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authorLinus Torvalds <torvalds@linux-foundation.org>2018-01-30 11:55:56 -0800
committerLinus Torvalds <torvalds@linux-foundation.org>2018-01-30 11:55:56 -0800
commitaf8c5e2d6071c71d228788d1ebb0b9676829001a (patch)
treec898379e89ed05fdc5c6b7ebddbf4a8d50f11657 /kernel
parentMerge branch 'ras-core-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip (diff)
parentsched/deadline: Make bandwidth enforcement scale-invariant (diff)
downloadlinux-dev-af8c5e2d6071c71d228788d1ebb0b9676829001a.tar.xz
linux-dev-af8c5e2d6071c71d228788d1ebb0b9676829001a.zip
Merge branch 'sched-core-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip
Pull scheduler updates from Ingo Molnar: "The main changes in this cycle were: - Implement frequency/CPU invariance and OPP selection for SCHED_DEADLINE (Juri Lelli) - Tweak the task migration logic for better multi-tasking workload scalability (Mel Gorman) - Misc cleanups, fixes and improvements" * 'sched-core-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip: sched/deadline: Make bandwidth enforcement scale-invariant sched/cpufreq: Move arch_scale_{freq,cpu}_capacity() outside of #ifdef CONFIG_SMP sched/cpufreq: Remove arch_scale_freq_capacity()'s 'sd' parameter sched/cpufreq: Always consider all CPUs when deciding next freq sched/cpufreq: Split utilization signals sched/cpufreq: Change the worker kthread to SCHED_DEADLINE sched/deadline: Move CPU frequency selection triggering points sched/cpufreq: Use the DEADLINE utilization signal sched/deadline: Implement "runtime overrun signal" support sched/fair: Only immediately migrate tasks due to interrupts if prev and target CPUs share cache sched/fair: Correct obsolete comment about cpufreq_update_util() sched/fair: Remove impossible condition from find_idlest_group_cpu() sched/cpufreq: Don't pass flags to sugov_set_iowait_boost() sched/cpufreq: Initialize sg_cpu->flags to 0 sched/fair: Consider RT/IRQ pressure in capacity_spare_wake() sched/fair: Use 'unsigned long' for utilization, consistently sched/core: Rework and clarify prepare_lock_switch() sched/fair: Remove unused 'curr' parameter from wakeup_gran sched/headers: Constify object_is_on_stack()
Diffstat (limited to 'kernel')
-rw-r--r--kernel/sched/core.c67
-rw-r--r--kernel/sched/cpufreq_schedutil.c93
-rw-r--r--kernel/sched/deadline.c143
-rw-r--r--kernel/sched/fair.c39
-rw-r--r--kernel/sched/sched.h112
-rw-r--r--kernel/time/posix-cpu-timers.c18
6 files changed, 321 insertions, 151 deletions
diff --git a/kernel/sched/core.c b/kernel/sched/core.c
index 5a31a85bbd84..3da7a2444a91 100644
--- a/kernel/sched/core.c
+++ b/kernel/sched/core.c
@@ -2046,7 +2046,7 @@ try_to_wake_up(struct task_struct *p, unsigned int state, int wake_flags)
* If the owning (remote) CPU is still in the middle of schedule() with
* this task as prev, wait until its done referencing the task.
*
- * Pairs with the smp_store_release() in finish_lock_switch().
+ * Pairs with the smp_store_release() in finish_task().
*
* This ensures that tasks getting woken will be fully ordered against
* their previous state and preserve Program Order.
@@ -2572,6 +2572,50 @@ fire_sched_out_preempt_notifiers(struct task_struct *curr,
#endif /* CONFIG_PREEMPT_NOTIFIERS */
+static inline void prepare_task(struct task_struct *next)
+{
+#ifdef CONFIG_SMP
+ /*
+ * Claim the task as running, we do this before switching to it
+ * such that any running task will have this set.
+ */
+ next->on_cpu = 1;
+#endif
+}
+
+static inline void finish_task(struct task_struct *prev)
+{
+#ifdef CONFIG_SMP
+ /*
+ * After ->on_cpu is cleared, the task can be moved to a different CPU.
+ * We must ensure this doesn't happen until the switch is completely
+ * finished.
+ *
+ * In particular, the load of prev->state in finish_task_switch() must
+ * happen before this.
+ *
+ * Pairs with the smp_cond_load_acquire() in try_to_wake_up().
+ */
+ smp_store_release(&prev->on_cpu, 0);
+#endif
+}
+
+static inline void finish_lock_switch(struct rq *rq)
+{
+#ifdef CONFIG_DEBUG_SPINLOCK
+ /* this is a valid case when another task releases the spinlock */
+ rq->lock.owner = current;
+#endif
+ /*
+ * If we are tracking spinlock dependencies then we have to
+ * fix up the runqueue lock - which gets 'carried over' from
+ * prev into current:
+ */
+ spin_acquire(&rq->lock.dep_map, 0, 0, _THIS_IP_);
+
+ raw_spin_unlock_irq(&rq->lock);
+}
+
/**
* prepare_task_switch - prepare to switch tasks
* @rq: the runqueue preparing to switch
@@ -2592,7 +2636,7 @@ prepare_task_switch(struct rq *rq, struct task_struct *prev,
sched_info_switch(rq, prev, next);
perf_event_task_sched_out(prev, next);
fire_sched_out_preempt_notifiers(prev, next);
- prepare_lock_switch(rq, next);
+ prepare_task(next);
prepare_arch_switch(next);
}
@@ -2647,7 +2691,7 @@ static struct rq *finish_task_switch(struct task_struct *prev)
* the scheduled task must drop that reference.
*
* We must observe prev->state before clearing prev->on_cpu (in
- * finish_lock_switch), otherwise a concurrent wakeup can get prev
+ * finish_task), otherwise a concurrent wakeup can get prev
* running on another CPU and we could rave with its RUNNING -> DEAD
* transition, resulting in a double drop.
