Merge branch 'sched/core'

1 files changed, 346 insertions, 94 deletions

diff --git a/kernel/sched/core.c b/kernel/sched/core.c
index 20ffcc044134..8dc67166aa6c 100644
--- a/kernel/sched/core.c
+++ b/kernel/sched/core.c
@@ -993,6 +993,7 @@ int get_nohz_timer_target(void)
 {
 	int i, cpu = smp_processor_id(), default_cpu = -1;
 	struct sched_domain *sd;
+	const struct cpumask *hk_mask;
 
 	if (housekeeping_cpu(cpu, HK_FLAG_TIMER)) {
 		if (!idle_cpu(cpu))
@@ -1000,10 +1001,11 @@ int get_nohz_timer_target(void)
 		default_cpu = cpu;
 	}
 
+	hk_mask = housekeeping_cpumask(HK_FLAG_TIMER);
+
 	rcu_read_lock();
 	for_each_domain(cpu, sd) {
-		for_each_cpu_and(i, sched_domain_span(sd),
-			housekeeping_cpumask(HK_FLAG_TIMER)) {
+		for_each_cpu_and(i, sched_domain_span(sd), hk_mask) {
 			if (cpu == i)
 				continue;
 
@@ -1619,6 +1621,23 @@ static inline void uclamp_rq_dec(struct rq *rq, struct task_struct *p)
 		uclamp_rq_dec_id(rq, p, clamp_id);
 }
 
+static inline void uclamp_rq_reinc_id(struct rq *rq, struct task_struct *p,
+				      enum uclamp_id clamp_id)
+{
+	if (!p->uclamp[clamp_id].active)
+		return;
+
+	uclamp_rq_dec_id(rq, p, clamp_id);
+	uclamp_rq_inc_id(rq, p, clamp_id);
+
+	/*
+	 * Make sure to clear the idle flag if we've transiently reached 0
+	 * active tasks on rq.
+	 */
+	if (clamp_id == UCLAMP_MAX && (rq->uclamp_flags & UCLAMP_FLAG_IDLE))
+		rq->uclamp_flags &= ~UCLAMP_FLAG_IDLE;
+}
+
 static inline void
 uclamp_update_active(struct task_struct *p)
 {
@@ -1642,12 +1661,8 @@ uclamp_update_active(struct task_struct *p)
 	 * affecting a valid clamp bucket, the next time it's enqueued,
 	 * it will already see the updated clamp bucket value.
 	 */
-	for_each_clamp_id(clamp_id) {
-		if (p->uclamp[clamp_id].active) {
-			uclamp_rq_dec_id(rq, p, clamp_id);
-			uclamp_rq_inc_id(rq, p, clamp_id);
-		}
-	}
+	for_each_clamp_id(clamp_id)
+		uclamp_rq_reinc_id(rq, p, clamp_id);
 
 	task_rq_unlock(rq, p, &rf);
 }
@@ -2161,7 +2176,7 @@ static inline bool is_cpu_allowed(struct task_struct *p, int cpu)
 
 	/* Non kernel threads are not allowed during either online or offline. */
 	if (!(p->flags & PF_KTHREAD))
-		return cpu_active(cpu);
+		return cpu_active(cpu) && task_cpu_possible(cpu, p);
 
 	/* KTHREAD_IS_PER_CPU is always allowed. */
 	if (kthread_is_per_cpu(p))
@@ -2468,6 +2483,34 @@ void do_set_cpus_allowed(struct task_struct *p, const struct cpumask *new_mask)
 	__do_set_cpus_allowed(p, new_mask, 0);
 }
 
