Commit-ID: af3fe03c562055bc3c116eabe73f141ae31bf234
Gitweb: https://git.kernel.org/tip/af3fe03c562055bc3c116eabe73f141ae31bf234
Author: Peter Zijlstra <peterz@xxxxxxxxxxxxx>
AuthorDate: Tue, 20 Feb 2018 10:58:39 +0100
Committer: Ingo Molnar <mingo@xxxxxxxxxx>
CommitDate: Fri, 9 Mar 2018 07:59:23 +0100
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@xxxxxxxxxxxxx>
Cc: Frederic Weisbecker <fweisbec@xxxxxxxxx>
Cc: Linus Torvalds <torvalds@xxxxxxxxxxxxxxxxxxxx>
Cc: Peter Zijlstra <peterz@xxxxxxxxxxxxx>
Cc: Thomas Gleixner <tglx@xxxxxxxxxxxxx>
Cc: linux-kernel@xxxxxxxxxxxxxxx
Signed-off-by: Ingo Molnar <mingo@xxxxxxxxxx>
---
kernel/sched/fair.c | 236 ++++++++++++++++++++++++++--------------------------
1 file changed, 118 insertions(+), 118 deletions(-)
diff --git a/kernel/sched/fair.c b/kernel/sched/fair.c
index 5c357561db5d..0da79d8a6a2c 100644
--- a/kernel/sched/fair.c
+++ b/kernel/sched/fair.c
@@ -9121,6 +9121,124 @@ out_unlock:
return 0;
}
+static DEFINE_SPINLOCK(balancing);
+
+/*
+ * Scale the max load_balance interval with the number of CPUs in the system.
+ * This trades load-balance latency on larger machines for less cross talk.
+ */
+void update_max_interval(void)
+{
+ max_load_balance_interval = HZ*num_online_cpus()/10;
+}
+
+/*
+ * It checks each scheduling domain to see if it is due to be balanced,
+ * and initiates a balancing operation if so.
+ *
+ * Balancing parameters are set up in init_sched_domains.
+ */
+static void rebalance_domains(struct rq *rq, enum cpu_idle_type idle)
+{
+ int continue_balancing = 1;
+ int cpu = rq->cpu;
+ unsigned long interval;
+ struct sched_domain *sd;
+ /* Earliest time when we have to do rebalance again */
+ unsigned long next_balance = jiffies + 60*HZ;
+ int update_next_balance = 0;
+ int need_serialize, need_decay = 0;
+ u64 max_cost = 0;
+
+ rcu_read_lock();
+ for_each_domain(cpu, sd) {
+ /*
+ * Decay the newidle max times here because this is a regular
+ * visit to all the domains. Decay ~1% per second.
+ */
+ if (time_after(jiffies, sd->next_decay_max_lb_cost)) {
+ sd->max_newidle_lb_cost =
+ (sd->max_newidle_lb_cost * 253) / 256;
+ sd->next_decay_max_lb_cost = jiffies + HZ;
+ need_decay = 1;
+ }
+ max_cost += sd->max_newidle_lb_cost;
+
+ if (!(sd->flags & SD_LOAD_BALANCE))
+ continue;
+
+ /*
+ * Stop the load balance at this level. There is another
+ * CPU in our sched group which is doing load balancing more
+ * actively.
+ */
+ if (!continue_balancing) {
+ if (need_decay)
+ continue;
+ break;
+ }
+
+ interval = get_sd_balance_interval(sd, idle != CPU_IDLE);
+
+ need_serialize = sd->flags & SD_SERIALIZE;
+ if (need_serialize) {
+ if (!spin_trylock(&balancing))
+ goto out;
+ }
+
+ if (time_after_eq(jiffies, sd->last_balance + interval)) {
+ if (load_balance(cpu, rq, sd, idle, &continue_balancing)) {
+ /*
+ * The LBF_DST_PINNED logic could have changed
+ * env->dst_cpu, so we can't know our idle
+ * state even if we migrated tasks. Update it.
+ */
+ idle = idle_cpu(cpu) ? CPU_IDLE : CPU_NOT_IDLE;
+ }
+ sd->last_balance = jiffies;
+ interval = get_sd_balance_interval(sd, idle != CPU_IDLE);
+ }
+ if (need_serialize)
+ spin_unlock(&balancing);
+out:
+ if (time_after(next_balance, sd->last_balance + interval)) {
+ next_balance = sd->last_balance + interval;
+ update_next_balance = 1;
+ }
+ }
+ if (need_decay) {
+ /*
+ * Ensure the rq-wide value also decays but keep it at a
+ * reasonable floor to avoid funnies with rq->avg_idle.
+ */
+ rq->max_idle_balance_cost =
+ max((u64)sysctl_sched_migration_cost, max_cost);
+ }
+ rcu_read_unlock();
+
+ /*
+ * next_balance will be updated only when there is a need.
+ * When the cpu is attached to null domain for ex, it will not be
+ * updated.
