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authorLinus Torvalds <torvalds@linux-foundation.org>2013-04-30 07:43:28 -0700
committerLinus Torvalds <torvalds@linux-foundation.org>2013-04-30 07:43:28 -0700
commit16fa94b532b1958f508e07eca1a9256351241fbc (patch)
tree90012a7b7fe2b8cf96f6f5ec12490e0c5e152291 /kernel/sched/fair.c
parente0972916e8fe943f342b0dd1c9d43dbf5bc261c2 (diff)
parent25f55d9d01ad7a7ad248fd5af1d22675ffd202c5 (diff)
downloadlinaro-lsk-16fa94b532b1958f508e07eca1a9256351241fbc.tar.gz
Merge branch 'sched-core-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip
Pull scheduler changes from Ingo Molnar: "The main changes in this development cycle were: - full dynticks preparatory work by Frederic Weisbecker - factor out the cpu time accounting code better, by Li Zefan - multi-CPU load balancer cleanups and improvements by Joonsoo Kim - various smaller fixes and cleanups" * 'sched-core-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip: (45 commits) sched: Fix init NOHZ_IDLE flag sched: Prevent to re-select dst-cpu in load_balance() sched: Rename load_balance_tmpmask to load_balance_mask sched: Move up affinity check to mitigate useless redoing overhead sched: Don't consider other cpus in our group in case of NEWLY_IDLE sched: Explicitly cpu_idle_type checking in rebalance_domains() sched: Change position of resched_cpu() in load_balance() sched: Fix wrong rq's runnable_avg update with rt tasks sched: Document task_struct::personality field sched/cpuacct/UML: Fix header file dependency bug on the UML build cgroup: Kill subsys.active flag sched/cpuacct: No need to check subsys active state sched/cpuacct: Initialize cpuacct subsystem earlier sched/cpuacct: Initialize root cpuacct earlier sched/cpuacct: Allocate per_cpu cpuusage for root cpuacct statically sched/cpuacct: Clean up cpuacct.h sched/cpuacct: Remove redundant NULL checks in cpuacct_acount_field() sched/cpuacct: Remove redundant NULL checks in cpuacct_charge() sched/cpuacct: Add cpuacct_acount_field() sched/cpuacct: Add cpuacct_init() ...
Diffstat (limited to 'kernel/sched/fair.c')
-rw-r--r--kernel/sched/fair.c148
1 files changed, 90 insertions, 58 deletions
diff --git a/kernel/sched/fair.c b/kernel/sched/fair.c
index 7a33e5986fc..8bf7081b1ec 100644
--- a/kernel/sched/fair.c
+++ b/kernel/sched/fair.c
@@ -431,13 +431,13 @@ void account_cfs_rq_runtime(struct cfs_rq *cfs_rq, unsigned long delta_exec);
* Scheduling class tree data structure manipulation methods:
*/
-static inline u64 max_vruntime(u64 min_vruntime, u64 vruntime)
+static inline u64 max_vruntime(u64 max_vruntime, u64 vruntime)
{
- s64 delta = (s64)(vruntime - min_vruntime);
+ s64 delta = (s64)(vruntime - max_vruntime);
if (delta > 0)
- min_vruntime = vruntime;
+ max_vruntime = vruntime;
- return min_vruntime;
+ return max_vruntime;
}
static inline u64 min_vruntime(u64 min_vruntime, u64 vruntime)
@@ -473,6 +473,7 @@ static void update_min_vruntime(struct cfs_rq *cfs_rq)
vruntime = min_vruntime(vruntime, se->vruntime);
}
+ /* ensure we never gain time by being placed backwards. */
cfs_rq->min_vruntime = max_vruntime(cfs_rq->min_vruntime, vruntime);
#ifndef CONFIG_64BIT
smp_wmb();
@@ -652,7 +653,7 @@ static u64 sched_slice(struct cfs_rq *cfs_rq, struct sched_entity *se)
}
/*
- * We calculate the vruntime slice of a to be inserted task
+ * We calculate the vruntime slice of a to-be-inserted task.
