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-rw-r--r--kernel/sched_fair.c126
1 files changed, 87 insertions, 39 deletions
diff --git a/kernel/sched_fair.c b/kernel/sched_fair.c
index 6fa833ab2cb..37f22626225 100644
--- a/kernel/sched_fair.c
+++ b/kernel/sched_fair.c
@@ -358,6 +358,10 @@ static void update_min_vruntime(struct cfs_rq *cfs_rq)
}
cfs_rq->min_vruntime = max_vruntime(cfs_rq->min_vruntime, vruntime);
+#ifndef CONFIG_64BIT
+ smp_wmb();
+ cfs_rq->min_vruntime_copy = cfs_rq->min_vruntime;
+#endif
}
/*
@@ -1340,6 +1344,8 @@ enqueue_task_fair(struct rq *rq, struct task_struct *p, int flags)
hrtick_update(rq);
}
+static void set_next_buddy(struct sched_entity *se);
+
/*
* The dequeue_task method is called before nr_running is
* decreased. We remove the task from the rbtree and
@@ -1349,14 +1355,22 @@ static void dequeue_task_fair(struct rq *rq, struct task_struct *p, int flags)
{
struct cfs_rq *cfs_rq;
struct sched_entity *se = &p->se;
+ int task_sleep = flags & DEQUEUE_SLEEP;
for_each_sched_entity(se) {
cfs_rq = cfs_rq_of(se);
dequeue_entity(cfs_rq, se, flags);
/* Don't dequeue parent if it has other entities besides us */
- if (cfs_rq->load.weight)
+ if (cfs_rq->load.weight) {
+ /*
+ * Bias pick_next to pick a task from this cfs_rq, as
+ * p is sleeping when it is within its sched_slice.
+ */
+ if (task_sleep && parent_entity(se))
+ set_next_buddy(parent_entity(se));
break;
+ }
flags |= DEQUEUE_SLEEP;
}
@@ -1372,12 +1386,25 @@ static void dequeue_task_fair(struct rq *rq, struct task_struct *p, int flags)
#ifdef CONFIG_SMP
-static void task_waking_fair(struct rq *rq, struct task_struct *p)
+static void task_waking_fair(struct task_struct *p)
{
struct sched_entity *se = &p->se;
struct cfs_rq *cfs_rq = cfs_rq_of(se);
+ u64 min_vruntime;
- se->vruntime -= cfs_rq->min_vruntime;
+#ifndef CONFIG_64BIT
+ u64 min_vruntime_copy;
+
+ do {
+ min_vruntime_copy = cfs_rq->min_vruntime_copy;
+ smp_rmb();
+ min_vruntime = cfs_rq->min_vruntime;
+ } while (min_vruntime != min_vruntime_copy);
+#else
+ min_vruntime = cfs_rq->min_vruntime;
+#endif
+
+ se->vruntime -= min_vruntime;
}
#ifdef CONFIG_FAIR_GROUP_SCHED
@@ -1622,6 +1649,7 @@ static int select_idle_sibling(struct task_struct *p, int target)
/*
* Otherwise, iterate the domains and find an elegible idle cpu.
*/
+ rcu_read_lock();
for_each_domain(target, sd) {
if (!(sd->flags & SD_SHARE_PKG_RESOURCES))
break;
@@ -1641,6 +1669,7 @@ static int select_idle_sibling(struct task_struct *p, int target)
cpumask_test_cpu(prev_cpu, sched_domain_span(sd)))
break;
}
+ rcu_read_unlock();
return target;
}
@@ -1657,7 +1686,7 @@ static int select_idle_sibling(struct task_struct *p, int target)
* preempt must be disabled.
*/
static int
-select_task_rq_fair(struct rq *rq, struct task_struct *p, int sd_flag, int wake_flags)
+select_task_rq_fair(struct task_struct *p, int sd_flag, int wake_flags)
{
struct sched_domain *tmp, *affine_sd = NULL, *sd = NULL;
int cpu = smp_processor_id();
@@ -1673,6 +1702,7 @@ select_task_rq_fair(struct rq *rq, struct task_struct *p, int sd_flag, int wake_
new_cpu = prev_cpu;
}
+ rcu_read_lock();
for_each_domain(cpu, tmp) {
if (!(tmp->flags & SD_LOAD_BALANCE))
continue;
@@ -1723,9 +1753,10 @@ select_task_rq_fair(struct rq *rq, struct task_struct *p, int sd_flag, int wake_
if (affine_sd) {
if (cpu == prev_cpu || wake_affine(affine_sd, p, sync))
- return select_idle_sibling(p, cpu);
- else
- return select_idle_sibling(p, prev_cpu);
+ prev_cpu = cpu;
+
+ new_cpu = select_idle_sibling(p, prev_cpu);
+ goto unlock;
}
while (sd) {
@@ -1766,6 +1797,8 @@ select_task_rq_fair(struct rq *rq, struct task_struct *p, int sd_flag, int wake_
}
/* while loop will break here if sd == NULL */
}
+unlock:
+ rcu_read_unlock();
return new_cpu;
}
@@ -1789,10 +1822,7 @@ wakeup_gran(struct sched_entity *curr, struct sched_entity *se)
* This is especially important for buddies when the leftmost
* task is higher priority than the buddy.