*/
@@ -2664,7 +2708,8 @@ static struct rq *finish_task_switch(struct task_struct *prev)
* to use.
*/
smp_mb__after_unlock_lock();
- finish_lock_switch(rq, prev);
+ finish_task(prev);
+ finish_lock_switch(rq);
finish_arch_post_lock_switch();
fire_sched_in_preempt_notifiers(current);
@@ -4041,8 +4086,7 @@ recheck:
return -EINVAL;
}
- if (attr->sched_flags &
- ~(SCHED_FLAG_RESET_ON_FORK | SCHED_FLAG_RECLAIM))
+ if (attr->sched_flags & ~(SCHED_FLAG_ALL | SCHED_FLAG_SUGOV))
return -EINVAL;
/*
@@ -4109,6 +4153,9 @@ recheck:
}
if (user) {
+ if (attr->sched_flags & SCHED_FLAG_SUGOV)
+ return -EINVAL;
+
retval = security_task_setscheduler(p);
if (retval)
return retval;
@@ -4164,7 +4211,8 @@ change:
}
#endif
#ifdef CONFIG_SMP
- if (dl_bandwidth_enabled() && dl_policy(policy)) {
+ if (dl_bandwidth_enabled() && dl_policy(policy) &&
+ !(attr->sched_flags & SCHED_FLAG_SUGOV)) {
cpumask_t *span = rq->rd->span;
/*
@@ -4294,6 +4342,11 @@ int sched_setattr(struct task_struct *p, const struct sched_attr *attr)
}
EXPORT_SYMBOL_GPL(sched_setattr);
+int sched_setattr_nocheck(struct task_struct *p, const struct sched_attr *attr)
+{
+ return __sched_setscheduler(p, attr, false, true);
+}
+
/**
* sched_setscheduler_nocheck - change the scheduling policy and/or RT priority of a thread from kernelspace.
* @p: the task in question.
diff --git a/kernel/sched/cpufreq_schedutil.c b/kernel/sched/cpufreq_schedutil.c
index d6717a3331a1..dd062a1c8cf0 100644
--- a/kernel/sched/cpufreq_schedutil.c
+++ b/kernel/sched/cpufreq_schedutil.c
@@ -60,7 +60,8 @@ struct sugov_cpu {
u64 last_update;
/* The fields below are only needed when sharing a policy. */
- unsigned long util;
+ unsigned long util_cfs;
+ unsigned long util_dl;
unsigned long max;
unsigned int flags;
@@ -176,21 +177,28 @@ static unsigned int get_next_freq(struct sugov_policy *sg_policy,
return cpufreq_driver_resolve_freq(policy, freq);
}
-static void sugov_get_util(unsigned long *util, unsigned long *max, int cpu)
+static void sugov_get_util(struct sugov_cpu *sg_cpu)
{
- struct rq *rq = cpu_rq(cpu);
- unsigned long cfs_max;
+ struct rq *rq = cpu_rq(sg_cpu->cpu);
- cfs_max = arch_scale_cpu_capacity(NULL, cpu);
+ sg_cpu->max = arch_scale_cpu_capacity(NULL, sg_cpu->cpu);
+ sg_cpu->util_cfs = cpu_util_cfs(rq);
+ sg_cpu->util_dl = cpu_util_dl(rq);
+}
- *util = min(rq->cfs.avg.util_avg, cfs_max);
- *max = cfs_max;
+static unsigned long sugov_aggregate_util(struct sugov_cpu *sg_cpu)
+{
+ /*
+ * Ideally we would like to set util_dl as min/guaranteed freq and
+ * util_cfs + util_dl as requested freq. However, cpufreq is not yet
+ * ready for such an interface. So, we only do the latter for now.
+ */
+ return min(sg_cpu->util_cfs + sg_cpu->util_dl, sg_cpu->max);
}
-static void sugov_set_iowait_boost(struct sugov_cpu *sg_cpu, u64 time,
- unsigned int flags)
+static void sugov_set_iowait_boost(struct sugov_cpu *sg_cpu, u64 time)
{
- if (flags & SCHED_CPUFREQ_IOWAIT) {
+ if (sg_cpu->flags & SCHED_CPUFREQ_IOWAIT) {
if (sg_cpu->iowait_boost_pending)
return;
@@ -264,7 +272,7 @@ static void sugov_update_single(struct update_util_data *hook, u64 time,
unsigned int next_f;
bool busy;
- sugov_set_iowait_boost(sg_cpu, time, flags);
+ sugov_set_iowait_boost(sg_cpu, time);
sg_cpu->last_update = time;
if (!sugov_should_update_freq(sg_policy, time))
@@ -272,10 +280,12 @@ static void sugov_update_single(struct update_util_data *hook, u64 time,
busy = sugov_cpu_is_busy(sg_cpu);
- if (flags & SCHED_CPUFREQ_RT_DL) {
+ if (flags & SCHED_CPUFREQ_RT) {
next_f = policy->cpuinfo.max_freq;
} else {
- sugov_get_util(&util, &max, sg_cpu->cpu);
+ sugov_get_util(sg_cpu);
+ max = sg_cpu->max;
+ util = sugov_aggregate_util(sg_cpu);
sugov_iowait_boost(sg_cpu, &util, &max);
next_f = get_next_freq(sg_policy, util, max);
/*
@@ -305,23 +315,27 @@ static unsigned int sugov_next_freq_shared(struct sugov_cpu *sg_cpu, u64 time)
s64 delta_ns;
/*
- * If the CPU utilization was last updated before the previous
- * frequency update and the time elapsed between the last update
- * of the CPU utilization and the last frequency update is long
- * enough, don't take the CPU into account as it probably is
- * idle now (and clear iowait_boost for it).
