Merge tag 'v3.17-rc4' into sched/core, to prevent conflicts with upcoming patches, and to refresh the tree
Linux 3.17-rc4
diff --git a/include/linux/wait.h b/include/linux/wait.h
index 6fb1ba5..034f6fc 100644
--- a/include/linux/wait.h
+++ b/include/linux/wait.h
@@ -280,9 +280,11 @@
* wake_up() has to be called after changing any variable that could
* change the result of the wait condition.
*
- * The function returns 0 if the @timeout elapsed, or the remaining
- * jiffies (at least 1) if the @condition evaluated to %true before
- * the @timeout elapsed.
+ * Returns:
+ * 0 if the @condition evaluated to %false after the @timeout elapsed,
+ * 1 if the @condition evaluated to %true after the @timeout elapsed,
+ * or the remaining jiffies (at least 1) if the @condition evaluated
+ * to %true before the @timeout elapsed.
*/
#define wait_event_timeout(wq, condition, timeout) \
({ \
@@ -363,9 +365,11 @@
* change the result of the wait condition.
*
* Returns:
- * 0 if the @timeout elapsed, -%ERESTARTSYS if it was interrupted by
- * a signal, or the remaining jiffies (at least 1) if the @condition
- * evaluated to %true before the @timeout elapsed.
+ * 0 if the @condition evaluated to %false after the @timeout elapsed,
+ * 1 if the @condition evaluated to %true after the @timeout elapsed,
+ * the remaining jiffies (at least 1) if the @condition evaluated
+ * to %true before the @timeout elapsed, or -%ERESTARTSYS if it was
+ * interrupted by a signal.
*/
#define wait_event_interruptible_timeout(wq, condition, timeout) \
({ \
diff --git a/kernel/sched/auto_group.c b/kernel/sched/auto_group.c
index e73efba..8a2e230 100644
--- a/kernel/sched/auto_group.c
+++ b/kernel/sched/auto_group.c
@@ -148,11 +148,8 @@
if (!ACCESS_ONCE(sysctl_sched_autogroup_enabled))
goto out;
- t = p;
- do {
+ for_each_thread(p, t)
sched_move_task(t);
- } while_each_thread(p, t);
-
out:
unlock_task_sighand(p, &flags);
autogroup_kref_put(prev);
diff --git a/kernel/sched/core.c b/kernel/sched/core.c
index ec1a286..a814b3c 100644
--- a/kernel/sched/core.c
+++ b/kernel/sched/core.c
@@ -333,9 +333,12 @@
for (;;) {
rq = task_rq(p);
raw_spin_lock(&rq->lock);
- if (likely(rq == task_rq(p)))
+ if (likely(rq == task_rq(p) && !task_on_rq_migrating(p)))
return rq;
raw_spin_unlock(&rq->lock);
+
+ while (unlikely(task_on_rq_migrating(p)))
+ cpu_relax();
}
}
@@ -352,10 +355,13 @@
raw_spin_lock_irqsave(&p->pi_lock, *flags);
rq = task_rq(p);
raw_spin_lock(&rq->lock);
- if (likely(rq == task_rq(p)))
+ if (likely(rq == task_rq(p) && !task_on_rq_migrating(p)))
return rq;
raw_spin_unlock(&rq->lock);
raw_spin_unlock_irqrestore(&p->pi_lock, *flags);
+
+ while (unlikely(task_on_rq_migrating(p)))
+ cpu_relax();
}
}
@@ -449,7 +455,15 @@
void hrtick_start(struct rq *rq, u64 delay)
{
struct hrtimer *timer = &rq->hrtick_timer;
- ktime_t time = ktime_add_ns(timer->base->get_time(), delay);
+ ktime_t time;
+ s64 delta;
+
+ /*
+ * Don't schedule slices shorter than 10000ns, that just
+ * doesn't make sense and can cause timer DoS.
+ */
+ delta = max_t(s64, delay, 10000LL);
+ time = ktime_add_ns(timer->base->get_time(), delta);
hrtimer_set_expires(timer, time);
@@ -1043,7 +1057,7 @@
* A queue event has occurred, and we're going to schedule. In
* this case, we can save a useless back to back clock update.
*/
- if (rq->curr->on_rq && test_tsk_need_resched(rq->curr))
+ if (task_on_rq_queued(rq->curr) && test_tsk_need_resched(rq->curr))
rq->skip_clock_update = 1;
}
@@ -1088,7 +1102,7 @@
static void __migrate_swap_task(struct task_struct *p, int cpu)
{
- if (p->on_rq) {
+ if (task_on_rq_queued(p)) {
struct rq *src_rq, *dst_rq;
src_rq = task_rq(p);
@@ -1214,7 +1228,7 @@
unsigned long wait_task_inactive(struct task_struct *p, long match_state)
{
unsigned long flags;
- int running, on_rq;
+ int running, queued;
unsigned long ncsw;
struct rq *rq;
@@ -1252,7 +1266,7 @@
rq = task_rq_lock(p, &flags);
trace_sched_wait_task(p);
running = task_running(rq, p);
- on_rq = p->on_rq;
+ queued = task_on_rq_queued(p);
ncsw = 0;
if (!match_state || p->state == match_state)
ncsw = p->nvcsw | LONG_MIN; /* sets MSB */
@@ -1284,7 +1298,7 @@
* running right now), it's preempted, and we should
* yield - it could be a while.
