diff options
| -rw-r--r-- | include/linux/sched.h | 1 | ||||
| -rw-r--r-- | kernel/sched.c | 59 |
2 files changed, 48 insertions, 12 deletions
diff --git a/include/linux/sched.h b/include/linux/sched.h index ea92e5c8908..72d6927d29e 100644 --- a/include/linux/sched.h +++ b/include/linux/sched.h @@ -707,6 +707,7 @@ struct sched_domain { unsigned long lb_hot_gained[MAX_IDLE_TYPES]; unsigned long lb_nobusyg[MAX_IDLE_TYPES]; unsigned long lb_nobusyq[MAX_IDLE_TYPES]; + unsigned long lb_stopbalance[MAX_IDLE_TYPES]; /* Active load balancing */ unsigned long alb_cnt; diff --git a/kernel/sched.c b/kernel/sched.c index 15ce772a471..4e453431c61 100644 --- a/kernel/sched.c +++ b/kernel/sched.c @@ -428,7 +428,7 @@ static inline void task_rq_unlock(struct rq *rq, unsigned long *flags) * bump this up when changing the output format or the meaning of an existing * format, so that tools can adapt (or abort) */ -#define SCHEDSTAT_VERSION 12 +#define SCHEDSTAT_VERSION 13 static int show_schedstat(struct seq_file *seq, void *v) { @@ -466,7 +466,7 @@ static int show_schedstat(struct seq_file *seq, void *v) seq_printf(seq, "domain%d %s", dcnt++, mask_str); for (itype = SCHED_IDLE; itype < MAX_IDLE_TYPES; itype++) { - seq_printf(seq, " %lu %lu %lu %lu %lu %lu %lu %lu", + seq_printf(seq, " %lu %lu %lu %lu %lu %lu %lu %lu %lu", sd->lb_cnt[itype], sd->lb_balanced[itype], sd->lb_failed[itype], @@ -474,7 +474,8 @@ static int show_schedstat(struct seq_file *seq, void *v) sd->lb_gained[itype], sd->lb_hot_gained[itype], sd->lb_nobusyq[itype], - sd->lb_nobusyg[itype]); + sd->lb_nobusyg[itype], + sd->lb_stopbalance[itype]); } seq_printf(seq, " %lu %lu %lu %lu %lu %lu %lu %lu %lu %lu %lu %lu\n", sd->alb_cnt, sd->alb_failed, sd->alb_pushed, @@ -2249,7 +2250,7 @@ out: static struct sched_group * find_busiest_group(struct sched_domain *sd, int this_cpu, unsigned long *imbalance, enum idle_type idle, int *sd_idle, - cpumask_t *cpus) + cpumask_t *cpus, int *balance) { struct sched_group *busiest = NULL, *this = NULL, *group = sd->groups; unsigned long max_load, avg_load, total_load, this_load, total_pwr; @@ -2278,10 +2279,14 @@ find_busiest_group(struct sched_domain *sd, int this_cpu, unsigned long load, group_capacity; int local_group; int i; + unsigned int balance_cpu = -1, first_idle_cpu = 0; unsigned long sum_nr_running, sum_weighted_load; local_group = cpu_isset(this_cpu, group->cpumask); + if (local_group) + balance_cpu = first_cpu(group->cpumask); + /* Tally up the load of all CPUs in the group */ sum_weighted_load = sum_nr_running = avg_load = 0; @@ -2297,9 +2302,14 @@ find_busiest_group(struct sched_domain *sd, int this_cpu, *sd_idle = 0; /* Bias balancing toward cpus of our domain */ - if (local_group) + if (local_group) { + if (idle_cpu(i) && !first_idle_cpu) { + first_idle_cpu = 1; + balance_cpu = i; + } + load = target_load(i, load_idx); - else + } else load = source_load(i, load_idx); avg_load += load; @@ -2307,6 +2317,16 @@ find_busiest_group(struct sched_domain *sd, int this_cpu, sum_weighted_load += rq->raw_weighted_load; } + /* + * First idle cpu or the first cpu(busiest) in this sched group + * is eligible for doing load balancing at this and above + * domains. + */ + if (local_group && balance_cpu != this_cpu && balance) { + *balance = 0; + goto ret; + } + total_load += avg_load; total_pwr += group->cpu_power; @@ -2498,8 +2518,8 @@ out_balanced: *imbalance = min_load_per_task; return group_min; } -ret: #endif +ret: *imbalance = 0; return NULL; } @@ -2550,7 +2570,8 @@ static inline unsigned long minus_1_or_zero(unsigned long n) * tasks if there is an imbalance. */ static int load_balance(int this_cpu, struct rq *this_rq, - struct sched_domain *sd, enum idle_type idle) + struct sched_domain *sd, enum idle_type idle, + int *balance) { int nr_moved, all_pinned = 0, active_balance = 0, sd_idle = 0; struct sched_group *group; @@ -2573,7 +2594,13 @@ static int load_balance(int this_cpu, struct rq *this_rq, redo: group = find_busiest_group(sd, this_cpu, &imbalance, idle, &sd_idle, - &cpus); + &cpus, balance); + + if (*balance == 0) { + schedstat_inc(sd, lb_stopbalance[idle]); + goto out_balanced; + } + if (!group) { schedstat_inc(sd, lb_nobusyg[idle]); goto out_balanced; @@ -2715,7 +2742,7 @@ load_balance_newidle(int this_cpu, struct rq *this_rq, struct sched_domain *sd) schedstat_inc(sd, lb_cnt[NEWLY_IDLE]); redo: group = find_busiest_group(sd, this_cpu, &imbalance, NEWLY_IDLE, - &sd_idle, &cpus); + &sd_idle, &cpus, NULL); if (!group) { schedstat_inc(sd, lb_nobusyg[NEWLY_IDLE]); goto out_balanced; @@ -2885,7 +2912,7 @@ static DEFINE_SPINLOCK(balancing); static void run_rebalance_domains(struct softirq_action *h) { - int this_cpu = smp_processor_id(); + int this_cpu = smp_processor_id(), balance = 1; struct rq *this_rq = cpu_rq(this_cpu); unsigned long interval; struct sched_domain *sd; @@ -2917,7 +2944,7 @@ static void run_rebalance_domains(struct softirq_action *h) } if (time_after_eq(jiffies, sd->last_balance + interval)) { - if (load_balance(this_cpu, this_rq, sd, idle)) { + if (load_balance(this_cpu, this_rq, sd, idle, &balance)) { /* * We've pulled tasks over so either we're no * longer idle, or one of our SMT siblings is @@ -2932,6 +2959,14 @@ static void run_rebalance_domains(struct softirq_action *h) out: if (time_after(next_balance, sd->last_balance + interval)) next_balance = sd->last_balance + interval; + + /* + * Stop the load balance at this level. There is another + * CPU in our sched group which is doing load balancing more + * actively. + */ + if (!balance) + break; } this_rq->next_balance = next_balance; } |