+ * If the CFS CPU utilization was last updated before the
+ * previous frequency update and the time elapsed between the
+ * last update of the CPU utilization and the last frequency
+ * update is long enough, reset iowait_boost and util_cfs, as
+ * they are now probably stale. However, still consider the
+ * CPU contribution if it has some DEADLINE utilization
+ * (util_dl).
*/
delta_ns = time - j_sg_cpu->last_update;
if (delta_ns > TICK_NSEC) {
j_sg_cpu->iowait_boost = 0;
j_sg_cpu->iowait_boost_pending = false;
- continue;
+ j_sg_cpu->util_cfs = 0;
+ if (j_sg_cpu->util_dl == 0)
+ continue;
}
- if (j_sg_cpu->flags & SCHED_CPUFREQ_RT_DL)
+ if (j_sg_cpu->flags & SCHED_CPUFREQ_RT)
return policy->cpuinfo.max_freq;
- j_util = j_sg_cpu->util;
j_max = j_sg_cpu->max;
+ j_util = sugov_aggregate_util(j_sg_cpu);
if (j_util * max > j_max * util) {
util = j_util;
max = j_max;
@@ -338,22 +352,18 @@ static void sugov_update_shared(struct update_util_data *hook, u64 time,
{
struct sugov_cpu *sg_cpu = container_of(hook, struct sugov_cpu, update_util);
struct sugov_policy *sg_policy = sg_cpu->sg_policy;
- unsigned long util, max;
unsigned int next_f;
- sugov_get_util(&util, &max, sg_cpu->cpu);
-
raw_spin_lock(&sg_policy->update_lock);
- sg_cpu->util = util;
- sg_cpu->max = max;
+ sugov_get_util(sg_cpu);
sg_cpu->flags = flags;
- sugov_set_iowait_boost(sg_cpu, time, flags);
+ sugov_set_iowait_boost(sg_cpu, time);
sg_cpu->last_update = time;
if (sugov_should_update_freq(sg_policy, time)) {
- if (flags & SCHED_CPUFREQ_RT_DL)
+ if (flags & SCHED_CPUFREQ_RT)
next_f = sg_policy->policy->cpuinfo.max_freq;
else
next_f = sugov_next_freq_shared(sg_cpu, time);
@@ -383,9 +393,9 @@ static void sugov_irq_work(struct irq_work *irq_work)
sg_policy = container_of(irq_work, struct sugov_policy, irq_work);
/*
- * For RT and deadline tasks, the schedutil governor shoots the
- * frequency to maximum. Special care must be taken to ensure that this
- * kthread doesn't result in the same behavior.
+ * For RT tasks, the schedutil governor shoots the frequency to maximum.
+ * Special care must be taken to ensure that this kthread doesn't result
+ * in the same behavior.
*
* This is (mostly) guaranteed by the work_in_progress flag. The flag is
* updated only at the end of the sugov_work() function and before that
@@ -470,7 +480,20 @@ static void sugov_policy_free(struct sugov_policy *sg_policy)
static int sugov_kthread_create(struct sugov_policy *sg_policy)
{
struct task_struct *thread;
- struct sched_param param = { .sched_priority = MAX_USER_RT_PRIO / 2 };
+ struct sched_attr attr = {
+ .size = sizeof(struct sched_attr),
+ .sched_policy = SCHED_DEADLINE,
+ .sched_flags = SCHED_FLAG_SUGOV,
+ .sched_nice = 0,
+ .sched_priority = 0,
+ /*
+ * Fake (unused) bandwidth; workaround to "fix"
+ * priority inheritance.
+ */
+ .sched_runtime = 1000000,
+ .sched_deadline = 10000000,
+ .sched_period = 10000000,
+ };
struct cpufreq_policy *policy = sg_policy->policy;
int ret;
@@ -488,10 +511,10 @@ static int sugov_kthread_create(struct sugov_policy *sg_policy)
return PTR_ERR(thread);
}
- ret = sched_setscheduler_nocheck(thread, SCHED_FIFO, &param);
+ ret = sched_setattr_nocheck(thread, &attr);
if (ret) {
kthread_stop(thread);
- pr_warn("%s: failed to set SCHED_FIFO\n", __func__);
+ pr_warn("%s: failed to set SCHED_DEADLINE\n", __func__);
return ret;
}
@@ -655,7 +678,7 @@ static int sugov_start(struct cpufreq_policy *policy)
memset(sg_cpu, 0, sizeof(*sg_cpu));
sg_cpu->cpu = cpu;
sg_cpu->sg_policy = sg_policy;
- sg_cpu->flags = SCHED_CPUFREQ_RT;
+ sg_cpu->flags = 0;
sg_cpu->iowait_boost_max = policy->cpuinfo.max_freq;
}
diff --git a/kernel/sched/deadline.c b/kernel/sched/deadline.c
index 2473736c7616..9bb0e0c412ec 100644
--- a/kernel/sched/deadline.c
+++ b/kernel/sched/deadline.c
@@ -78,7 +78,7 @@ static inline int dl_bw_cpus(int i)
#endif