*/
- if (unlikely(on_rq)) {
+ if (unlikely(queued)) {
ktime_t to = ktime_set(0, NSEC_PER_SEC/HZ);
set_current_state(TASK_UNINTERRUPTIBLE);
@@ -1478,7 +1492,7 @@
static void ttwu_activate(struct rq *rq, struct task_struct *p, int en_flags)
{
activate_task(rq, p, en_flags);
- p->on_rq = 1;
+ p->on_rq = TASK_ON_RQ_QUEUED;
/* if a worker is waking up, notify workqueue */
if (p->flags & PF_WQ_WORKER)
@@ -1537,7 +1551,7 @@
int ret = 0;
rq = __task_rq_lock(p);
- if (p->on_rq) {
+ if (task_on_rq_queued(p)) {
/* check_preempt_curr() may use rq clock */
update_rq_clock(rq);
ttwu_do_wakeup(rq, p, wake_flags);
@@ -1742,7 +1756,7 @@
if (!(p->state & TASK_NORMAL))
goto out;
- if (!p->on_rq)
+ if (!task_on_rq_queued(p))
ttwu_activate(rq, p, ENQUEUE_WAKEUP);
ttwu_do_wakeup(rq, p, 0);
@@ -2095,7 +2109,7 @@
init_task_runnable_average(p);
rq = __task_rq_lock(p);
activate_task(rq, p, 0);
- p->on_rq = 1;
+ p->on_rq = TASK_ON_RQ_QUEUED;
trace_sched_wakeup_new(p, true);
check_preempt_curr(rq, p, WF_FORK);
#ifdef CONFIG_SMP
@@ -2451,7 +2465,7 @@
* project cycles that may never be accounted to this
* thread, breaking clock_gettime().
*/
- if (task_current(rq, p) && p->on_rq) {
+ if (task_current(rq, p) && task_on_rq_queued(p)) {
update_rq_clock(rq);
ns = rq_clock_task(rq) - p->se.exec_start;
if ((s64)ns < 0)
@@ -2497,7 +2511,7 @@
* If we see ->on_cpu without ->on_rq, the task is leaving, and has
* been accounted, so we're correct here as well.
*/
- if (!p->on_cpu || !p->on_rq)
+ if (!p->on_cpu || !task_on_rq_queued(p))
return p->se.sum_exec_runtime;
#endif
@@ -2801,7 +2815,7 @@
switch_count = &prev->nvcsw;
}
- if (prev->on_rq || rq->skip_clock_update < 0)
+ if (task_on_rq_queued(prev) || rq->skip_clock_update < 0)
update_rq_clock(rq);
next = pick_next_task(rq, prev);
@@ -2966,7 +2980,7 @@
*/
void rt_mutex_setprio(struct task_struct *p, int prio)
{
- int oldprio, on_rq, running, enqueue_flag = 0;
+ int oldprio, queued, running, enqueue_flag = 0;
struct rq *rq;
const struct sched_class *prev_class;
@@ -2995,9 +3009,9 @@
trace_sched_pi_setprio(p, prio);
oldprio = p->prio;
prev_class = p->sched_class;
- on_rq = p->on_rq;
+ queued = task_on_rq_queued(p);
running = task_current(rq, p);
- if (on_rq)
+ if (queued)
dequeue_task(rq, p, 0);
if (running)
p->sched_class->put_prev_task(rq, p);
@@ -3037,7 +3051,7 @@
if (running)
p->sched_class->set_curr_task(rq);
- if (on_rq)
+ if (queued)
enqueue_task(rq, p, enqueue_flag);
check_class_changed(rq, p, prev_class, oldprio);
@@ -3048,7 +3062,7 @@
void set_user_nice(struct task_struct *p, long nice)
{
- int old_prio, delta, on_rq;
+ int old_prio, delta, queued;
unsigned long flags;
struct rq *rq;
@@ -3069,8 +3083,8 @@
p->static_prio = NICE_TO_PRIO(nice);
goto out_unlock;
}
- on_rq = p->on_rq;
- if (on_rq)
+ queued = task_on_rq_queued(p);
+ if (queued)
dequeue_task(rq, p, 0);
p->static_prio = NICE_TO_PRIO(nice);
@@ -3079,7 +3093,7 @@
p->prio = effective_prio(p);
delta = p->prio - old_prio;
- if (on_rq) {
+ if (queued) {
enqueue_task(rq, p, 0);
/*
* If the task increased its priority or is running and
@@ -3351,7 +3365,7 @@
{
int newprio = dl_policy(attr->sched_policy) ? MAX_DL_PRIO - 1 :
MAX_RT_PRIO - 1 - attr->sched_priority;
- int retval, oldprio, oldpolicy = -1, on_rq, running;
+ int retval, oldprio, oldpolicy = -1, queued, running;
int policy = attr->sched_policy;
unsigned long flags;
const struct sched_class *prev_class;
@@ -3548,9 +3562,9 @@
return 0;
}
- on_rq = p->on_rq;
+ queued = task_on_rq_queued(p);
running = task_current(rq, p);
- if (on_rq)
+ if (queued)
dequeue_task(rq, p, 0);
if (running)
p->sched_class->put_prev_task(rq, p);
@@ -3560,7 +3574,7 @@
if (running)
p->sched_class->set_curr_task(rq);
- if (on_rq) {
+ if (queued) {
/*
* We enqueue to tail when the priority of a task is
* increased (user space view).