*
* vs = s/w
*/
@@ -1562,6 +1563,27 @@ static inline void dequeue_entity_load_avg(struct cfs_rq *cfs_rq,
se->avg.decay_count = atomic64_read(&cfs_rq->decay_counter);
} /* migrations, e.g. sleep=0 leave decay_count == 0 */
}
+
+/*
+ * Update the rq's load with the elapsed running time before entering
+ * idle. if the last scheduled task is not a CFS task, idle_enter will
+ * be the only way to update the runnable statistic.
+ */
+void idle_enter_fair(struct rq *this_rq)
+{
+ update_rq_runnable_avg(this_rq, 1);
+}
+
+/*
+ * Update the rq's load with the elapsed idle time before a task is
+ * scheduled. if the newly scheduled task is not a CFS task, idle_exit will
+ * be the only way to update the runnable statistic.
+ */
+void idle_exit_fair(struct rq *this_rq)
+{
+ update_rq_runnable_avg(this_rq, 0);
+}
+
#else
static inline void update_entity_load_avg(struct sched_entity *se,
int update_cfs_rq) {}
@@ -3874,12 +3896,16 @@ int can_migrate_task(struct task_struct *p, struct lb_env *env)
int tsk_cache_hot = 0;
/*
* We do not migrate tasks that are:
- * 1) running (obviously), or
+ * 1) throttled_lb_pair, or
* 2) cannot be migrated to this CPU due to cpus_allowed, or
- * 3) are cache-hot on their current CPU.
+ * 3) running (obviously), or
+ * 4) are cache-hot on their current CPU.
*/
+ if (throttled_lb_pair(task_group(p), env->src_cpu, env->dst_cpu))
+ return 0;
+
if (!cpumask_test_cpu(env->dst_cpu, tsk_cpus_allowed(p))) {
- int new_dst_cpu;
+ int cpu;
schedstat_inc(p, se.statistics.nr_failed_migrations_affine);
@@ -3894,12 +3920,15 @@ int can_migrate_task(struct task_struct *p, struct lb_env *env)
if (!env->dst_grpmask || (env->flags & LBF_SOME_PINNED))
return 0;
- new_dst_cpu = cpumask_first_and(env->dst_grpmask,
- tsk_cpus_allowed(p));
- if (new_dst_cpu < nr_cpu_ids) {
- env->flags |= LBF_SOME_PINNED;
- env->new_dst_cpu = new_dst_cpu;
+ /* Prevent to re-select dst_cpu via env's cpus */
+ for_each_cpu_and(cpu, env->dst_grpmask, env->cpus) {
+ if (cpumask_test_cpu(cpu, tsk_cpus_allowed(p))) {
+ env->flags |= LBF_SOME_PINNED;
+ env->new_dst_cpu = cpu;
+ break;
+ }
}
+
return 0;
}
@@ -3920,20 +3949,17 @@ int can_migrate_task(struct task_struct *p, struct lb_env *env)
tsk_cache_hot = task_hot(p, env->src_rq->clock_task, env->sd);
if (!tsk_cache_hot ||
env->sd->nr_balance_failed > env->sd->cache_nice_tries) {
-#ifdef CONFIG_SCHEDSTATS
+
if (tsk_cache_hot) {
schedstat_inc(env->sd, lb_hot_gained[env->idle]);
schedstat_inc(p, se.statistics.nr_forced_migrations);
}
-#endif
+
return 1;
}
- if (tsk_cache_hot) {
- schedstat_inc(p, se.statistics.nr_failed_migrations_hot);
- return 0;
- }
- return 1;
+ schedstat_inc(p, se.statistics.nr_failed_migrations_hot);
+ return 0;
}
/*
@@ -3948,9 +3974,6 @@ static int move_one_task(struct lb_env *env)
struct task_struct *p, *n;
list_for_each_entry_safe(p, n, &env->src_rq->cfs_tasks, se.group_node) {
- if (throttled_lb_pair(task_group(p), env->src_rq->cpu, env->dst_cpu))
- continue;
-