static inline
-void add_running_bw(u64 dl_bw, struct dl_rq *dl_rq)
+void __add_running_bw(u64 dl_bw, struct dl_rq *dl_rq)
{
u64 old = dl_rq->running_bw;
@@ -86,10 +86,12 @@ void add_running_bw(u64 dl_bw, struct dl_rq *dl_rq)
dl_rq->running_bw += dl_bw;
SCHED_WARN_ON(dl_rq->running_bw < old); /* overflow */
SCHED_WARN_ON(dl_rq->running_bw > dl_rq->this_bw);
+ /* kick cpufreq (see the comment in kernel/sched/sched.h). */
+ cpufreq_update_util(rq_of_dl_rq(dl_rq), SCHED_CPUFREQ_DL);
}
static inline
-void sub_running_bw(u64 dl_bw, struct dl_rq *dl_rq)
+void __sub_running_bw(u64 dl_bw, struct dl_rq *dl_rq)
{
u64 old = dl_rq->running_bw;
@@ -98,10 +100,12 @@ void sub_running_bw(u64 dl_bw, struct dl_rq *dl_rq)
SCHED_WARN_ON(dl_rq->running_bw > old); /* underflow */
if (dl_rq->running_bw > old)
dl_rq->running_bw = 0;
+ /* kick cpufreq (see the comment in kernel/sched/sched.h). */
+ cpufreq_update_util(rq_of_dl_rq(dl_rq), SCHED_CPUFREQ_DL);
}
static inline
-void add_rq_bw(u64 dl_bw, struct dl_rq *dl_rq)
+void __add_rq_bw(u64 dl_bw, struct dl_rq *dl_rq)
{
u64 old = dl_rq->this_bw;
@@ -111,7 +115,7 @@ void add_rq_bw(u64 dl_bw, struct dl_rq *dl_rq)
}
static inline
-void sub_rq_bw(u64 dl_bw, struct dl_rq *dl_rq)
+void __sub_rq_bw(u64 dl_bw, struct dl_rq *dl_rq)
{
u64 old = dl_rq->this_bw;
@@ -123,16 +127,46 @@ void sub_rq_bw(u64 dl_bw, struct dl_rq *dl_rq)
SCHED_WARN_ON(dl_rq->running_bw > dl_rq->this_bw);
}
+static inline
+void add_rq_bw(struct sched_dl_entity *dl_se, struct dl_rq *dl_rq)
+{
+ if (!dl_entity_is_special(dl_se))
+ __add_rq_bw(dl_se->dl_bw, dl_rq);
+}
+
+static inline
+void sub_rq_bw(struct sched_dl_entity *dl_se, struct dl_rq *dl_rq)
+{
+ if (!dl_entity_is_special(dl_se))
+ __sub_rq_bw(dl_se->dl_bw, dl_rq);
+}
+
+static inline
+void add_running_bw(struct sched_dl_entity *dl_se, struct dl_rq *dl_rq)
+{
+ if (!dl_entity_is_special(dl_se))
+ __add_running_bw(dl_se->dl_bw, dl_rq);
+}
+
+static inline
+void sub_running_bw(struct sched_dl_entity *dl_se, struct dl_rq *dl_rq)
+{
+ if (!dl_entity_is_special(dl_se))
+ __sub_running_bw(dl_se->dl_bw, dl_rq);
+}
+
void dl_change_utilization(struct task_struct *p, u64 new_bw)
{
struct rq *rq;
+ BUG_ON(p->dl.flags & SCHED_FLAG_SUGOV);
+
if (task_on_rq_queued(p))
return;
rq = task_rq(p);
if (p->dl.dl_non_contending) {
- sub_running_bw(p->dl.dl_bw, &rq->dl);
+ sub_running_bw(&p->dl, &rq->dl);
p->dl.dl_non_contending = 0;
/*
* If the timer handler is currently running and the
@@ -144,8 +178,8 @@ void dl_change_utilization(struct task_struct *p, u64 new_bw)
if (hrtimer_try_to_cancel(&p->dl.inactive_timer) == 1)
put_task_struct(p);
}
- sub_rq_bw(p->dl.dl_bw, &rq->dl);
- add_rq_bw(new_bw, &rq->dl);
+ __sub_rq_bw(p->dl.dl_bw, &rq->dl);
+ __add_rq_bw(new_bw, &rq->dl);
}
/*
@@ -217,6 +251,9 @@ static void task_non_contending(struct task_struct *p)
if (dl_se->dl_runtime == 0)
return;
+ if (dl_entity_is_special(dl_se))
+ return;
+
WARN_ON(hrtimer_active(&dl_se->inactive_timer));
WARN_ON(dl_se->dl_non_contending);
@@ -236,12 +273,12 @@ static void task_non_contending(struct task_struct *p)
*/
if (zerolag_time < 0) {
if (dl_task(p))
- sub_running_bw(dl_se->dl_bw, dl_rq);
+ sub_running_bw(dl_se, dl_rq);
if (!dl_task(p) || p->state == TASK_DEAD) {
struct dl_bw *dl_b = dl_bw_of(task_cpu(p));
if (p->state == TASK_DEAD)
- sub_rq_bw(p->dl.dl_bw, &rq->dl);
+ sub_rq_bw(&p->dl, &rq->dl);
raw_spin_lock(&dl_b->lock);
__dl_sub(dl_b, p->dl.dl_bw, dl_bw_cpus(task_cpu(p)));
__dl_clear_params(p);
@@ -268,7 +305,7 @@ static void task_contending(struct sched_dl_entity *dl_se, int flags)
return;
if (flags & ENQUEUE_MIGRATED)
- add_rq_bw(dl_se->dl_bw, dl_rq);
+ add_rq_bw(dl_se, dl_rq);
if (dl_se->dl_non_contending) {
dl_se->dl_non_contending = 0;
@@ -289,7 +326,7 @@ static void task_contending(struct sched_dl_entity *dl_se, int flags)
* when the "inactive timer" fired).
* So, add it back.