@@ -4512,7 +4526,7 @@
" task PC stack pid father\n");
#endif
rcu_read_lock();
- do_each_thread(g, p) {
+ for_each_process_thread(g, p) {
/*
* reset the NMI-timeout, listing all files on a slow
* console might take a lot of time:
@@ -4520,7 +4534,7 @@
touch_nmi_watchdog();
if (!state_filter || (p->state & state_filter))
sched_show_task(p);
- } while_each_thread(g, p);
+ }
touch_all_softlockup_watchdogs();
@@ -4575,7 +4589,7 @@
rcu_read_unlock();
rq->curr = rq->idle = idle;
- idle->on_rq = 1;
+ idle->on_rq = TASK_ON_RQ_QUEUED;
#if defined(CONFIG_SMP)
idle->on_cpu = 1;
#endif
@@ -4652,7 +4666,7 @@
goto out;
dest_cpu = cpumask_any_and(cpu_active_mask, new_mask);
- if (p->on_rq) {
+ if (task_on_rq_queued(p)) {
struct migration_arg arg = { p, dest_cpu };
/* Need help from migration thread: drop lock and wait. */
task_rq_unlock(rq, p, &flags);
@@ -4680,20 +4694,20 @@
*/
static int __migrate_task(struct task_struct *p, int src_cpu, int dest_cpu)
{
- struct rq *rq_dest, *rq_src;
+ struct rq *rq;
int ret = 0;
if (unlikely(!cpu_active(dest_cpu)))
return ret;
- rq_src = cpu_rq(src_cpu);
- rq_dest = cpu_rq(dest_cpu);
+ rq = cpu_rq(src_cpu);
raw_spin_lock(&p->pi_lock);
- double_rq_lock(rq_src, rq_dest);
+ raw_spin_lock(&rq->lock);
/* Already moved. */
if (task_cpu(p) != src_cpu)
goto done;
+
/* Affinity changed (again). */
if (!cpumask_test_cpu(dest_cpu, tsk_cpus_allowed(p)))
goto fail;
@@ -4702,16 +4716,23 @@
* If we're not on a rq, the next wake-up will ensure we're
* placed properly.
*/
- if (p->on_rq) {
- dequeue_task(rq_src, p, 0);
+ if (task_on_rq_queued(p)) {
+ dequeue_task(rq, p, 0);
+ p->on_rq = TASK_ON_RQ_MIGRATING;
set_task_cpu(p, dest_cpu);
- enqueue_task(rq_dest, p, 0);
- check_preempt_curr(rq_dest, p, 0);
+ raw_spin_unlock(&rq->lock);
+
+ rq = cpu_rq(dest_cpu);
+ raw_spin_lock(&rq->lock);
+ BUG_ON(task_rq(p) != rq);
+ p->on_rq = TASK_ON_RQ_QUEUED;
+ enqueue_task(rq, p, 0);
+ check_preempt_curr(rq, p, 0);
}
done:
ret = 1;
fail:
- double_rq_unlock(rq_src, rq_dest);
+ raw_spin_unlock(&rq->lock);
raw_spin_unlock(&p->pi_lock);
return ret;
}
@@ -4743,13 +4764,13 @@
{
struct rq *rq;
unsigned long flags;
- bool on_rq, running;
+ bool queued, running;
rq = task_rq_lock(p, &flags);
- on_rq = p->on_rq;
+ queued = task_on_rq_queued(p);
running = task_current(rq, p);
- if (on_rq)
+ if (queued)
dequeue_task(rq, p, 0);
if (running)
p->sched_class->put_prev_task(rq, p);
@@ -4758,7 +4779,7 @@
if (running)
p->sched_class->set_curr_task(rq);
- if (on_rq)
+ if (queued)
enqueue_task(rq, p, 0);
task_rq_unlock(rq, p, &flags);
}
@@ -5746,7 +5767,7 @@
const struct cpumask *span = sched_domain_span(sd);
struct cpumask *covered = sched_domains_tmpmask;
struct sd_data *sdd = sd->private;
- struct sched_domain *child;
+ struct sched_domain *sibling;
int i;
cpumask_clear(covered);
@@ -5757,10 +5778,10 @@
if (cpumask_test_cpu(i, covered))
continue;
- child = *per_cpu_ptr(sdd->sd, i);
+ sibling = *per_cpu_ptr(sdd->sd, i);
/* See the comment near build_group_mask(). */
- if (!cpumask_test_cpu(i, sched_domain_span(child)))
+ if (!cpumask_test_cpu(i, sched_domain_span(sibling)))
continue;
sg = kzalloc_node(sizeof(struct sched_group) + cpumask_size(),
@@ -5770,10 +5791,9 @@
goto fail;
sg_span = sched_group_cpus(sg);
- if (child->child) {
- child = child->child;
- cpumask_copy(sg_span, sched_domain_span(child));
- } else
+ if (sibling->child)
+ cpumask_copy(sg_span, sched_domain_span(sibling->child));
+ else
cpumask_set_cpu(i, sg_span);
cpumask_or(covered, covered, sg_span);
@@ -7124,13 +7144,13 @@
.sched_policy = SCHED_NORMAL,
};
int old_prio = p->prio;
- int on_rq;
+ int queued;
- on_rq = p->on_rq;
- if (on_rq)
+ queued = task_on_rq_queued(p);
+ if (queued)
dequeue_task(rq, p, 0);
__setscheduler(rq, p, &attr);
- if (on_rq) {
+ if (queued) {
enqueue_task(rq, p, 0);
resched_curr(rq);
}
@@ -7145,7 +7165,7 @@
struct rq *rq;
read_lock_irqsave(&tasklist_lock, flags);
- do_each_thread(g, p) {
+ for_each_process_thread(g, p) {
/*
* Only normalize user tasks:
*/
@@ -7176,8 +7196,7 @@
__task_rq_unlock(rq);
raw_spin_unlock(&p->pi_lock);
- } while_each_thread(g, p);
-
+ }
read_unlock_irqrestore(&tasklist_lock, flags);
}
@@ -7318,16 +7337,16 @@
void sched_move_task(struct task_struct *tsk)
{
struct task_group *tg;
- int on_rq, running;
+ int queued, running;
unsigned long flags;
struct rq *rq;
rq = task_rq_lock(tsk, &flags);
