sched: Rename load-balancing fields
s/env->this_/env->dst_/g s/env->busiest_/env->src_/g s/pull_task/move_task/g Makes everything clearer. Signed-off-by: Peter Zijlstra <a.p.zijlstra@chello.nl> Cc: pjt@google.com Link: http://lkml.kernel.org/n/tip-0yvgms8t8x962drpvl0fu0kk@git.kernel.org Signed-off-by: Ingo Molnar <mingo@elte.hu>
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@ -2918,7 +2918,7 @@ static void check_preempt_wakeup(struct rq *rq, struct task_struct *p, int wake_
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return;
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/*
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* This is possible from callers such as pull_task(), in which we
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* This is possible from callers such as move_task(), in which we
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* unconditionally check_prempt_curr() after an enqueue (which may have
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* lead to a throttle). This both saves work and prevents false
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* next-buddy nomination below.
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@ -3084,17 +3084,37 @@ static bool yield_to_task_fair(struct rq *rq, struct task_struct *p, bool preemp
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static unsigned long __read_mostly max_load_balance_interval = HZ/10;
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#define LBF_ALL_PINNED 0x01
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#define LBF_NEED_BREAK 0x02 /* clears into HAD_BREAK */
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#define LBF_HAD_BREAK 0x04
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#define LBF_HAD_BREAKS 0x0C /* count HAD_BREAKs overflows into ABORT */
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#define LBF_ABORT 0x10
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struct lb_env {
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struct sched_domain *sd;
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int src_cpu;
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struct rq *src_rq;
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struct cfs_rq *src_cfs_rq;
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int dst_cpu;
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struct rq *dst_rq;
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enum cpu_idle_type idle;
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unsigned long max_load_move;
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unsigned int flags;
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};
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/*
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* pull_task - move a task from a remote runqueue to the local runqueue.
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* move_task - move a task from one runqueue to another runqueue.
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* Both runqueues must be locked.
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*/
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static void pull_task(struct rq *src_rq, struct task_struct *p,
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struct rq *this_rq, int this_cpu)
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static void move_task(struct task_struct *p, struct lb_env *env)
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{
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deactivate_task(src_rq, p, 0);
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set_task_cpu(p, this_cpu);
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activate_task(this_rq, p, 0);
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check_preempt_curr(this_rq, p, 0);
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deactivate_task(env->src_rq, p, 0);
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set_task_cpu(p, env->dst_cpu);
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activate_task(env->dst_rq, p, 0);
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check_preempt_curr(env->dst_rq, p, 0);
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}
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/*
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@ -3129,26 +3149,6 @@ task_hot(struct task_struct *p, u64 now, struct sched_domain *sd)
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return delta < (s64)sysctl_sched_migration_cost;
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}
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#define LBF_ALL_PINNED 0x01
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#define LBF_NEED_BREAK 0x02 /* clears into HAD_BREAK */
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#define LBF_HAD_BREAK 0x04
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#define LBF_HAD_BREAKS 0x0C /* count HAD_BREAKs overflows into ABORT */
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#define LBF_ABORT 0x10
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struct lb_env {
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struct sched_domain *sd;
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int this_cpu;
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struct rq *this_rq;
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struct rq *busiest_rq;
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struct cfs_rq *busiest_cfs_rq;
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enum cpu_idle_type idle;
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unsigned long max_load_move;
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unsigned int flags;
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};
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/*
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* can_migrate_task - may task p from runqueue rq be migrated to this_cpu?
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*/
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@ -3162,13 +3162,13 @@ int can_migrate_task(struct task_struct *p, struct lb_env *env)
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* 2) cannot be migrated to this CPU due to cpus_allowed, or
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* 3) are cache-hot on their current CPU.
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*/
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if (!cpumask_test_cpu(env->this_cpu, tsk_cpus_allowed(p))) {
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if (!cpumask_test_cpu(env->dst_cpu, tsk_cpus_allowed(p))) {
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schedstat_inc(p, se.statistics.nr_failed_migrations_affine);
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return 0;
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}
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env->flags &= ~LBF_ALL_PINNED;
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if (task_running(env->busiest_rq, p)) {
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if (task_running(env->src_rq, p)) {
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schedstat_inc(p, se.statistics.nr_failed_migrations_running);
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return 0;
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}
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@ -3179,7 +3179,7 @@ int can_migrate_task(struct task_struct *p, struct lb_env *env)
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* 2) too many balance attempts have failed.
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*/
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tsk_cache_hot = task_hot(p, env->busiest_rq->clock_task, env->sd);
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tsk_cache_hot = task_hot(p, env->src_rq->clock_task, env->sd);
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if (!tsk_cache_hot ||
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env->sd->nr_balance_failed > env->sd->cache_nice_tries) {
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#ifdef CONFIG_SCHEDSTATS
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@ -3210,20 +3210,20 @@ static int move_one_task(struct lb_env *env)
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struct task_struct *p, *n;
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struct cfs_rq *cfs_rq;
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for_each_leaf_cfs_rq(env->busiest_rq, cfs_rq) {
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for_each_leaf_cfs_rq(env->src_rq, cfs_rq) {
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list_for_each_entry_safe(p, n, &cfs_rq->tasks, se.group_node) {
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if (throttled_lb_pair(task_group(p),
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env->busiest_rq->cpu, env->this_cpu))
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env->src_cpu, env->dst_cpu))
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break;
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if (!can_migrate_task(p, env))
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continue;
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pull_task(env->busiest_rq, p, env->this_rq, env->this_cpu);
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move_task(p, env);
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/*
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* Right now, this is only the second place pull_task()
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* is called, so we can safely collect pull_task()
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* stats here rather than inside pull_task().