*/
- add_running_bw(dl_se->dl_bw, dl_rq);
+ add_running_bw(dl_se, dl_rq);
}
}
@@ -1114,7 +1151,8 @@ static void update_curr_dl(struct rq *rq)
{
struct task_struct *curr = rq->curr;
struct sched_dl_entity *dl_se = &curr->dl;
- u64 delta_exec;
+ u64 delta_exec, scaled_delta_exec;
+ int cpu = cpu_of(rq);
if (!dl_task(curr) || !on_dl_rq(dl_se))
return;
@@ -1134,9 +1172,6 @@ static void update_curr_dl(struct rq *rq)
return;
}
- /* kick cpufreq (see the comment in kernel/sched/sched.h). */
- cpufreq_update_util(rq, SCHED_CPUFREQ_DL);
-
schedstat_set(curr->se.statistics.exec_max,
max(curr->se.statistics.exec_max, delta_exec));
@@ -1148,13 +1183,39 @@ static void update_curr_dl(struct rq *rq)
sched_rt_avg_update(rq, delta_exec);
- if (unlikely(dl_se->flags & SCHED_FLAG_RECLAIM))
- delta_exec = grub_reclaim(delta_exec, rq, &curr->dl);
- dl_se->runtime -= delta_exec;
+ if (dl_entity_is_special(dl_se))
+ return;
+
+ /*
+ * For tasks that participate in GRUB, we implement GRUB-PA: the
+ * spare reclaimed bandwidth is used to clock down frequency.
+ *
+ * For the others, we still need to scale reservation parameters
+ * according to current frequency and CPU maximum capacity.
+ */
+ if (unlikely(dl_se->flags & SCHED_FLAG_RECLAIM)) {
+ scaled_delta_exec = grub_reclaim(delta_exec,
+ rq,
+ &curr->dl);
+ } else {
+ unsigned long scale_freq = arch_scale_freq_capacity(cpu);
+ unsigned long scale_cpu = arch_scale_cpu_capacity(NULL, cpu);
+
+ scaled_delta_exec = cap_scale(delta_exec, scale_freq);
+ scaled_delta_exec = cap_scale(scaled_delta_exec, scale_cpu);
+ }
+
+ dl_se->runtime -= scaled_delta_exec;
throttle:
if (dl_runtime_exceeded(dl_se) || dl_se->dl_yielded) {
dl_se->dl_throttled = 1;
+
+ /* If requested, inform the user about runtime overruns. */
+ if (dl_runtime_exceeded(dl_se) &&
+ (dl_se->flags & SCHED_FLAG_DL_OVERRUN))
+ dl_se->dl_overrun = 1;
+
__dequeue_task_dl(rq, curr, 0);
if (unlikely(dl_se->dl_boosted || !start_dl_timer(curr)))
enqueue_task_dl(rq, curr, ENQUEUE_REPLENISH);
@@ -1204,8 +1265,8 @@ static enum hrtimer_restart inactive_task_timer(struct hrtimer *timer)
struct dl_bw *dl_b = dl_bw_of(task_cpu(p));
if (p->state == TASK_DEAD && dl_se->dl_non_contending) {
- sub_running_bw(p->dl.dl_bw, dl_rq_of_se(&p->dl));
- sub_rq_bw(p->dl.dl_bw, dl_rq_of_se(&p->dl));
+ sub_running_bw(&p->dl, dl_rq_of_se(&p->dl));
+ sub_rq_bw(&p->dl, dl_rq_of_se(&p->dl));
dl_se->dl_non_contending = 0;
}
@@ -1222,7 +1283,7 @@ static enum hrtimer_restart inactive_task_timer(struct hrtimer *timer)
sched_clock_tick();
update_rq_clock(rq);
- sub_running_bw(dl_se->dl_bw, &rq->dl);
+ sub_running_bw(dl_se, &rq->dl);
dl_se->dl_non_contending = 0;
unlock:
task_rq_unlock(rq, p, &rf);
@@ -1416,8 +1477,8 @@ static void enqueue_task_dl(struct rq *rq, struct task_struct *p, int flags)
dl_check_constrained_dl(&p->dl);
if (p->on_rq == TASK_ON_RQ_MIGRATING || flags & ENQUEUE_RESTORE) {
- add_rq_bw(p->dl.dl_bw, &rq->dl);
- add_running_bw(p->dl.dl_bw, &rq->dl);
+ add_rq_bw(&p->dl, &rq->dl);
+ add_running_bw(&p->dl, &rq->dl);
}
/*
@@ -1457,8 +1518,8 @@ static void dequeue_task_dl(struct rq *rq, struct task_struct *p, int flags)
__dequeue_task_dl(rq, p, flags);
if (p->on_rq == TASK_ON_RQ_MIGRATING || flags & DEQUEUE_SAVE) {
- sub_running_bw(p->dl.dl_bw, &rq->dl);
- sub_rq_bw(p->dl.dl_bw, &rq->dl);
+ sub_running_bw(&p->dl, &rq->dl);
+ sub_rq_bw(&p->dl, &rq->dl);
}
/*
@@ -1564,7 +1625,7 @@ static void migrate_task_rq_dl(struct task_struct *p)
*/
raw_spin_lock(&rq->lock);
if (p->dl.dl_non_contending) {
- sub_running_bw(p->dl.dl_bw, &rq->dl);
+ sub_running_bw(&p->dl, &rq->dl);
p->dl.dl_non_contending = 0;
/*
* If the timer handler is currently running and the
@@ -1576,7 +1637,7 @@ static void migrate_task_rq_dl(struct task_struct *p)
if (hrtimer_try_to_cancel(&p->dl.inactive_timer) == 1)
put_task_struct(p);
}
- sub_rq_bw(p->dl.dl_bw, &rq->dl);
+ sub_rq_bw(&p->dl, &rq->dl);
raw_spin_unlock(&rq->lock);
}
@@ -2019,11 +2080,11 @@ retry:
}
deactivate_task(rq, next_task, 0);
- sub_running_bw(next_task->dl.dl_bw, &rq->dl);
- sub_rq_bw(next_task->dl.dl_bw, &rq->dl);
+ sub_running_bw(&next_task->dl, &rq->dl);
+ sub_rq_bw(&next_task->dl, &rq->dl);
set_task_cpu(next_task, later_rq->cpu);
- add_rq_bw(next_task->dl.dl_bw, &later_rq->dl);
- add_running_bw(next_task->dl.dl_bw, &later_rq->dl);
