != sd->groups); + } while (ilbg != sd->groups); } unlock: rcu_read_unlock(); out_done: - return ilb; + if (ilb < nr_cpu_ids && idle_cpu(ilb)) + return ilb; + + return nr_cpu_ids; } #else /* (CONFIG_SCHED_MC || CONFIG_SCHED_SMT) */ static inline int find_new_ilb(int call_cpu) @@ -5588,7 +5565,6 @@ __init void init_sched_fair_class(void) #ifdef CONFIG_NO_HZ zalloc_cpumask_var(&nohz.idle_cpus_mask, GFP_NOWAIT); - alloc_cpumask_var(&nohz.grp_idle_mask, GFP_NOWAIT); #endif #endif /* SMP */ |