*/
- if (unlikely(se->load.weight != NICE_0_LOAD))
- gran = calc_delta_fair(gran, se);
-
- return gran;
+ return calc_delta_fair(gran, se);
}
/*
@@ -1826,26 +1856,26 @@ wakeup_preempt_entity(struct sched_entity *curr, struct sched_entity *se)
static void set_last_buddy(struct sched_entity *se)
{
- if (likely(task_of(se)->policy != SCHED_IDLE)) {
- for_each_sched_entity(se)
- cfs_rq_of(se)->last = se;
- }
+ if (entity_is_task(se) && unlikely(task_of(se)->policy == SCHED_IDLE))
+ return;
+
+ for_each_sched_entity(se)
+ cfs_rq_of(se)->last = se;
}
static void set_next_buddy(struct sched_entity *se)
{
- if (likely(task_of(se)->policy != SCHED_IDLE)) {
- for_each_sched_entity(se)
- cfs_rq_of(se)->next = se;
- }
+ if (entity_is_task(se) && unlikely(task_of(se)->policy == SCHED_IDLE))
+ return;
+
+ for_each_sched_entity(se)
+ cfs_rq_of(se)->next = se;
}
static void set_skip_buddy(struct sched_entity *se)
{
- if (likely(task_of(se)->policy != SCHED_IDLE)) {
- for_each_sched_entity(se)
- cfs_rq_of(se)->skip = se;
- }
+ for_each_sched_entity(se)
+ cfs_rq_of(se)->skip = se;
}
/*
@@ -1857,12 +1887,15 @@ static void check_preempt_wakeup(struct rq *rq, struct task_struct *p, int wake_
struct sched_entity *se = &curr->se, *pse = &p->se;
struct cfs_rq *cfs_rq = task_cfs_rq(curr);
int scale = cfs_rq->nr_running >= sched_nr_latency;
+ int next_buddy_marked = 0;
if (unlikely(se == pse))
return;
- if (sched_feat(NEXT_BUDDY) && scale && !(wake_flags & WF_FORK))
+ if (sched_feat(NEXT_BUDDY) && scale && !(wake_flags & WF_FORK)) {
set_next_buddy(pse);
+ next_buddy_marked = 1;
+ }
/*
* We can come here with TIF_NEED_RESCHED already set from new task
@@ -1890,8 +1923,15 @@ static void check_preempt_wakeup(struct rq *rq, struct task_struct *p, int wake_
update_curr(cfs_rq);
find_matching_se(&se, &pse);
BUG_ON(!pse);
- if (wakeup_preempt_entity(se, pse) == 1)
+ if (wakeup_preempt_entity(se, pse) == 1) {
+ /*
+ * Bias pick_next to pick the sched entity that is
+ * triggering this preemption.