+ add_rq_bw(&next_task->dl, &later_rq->dl);
+ add_running_bw(&next_task->dl, &later_rq->dl);
activate_task(later_rq, next_task, 0);
ret = 1;
@@ -2111,11 +2172,11 @@ static void pull_dl_task(struct rq *this_rq)
resched = true;
deactivate_task(src_rq, p, 0);
- sub_running_bw(p->dl.dl_bw, &src_rq->dl);
- sub_rq_bw(p->dl.dl_bw, &src_rq->dl);
+ sub_running_bw(&p->dl, &src_rq->dl);
+ sub_rq_bw(&p->dl, &src_rq->dl);
set_task_cpu(p, this_cpu);
- add_rq_bw(p->dl.dl_bw, &this_rq->dl);
- add_running_bw(p->dl.dl_bw, &this_rq->dl);
+ add_rq_bw(&p->dl, &this_rq->dl);
+ add_running_bw(&p->dl, &this_rq->dl);
activate_task(this_rq, p, 0);
dmin = p->dl.deadline;
@@ -2224,7 +2285,7 @@ static void switched_from_dl(struct rq *rq, struct task_struct *p)
task_non_contending(p);
if (!task_on_rq_queued(p))
- sub_rq_bw(p->dl.dl_bw, &rq->dl);
+ sub_rq_bw(&p->dl, &rq->dl);
/*
* We cannot use inactive_task_timer() to invoke sub_running_bw()
@@ -2256,7 +2317,7 @@ static void switched_to_dl(struct rq *rq, struct task_struct *p)
/* If p is not queued we will update its parameters at next wakeup. */
if (!task_on_rq_queued(p)) {
- add_rq_bw(p->dl.dl_bw, &rq->dl);
+ add_rq_bw(&p->dl, &rq->dl);
return;
}
@@ -2435,6 +2496,9 @@ int sched_dl_overflow(struct task_struct *p, int policy,
u64 new_bw = dl_policy(policy) ? to_ratio(period, runtime) : 0;
int cpus, err = -1;
+ if (attr->sched_flags & SCHED_FLAG_SUGOV)
+ return 0;
+
/* !deadline task may carry old deadline bandwidth */
if (new_bw == p->dl.dl_bw && task_has_dl_policy(p))
return 0;
@@ -2521,6 +2585,10 @@ void __getparam_dl(struct task_struct *p, struct sched_attr *attr)
*/
bool __checkparam_dl(const struct sched_attr *attr)
{
+ /* special dl tasks don't actually use any parameter */
+ if (attr->sched_flags & SCHED_FLAG_SUGOV)
+ return true;
+
/* deadline != 0 */
if (attr->sched_deadline == 0)
return false;
@@ -2566,6 +2634,7 @@ void __dl_clear_params(struct task_struct *p)
dl_se->dl_throttled = 0;
dl_se->dl_yielded = 0;
dl_se->dl_non_contending = 0;
+ dl_se->dl_overrun = 0;
}
bool dl_param_changed(struct task_struct *p, const struct sched_attr *attr)
diff --git a/kernel/sched/fair.c b/kernel/sched/fair.c
index 26a71ebcd3c2..7b6535987500 100644
--- a/kernel/sched/fair.c
+++ b/kernel/sched/fair.c
@@ -3020,9 +3020,7 @@ static inline void cfs_rq_util_change(struct cfs_rq *cfs_rq)
/*
* There are a few boundary cases this might miss but it should
* get called often enough that that should (hopefully) not be
- * a real problem -- added to that it only calls on the local
- * CPU, so if we enqueue remotely we'll miss an update, but
- * the next tick/schedule should update.
+ * a real problem.
*
* It will not get called when we go idle, because the idle
* thread is a different class (!fair), nor will the utilization
@@ -3091,8 +3089,6 @@ static u32 __accumulate_pelt_segments(u64 periods, u32 d1, u32 d3)
return c1 + c2 + c3;
}
-#define cap_scale(v, s) ((v)*(s) >> SCHED_CAPACITY_SHIFT)
-
/*
* Accumulate the three separate parts of the sum; d1 the remainder
* of the last (incomplete) period, d2 the span of full periods and d3
@@ -3122,7 +3118,7 @@ accumulate_sum(u64 delta, int cpu, struct sched_avg *sa,
u32 contrib = (u32)delta; /* p == 0 -> delta < 1024 */
u64 periods;
- scale_freq = arch_scale_freq_capacity(NULL, cpu);
+ scale_freq = arch_scale_freq_capacity(cpu);
scale_cpu = arch_scale_cpu_capacity(NULL, cpu);
delta += sa->period_contrib;
@@ -5689,8 +5685,8 @@ static int wake_wide(struct task_struct *p)
* soonest. For the purpose of speed we only consider the waking and previous
* CPU.
*
- * wake_affine_idle() - only considers 'now', it check if the waking CPU is (or
- * will be) idle.
+ * wake_affine_idle() - only considers 'now', it check if the waking CPU is
+ * cache-affine and is (or will be) idle.
*
* wake_affine_weight() - considers the weight to reflect the average
* scheduling latency of the CPUs. This seems to work
@@ -5701,7 +5697,13 @@ static bool
wake_affine_idle(struct sched_domain *sd, struct task_struct *p,
int this_cpu, int prev_cpu, int sync)
{
- if (idle_cpu(this_cpu))
+ /*
+ * If this_cpu is idle, it implies the wakeup is from interrupt
+ * context. Only allow the move if cache is shared. Otherwise an
+ * interrupt intensive workload could force all tasks onto one
+ * node depending on the IO topology or IRQ affinity settings.
