aboutsummaryrefslogtreecommitdiff
path: root/kernel
diff options
context:
space:
mode:
Diffstat (limited to 'kernel')
-rw-r--r--kernel/Kconfig.preempt3
-rw-r--r--kernel/sched.c117
-rw-r--r--kernel/sched_autogroup.h1
-rw-r--r--kernel/sched_fair.c72
-rw-r--r--kernel/sched_rt.c26
5 files changed, 101 insertions, 118 deletions
diff --git a/kernel/Kconfig.preempt b/kernel/Kconfig.preempt
index bf987b95b356..24e7cb0ba26a 100644
--- a/kernel/Kconfig.preempt
+++ b/kernel/Kconfig.preempt
@@ -35,6 +35,7 @@ config PREEMPT_VOLUNTARY
config PREEMPT
bool "Preemptible Kernel (Low-Latency Desktop)"
+ select PREEMPT_COUNT
help
This option reduces the latency of the kernel by making
all kernel code (that is not executing in a critical section)
@@ -52,3 +53,5 @@ config PREEMPT
endchoice
+config PREEMPT_COUNT
+ bool \ No newline at end of file
diff --git a/kernel/sched.c b/kernel/sched.c
index 84b9e076812e..9aaf567c5da5 100644
--- a/kernel/sched.c
+++ b/kernel/sched.c
@@ -124,7 +124,7 @@
static inline int rt_policy(int policy)
{
- if (unlikely(policy == SCHED_FIFO || policy == SCHED_RR))
+ if (policy == SCHED_FIFO || policy == SCHED_RR)
return 1;
return 0;
}
@@ -422,6 +422,7 @@ struct rt_rq {
*/
struct root_domain {
atomic_t refcount;
+ atomic_t rto_count;
struct rcu_head rcu;
cpumask_var_t span;
cpumask_var_t online;
@@ -431,7 +432,6 @@ struct root_domain {
* one runnable RT task.
*/
cpumask_var_t rto_mask;
- atomic_t rto_count;
struct cpupri cpupri;
};
@@ -1568,38 +1568,6 @@ static unsigned long cpu_avg_load_per_task(int cpu)
return rq->avg_load_per_task;
}
-#ifdef CONFIG_FAIR_GROUP_SCHED
-
-/*
- * Compute the cpu's hierarchical load factor for each task group.
- * This needs to be done in a top-down fashion because the load of a child
- * group is a fraction of its parents load.
- */
-static int tg_load_down(struct task_group *tg, void *data)
-{
- unsigned long load;
- long cpu = (long)data;
-
- if (!tg->parent) {
- load = cpu_rq(cpu)->load.weight;
- } else {
- load = tg->parent->cfs_rq[cpu]->h_load;
- load *= tg->se[cpu]->load.weight;
- load /= tg->parent->cfs_rq[cpu]->load.weight + 1;
- }
-
- tg->cfs_rq[cpu]->h_load = load;
-
- return 0;
-}
-
-static void update_h_load(long cpu)
-{
- walk_tg_tree(tg_load_down, tg_nop, (void *)cpu);
-}
-
-#endif
-
#ifdef CONFIG_PREEMPT
static void double_rq_lock(struct rq *rq1, struct rq *rq2);
@@ -2497,7 +2465,7 @@ ttwu_do_wakeup(struct rq *rq, struct task_struct *p, int wake_flags)
if (p->sched_class->task_woken)
p->sched_class->task_woken(rq, p);
- if (unlikely(rq->idle_stamp)) {
+ if (rq->idle_stamp) {
u64 delta = rq->clock - rq->idle_stamp;
u64 max = 2*sysctl_sched_migration_cost;
@@ -2886,7 +2854,7 @@ void sched_fork(struct task_struct *p)
#if defined(CONFIG_SMP)
p->on_cpu = 0;
#endif
-#ifdef CONFIG_PREEMPT
+#ifdef CONFIG_PREEMPT_COUNT
/* Want to start with kernel preemption disabled. */
task_thread_info(p)->preempt_count = 1;
#endif
@@ -4338,11 +4306,8 @@ EXPORT_SYMBOL(schedule);
static inline bool owner_running(struct mutex *lock, struct task_struct *owner)
{
- bool ret = false;
-
- rcu_read_lock();
if (lock->owner != owner)
- goto fail;
+ return false;
/*
* Ensure we emit the owner->on_cpu, dereference _after_ checking
@@ -4352,11 +4317,7 @@ static inline bool owner_running(struct mutex *lock, struct task_struct *owner)
*/
barrier();
- ret = owner->on_cpu;
-fail:
- rcu_read_unlock();
-
- return ret;
+ return owner->on_cpu;
}
/*
@@ -4368,21 +4329,21 @@ int mutex_spin_on_owner(struct mutex *lock, struct task_struct *owner)
if (!sched_feat(OWNER_SPIN))
return 0;
+ rcu_read_lock();
while (owner_running(lock, owner)) {
if (need_resched())
- return 0;
+ break;
arch_mutex_cpu_relax();
}
+ rcu_read_unlock();
/*
- * If the owner changed to another task there is likely
- * heavy contention, stop spinning.