running = task_current(rq, tsk);
- on_rq = tsk->on_rq;
+ queued = task_on_rq_queued(tsk);
- if (on_rq)
+ if (queued)
dequeue_task(rq, tsk, 0);
if (unlikely(running))
tsk->sched_class->put_prev_task(rq, tsk);
@@ -7340,14 +7359,14 @@
#ifdef CONFIG_FAIR_GROUP_SCHED
if (tsk->sched_class->task_move_group)
- tsk->sched_class->task_move_group(tsk, on_rq);
+ tsk->sched_class->task_move_group(tsk, queued);
else
#endif
set_task_rq(tsk, task_cpu(tsk));
if (unlikely(running))
tsk->sched_class->set_curr_task(rq);
- if (on_rq)
+ if (queued)
enqueue_task(rq, tsk, 0);
task_rq_unlock(rq, tsk, &flags);
@@ -7365,10 +7384,10 @@
{
struct task_struct *g, *p;
- do_each_thread(g, p) {
+ for_each_process_thread(g, p) {
if (rt_task(p) && task_rq(p)->rt.tg == tg)
return 1;
- } while_each_thread(g, p);
+ }
return 0;
}
diff --git a/kernel/sched/cputime.c b/kernel/sched/cputime.c
index 72fdf06..3e52836 100644
--- a/kernel/sched/cputime.c
+++ b/kernel/sched/cputime.c
@@ -294,18 +294,12 @@
times->sum_exec_runtime = sig->sum_sched_runtime;
rcu_read_lock();
- /* make sure we can trust tsk->thread_group list */
- if (!likely(pid_alive(tsk)))
- goto out;
-
- t = tsk;
- do {
+ for_each_thread(tsk, t) {
task_cputime(t, &utime, &stime);
times->utime += utime;
times->stime += stime;
times->sum_exec_runtime += task_sched_runtime(t);
- } while_each_thread(tsk, t);
-out:
+ }
rcu_read_unlock();
}
diff --git a/kernel/sched/deadline.c b/kernel/sched/deadline.c
index 255ce13..cc4eb89 100644
--- a/kernel/sched/deadline.c
+++ b/kernel/sched/deadline.c
@@ -530,7 +530,7 @@
update_rq_clock(rq);
dl_se->dl_throttled = 0;
dl_se->dl_yielded = 0;
- if (p->on_rq) {
+ if (task_on_rq_queued(p)) {
enqueue_task_dl(rq, p, ENQUEUE_REPLENISH);
if (task_has_dl_policy(rq->curr))
check_preempt_curr_dl(rq, p, 0);
@@ -997,10 +997,7 @@
#ifdef CONFIG_SCHED_HRTICK
static void start_hrtick_dl(struct rq *rq, struct task_struct *p)
{
- s64 delta = p->dl.dl_runtime - p->dl.runtime;
-
- if (delta > 10000)
- hrtick_start(rq, p->dl.runtime);
+ hrtick_start(rq, p->dl.runtime);
}
#endif
@@ -1030,7 +1027,7 @@
* means a stop task can slip in, in which case we need to
* re-start task selection.
*/
- if (rq->stop && rq->stop->on_rq)
+ if (rq->stop && task_on_rq_queued(rq->stop))
return RETRY_TASK;
}
@@ -1257,7 +1254,8 @@
if (unlikely(task_rq(task) != rq ||
!cpumask_test_cpu(later_rq->cpu,
&task->cpus_allowed) ||
- task_running(rq, task) || !task->on_rq)) {
+ task_running(rq, task) ||
+ !task_on_rq_queued(task))) {
double_unlock_balance(rq, later_rq);
later_rq = NULL;
break;
@@ -1296,7 +1294,7 @@
BUG_ON(task_current(rq, p));
BUG_ON(p->nr_cpus_allowed <= 1);
- BUG_ON(!p->on_rq);
+ BUG_ON(!task_on_rq_queued(p));
BUG_ON(!dl_task(p));
return p;
@@ -1443,7 +1441,7 @@
dl_time_before(p->dl.deadline,
this_rq->dl.earliest_dl.curr))) {
WARN_ON(p == src_rq->curr);
- WARN_ON(!p->on_rq);
+ WARN_ON(!task_on_rq_queued(p));
/*
* Then we pull iff p has actually an earlier
@@ -1596,7 +1594,7 @@
if (unlikely(p->dl.dl_throttled))
return;
- if (p->on_rq && rq->curr != p) {
+ if (task_on_rq_queued(p) && rq->curr != p) {
#ifdef CONFIG_SMP
if (rq->dl.overloaded && push_dl_task(rq) && rq != task_rq(p))
/* Only reschedule if pushing failed */
@@ -1614,7 +1612,7 @@
static void prio_changed_dl(struct rq *rq, struct task_struct *p,
int oldprio)
{
- if (p->on_rq || rq->curr == p) {
+ if (task_on_rq_queued(p) || rq->curr == p) {
#ifdef CONFIG_SMP
/*
* This might be too much, but unfortunately
diff --git a/kernel/sched/debug.c b/kernel/sched/debug.c
index 627b3c3..c7fe1ea0 100644
--- a/kernel/sched/debug.c
+++ b/kernel/sched/debug.c
@@ -160,14 +160,12 @@
"----------------------------------------------------\n");
read_lock_irqsave(&tasklist_lock, flags);
-
- do_each_thread(g, p) {
+ for_each_process_thread(g, p) {
if (task_cpu(p) != rq_cpu)
continue;
print_task(m, rq, p);
- } while_each_thread(g, p);
-
+ }
read_unlock_irqrestore(&tasklist_lock, flags);
}
diff --git a/kernel/sched/fair.c b/kernel/sched/fair.c
index bfa3c86..50d2025 100644
--- a/kernel/sched/fair.c
+++ b/kernel/sched/fair.c
@@ -1038,7 +1038,8 @@
*/
static void update_numa_stats(struct numa_stats *ns, int nid)
{
- int cpu, cpus = 0;
+ int smt, cpu, cpus = 0;
+ unsigned long capacity;
memset(ns, 0, sizeof(*ns));
for_each_cpu(cpu, cpumask_of_node(nid)) {
@@ -1062,8 +1063,12 @@
if (!cpus)
return;
- ns->task_capacity =
