sched/fair: Move rebalance_domains()
This pure code movement results in two #ifdef CONFIG_NO_HZ_COMMON sections landing next to each other. Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org> Cc: Frederic Weisbecker <fweisbec@gmail.com> Cc: Linus Torvalds <torvalds@linux-foundation.org> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Thomas Gleixner <tglx@linutronix.de> Cc: linux-kernel@vger.kernel.org Signed-off-by: Ingo Molnar <mingo@kernel.org>
This commit is contained in:
Peter Zijlstra
Ingo Molnar
parent
63928384fa
commit
af3fe03c56
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@ -9121,6 +9121,124 @@ static int active_load_balance_cpu_stop(void *data)
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return 0;
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}
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static DEFINE_SPINLOCK(balancing);
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/*
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* Scale the max load_balance interval with the number of CPUs in the system.
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* This trades load-balance latency on larger machines for less cross talk.
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*/
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void update_max_interval(void)
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{
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max_load_balance_interval = HZ*num_online_cpus()/10;
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}
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/*
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* It checks each scheduling domain to see if it is due to be balanced,
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* and initiates a balancing operation if so.
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*
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* Balancing parameters are set up in init_sched_domains.
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*/
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static void rebalance_domains(struct rq *rq, enum cpu_idle_type idle)
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{
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int continue_balancing = 1;
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int cpu = rq->cpu;
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unsigned long interval;
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struct sched_domain *sd;
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/* Earliest time when we have to do rebalance again */
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unsigned long next_balance = jiffies + 60*HZ;
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int update_next_balance = 0;
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int need_serialize, need_decay = 0;
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u64 max_cost = 0;
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rcu_read_lock();
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for_each_domain(cpu, sd) {
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/*
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* Decay the newidle max times here because this is a regular
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* visit to all the domains. Decay ~1% per second.
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*/
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if (time_after(jiffies, sd->next_decay_max_lb_cost)) {
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sd->max_newidle_lb_cost =
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(sd->max_newidle_lb_cost * 253) / 256;
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sd->next_decay_max_lb_cost = jiffies + HZ;
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need_decay = 1;
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}
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max_cost += sd->max_newidle_lb_cost;
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if (!(sd->flags & SD_LOAD_BALANCE))
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continue;
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/*
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* Stop the load balance at this level. There is another
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* CPU in our sched group which is doing load balancing more
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* actively.
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*/
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if (!continue_balancing) {
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if (need_decay)
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continue;
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break;
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}
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interval = get_sd_balance_interval(sd, idle != CPU_IDLE);
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need_serialize = sd->flags & SD_SERIALIZE;
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if (need_serialize) {
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if (!spin_trylock(&balancing))
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goto out;
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}
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if (time_after_eq(jiffies, sd->last_balance + interval)) {
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if (load_balance(cpu, rq, sd, idle, &continue_balancing)) {
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/*
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* The LBF_DST_PINNED logic could have changed
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* env->dst_cpu, so we can't know our idle
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* state even if we migrated tasks. Update it.
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*/
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idle = idle_cpu(cpu) ? CPU_IDLE : CPU_NOT_IDLE;
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}
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sd->last_balance = jiffies;
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interval = get_sd_balance_interval(sd, idle != CPU_IDLE);
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}
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if (need_serialize)
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spin_unlock(&balancing);
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out:
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if (time_after(next_balance, sd->last_balance + interval)) {
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next_balance = sd->last_balance + interval;
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update_next_balance = 1;
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}
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}
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if (need_decay) {
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/*
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* Ensure the rq-wide value also decays but keep it at a
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* reasonable floor to avoid funnies with rq->avg_idle.
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*/
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rq->max_idle_balance_cost =
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max((u64)sysctl_sched_migration_cost, max_cost);
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}
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rcu_read_unlock();
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/*
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* next_balance will be updated only when there is a need.
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* When the cpu is attached to null domain for ex, it will not be
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* updated.
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*/
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if (likely(update_next_balance)) {
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rq->next_balance = next_balance;
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#ifdef CONFIG_NO_HZ_COMMON
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/*
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* If this CPU has been elected to perform the nohz idle
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* balance. Other idle CPUs have already rebalanced with
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* nohz_idle_balance() and nohz.next_balance has been
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* updated accordingly. This CPU is now running the idle load
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* balance for itself and we need to update the
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* nohz.next_balance accordingly.