+ * We break out the loop above on need_resched() and when the
+ * owner changed, which is a sign for heavy contention. Return
+ * success only when lock->owner is NULL.
*/
- if (lock->owner)
- return 0;
-
- return 1;
+ return lock->owner == NULL;
}
#endif
@@ -7898,17 +7859,10 @@ int in_sched_functions(unsigned long addr)
&& addr < (unsigned long)__sched_text_end);
}
-static void init_cfs_rq(struct cfs_rq *cfs_rq, struct rq *rq)
+static void init_cfs_rq(struct cfs_rq *cfs_rq)
{
cfs_rq->tasks_timeline = RB_ROOT;
INIT_LIST_HEAD(&cfs_rq->tasks);
-#ifdef CONFIG_FAIR_GROUP_SCHED
- cfs_rq->rq = rq;
- /* allow initial update_cfs_load() to truncate */
-#ifdef CONFIG_SMP
- cfs_rq->load_stamp = 1;
-#endif
-#endif
cfs_rq->min_vruntime = (u64)(-(1LL << 20));
#ifndef CONFIG_64BIT
cfs_rq->min_vruntime_copy = cfs_rq->min_vruntime;
@@ -7928,13 +7882,9 @@ static void init_rt_rq(struct rt_rq *rt_rq, struct rq *rq)
/* delimiter for bitsearch: */
__set_bit(MAX_RT_PRIO, array->bitmap);
-#if defined CONFIG_SMP || defined CONFIG_RT_GROUP_SCHED
+#if defined CONFIG_SMP
rt_rq->highest_prio.curr = MAX_RT_PRIO;
-#ifdef CONFIG_SMP
rt_rq->highest_prio.next = MAX_RT_PRIO;
-#endif
-#endif
-#ifdef CONFIG_SMP
rt_rq->rt_nr_migratory = 0;
rt_rq->overloaded = 0;
plist_head_init(&rt_rq->pushable_tasks);
@@ -7944,11 +7894,6 @@ static void init_rt_rq(struct rt_rq *rt_rq, struct rq *rq)
rt_rq->rt_throttled = 0;
rt_rq->rt_runtime = 0;
raw_spin_lock_init(&rt_rq->rt_runtime_lock);
-
-#ifdef CONFIG_RT_GROUP_SCHED
- rt_rq->rt_nr_boosted = 0;
- rt_rq->rq = rq;
-#endif
}
#ifdef CONFIG_FAIR_GROUP_SCHED
@@ -7957,11 +7902,17 @@ static void init_tg_cfs_entry(struct task_group *tg, struct cfs_rq *cfs_rq,
struct sched_entity *parent)
{
struct rq *rq = cpu_rq(cpu);
- tg->cfs_rq[cpu] = cfs_rq;
- init_cfs_rq(cfs_rq, rq);
+
cfs_rq->tg = tg;
+ cfs_rq->rq = rq;
+#ifdef CONFIG_SMP
+ /* allow initial update_cfs_load() to truncate */
+ cfs_rq->load_stamp = 1;
+#endif
+ tg->cfs_rq[cpu] = cfs_rq;
tg->se[cpu] = se;
+
/* se could be NULL for root_task_group */
if (!se)
return;
@@ -7984,12 +7935,14 @@ static void init_tg_rt_entry(struct task_group *tg, struct rt_rq *rt_rq,
{
struct rq *rq = cpu_rq(cpu);
- tg->rt_rq[cpu] = rt_rq;
- init_rt_rq(rt_rq, rq);
+ rt_rq->highest_prio.curr = MAX_RT_PRIO;
+ rt_rq->rt_nr_boosted = 0;
+ rt_rq->rq = rq;
rt_rq->tg = tg;
- rt_rq->rt_runtime = tg->rt_bandwidth.rt_runtime;
+ tg->rt_rq[cpu] = rt_rq;
tg->rt_se[cpu] = rt_se;
+
if (!rt_se)
return;
@@ -8071,7 +8024,7 @@ void __init sched_init(void)
rq->nr_running = 0;
rq->calc_load_active = 0;
rq->calc_load_update = jiffies + LOAD_FREQ;
- init_cfs_rq(&rq->cfs, rq);
+ init_cfs_rq(&rq->cfs);
init_rt_rq(&rq->rt, rq);
#ifdef CONFIG_FAIR_GROUP_SCHED
root_task_group.shares = root_task_group_load;
@@ -8185,7 +8138,7 @@ void __init sched_init(void)