- DIV_ROUND_CLOSEST(ns->compute_capacity, SCHED_CAPACITY_SCALE);
+ /* smt := ceil(cpus / capacity), assumes: 1 < smt_power < 2 */
+ smt = DIV_ROUND_UP(SCHED_CAPACITY_SCALE * cpus, ns->compute_capacity);
+ capacity = cpus / smt; /* cores */
+
+ ns->task_capacity = min_t(unsigned, capacity,
+ DIV_ROUND_CLOSEST(ns->compute_capacity, SCHED_CAPACITY_SCALE));
ns->has_free_capacity = (ns->nr_running < ns->task_capacity);
}
@@ -1206,7 +1211,7 @@
if (!cur) {
/* Is there capacity at our destination? */
- if (env->src_stats.has_free_capacity &&
+ if (env->src_stats.nr_running <= env->src_stats.task_capacity &&
!env->dst_stats.has_free_capacity)
goto unlock;
@@ -1775,7 +1780,7 @@
list_del(&p->numa_entry);
grp->nr_tasks--;
spin_unlock_irqrestore(&grp->lock, flags);
- rcu_assign_pointer(p->numa_group, NULL);
+ RCU_INIT_POINTER(p->numa_group, NULL);
put_numa_group(grp);
}
@@ -3892,14 +3897,6 @@
resched_curr(rq);
return;
}
-
- /*
- * Don't schedule slices shorter than 10000ns, that just
- * doesn't make sense. Rely on vruntime for fairness.
- */
- if (rq->curr != p)
- delta = max_t(s64, 10000LL, delta);
-
hrtick_start(rq, delta);
}
}
@@ -4704,7 +4701,7 @@
return;
/*
- * This is possible from callers such as move_task(), in which we
+ * This is possible from callers such as attach_tasks(), in which we
* unconditionally check_prempt_curr() after an enqueue (which may have
* lead to a throttle). This both saves work and prevents false
* next-buddy nomination below.
@@ -5112,27 +5109,18 @@
unsigned int loop_max;
enum fbq_type fbq_type;
+ struct list_head tasks;
};
/*
- * move_task - move a task from one runqueue to another runqueue.
- * Both runqueues must be locked.
- */
-static void move_task(struct task_struct *p, struct lb_env *env)
-{
- deactivate_task(env->src_rq, p, 0);
- set_task_cpu(p, env->dst_cpu);
- activate_task(env->dst_rq, p, 0);
- check_preempt_curr(env->dst_rq, p, 0);
-}
-
-/*
* Is this task likely cache-hot:
*/
static int task_hot(struct task_struct *p, struct lb_env *env)
{
s64 delta;
+ lockdep_assert_held(&env->src_rq->lock);
+
if (p->sched_class != &fair_sched_class)
return 0;
@@ -5252,6 +5240,9 @@
int can_migrate_task(struct task_struct *p, struct lb_env *env)
{
int tsk_cache_hot = 0;
+
+ lockdep_assert_held(&env->src_rq->lock);
+
/*
* We do not migrate tasks that are:
* 1) throttled_lb_pair, or
@@ -5336,47 +5327,63 @@
}
/*
- * move_one_task tries to move exactly one task from busiest to this_rq, as
- * part of active balancing operations within "domain".
- * Returns 1 if successful and 0 otherwise.
- *
- * Called with both runqueues locked.
+ * detach_task() -- detach the task for the migration specified in env
*/
-static int move_one_task(struct lb_env *env)
+static void detach_task(struct task_struct *p, struct lb_env *env)
+{
+ lockdep_assert_held(&env->src_rq->lock);
+
+ deactivate_task(env->src_rq, p, 0);
+ p->on_rq = TASK_ON_RQ_MIGRATING;
+ set_task_cpu(p, env->dst_cpu);
+}
+
+/*
+ * detach_one_task() -- tries to dequeue exactly one task from env->src_rq, as
+ * part of active balancing operations within "domain".
+ *
+ * Returns a task if successful and NULL otherwise.
+ */
+static struct task_struct *detach_one_task(struct lb_env *env)
{
struct task_struct *p, *n;
+ lockdep_assert_held(&env->src_rq->lock);
+
list_for_each_entry_safe(p, n, &env->src_rq->cfs_tasks, se.group_node) {
if (!can_migrate_task(p, env))
continue;
- move_task(p, env);
+ detach_task(p, env);
+
/*
- * Right now, this is only the second place move_task()
- * is called, so we can safely collect move_task()
- * stats here rather than inside move_task().
+ * Right now, this is only the second place where
+ * lb_gained[env->idle] is updated (other is detach_tasks)
+ * so we can safely collect stats here rather than
+ * inside detach_tasks().
*/
schedstat_inc(env->sd, lb_gained[env->idle]);
- return 1;
+ return p;
}
- return 0;
+ return NULL;
}
static const unsigned int sched_nr_migrate_break = 32;
/*
- * move_tasks tries to move up to imbalance weighted load from busiest to
- * this_rq, as part of a balancing operation within domain "sd".
- * Returns 1 if successful and 0 otherwise.
+ * detach_tasks() -- tries to detach up to imbalance weighted load from
+ * busiest_rq, as part of a balancing operation within domain "sd".
*
- * Called with both runqueues locked.
+ * Returns number of detached tasks if successful and 0 otherwise.
