The cpu information is already stored in the struct rq, so no need to pass it as parameter to the nohz_kick_needed function.

The caller of this function just called idle_cpu() before to fill the rq->idle_balance field.

Use rq->cpu and rq->idle_balance.

Signed-off-by: Daniel Lezcano daniel.lezcano@linaro.org --- kernel/sched/fair.c | 8 ++++---- 1 file changed, 4 insertions(+), 4 deletions(-)

diff --git a/kernel/sched/fair.c b/kernel/sched/fair.c index 600301c..4cb414a 100644 --- a/kernel/sched/fair.c +++ b/kernel/sched/fair.c @@ -6781,14 +6781,14 @@ end: * - For SD_ASYM_PACKING, if the lower numbered cpu's in the scheduler * domain span are idle. */ -static inline int nohz_kick_needed(struct rq *rq, int cpu) +static inline int nohz_kick_needed(struct rq *rq) { unsigned long now = jiffies; struct sched_domain *sd; struct sched_group_power *sgp; - int nr_busy; + int nr_busy, cpu = rq->cpu;

- if (unlikely(idle_cpu(cpu))) + if (unlikely(rq->idle_balance)) return 0;

/* @@ -6878,7 +6878,7 @@ void trigger_load_balance(struct rq *rq) likely(!on_null_domain(cpu))) raise_softirq(SCHED_SOFTIRQ); #ifdef CONFIG_NO_HZ_COMMON - if (nohz_kick_needed(rq, cpu) && likely(!on_null_domain(cpu))) + if (nohz_kick_needed(rq) && likely(!on_null_domain(cpu))) nohz_balancer_kick(cpu); #endif }

The 'call_cpu' is never used in the function. Remove it.

Signed-off-by: Daniel Lezcano daniel.lezcano@linaro.org --- kernel/sched/fair.c | 4 ++-- 1 file changed, 2 insertions(+), 2 deletions(-)

diff --git a/kernel/sched/fair.c b/kernel/sched/fair.c index 82dd145..1f7ed1a 100644 --- a/kernel/sched/fair.c +++ b/kernel/sched/fair.c @@ -6502,7 +6502,7 @@ static struct { unsigned long next_balance; /* in jiffy units */ } nohz ____cacheline_aligned;

-static inline int find_new_ilb(int call_cpu) +static inline int find_new_ilb(void) { int ilb = cpumask_first(nohz.idle_cpus_mask);

@@ -6523,7 +6523,7 @@ static void nohz_balancer_kick(int cpu)

nohz.next_balance++;

- ilb_cpu = find_new_ilb(cpu); + ilb_cpu = find_new_ilb();

if (ilb_cpu >= nr_cpu_ids) return;

The cpu information is stored in the struct rq and the caller of the rebalance_domains function pass the cpu to retrieve the struct rq but it already has the struct rq info. Replace the cpu parameter with the struct rq.

Signed-off-by: Daniel Lezcano daniel.lezcano@linaro.org --- kernel/sched/fair.c | 8 ++++---- 1 file changed, 4 insertions(+), 4 deletions(-)

diff --git a/kernel/sched/fair.c b/kernel/sched/fair.c index c647c45..0fbd8d0 100644 --- a/kernel/sched/fair.c +++ b/kernel/sched/fair.c @@ -6633,10 +6633,10 @@ void update_max_interval(void) * * Balancing parameters are set up in init_sched_domains. */ -static void rebalance_domains(int cpu, enum cpu_idle_type idle) +static void rebalance_domains(struct rq *rq, enum cpu_idle_type idle) { int continue_balancing = 1; - struct rq *rq = cpu_rq(cpu); + int cpu = rq->cpu; unsigned long interval; struct sched_domain *sd; /* Earliest time when we have to do rebalance again */ @@ -6762,7 +6762,7 @@ static void nohz_idle_balance(int this_cpu, enum cpu_idle_type idle) update_idle_cpu_load(rq); raw_spin_unlock_irq(&rq->lock);

- rebalance_domains(balance_cpu, CPU_IDLE); + rebalance_domains(rq, CPU_IDLE);

if (time_after(this_rq->next_balance, rq->next_balance)) this_rq->next_balance = rq->next_balance; @@ -6851,7 +6851,7 @@ static void run_rebalance_domains(struct softirq_action *h) enum cpu_idle_type idle = this_rq->idle_balance ? CPU_IDLE : CPU_NOT_IDLE;

- rebalance_domains(this_cpu, idle); + rebalance_domains(this_rq, idle);

/* * If this cpu has a pending nohz_balance_kick, then do the

The test on_null_domain is done twice in the trigger_load_balance function.

Move the test at the begin of the function, so there is only one check.

Signed-off-by: Daniel Lezcano daniel.lezcano@linaro.org --- kernel/sched/fair.c | 8 +++++--- 1 file changed, 5 insertions(+), 3 deletions(-)

diff --git a/kernel/sched/fair.c b/kernel/sched/fair.c index 59c57e7..ef95ddf 100644 --- a/kernel/sched/fair.c +++ b/kernel/sched/fair.c @@ -6871,11 +6871,13 @@ static inline int on_null_domain(struct rq *rq) void trigger_load_balance(struct rq *rq) { /* Don't need to rebalance while attached to NULL domain */ - if (time_after_eq(jiffies, rq->next_balance) && - likely(!on_null_domain(rq))) + if (unlikely(on_null_domain(rq))) + return; + + if (time_after_eq(jiffies, rq->next_balance)) raise_softirq(SCHED_SOFTIRQ); #ifdef CONFIG_NO_HZ_COMMON - if (nohz_kick_needed(rq) && likely(!on_null_domain(rq))) + if (nohz_kick_needed(rq)) nohz_balancer_kick(); #endif }