+ */
+ if (!next_buddy_marked)
+ set_next_buddy(pse);
goto preempt;
+ }
return;
@@ -2102,7 +2142,7 @@ static unsigned long
balance_tasks(struct rq *this_rq, int this_cpu, struct rq *busiest,
unsigned long max_load_move, struct sched_domain *sd,
enum cpu_idle_type idle, int *all_pinned,
- int *this_best_prio, struct cfs_rq *busiest_cfs_rq)
+ struct cfs_rq *busiest_cfs_rq)
{
int loops = 0, pulled = 0;
long rem_load_move = max_load_move;
@@ -2140,9 +2180,6 @@ balance_tasks(struct rq *this_rq, int this_cpu, struct rq *busiest,
*/
if (rem_load_move <= 0)
break;
-
- if (p->prio < *this_best_prio)
- *this_best_prio = p->prio;
}
out:
/*
@@ -2202,7 +2239,7 @@ static unsigned long
load_balance_fair(struct rq *this_rq, int this_cpu, struct rq *busiest,
unsigned long max_load_move,
struct sched_domain *sd, enum cpu_idle_type idle,
- int *all_pinned, int *this_best_prio)
+ int *all_pinned)
{
long rem_load_move = max_load_move;
int busiest_cpu = cpu_of(busiest);
@@ -2227,7 +2264,7 @@ load_balance_fair(struct rq *this_rq, int this_cpu, struct rq *busiest,
rem_load = div_u64(rem_load, busiest_h_load + 1);
moved_load = balance_tasks(this_rq, this_cpu, busiest,
- rem_load, sd, idle, all_pinned, this_best_prio,
+ rem_load, sd, idle, all_pinned,
busiest_cfs_rq);
if (!moved_load)
@@ -2253,11 +2290,11 @@ static unsigned long
load_balance_fair(struct rq *this_rq, int this_cpu, struct rq *busiest,
unsigned long max_load_move,
struct sched_domain *sd, enum cpu_idle_type idle,
- int *all_pinned, int *this_best_prio)
+ int *all_pinned)
{
return balance_tasks(this_rq, this_cpu, busiest,
max_load_move, sd, idle, all_pinned,
- this_best_prio, &busiest->cfs);
+ &busiest->cfs);
}
#endif
@@ -2274,12 +2311,11 @@ static int move_tasks(struct rq *this_rq, int this_cpu, struct rq *busiest,
int *all_pinned)
{
unsigned long total_load_moved = 0, load_moved;
- int this_best_prio = this_rq->curr->prio;
do {
load_moved = load_balance_fair(this_rq, this_cpu, busiest,
max_load_move - total_load_moved,
- sd, idle, all_pinned, &this_best_prio);
+ sd, idle, all_pinned);
total_load_moved += load_moved;
@@ -2648,7 +2684,7 @@ fix_small_capacity(struct sched_domain *sd, struct sched_group *group)
/*
* Only siblings can have significantly less than SCHED_LOAD_SCALE
*/
- if (sd->level != SD_LV_SIBLING)
+ if (!(sd->flags & SD_SHARE_CPUPOWER))
return 0;
/*
@@ -3465,6 +3501,7 @@ static void idle_balance(int this_cpu, struct rq *this_rq)
raw_spin_unlock(&this_rq->lock);
update_shares(this_cpu);
+ rcu_read_lock();
for_each_domain(this_cpu, sd) {
unsigned long interval;
int balance = 1;
@@ -3486,6 +3523,7 @@ static void idle_balance(int this_cpu, struct rq *this_rq)
break;
}
}
+ rcu_read_unlock();
raw_spin_lock(&this_rq->lock);
@@ -3534,6 +3572,7 @@ static int active_load_balance_cpu_stop(void *data)
double_lock_balance(busiest_rq, target_rq);
/* Search for an sd spanning us and the target CPU. */
+ rcu_read_lock();
for_each_domain(target_cpu, sd) {
if ((sd->flags & SD_LOAD_BALANCE) &&
cpumask_test_cpu(busiest_cpu, sched_domain_span(sd)))
@@ -3549,6 +3588,7 @@ static int active_load_balance_cpu_stop(void *data)
else
schedstat_inc(sd, alb_failed);
}
+ rcu_read_unlock();
double_unlock_balance(busiest_rq, target_rq);
out_unlock:
busiest_rq->active_balance = 0;
@@ -3675,6 +3715,7 @@ static int find_new_ilb(int cpu)
{
struct sched_domain *sd;
struct sched_group *ilb_group;
+ int ilb = nr_cpu_ids;
/*
* Have idle load balancer selection from semi-idle packages only
@@ -3690,20 +3731,25 @@ static int find_new_ilb(int cpu)
if (cpumask_weight(nohz.idle_cpus_mask) < 2)
goto out_done;
+ rcu_read_lock();
for_each_flag_domain(cpu, sd, SD_POWERSAVINGS_BALANCE) {
ilb_group = sd->groups;
do {
- if (is_semi_idle_group(ilb_group))
- return cpumask_first(nohz.grp_idle_mask);
+ if (is_semi_idle_group(ilb_group)) {
+ ilb = cpumask_first(nohz.grp_idle_mask);
+ goto unlock;
+ }
ilb_group = ilb_group->next;
} while (ilb_group != sd->groups);
}
+unlock:
+ rcu_read_unlock();
out_done:
- return nr_cpu_ids;
+ return ilb;
}
#else /* (CONFIG_SCHED_MC || CONFIG_SCHED_SMT) */
static inline int find_new_ilb(int call_cpu)
@@ -3848,6 +3894,7 @@ static void rebalance_domains(int cpu, enum cpu_idle_type idle)
update_shares(cpu);
+ rcu_read_lock();
for_each_domain(cpu, sd) {
if (!(sd->flags & SD_LOAD_BALANCE))
continue;
@@ -3893,6 +3940,7 @@ out:
if (!balance)
break;
}
+ rcu_read_unlock();
/*
* next_balance will be updated only when there is a need.