*/
-static int move_tasks(struct lb_env *env)
+static int detach_tasks(struct lb_env *env)
{
struct list_head *tasks = &env->src_rq->cfs_tasks;
struct task_struct *p;
unsigned long load;
- int pulled = 0;
+ int detached = 0;
+
+ lockdep_assert_held(&env->src_rq->lock);
if (env->imbalance <= 0)
return 0;
@@ -5407,14 +5414,16 @@
if ((load / 2) > env->imbalance)
goto next;
- move_task(p, env);
- pulled++;
+ detach_task(p, env);
+ list_add(&p->se.group_node, &env->tasks);
+
+ detached++;
env->imbalance -= load;
#ifdef CONFIG_PREEMPT
/*
* NEWIDLE balancing is a source of latency, so preemptible
- * kernels will stop after the first task is pulled to minimize
+ * kernels will stop after the first task is detached to minimize
* the critical section.
*/
if (env->idle == CPU_NEWLY_IDLE)
@@ -5434,13 +5443,58 @@
}
/*
- * Right now, this is one of only two places move_task() is called,
- * so we can safely collect move_task() stats here rather than
- * inside move_task().
+ * Right now, this is one of only two places we collect this stat
+ * so we can safely collect detach_one_task() stats here rather
+ * than inside detach_one_task().
*/
- schedstat_add(env->sd, lb_gained[env->idle], pulled);
+ schedstat_add(env->sd, lb_gained[env->idle], detached);
- return pulled;
+ return detached;
+}
+
+/*
+ * attach_task() -- attach the task detached by detach_task() to its new rq.
+ */
+static void attach_task(struct rq *rq, struct task_struct *p)
+{
+ lockdep_assert_held(&rq->lock);
+
+ BUG_ON(task_rq(p) != rq);
+ p->on_rq = TASK_ON_RQ_QUEUED;
+ activate_task(rq, p, 0);
+ check_preempt_curr(rq, p, 0);
+}
+
+/*
+ * attach_one_task() -- attaches the task returned from detach_one_task() to
+ * its new rq.
+ */
+static void attach_one_task(struct rq *rq, struct task_struct *p)
+{
+ raw_spin_lock(&rq->lock);
+ attach_task(rq, p);
+ raw_spin_unlock(&rq->lock);
+}
+
+/*
+ * attach_tasks() -- attaches all tasks detached by detach_tasks() to their
+ * new rq.
+ */
+static void attach_tasks(struct lb_env *env)
+{
+ struct list_head *tasks = &env->tasks;
+ struct task_struct *p;
+
+ raw_spin_lock(&env->dst_rq->lock);
+
+ while (!list_empty(tasks)) {
+ p = list_first_entry(tasks, struct task_struct, se.group_node);
+ list_del_init(&p->se.group_node);
+
+ attach_task(env->dst_rq, p);
+ }
+
+ raw_spin_unlock(&env->dst_rq->lock);
}
#ifdef CONFIG_FAIR_GROUP_SCHED
@@ -5559,6 +5613,13 @@
#endif
/********** Helpers for find_busiest_group ************************/
+
+enum group_type {
+ group_other = 0,
+ group_imbalanced,
+ group_overloaded,
+};
+
/*
* sg_lb_stats - stats of a sched_group required for load_balancing
*/
@@ -5572,7 +5633,7 @@
unsigned int group_capacity_factor;
unsigned int idle_cpus;
unsigned int group_weight;
- int group_imb; /* Is there an imbalance in the group ? */
+ enum group_type group_type;
int group_has_free_capacity;
#ifdef CONFIG_NUMA_BALANCING
unsigned int nr_numa_running;
@@ -5610,6 +5671,8 @@
.total_capacity = 0UL,
.busiest_stat = {
.avg_load = 0UL,
+ .sum_nr_running = 0,
+ .group_type = group_other,
},
};
}
@@ -5891,6 +5954,18 @@
return capacity_factor;
}
+static enum group_type
+group_classify(struct sched_group *group, struct sg_lb_stats *sgs)
+{
+ if (sgs->sum_nr_running > sgs->group_capacity_factor)
+ return group_overloaded;
+
+ if (sg_imbalanced(group))
+ return group_imbalanced;
+
+ return group_other;
+}
+
/**
* update_sg_lb_stats - Update sched_group's statistics for load balancing.
* @env: The load balancing environment.
@@ -5942,9 +6017,8 @@
sgs->load_per_task = sgs->sum_weighted_load / sgs->sum_nr_running;
sgs->group_weight = group->group_weight;
-
- sgs->group_imb = sg_imbalanced(group);
sgs->group_capacity_factor = sg_capacity_factor(env, group);
+ sgs->group_type = group_classify(group, sgs);
if (sgs->group_capacity_factor > sgs->sum_nr_running)
sgs->group_has_free_capacity = 1;
@@ -5968,13 +6042,19 @@
struct sched_group *sg,
struct sg_lb_stats *sgs)
{
- if (sgs->avg_load <= sds->busiest_stat.avg_load)
- return false;
+ struct sg_lb_stats *busiest = &sds->busiest_stat;
- if (sgs->sum_nr_running > sgs->group_capacity_factor)
+ if (sgs->group_type > busiest->group_type)
return true;
- if (sgs->group_imb)
+ if (sgs->group_type < busiest->group_type)
+ return false;
+
+ if (sgs->avg_load <= busiest->avg_load)
+ return false;
+
+ /* This is the busiest node in its class. */
+ if (!(env->sd->flags & SD_ASYM_PACKING))
return true;
/*
@@ -5982,8 +6062,7 @@
* numbered CPUs in the group, therefore mark all groups
* higher than ourself as busy.