+int dup_user_cpus_ptr(struct task_struct *dst, struct task_struct *src,
+		      int node)
+{
+	if (!src->user_cpus_ptr)
+		return 0;
+
+	dst->user_cpus_ptr = kmalloc_node(cpumask_size(), GFP_KERNEL, node);
+	if (!dst->user_cpus_ptr)
+		return -ENOMEM;
+
+	cpumask_copy(dst->user_cpus_ptr, src->user_cpus_ptr);
+	return 0;
+}
+
+static inline struct cpumask *clear_user_cpus_ptr(struct task_struct *p)
+{
+	struct cpumask *user_mask = NULL;
+
+	swap(p->user_cpus_ptr, user_mask);
+
+	return user_mask;
+}
+
+void release_user_cpus_ptr(struct task_struct *p)
+{
+	kfree(clear_user_cpus_ptr(p));
+}
+
 /*
  * This function is wildly self concurrent; here be dragons.
  *
@@ -2685,28 +2728,26 @@ static int affine_move_task(struct rq *rq, struct task_struct *p, struct rq_flag
 }
 
 /*
- * Change a given task's CPU affinity. Migrate the thread to a
- * proper CPU and schedule it away if the CPU it's executing on
- * is removed from the allowed bitmask.
- *
- * NOTE: the caller must have a valid reference to the task, the
- * task must not exit() & deallocate itself prematurely. The
- * call is not atomic; no spinlocks may be held.
+ * Called with both p->pi_lock and rq->lock held; drops both before returning.
  */
-static int __set_cpus_allowed_ptr(struct task_struct *p,
-				  const struct cpumask *new_mask,
-				  u32 flags)
+static int __set_cpus_allowed_ptr_locked(struct task_struct *p,
+					 const struct cpumask *new_mask,
+					 u32 flags,
+					 struct rq *rq,
+					 struct rq_flags *rf)
+	__releases(rq->lock)
+	__releases(p->pi_lock)
 {
+	const struct cpumask *cpu_allowed_mask = task_cpu_possible_mask(p);
 	const struct cpumask *cpu_valid_mask = cpu_active_mask;
+	bool kthread = p->flags & PF_KTHREAD;
+	struct cpumask *user_mask = NULL;
 	unsigned int dest_cpu;
-	struct rq_flags rf;
-	struct rq *rq;
 	int ret = 0;
 
-	rq = task_rq_lock(p, &rf);
 	update_rq_clock(rq);
 
-	if (p->flags & PF_KTHREAD || is_migration_disabled(p)) {
+	if (kthread || is_migration_disabled(p)) {
 		/*
 		 * Kernel threads are allowed on online && !active CPUs,
 		 * however, during cpu-hot-unplug, even these might get pushed
@@ -2720,6 +2761,11 @@ static int __set_cpus_allowed_ptr(struct task_struct *p,
 		cpu_valid_mask = cpu_online_mask;
 	}
 
+	if (!kthread && !cpumask_subset(new_mask, cpu_allowed_mask)) {
+		ret = -EINVAL;
+		goto out;
+	}
+
 	/*
 	 * Must re-check here, to close a race against __kthread_bind(),
 	 * sched_setaffinity() is not guaranteed to observe the flag.
@@ -2754,20 +2800,178 @@ static int __set_cpus_allowed_ptr(struct task_struct *p,
 
 	__do_set_cpus_allowed(p, new_mask, flags);
 
-	return affine_move_task(rq, p, &rf, dest_cpu, flags);
+	if (flags & SCA_USER)
+		user_mask = clear_user_cpus_ptr(p);
+
+	ret = affine_move_task(rq, p, rf, dest_cpu, flags);
+
+	kfree(user_mask);
+
+	return ret;
 
 out:
-	task_rq_unlock(rq, p, &rf);
+	task_rq_unlock(rq, p, rf);
 
 	return ret;
 }
 
+/*
+ * Change a given task's CPU affinity. Migrate the thread to a
+ * proper CPU and schedule it away if the CPU it's executing on
+ * is removed from the allowed bitmask.
+ *
+ * NOTE: the caller must have a valid reference to the task, the
+ * task must not exit() & deallocate itself prematurely. The
+ * call is not atomic; no spinlocks may be held.
+ */
+static int __set_cpus_allowed_ptr(struct task_struct *p,
+				  const struct cpumask *new_mask, u32 flags)
+{
+	struct rq_flags rf;
+	struct rq *rq;
+
+	rq = task_rq_lock(p, &rf);
+	return __set_cpus_allowed_ptr_locked(p, new_mask, flags, rq, &rf);
+}
+
 int set_cpus_allowed_ptr(struct task_struct *p, const struct cpumask *new_mask)
 {
 	return __set_cpus_allowed_ptr(p, new_mask, 0);
 }
 EXPORT_SYMBOL_GPL(set_cpus_allowed_ptr);
 