if (!can_migrate_task(p, env))
continue;
@@ -4002,7 +4025,7 @@ static int move_tasks(struct lb_env *env)
break;
}
- if (throttled_lb_pair(task_group(p), env->src_cpu, env->dst_cpu))
+ if (!can_migrate_task(p, env))
goto next;
load = task_h_load(p);
@@ -4013,9 +4036,6 @@ static int move_tasks(struct lb_env *env)
if ((load / 2) > env->imbalance)
goto next;
- if (!can_migrate_task(p, env))
- goto next;
-
move_task(p, env);
pulled++;
env->imbalance -= load;
@@ -4245,7 +4265,7 @@ static inline int get_sd_load_idx(struct sched_domain *sd,
return load_idx;
}
-unsigned long default_scale_freq_power(struct sched_domain *sd, int cpu)
+static unsigned long default_scale_freq_power(struct sched_domain *sd, int cpu)
{
return SCHED_POWER_SCALE;
}
@@ -4255,7 +4275,7 @@ unsigned long __weak arch_scale_freq_power(struct sched_domain *sd, int cpu)
return default_scale_freq_power(sd, cpu);
}
-unsigned long default_scale_smt_power(struct sched_domain *sd, int cpu)
+static unsigned long default_scale_smt_power(struct sched_domain *sd, int cpu)
{
unsigned long weight = sd->span_weight;
unsigned long smt_gain = sd->smt_gain;
@@ -4270,7 +4290,7 @@ unsigned long __weak arch_scale_smt_power(struct sched_domain *sd, int cpu)
return default_scale_smt_power(sd, cpu);
}
-unsigned long scale_rt_power(int cpu)
+static unsigned long scale_rt_power(int cpu)
{
struct rq *rq = cpu_rq(cpu);
u64 total, available, age_stamp, avg;
@@ -4960,7 +4980,7 @@ static struct rq *find_busiest_queue(struct lb_env *env,
#define MAX_PINNED_INTERVAL 512
/* Working cpumask for load_balance and load_balance_newidle. */
-DEFINE_PER_CPU(cpumask_var_t, load_balance_tmpmask);
+DEFINE_PER_CPU(cpumask_var_t, load_balance_mask);
static int need_active_balance(struct lb_env *env)
{
@@ -4991,11 +5011,10 @@ static int load_balance(int this_cpu, struct rq *this_rq,
int *balance)
{
int ld_moved, cur_ld_moved, active_balance = 0;
- int lb_iterations, max_lb_iterations;
struct sched_group *group;
struct rq *busiest;
unsigned long flags;
- struct cpumask *cpus = __get_cpu_var(load_balance_tmpmask);
+ struct cpumask *cpus = __get_cpu_var(load_balance_mask);
struct lb_env env = {
.sd = sd,
@@ -5007,8 +5026,14 @@ static int load_balance(int this_cpu, struct rq *this_rq,
.cpus = cpus,
};
+ /*
+ * For NEWLY_IDLE load_balancing, we don't need to consider
+ * other cpus in our group
+ */
+ if (idle == CPU_NEWLY_IDLE)
+ env.dst_grpmask = NULL;
+
cpumask_copy(cpus, cpu_active_mask);
- max_lb_iterations = cpumask_weight(env.dst_grpmask);
schedstat_inc(sd, lb_count[idle]);
@@ -5034,7 +5059,6 @@ redo:
schedstat_add(sd, lb_imbalance[idle], env.imbalance);
ld_moved = 0;
- lb_iterations = 1;
if (busiest->nr_running > 1) {
/*
* Attempt to move tasks. If find_busiest_group has found
@@ -5061,17 +5085,17 @@ more_balance:
double_rq_unlock(env.dst_rq, busiest);
local_irq_restore(flags);
- if (env.flags & LBF_NEED_BREAK) {
- env.flags &= ~LBF_NEED_BREAK;
- goto more_balance;
- }
-
/*
* some other cpu did the load balance for us.