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* Right now, this is only the second place move_task()
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* is called, so we can safely collect move_task()
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* stats here rather than inside move_task().
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*/
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schedstat_inc(env->sd, lb_gained[env->idle]);
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return 1;
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@ -3242,7 +3242,7 @@ static unsigned long balance_tasks(struct lb_env *env)
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if (env->max_load_move == 0)
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goto out;
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list_for_each_entry_safe(p, n, &env->busiest_cfs_rq->tasks, se.group_node) {
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list_for_each_entry_safe(p, n, &env->src_cfs_rq->tasks, se.group_node) {
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if (loops++ > sysctl_sched_nr_migrate) {
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env->flags |= LBF_NEED_BREAK;
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break;
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@ -3252,7 +3252,7 @@ static unsigned long balance_tasks(struct lb_env *env)
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!can_migrate_task(p, env))
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continue;
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pull_task(env->busiest_rq, p, env->this_rq, env->this_cpu);
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move_task(p, env);
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pulled++;
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rem_load_move -= p->se.load.weight;
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@ -3277,9 +3277,9 @@ static unsigned long balance_tasks(struct lb_env *env)
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}
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out:
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/*
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* Right now, this is one of only two places pull_task() is called,
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* so we can safely collect pull_task() stats here rather than
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* inside pull_task().
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* Right now, this is one of only two places move_task() is called,
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* so we can safely collect move_task() stats here rather than
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* inside move_task().
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*/
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schedstat_add(env->sd, lb_gained[env->idle], pulled);
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@ -3372,11 +3372,11 @@ static unsigned long load_balance_fair(struct lb_env *env)
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long rem_load_move = env->max_load_move;
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rcu_read_lock();
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update_h_load(cpu_of(env->busiest_rq));
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update_h_load(cpu_of(env->src_rq));
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for_each_leaf_cfs_rq(env->busiest_rq, env->busiest_cfs_rq) {
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unsigned long busiest_h_load = env->busiest_cfs_rq->h_load;
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unsigned long busiest_weight = env->busiest_cfs_rq->load.weight;
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for_each_leaf_cfs_rq(env->src_rq, env->src_cfs_rq) {
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unsigned long busiest_h_load = env->src_cfs_rq->h_load;
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unsigned long busiest_weight = env->src_cfs_rq->load.weight;
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u64 rem_load, moved_load;
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if (env->flags & (LBF_NEED_BREAK|LBF_ABORT))
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@ -3385,12 +3385,12 @@ static unsigned long load_balance_fair(struct lb_env *env)
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/*
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* empty group or part of a throttled hierarchy
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*/
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if (!env->busiest_cfs_rq->task_weight)
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if (!env->src_cfs_rq->task_weight)
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continue;
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if (throttled_lb_pair(env->busiest_cfs_rq->tg,
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cpu_of(env->busiest_rq),
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env->this_cpu))
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if (throttled_lb_pair(env->src_cfs_rq->tg,
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cpu_of(env->src_rq),
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env->dst_cpu))
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continue;
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rem_load = (u64)rem_load_move * busiest_weight;
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@ -3420,7 +3420,7 @@ static inline void update_shares(int cpu)
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static unsigned long load_balance_fair(struct lb_env *env)
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{
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env->busiest_cfs_rq = &env->busiest_rq->cfs;
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env->src_cfs_rq = &env->src_rq->cfs;
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return balance_tasks(env);
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}
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#endif
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@ -3451,7 +3451,7 @@ static int move_tasks(struct lb_env *env)
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* kernels will stop after the first task is pulled to minimize
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* the critical section.
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*/
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if (env->idle == CPU_NEWLY_IDLE && env->this_rq->nr_running) {
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if (env->idle == CPU_NEWLY_IDLE && env->dst_rq->nr_running) {
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env->flags |= LBF_ABORT;
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break;
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}
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@ -4461,8 +4461,8 @@ static int load_balance(int this_cpu, struct rq *this_rq,
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struct lb_env env = {
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.sd = sd,
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.this_cpu = this_cpu,
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.this_rq = this_rq,
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.dst_cpu = this_cpu,
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.dst_rq = this_rq,
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.idle = idle,
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};
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@ -4502,7 +4502,8 @@ redo:
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*/
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env.flags |= LBF_ALL_PINNED;
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env.max_load_move = imbalance;
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env.busiest_rq = busiest;
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env.src_cpu = busiest->cpu;
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env.src_rq = busiest;
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local_irq_save(flags);
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double_rq_lock(this_rq, busiest);
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@ -4722,9 +4723,10 @@ static int active_load_balance_cpu_stop(void *data)
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if (likely(sd)) {
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struct lb_env env = {
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.sd = sd,
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.this_cpu = target_cpu,
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.this_rq = target_rq,
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.busiest_rq = busiest_rq,
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.dst_cpu = target_cpu,
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.dst_rq = target_rq,
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.src_cpu = busiest_rq->cpu,
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.src_rq = busiest_rq,
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.idle = CPU_IDLE,
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};
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