scheduler_running = 1;
}
-#ifdef CONFIG_DEBUG_SPINLOCK_SLEEP
+#ifdef CONFIG_DEBUG_ATOMIC_SLEEP
static inline int preempt_count_equals(int preempt_offset)
{
int nested = (preempt_count() & ~PREEMPT_ACTIVE) + rcu_preempt_depth();
@@ -8195,7 +8148,6 @@ static inline int preempt_count_equals(int preempt_offset)
void __might_sleep(const char *file, int line, int preempt_offset)
{
-#ifdef in_atomic
static unsigned long prev_jiffy; /* ratelimiting */
if ((preempt_count_equals(preempt_offset) && !irqs_disabled()) ||
@@ -8217,7 +8169,6 @@ void __might_sleep(const char *file, int line, int preempt_offset)
if (irqs_disabled())
print_irqtrace_events(current);
dump_stack();
-#endif
}
EXPORT_SYMBOL(__might_sleep);
#endif
@@ -8376,6 +8327,7 @@ int alloc_fair_sched_group(struct task_group *tg, struct task_group *parent)
if (!se)
goto err_free_rq;
+ init_cfs_rq(cfs_rq);
init_tg_cfs_entry(tg, cfs_rq, se, i, parent->se[i]);
}
@@ -8403,7 +8355,7 @@ static inline void unregister_fair_sched_group(struct task_group *tg, int cpu)
list_del_leaf_cfs_rq(tg->cfs_rq[cpu]);
raw_spin_unlock_irqrestore(&rq->lock, flags);
}
-#else /* !CONFG_FAIR_GROUP_SCHED */
+#else /* !CONFIG_FAIR_GROUP_SCHED */
static inline void free_fair_sched_group(struct task_group *tg)
{
}
@@ -8424,7 +8376,8 @@ static void free_rt_sched_group(struct task_group *tg)
{
int i;
- destroy_rt_bandwidth(&tg->rt_bandwidth);
+ if (tg->rt_se)
+ destroy_rt_bandwidth(&tg->rt_bandwidth);
for_each_possible_cpu(i) {
if (tg->rt_rq)
@@ -8465,6 +8418,8 @@ int alloc_rt_sched_group(struct task_group *tg, struct task_group *parent)
if (!rt_se)
goto err_free_rq;
+ init_rt_rq(rt_rq, cpu_rq(i));
+ rt_rq->rt_runtime = tg->rt_bandwidth.rt_runtime;
init_tg_rt_entry(tg, rt_rq, rt_se, i, parent->rt_se[i]);
}
diff --git a/kernel/sched_autogroup.h b/kernel/sched_autogroup.h
index 05577055cfca..c2f0e7248dca 100644
--- a/kernel/sched_autogroup.h
+++ b/kernel/sched_autogroup.h
@@ -13,6 +13,7 @@ struct autogroup {
int nice;
};
+static inline bool task_group_is_autogroup(struct task_group *tg);
static inline struct task_group *
autogroup_task_group(struct task_struct *p, struct task_group *tg);
diff --git a/kernel/sched_fair.c b/kernel/sched_fair.c
index c768588e180b..bc8ee9993814 100644
--- a/kernel/sched_fair.c
+++ b/kernel/sched_fair.c
@@ -135,14 +135,6 @@ static inline struct cfs_rq *group_cfs_rq(struct sched_entity *grp)
return grp->my_q;
}
-/* Given a group's cfs_rq on one cpu, return its corresponding cfs_rq on
- * another cpu ('this_cpu')
- */
-static inline struct cfs_rq *cpu_cfs_rq(struct cfs_rq *cfs_rq, int this_cpu)
-{
- return cfs_rq->tg->cfs_rq[this_cpu];
-}
-
static inline void list_add_leaf_cfs_rq(struct cfs_rq *cfs_rq)
{
if (!cfs_rq->on_list) {
@@ -271,11 +263,6 @@ static inline struct cfs_rq *group_cfs_rq(struct sched_entity *grp)
return NULL;