*/
if (cur_ld_moved && env.dst_cpu != smp_processor_id())
resched_cpu(env.dst_cpu);
+ if (env.flags & LBF_NEED_BREAK) {
+ env.flags &= ~LBF_NEED_BREAK;
+ goto more_balance;
+ }
+
/*
* Revisit (affine) tasks on src_cpu that couldn't be moved to
* us and move them to an alternate dst_cpu in our sched_group
@@ -5091,14 +5115,17 @@ more_balance:
* moreover subsequent load balance cycles should correct the
* excess load moved.
*/
- if ((env.flags & LBF_SOME_PINNED) && env.imbalance > 0 &&
- lb_iterations++ < max_lb_iterations) {
+ if ((env.flags & LBF_SOME_PINNED) && env.imbalance > 0) {
env.dst_rq = cpu_rq(env.new_dst_cpu);
env.dst_cpu = env.new_dst_cpu;
env.flags &= ~LBF_SOME_PINNED;
env.loop = 0;
env.loop_break = sched_nr_migrate_break;
+
+ /* Prevent to re-select dst_cpu via env's cpus */
+ cpumask_clear_cpu(env.dst_cpu, env.cpus);
+
/*
* Go back to "more_balance" rather than "redo" since we
* need to continue with same src_cpu.
@@ -5219,8 +5246,6 @@ void idle_balance(int this_cpu, struct rq *this_rq)
if (this_rq->avg_idle < sysctl_sched_migration_cost)
return;
- update_rq_runnable_avg(this_rq, 1);
-
/*
* Drop the rq->lock, but keep IRQ/preempt disabled.
*/
@@ -5395,13 +5420,16 @@ static inline void set_cpu_sd_state_busy(void)
struct sched_domain *sd;
int cpu = smp_processor_id();
- if (!test_bit(NOHZ_IDLE, nohz_flags(cpu)))
- return;
- clear_bit(NOHZ_IDLE, nohz_flags(cpu));
-
rcu_read_lock();
- for_each_domain(cpu, sd)
+ sd = rcu_dereference_check_sched_domain(cpu_rq(cpu)->sd);
+
+ if (!sd || !sd->nohz_idle)
+ goto unlock;
+ sd->nohz_idle = 0;
+
+ for (; sd; sd = sd->parent)
atomic_inc(&sd->groups->sgp->nr_busy_cpus);
+unlock:
rcu_read_unlock();
}
@@ -5410,13 +5438,16 @@ void set_cpu_sd_state_idle(void)
struct sched_domain *sd;
int cpu = smp_processor_id();
- if (test_bit(NOHZ_IDLE, nohz_flags(cpu)))
- return;
- set_bit(NOHZ_IDLE, nohz_flags(cpu));
-
rcu_read_lock();
- for_each_domain(cpu, sd)
+ sd = rcu_dereference_check_sched_domain(cpu_rq(cpu)->sd);
+
+ if (!sd || sd->nohz_idle)
+ goto unlock;
+ sd->nohz_idle = 1;
+
+ for (; sd; sd = sd->parent)
atomic_dec(&sd->groups->sgp->nr_busy_cpus);
+unlock:
rcu_read_unlock();
}
@@ -5468,7 +5499,7 @@ void update_max_interval(void)
* 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 arch_init_sched_domains.
+ * Balancing parameters are set up in init_sched_domains.
*/
static void rebalance_domains(int cpu, enum cpu_idle_type idle)
{
@@ -5506,10 +5537,11 @@ static void rebalance_domains(int cpu, enum cpu_idle_type idle)
if (time_after_eq(jiffies, sd->last_balance + interval)) {
if (load_balance(cpu, rq, sd, idle, &balance)) {
/*
- * We've pulled tasks over so either we're no
- * longer idle.
+ * The LBF_SOME_PINNED logic could have changed
+ * env->dst_cpu, so we can't know our idle
+ * state even if we migrated tasks. Update it.
*/
- idle = CPU_NOT_IDLE;
+ idle = idle_cpu(cpu) ? CPU_IDLE : CPU_NOT_IDLE;
}
sd->last_balance = jiffies;
}