+ */
+ if (idle_cpu(this_cpu) && cpus_share_cache(this_cpu, prev_cpu))
return true;
if (sync && cpu_rq(this_cpu)->nr_running == 1)
@@ -5765,12 +5767,12 @@ static int wake_affine(struct sched_domain *sd, struct task_struct *p,
return affine;
}
-static inline int task_util(struct task_struct *p);
-static int cpu_util_wake(int cpu, struct task_struct *p);
+static inline unsigned long task_util(struct task_struct *p);
+static unsigned long cpu_util_wake(int cpu, struct task_struct *p);
static unsigned long capacity_spare_wake(int cpu, struct task_struct *p)
{
- return capacity_orig_of(cpu) - cpu_util_wake(cpu, p);
+ return max_t(long, capacity_of(cpu) - cpu_util_wake(cpu, p), 0);
}
/*
@@ -5950,7 +5952,7 @@ find_idlest_group_cpu(struct sched_group *group, struct task_struct *p, int this
}
} else if (shallowest_idle_cpu == -1) {
load = weighted_cpuload(cpu_rq(i));
- if (load < min_load || (load == min_load && i == this_cpu)) {
+ if (load < min_load) {
min_load = load;
least_loaded_cpu = i;
}
@@ -6247,7 +6249,7 @@ static int select_idle_sibling(struct task_struct *p, int prev, int target)
* capacity_orig) as it useful for predicting the capacity required after task
* migrations (scheduler-driven DVFS).
*/
-static int cpu_util(int cpu)
+static unsigned long cpu_util(int cpu)
{
unsigned long util = cpu_rq(cpu)->cfs.avg.util_avg;
unsigned long capacity = capacity_orig_of(cpu);
@@ -6255,7 +6257,7 @@ static int cpu_util(int cpu)
return (util >= capacity) ? capacity : util;
}
-static inline int task_util(struct task_struct *p)
+static inline unsigned long task_util(struct task_struct *p)
{
return p->se.avg.util_avg;
}
@@ -6264,7 +6266,7 @@ static inline int task_util(struct task_struct *p)
* cpu_util_wake: Compute cpu utilization with any contributions from
* the waking task p removed.
*/
-static int cpu_util_wake(int cpu, struct task_struct *p)
+static unsigned long cpu_util_wake(int cpu, struct task_struct *p)
{
unsigned long util, capacity;
@@ -6449,8 +6451,7 @@ static void task_dead_fair(struct task_struct *p)
}
#endif /* CONFIG_SMP */
-static unsigned long
-wakeup_gran(struct sched_entity *curr, struct sched_entity *se)
+static unsigned long wakeup_gran(struct sched_entity *se)
{
unsigned long gran = sysctl_sched_wakeup_granularity;
@@ -6492,7 +6493,7 @@ wakeup_preempt_entity(struct sched_entity *curr, struct sched_entity *se)
if (vdiff <= 0)
return -1;
- gran = wakeup_gran(curr, se);
+ gran = wakeup_gran(se);
if (vdiff > gran)
return 1;
diff --git a/kernel/sched/sched.h b/kernel/sched/sched.h
index b19552a212de..2e95505e23c6 100644
--- a/kernel/sched/sched.h
+++ b/kernel/sched/sched.h
@@ -156,13 +156,39 @@ static inline int task_has_dl_policy(struct task_struct *p)
return dl_policy(p->policy);
}
+#define cap_scale(v, s) ((v)*(s) >> SCHED_CAPACITY_SHIFT)
+
+/*
+ * !! For sched_setattr_nocheck() (kernel) only !!
+ *
+ * This is actually gross. :(
+ *
+ * It is used to make schedutil kworker(s) higher priority than SCHED_DEADLINE
+ * tasks, but still be able to sleep. We need this on platforms that cannot
+ * atomically change clock frequency. Remove once fast switching will be
+ * available on such platforms.
+ *
+ * SUGOV stands for SchedUtil GOVernor.
+ */
+#define SCHED_FLAG_SUGOV 0x10000000
+
+static inline bool dl_entity_is_special(struct sched_dl_entity *dl_se)
+{
+#ifdef CONFIG_CPU_FREQ_GOV_SCHEDUTIL
+ return unlikely(dl_se->flags & SCHED_FLAG_SUGOV);
+#else
+ return false;
+#endif
+}
+
/*
* Tells if entity @a should preempt entity @b.
*/
static inline bool
dl_entity_preempt(struct sched_dl_entity *a, struct sched_dl_entity *b)
{
- return dl_time_before(a->deadline, b->deadline);
+ return dl_entity_is_special(a) ||
+ dl_time_before(a->deadline, b->deadline);
}
/*
@@ -1328,47 +1354,6 @@ static inline int task_on_rq_migrating(struct task_struct *p)
# define finish_arch_post_lock_switch() do { } while (0)
#endif
-static inline void prepare_lock_switch(struct rq *rq, struct task_struct *next)
-{
-#ifdef CONFIG_SMP
- /*
- * We can optimise this out completely for !SMP, because the
- * SMP rebalancing from interrupt is the only thing that cares
- * here.
- */
- next->on_cpu = 1;
-#endif
-}
-
-static inline void finish_lock_switch(struct rq *rq, struct task_struct *prev)
-{
-#ifdef CONFIG_SMP
- /*
- * After ->on_cpu is cleared, the task can be moved to a different CPU.
- * We must ensure this doesn't happen until the switch is completely
- * finished.
- *
- * In particular, the load of prev->state in finish_task_switch() must
- * happen before this.
- *
- * Pairs with the smp_cond_load_acquire() in try_to_wake_up().