*/
- if ((env->sd->flags & SD_ASYM_PACKING) && sgs->sum_nr_running &&
- env->dst_cpu < group_first_cpu(sg)) {
+ if (sgs->sum_nr_running && env->dst_cpu < group_first_cpu(sg)) {
if (!sds->busiest)
return true;
@@ -6228,7 +6307,7 @@
local = &sds->local_stat;
busiest = &sds->busiest_stat;
- if (busiest->group_imb) {
+ if (busiest->group_type == group_imbalanced) {
/*
* In the group_imb case we cannot rely on group-wide averages
* to ensure cpu-load equilibrium, look at wider averages. XXX
@@ -6248,12 +6327,11 @@
return fix_small_imbalance(env, sds);
}
- if (!busiest->group_imb) {
- /*
- * Don't want to pull so many tasks that a group would go idle.
- * Except of course for the group_imb case, since then we might
- * have to drop below capacity to reach cpu-load equilibrium.
- */
+ /*
+ * If there aren't any idle cpus, avoid creating some.
+ */
+ if (busiest->group_type == group_overloaded &&
+ local->group_type == group_overloaded) {
load_above_capacity =
(busiest->sum_nr_running - busiest->group_capacity_factor);
@@ -6337,7 +6415,7 @@
* work because they assume all things are equal, which typically
* isn't true due to cpus_allowed constraints and the like.
*/
- if (busiest->group_imb)
+ if (busiest->group_type == group_imbalanced)
goto force_balance;
/* SD_BALANCE_NEWIDLE trumps SMP nice when underutilized */
@@ -6550,6 +6628,7 @@
.loop_break = sched_nr_migrate_break,
.cpus = cpus,
.fbq_type = all,
+ .tasks = LIST_HEAD_INIT(env.tasks),
};
/*
@@ -6599,16 +6678,29 @@
env.loop_max = min(sysctl_sched_nr_migrate, busiest->nr_running);
more_balance:
- local_irq_save(flags);
- double_rq_lock(env.dst_rq, busiest);
+ raw_spin_lock_irqsave(&busiest->lock, flags);
/*
* cur_ld_moved - load moved in current iteration
* ld_moved - cumulative load moved across iterations
*/
- cur_ld_moved = move_tasks(&env);
- ld_moved += cur_ld_moved;
- double_rq_unlock(env.dst_rq, busiest);
+ cur_ld_moved = detach_tasks(&env);
+
+ /*
+ * We've detached some tasks from busiest_rq. Every
+ * task is masked "TASK_ON_RQ_MIGRATING", so we can safely
+ * unlock busiest->lock, and we are able to be sure
+ * that nobody can manipulate the tasks in parallel.
+ * See task_rq_lock() family for the details.
+ */
+
+ raw_spin_unlock(&busiest->lock);
+
+ if (cur_ld_moved) {
+ attach_tasks(&env);
+ ld_moved += cur_ld_moved;
+ }
+
local_irq_restore(flags);
/*
@@ -6744,7 +6836,7 @@
* If we've begun active balancing, start to back off. This
* case may not be covered by the all_pinned logic if there
* is only 1 task on the busy runqueue (because we don't call
- * move_tasks).
+ * detach_tasks).
*/
if (sd->balance_interval < sd->max_interval)
sd->balance_interval *= 2;
@@ -6914,6 +7006,7 @@
int target_cpu = busiest_rq->push_cpu;
struct rq *target_rq = cpu_rq(target_cpu);
struct sched_domain *sd;
+ struct task_struct *p = NULL;
raw_spin_lock_irq(&busiest_rq->lock);
@@ -6933,9 +7026,6 @@
*/
BUG_ON(busiest_rq == target_rq);
- /* move a task from busiest_rq to target_rq */
- 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) {
@@ -6956,16 +7046,22 @@
schedstat_inc(sd, alb_count);
- if (move_one_task(&env))
+ p = detach_one_task(&env);
+ if (p)
schedstat_inc(sd, alb_pushed);
else
schedstat_inc(sd, alb_failed);
}
rcu_read_unlock();
- double_unlock_balance(busiest_rq, target_rq);
out_unlock:
busiest_rq->active_balance = 0;
- raw_spin_unlock_irq(&busiest_rq->lock);
+ raw_spin_unlock(&busiest_rq->lock);
+
+ if (p)
+ attach_one_task(target_rq, p);
+
+ local_irq_enable();
+
return 0;
}
@@ -7465,7 +7561,7 @@
static void
prio_changed_fair(struct rq *rq, struct task_struct *p, int oldprio)
{
- if (!p->se.on_rq)
+ if (!task_on_rq_queued(p))
return;
/*
@@ -7490,11 +7586,11 @@
* switched back to the fair class the enqueue_entity(.flags=0) will
* do the right thing.
*
- * If it's on_rq, then the dequeue_entity(.flags=0) will already
- * have normalized the vruntime, if it's !on_rq, then only when
+ * If it's queued, then the dequeue_entity(.flags=0) will already
+ * have normalized the vruntime, if it's !queued, then only when
* the task is sleeping will it still have non-normalized vruntime.
*/
- if (!p->on_rq && p->state != TASK_RUNNING) {
+ if (!task_on_rq_queued(p) && p->state != TASK_RUNNING) {
/*
* Fix up our vruntime so that the current sleep doesn't
* cause 'unlimited' sleep bonus.
@@ -7521,15 +7617,15 @@
*/
static void switched_to_fair(struct rq *rq, struct task_struct *p)
{
- struct sched_entity *se = &p->se;
#ifdef CONFIG_FAIR_GROUP_SCHED
+ struct sched_entity *se = &p->se;
/*
* Since the real-depth could have been changed (only FAIR
* class maintain depth value), reset depth properly.
*/
se->depth = se->parent ? se->parent->depth + 1 : 0;
#endif
- if (!se->on_rq)
+ if (!task_on_rq_queued(p))
return;
/*
@@ -7575,7 +7671,7 @@
}
#ifdef CONFIG_FAIR_GROUP_SCHED
-static void task_move_group_fair(struct task_struct *p, int on_rq)
+static void task_move_group_fair(struct task_struct *p, int queued)
{
struct sched_entity *se = &p->se;
struct cfs_rq *cfs_rq;
@@ -7594,7 +7690,7 @@
* fair sleeper stuff for the first placement, but who cares.