}
-static inline struct cfs_rq *cpu_cfs_rq(struct cfs_rq *cfs_rq, int this_cpu)
-{
- return &cpu_rq(this_cpu)->cfs;
-}
-
static inline void list_add_leaf_cfs_rq(struct cfs_rq *cfs_rq)
{
}
@@ -334,11 +321,6 @@ static inline int entity_before(struct sched_entity *a,
return (s64)(a->vruntime - b->vruntime) < 0;
}
-static inline s64 entity_key(struct cfs_rq *cfs_rq, struct sched_entity *se)
-{
- return se->vruntime - cfs_rq->min_vruntime;
-}
-
static void update_min_vruntime(struct cfs_rq *cfs_rq)
{
u64 vruntime = cfs_rq->min_vruntime;
@@ -372,7 +354,6 @@ static void __enqueue_entity(struct cfs_rq *cfs_rq, struct sched_entity *se)
struct rb_node **link = &cfs_rq->tasks_timeline.rb_node;
struct rb_node *parent = NULL;
struct sched_entity *entry;
- s64 key = entity_key(cfs_rq, se);
int leftmost = 1;
/*
@@ -385,7 +366,7 @@ static void __enqueue_entity(struct cfs_rq *cfs_rq, struct sched_entity *se)
* We dont care about collisions. Nodes with
* the same key stay together.
*/
- if (key < entity_key(cfs_rq, entry)) {
+ if (entity_before(se, entry)) {
link = &parent->rb_left;
} else {
link = &parent->rb_right;
@@ -1336,7 +1317,7 @@ enqueue_task_fair(struct rq *rq, struct task_struct *p, int flags)
}
for_each_sched_entity(se) {
- struct cfs_rq *cfs_rq = cfs_rq_of(se);
+ cfs_rq = cfs_rq_of(se);
update_cfs_load(cfs_rq, 0);
update_cfs_shares(cfs_rq);
@@ -1370,13 +1351,16 @@ static void dequeue_task_fair(struct rq *rq, struct task_struct *p, int flags)
*/
if (task_sleep && parent_entity(se))
set_next_buddy(parent_entity(se));
+
+ /* avoid re-evaluating load for this entity */
+ se = parent_entity(se);
break;
}
flags |= DEQUEUE_SLEEP;
}
for_each_sched_entity(se) {
- struct cfs_rq *cfs_rq = cfs_rq_of(se);
+ cfs_rq = cfs_rq_of(se);
update_cfs_load(cfs_rq, 0);
update_cfs_shares(cfs_rq);
@@ -1481,7 +1465,6 @@ static int wake_affine(struct sched_domain *sd, struct task_struct *p, int sync)
* effect of the currently running task from the load
* of the current CPU:
*/
- rcu_read_lock();
if (sync) {
tg = task_group(current);
weight = current->se.load.weight;
@@ -1517,7 +1500,6 @@ static int wake_affine(struct sched_domain *sd, struct task_struct *p, int sync)
balanced = this_eff_load <= prev_eff_load;
} else
balanced = true;
- rcu_read_unlock();
/*
* If the currently running task will sleep within
@@ -1921,8 +1903,8 @@ static void check_preempt_wakeup(struct rq *rq, struct task_struct *p, int wake_
if (!sched_feat(WAKEUP_PREEMPT))
return;
- update_curr(cfs_rq);
find_matching_se(&se, &pse);
+ update_curr(cfs_rq_of(se));
BUG_ON(!pse);
if (wakeup_preempt_entity(se, pse) == 1) {
/*
@@ -2231,11 +2213,43 @@ static void update_shares(int cpu)
struct rq *rq = cpu_rq(cpu);
rcu_read_lock();
+ /*
+ * Iterates the task_group tree in a bottom up fashion, see
+ * list_add_leaf_cfs_rq() for details.