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*/
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if ((idle == CPU_IDLE) && time_after(nohz.next_balance, rq->next_balance))
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nohz.next_balance = rq->next_balance;
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#endif
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}
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}
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static inline int on_null_domain(struct rq *rq)
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{
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return unlikely(!rcu_dereference_sched(rq->sd));
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@ -9373,124 +9491,6 @@ void nohz_balance_enter_idle(int cpu)
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static inline void nohz_balancer_kick(struct rq *rq) { }
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#endif
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static DEFINE_SPINLOCK(balancing);
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/*
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* Scale the max load_balance interval with the number of CPUs in the system.
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* This trades load-balance latency on larger machines for less cross talk.
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*/
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void update_max_interval(void)
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{
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max_load_balance_interval = HZ*num_online_cpus()/10;
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}
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/*
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* It checks each scheduling domain to see if it is due to be balanced,
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* and initiates a balancing operation if so.
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*
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* Balancing parameters are set up in init_sched_domains.
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*/
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static void rebalance_domains(struct rq *rq, enum cpu_idle_type idle)
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{
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int continue_balancing = 1;
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int cpu = rq->cpu;
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unsigned long interval;
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struct sched_domain *sd;
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/* Earliest time when we have to do rebalance again */
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unsigned long next_balance = jiffies + 60*HZ;
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int update_next_balance = 0;
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int need_serialize, need_decay = 0;
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u64 max_cost = 0;
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rcu_read_lock();
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for_each_domain(cpu, sd) {
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/*
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* Decay the newidle max times here because this is a regular
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* visit to all the domains. Decay ~1% per second.
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*/
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if (time_after(jiffies, sd->next_decay_max_lb_cost)) {
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sd->max_newidle_lb_cost =
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(sd->max_newidle_lb_cost * 253) / 256;
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sd->next_decay_max_lb_cost = jiffies + HZ;
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need_decay = 1;
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}
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max_cost += sd->max_newidle_lb_cost;
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if (!(sd->flags & SD_LOAD_BALANCE))
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continue;
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/*
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* Stop the load balance at this level. There is another
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* CPU in our sched group which is doing load balancing more
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* actively.
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*/
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if (!continue_balancing) {
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if (need_decay)
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continue;
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break;
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}
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interval = get_sd_balance_interval(sd, idle != CPU_IDLE);
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need_serialize = sd->flags & SD_SERIALIZE;
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if (need_serialize) {
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if (!spin_trylock(&balancing))
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goto out;
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}
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if (time_after_eq(jiffies, sd->last_balance + interval)) {
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if (load_balance(cpu, rq, sd, idle, &continue_balancing)) {
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/*
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* The LBF_DST_PINNED logic could have changed
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* env->dst_cpu, so we can't know our idle
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* state even if we migrated tasks. Update it.
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*/
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idle = idle_cpu(cpu) ? CPU_IDLE : CPU_NOT_IDLE;
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}
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sd->last_balance = jiffies;
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interval = get_sd_balance_interval(sd, idle != CPU_IDLE);
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}
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if (need_serialize)
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spin_unlock(&balancing);
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out:
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if (time_after(next_balance, sd->last_balance + interval)) {
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next_balance = sd->last_balance + interval;
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update_next_balance = 1;
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}
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}
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if (need_decay) {
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/*
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* Ensure the rq-wide value also decays but keep it at a
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* reasonable floor to avoid funnies with rq->avg_idle.
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*/
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rq->max_idle_balance_cost =
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max((u64)sysctl_sched_migration_cost, max_cost);
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}
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rcu_read_unlock();
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/*
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* next_balance will be updated only when there is a need.
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* When the CPU is attached to null domain for ex, it will not be
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* updated.
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*/
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if (likely(update_next_balance)) {
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rq->next_balance = next_balance;
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#ifdef CONFIG_NO_HZ_COMMON
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/*
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* If this CPU has been elected to perform the nohz idle
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* balance. Other idle CPUs have already rebalanced with
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* nohz_idle_balance() and nohz.next_balance has been
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* updated accordingly. This CPU is now running the idle load
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* balance for itself and we need to update the
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* nohz.next_balance accordingly.
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*/
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if ((idle == CPU_IDLE) && time_after(nohz.next_balance, rq->next_balance))
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nohz.next_balance = rq->next_balance;
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#endif
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}
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}
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#ifdef CONFIG_NO_HZ_COMMON
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/*
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* In CONFIG_NO_HZ_COMMON case, the idle balance kickee will do the
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