+ */
+ if (likely(update_next_balance)) {
+ rq->next_balance = next_balance;
+
+#ifdef CONFIG_NO_HZ_COMMON
+ /*
+ * If this CPU has been elected to perform the nohz idle
+ * balance. Other idle CPUs have already rebalanced with
+ * nohz_idle_balance() and nohz.next_balance has been
+ * updated accordingly. This CPU is now running the idle load
+ * balance for itself and we need to update the
+ * nohz.next_balance accordingly.
+ */
+ if ((idle == CPU_IDLE) && time_after(nohz.next_balance, rq->next_balance))
+ nohz.next_balance = rq->next_balance;
+#endif
+ }
+}
+
static inline int on_null_domain(struct rq *rq)
{
return unlikely(!rcu_dereference_sched(rq->sd));
@@ -9373,124 +9491,6 @@ out:
static inline void nohz_balancer_kick(struct rq *rq) { }
#endif
-static DEFINE_SPINLOCK(balancing);
-
-/*
- * Scale the max load_balance interval with the number of CPUs in the system.
- * This trades load-balance latency on larger machines for less cross talk.
- */
-void update_max_interval(void)
-{
- max_load_balance_interval = HZ*num_online_cpus()/10;
-}
-
-/*
- * It checks each scheduling domain to see if it is due to be balanced,
- * and initiates a balancing operation if so.
- *
- * Balancing parameters are set up in init_sched_domains.
- */
-static void rebalance_domains(struct rq *rq, enum cpu_idle_type idle)
-{
- int continue_balancing = 1;
- int cpu = rq->cpu;
- unsigned long interval;
- struct sched_domain *sd;
- /* Earliest time when we have to do rebalance again */
- unsigned long next_balance = jiffies + 60*HZ;
- int update_next_balance = 0;
- int need_serialize, need_decay = 0;
- u64 max_cost = 0;
-
- rcu_read_lock();
- for_each_domain(cpu, sd) {
- /*
- * Decay the newidle max times here because this is a regular
- * visit to all the domains. Decay ~1% per second.
- */
- if (time_after(jiffies, sd->next_decay_max_lb_cost)) {
- sd->max_newidle_lb_cost =
- (sd->max_newidle_lb_cost * 253) / 256;
- sd->next_decay_max_lb_cost = jiffies + HZ;
- need_decay = 1;
- }
- max_cost += sd->max_newidle_lb_cost;
-
- if (!(sd->flags & SD_LOAD_BALANCE))
- continue;
-
- /*
- * Stop the load balance at this level. There is another
- * CPU in our sched group which is doing load balancing more
- * actively.
- */
- if (!continue_balancing) {
- if (need_decay)
- continue;
- break;
- }
-
- interval = get_sd_balance_interval(sd, idle != CPU_IDLE);
-
- need_serialize = sd->flags & SD_SERIALIZE;
- if (need_serialize) {
- if (!spin_trylock(&balancing))
- goto out;
- }
-
- if (time_after_eq(jiffies, sd->last_balance + interval)) {
- if (load_balance(cpu, rq, sd, idle, &continue_balancing)) {
- /*
- * The LBF_DST_PINNED logic could have changed
- * env->dst_cpu, so we can't know our idle
- * state even if we migrated tasks. Update it.
- */
- idle = idle_cpu(cpu) ? CPU_IDLE : CPU_NOT_IDLE;
- }
- sd->last_balance = jiffies;
- interval = get_sd_balance_interval(sd, idle != CPU_IDLE);
- }
- if (need_serialize)
- spin_unlock(&balancing);
-out:
- if (time_after(next_balance, sd->last_balance + interval)) {
- next_balance = sd->last_balance + interval;
- update_next_balance = 1;
- }
- }
- if (need_decay) {
- /*
- * Ensure the rq-wide value also decays but keep it at a
- * reasonable floor to avoid funnies with rq->avg_idle.
- */
- rq->max_idle_balance_cost =
- max((u64)sysctl_sched_migration_cost, max_cost);
- }
- rcu_read_unlock();
-
- /*
- * next_balance will be updated only when there is a need.
- * When the CPU is attached to null domain for ex, it will not be
- * updated.
- */
- if (likely(update_next_balance)) {
- rq->next_balance = next_balance;
-
-#ifdef CONFIG_NO_HZ_COMMON
- /*
- * If this CPU has been elected to perform the nohz idle
- * balance. Other idle CPUs have already rebalanced with
- * nohz_idle_balance() and nohz.next_balance has been
- * updated accordingly. This CPU is now running the idle load
- * balance for itself and we need to update the
- * nohz.next_balance accordingly.
- */
- if ((idle == CPU_IDLE) && time_after(nohz.next_balance, rq->next_balance))
- nohz.next_balance = rq->next_balance;
-#endif
- }
-}
-
#ifdef CONFIG_NO_HZ_COMMON
/*
* In CONFIG_NO_HZ_COMMON case, the idle balance kickee will do the
--
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