+ */
for_each_leaf_cfs_rq(rq, cfs_rq)
update_shares_cpu(cfs_rq->tg, cpu);
rcu_read_unlock();
}
+/*
+ * Compute the cpu's hierarchical load factor for each task group.
+ * This needs to be done in a top-down fashion because the load of a child
+ * group is a fraction of its parents load.
+ */
+static int tg_load_down(struct task_group *tg, void *data)
+{
+ unsigned long load;
+ long cpu = (long)data;
+
+ if (!tg->parent) {
+ load = cpu_rq(cpu)->load.weight;
+ } else {
+ load = tg->parent->cfs_rq[cpu]->h_load;
+ load *= tg->se[cpu]->load.weight;
+ load /= tg->parent->cfs_rq[cpu]->load.weight + 1;
+ }
+
+ tg->cfs_rq[cpu]->h_load = load;
+
+ return 0;
+}
+
+static void update_h_load(long cpu)
+{
+ walk_tg_tree(tg_load_down, tg_nop, (void *)cpu);
+}
+
static unsigned long
load_balance_fair(struct rq *this_rq, int this_cpu, struct rq *busiest,
unsigned long max_load_move,
@@ -2243,14 +2257,12 @@ load_balance_fair(struct rq *this_rq, int this_cpu, struct rq *busiest,
int *all_pinned)
{
long rem_load_move = max_load_move;
- int busiest_cpu = cpu_of(busiest);
- struct task_group *tg;
+ struct cfs_rq *busiest_cfs_rq;
rcu_read_lock();
- update_h_load(busiest_cpu);
+ update_h_load(cpu_of(busiest));
- list_for_each_entry_rcu(tg, &task_groups, list) {
- struct cfs_rq *busiest_cfs_rq = tg->cfs_rq[busiest_cpu];
+ for_each_leaf_cfs_rq(busiest, busiest_cfs_rq) {
unsigned long busiest_h_load = busiest_cfs_rq->h_load;
unsigned long busiest_weight = busiest_cfs_rq->load.weight;
u64 rem_load, moved_load;
diff --git a/kernel/sched_rt.c b/kernel/sched_rt.c
index 10d018212bab..97540f0c9e47 100644
--- a/kernel/sched_rt.c
+++ b/kernel/sched_rt.c
@@ -185,11 +185,23 @@ static inline u64 sched_rt_period(struct rt_rq *rt_rq)
typedef struct task_group *rt_rq_iter_t;
-#define for_each_rt_rq(rt_rq, iter, rq) \
- for (iter = list_entry_rcu(task_groups.next, typeof(*iter), list); \
- (&iter->list != &task_groups) && \
- (rt_rq = iter->rt_rq[cpu_of(rq)]); \
- iter = list_entry_rcu(iter->list.next, typeof(*iter), list))
+static inline struct task_group *next_task_group(struct task_group *tg)
+{
+ do {
+ tg = list_entry_rcu(tg->list.next,
+ typeof(struct task_group), list);
+ } while (&tg->list != &task_groups && task_group_is_autogroup(tg));
+
+ if (&tg->list == &task_groups)
+ tg = NULL;
+
+ return tg;
+}
+
+#define for_each_rt_rq(rt_rq, iter, rq) \
+ for (iter = container_of(&task_groups, typeof(*iter), list); \
+ (iter = next_task_group(iter)) && \
+ (rt_rq = iter->rt_rq[cpu_of(rq)]);)
static inline void list_add_leaf_rt_rq(struct rt_rq *rt_rq)
{
@@ -1126,7 +1138,7 @@ static struct task_struct *_pick_next_task_rt(struct rq *rq)
rt_rq = &rq->rt;
- if (unlikely(!rt_rq->rt_nr_running))
+ if (!rt_rq->rt_nr_running)
return NULL;
if (rt_rq_throttled(rt_rq))
@@ -1548,7 +1560,7 @@ skip:
static void pre_schedule_rt(struct rq *rq, struct task_struct *prev)
{
/* Try to pull RT tasks here if we lower this rq's prio */
- if (unlikely(rt_task(prev)) && rq->rt.highest_prio.curr > prev->prio)
+ if (rq->rt.highest_prio.curr > prev->prio)
pull_rt_task(rq);
}
generated by cgit v1.2.3 (git 2.39.1) at 2024-11-21 22:26:44 +0000