*/
/*
- * When !on_rq, vruntime of the task has usually NOT been normalized.
+ * When !queued, vruntime of the task has usually NOT been normalized.
* But there are some cases where it has already been normalized:
*
* - Moving a forked child which is waiting for being woken up by
@@ -7605,14 +7701,14 @@
* To prevent boost or penalty in the new cfs_rq caused by delta
* min_vruntime between the two cfs_rqs, we skip vruntime adjustment.
*/
- if (!on_rq && (!se->sum_exec_runtime || p->state == TASK_WAKING))
- on_rq = 1;
+ if (!queued && (!se->sum_exec_runtime || p->state == TASK_WAKING))
+ queued = 1;
- if (!on_rq)
+ if (!queued)
se->vruntime -= cfs_rq_of(se)->min_vruntime;
set_task_rq(p, task_cpu(p));
se->depth = se->parent ? se->parent->depth + 1 : 0;
- if (!on_rq) {
+ if (!queued) {
cfs_rq = cfs_rq_of(se);
se->vruntime += cfs_rq->min_vruntime;
#ifdef CONFIG_SMP
diff --git a/kernel/sched/rt.c b/kernel/sched/rt.c
index 5f6edca..4feac8f 100644
--- a/kernel/sched/rt.c
+++ b/kernel/sched/rt.c
@@ -1448,7 +1448,7 @@
* means a dl or stop task can slip in, in which case we need
* to re-start task selection.
*/
- if (unlikely((rq->stop && rq->stop->on_rq) ||
+ if (unlikely((rq->stop && task_on_rq_queued(rq->stop)) ||
rq->dl.dl_nr_running))
return RETRY_TASK;
}
@@ -1624,7 +1624,7 @@
!cpumask_test_cpu(lowest_rq->cpu,
tsk_cpus_allowed(task)) ||
task_running(rq, task) ||
- !task->on_rq)) {
+ !task_on_rq_queued(task))) {
double_unlock_balance(rq, lowest_rq);
lowest_rq = NULL;
@@ -1658,7 +1658,7 @@
BUG_ON(task_current(rq, p));
BUG_ON(p->nr_cpus_allowed <= 1);
- BUG_ON(!p->on_rq);
+ BUG_ON(!task_on_rq_queued(p));
BUG_ON(!rt_task(p));
return p;
@@ -1809,7 +1809,7 @@
*/
if (p && (p->prio < this_rq->rt.highest_prio.curr)) {
WARN_ON(p == src_rq->curr);
- WARN_ON(!p->on_rq);
+ WARN_ON(!task_on_rq_queued(p));
/*
* There's a chance that p is higher in priority
@@ -1870,7 +1870,7 @@
BUG_ON(!rt_task(p));
- if (!p->on_rq)
+ if (!task_on_rq_queued(p))
return;
weight = cpumask_weight(new_mask);
@@ -1936,7 +1936,7 @@
* we may need to handle the pulling of RT tasks
* now.
*/
- if (!p->on_rq || rq->rt.rt_nr_running)
+ if (!task_on_rq_queued(p) || rq->rt.rt_nr_running)
return;
if (pull_rt_task(rq))
@@ -1970,7 +1970,7 @@
* If that current running task is also an RT task
* then see if we can move to another run queue.
*/
- if (p->on_rq && rq->curr != p) {
+ if (task_on_rq_queued(p) && rq->curr != p) {
#ifdef CONFIG_SMP
if (p->nr_cpus_allowed > 1 && rq->rt.overloaded &&
/* Don't resched if we changed runqueues */
@@ -1989,7 +1989,7 @@
static void
prio_changed_rt(struct rq *rq, struct task_struct *p, int oldprio)
{
- if (!p->on_rq)
+ if (!task_on_rq_queued(p))
return;
if (rq->curr == p) {
diff --git a/kernel/sched/sched.h b/kernel/sched/sched.h
index 579712f..aa0f73b 100644
--- a/kernel/sched/sched.h
+++ b/kernel/sched/sched.h
@@ -15,6 +15,10 @@
struct rq;
+/* task_struct::on_rq states: */
+#define TASK_ON_RQ_QUEUED 1
+#define TASK_ON_RQ_MIGRATING 2
+
extern __read_mostly int scheduler_running;
extern unsigned long calc_load_update;
@@ -647,7 +651,7 @@
#endif
}
-DECLARE_PER_CPU(struct rq, runqueues);
+DECLARE_PER_CPU_SHARED_ALIGNED(struct rq, runqueues);
#define cpu_rq(cpu) (&per_cpu(runqueues, (cpu)))
#define this_rq() (&__get_cpu_var(runqueues))
@@ -942,6 +946,15 @@
#endif
}
+static inline int task_on_rq_queued(struct task_struct *p)
+{
+ return p->on_rq == TASK_ON_RQ_QUEUED;
+}
+
+static inline int task_on_rq_migrating(struct task_struct *p)
+{
+ return p->on_rq == TASK_ON_RQ_MIGRATING;
+}
#ifndef prepare_arch_switch
# define prepare_arch_switch(next) do { } while (0)
diff --git a/kernel/sched/stop_task.c b/kernel/sched/stop_task.c
index bfe0eda..67426e5 100644
--- a/kernel/sched/stop_task.c
+++ b/kernel/sched/stop_task.c
@@ -28,7 +28,7 @@
{
struct task_struct *stop = rq->stop;
- if (!stop || !stop->on_rq)
+ if (!stop || !task_on_rq_queued(stop))
return NULL;
put_prev_task(rq, prev);