- */
- smp_store_release(&prev->on_cpu, 0);
-#endif
-#ifdef CONFIG_DEBUG_SPINLOCK
- /* this is a valid case when another task releases the spinlock */
- rq->lock.owner = current;
-#endif
- /*
- * If we are tracking spinlock dependencies then we have to
- * fix up the runqueue lock - which gets 'carried over' from
- * prev into current:
- */
- spin_acquire(&rq->lock.dep_map, 0, 0, _THIS_IP_);
-
- raw_spin_unlock_irq(&rq->lock);
-}
-
/*
* wake flags
*/
@@ -1687,17 +1672,17 @@ static inline int hrtick_enabled(struct rq *rq)
#endif /* CONFIG_SCHED_HRTICK */
-#ifdef CONFIG_SMP
-extern void sched_avg_update(struct rq *rq);
-
#ifndef arch_scale_freq_capacity
static __always_inline
-unsigned long arch_scale_freq_capacity(struct sched_domain *sd, int cpu)
+unsigned long arch_scale_freq_capacity(int cpu)
{
return SCHED_CAPACITY_SCALE;
}
#endif
+#ifdef CONFIG_SMP
+extern void sched_avg_update(struct rq *rq);
+
#ifndef arch_scale_cpu_capacity
static __always_inline
unsigned long arch_scale_cpu_capacity(struct sched_domain *sd, int cpu)
@@ -1711,10 +1696,17 @@ unsigned long arch_scale_cpu_capacity(struct sched_domain *sd, int cpu)
static inline void sched_rt_avg_update(struct rq *rq, u64 rt_delta)
{
- rq->rt_avg += rt_delta * arch_scale_freq_capacity(NULL, cpu_of(rq));
+ rq->rt_avg += rt_delta * arch_scale_freq_capacity(cpu_of(rq));
sched_avg_update(rq);
}
#else
+#ifndef arch_scale_cpu_capacity
+static __always_inline
+unsigned long arch_scale_cpu_capacity(void __always_unused *sd, int cpu)
+{
+ return SCHED_CAPACITY_SCALE;
+}
+#endif
static inline void sched_rt_avg_update(struct rq *rq, u64 rt_delta) { }
static inline void sched_avg_update(struct rq *rq) { }
#endif
@@ -2096,14 +2088,14 @@ DECLARE_PER_CPU(struct update_util_data *, cpufreq_update_util_data);
* The way cpufreq is currently arranged requires it to evaluate the CPU
* performance state (frequency/voltage) on a regular basis to prevent it from
* being stuck in a completely inadequate performance level for too long.
- * That is not guaranteed to happen if the updates are only triggered from CFS,
- * though, because they may not be coming in if RT or deadline tasks are active
- * all the time (or there are RT and DL tasks only).
+ * That is not guaranteed to happen if the updates are only triggered from CFS
+ * and DL, though, because they may not be coming in if only RT tasks are
+ * active all the time (or there are RT tasks only).
*
- * As a workaround for that issue, this function is called by the RT and DL
- * sched classes to trigger extra cpufreq updates to prevent it from stalling,
+ * As a workaround for that issue, this function is called periodically by the
+ * RT sched class to trigger extra cpufreq updates to prevent it from stalling,
* but that really is a band-aid. Going forward it should be replaced with
- * solutions targeted more specifically at RT and DL tasks.
+ * solutions targeted more specifically at RT tasks.
*/
static inline void cpufreq_update_util(struct rq *rq, unsigned int flags)
{
@@ -2125,3 +2117,17 @@ static inline void cpufreq_update_util(struct rq *rq, unsigned int flags) {}
#else /* arch_scale_freq_capacity */
#define arch_scale_freq_invariant() (false)
#endif
+
+#ifdef CONFIG_CPU_FREQ_GOV_SCHEDUTIL
+
+static inline unsigned long cpu_util_dl(struct rq *rq)
+{
+ return (rq->dl.running_bw * SCHED_CAPACITY_SCALE) >> BW_SHIFT;
+}
+
+static inline unsigned long cpu_util_cfs(struct rq *rq)
+{
+ return rq->cfs.avg.util_avg;
+}
+
+#endif
diff --git a/kernel/time/posix-cpu-timers.c b/kernel/time/posix-cpu-timers.c
index ec9f5da6f163..2541bd89f20e 100644
--- a/kernel/time/posix-cpu-timers.c
+++ b/kernel/time/posix-cpu-timers.c
@@ -14,6 +14,7 @@
#include <linux/tick.h>
#include <linux/workqueue.h>
#include <linux/compat.h>
+#include <linux/sched/deadline.h>
#include "posix-timers.h"
@@ -791,6 +792,14 @@ check_timers_list(struct list_head *timers,
return 0;
}
+static inline void check_dl_overrun(struct task_struct *tsk)
+{
+ if (tsk->dl.dl_overrun) {
+ tsk->dl.dl_overrun = 0;
+ __group_send_sig_info(SIGXCPU, SEND_SIG_PRIV, tsk);
+ }
+}
+
/*
* Check for any per-thread CPU timers that have fired and move them off
* the tsk->cpu_timers[N] list onto the firing list. Here we update the
@@ -804,6 +813,9 @@ static void check_thread_timers(struct task_struct *tsk,
u64 expires;
unsigned long soft;
+ if (dl_task(tsk))
+ check_dl_overrun(tsk);
+
/*
* If cputime_expires is zero, then there are no active
* per thread CPU timers.
@@ -906,6 +918,9 @@ static void check_process_timers(struct task_struct *tsk,
struct task_cputime cputime;
unsigned long soft;
+ if (dl_task(tsk))
+ check_dl_overrun(tsk);
+
/*
* If cputimer is not running, then there are no active
* process wide timers (POSIX 1.b, itimers, RLIMIT_CPU).
@@ -1111,6 +1126,9 @@ static inline int fastpath_timer_check(struct task_struct *tsk)
return 1;
}
+ if (dl_task(tsk) && tsk->dl.dl_overrun)
+ return 1;
+
return 0;
}