+/*
+ * Change a given task's CPU affinity to the intersection of its current
+ * affinity mask and @subset_mask, writing the resulting mask to @new_mask
+ * and pointing @p->user_cpus_ptr to a copy of the old mask.
+ * If the resulting mask is empty, leave the affinity unchanged and return
+ * -EINVAL.
+ */
+static int restrict_cpus_allowed_ptr(struct task_struct *p,
+				     struct cpumask *new_mask,
+				     const struct cpumask *subset_mask)
+{
+	struct cpumask *user_mask = NULL;
+	struct rq_flags rf;
+	struct rq *rq;
+	int err;
+
+	if (!p->user_cpus_ptr) {
+		user_mask = kmalloc(cpumask_size(), GFP_KERNEL);
+		if (!user_mask)
+			return -ENOMEM;
+	}
+
+	rq = task_rq_lock(p, &rf);
+
+	/*
+	 * Forcefully restricting the affinity of a deadline task is
+	 * likely to cause problems, so fail and noisily override the
+	 * mask entirely.
+	 */
+	if (task_has_dl_policy(p) && dl_bandwidth_enabled()) {
+		err = -EPERM;
+		goto err_unlock;
+	}
+
+	if (!cpumask_and(new_mask, &p->cpus_mask, subset_mask)) {
+		err = -EINVAL;
+		goto err_unlock;
+	}
+
+	/*
+	 * We're about to butcher the task affinity, so keep track of what
+	 * the user asked for in case we're able to restore it later on.
+	 */
+	if (user_mask) {
+		cpumask_copy(user_mask, p->cpus_ptr);
+		p->user_cpus_ptr = user_mask;
+	}
+
+	return __set_cpus_allowed_ptr_locked(p, new_mask, 0, rq, &rf);
+
+err_unlock:
+	task_rq_unlock(rq, p, &rf);
+	kfree(user_mask);
+	return err;
+}
+
+/*
+ * Restrict the CPU affinity of task @p so that it is a subset of
+ * task_cpu_possible_mask() and point @p->user_cpu_ptr to a copy of the
+ * old affinity mask. If the resulting mask is empty, we warn and walk
+ * up the cpuset hierarchy until we find a suitable mask.
+ */
+void force_compatible_cpus_allowed_ptr(struct task_struct *p)
+{
+	cpumask_var_t new_mask;
+	const struct cpumask *override_mask = task_cpu_possible_mask(p);
+
+	alloc_cpumask_var(&new_mask, GFP_KERNEL);
+
+	/*
+	 * __migrate_task() can fail silently in the face of concurrent
+	 * offlining of the chosen destination CPU, so take the hotplug
+	 * lock to ensure that the migration succeeds.
+	 */
+	cpus_read_lock();
+	if (!cpumask_available(new_mask))
+		goto out_set_mask;
+
+	if (!restrict_cpus_allowed_ptr(p, new_mask, override_mask))
+		goto out_free_mask;
+
+	/*
+	 * We failed to find a valid subset of the affinity mask for the
+	 * task, so override it based on its cpuset hierarchy.
+	 */
+	cpuset_cpus_allowed(p, new_mask);
+	override_mask = new_mask;
+
+out_set_mask:
+	if (printk_ratelimit()) {
+		printk_deferred("Overriding affinity for process %d (%s) to CPUs %*pbl\n",
+				task_pid_nr(p), p->comm,
+				cpumask_pr_args(override_mask));
+	}
+
+	WARN_ON(set_cpus_allowed_ptr(p, override_mask));
+out_free_mask:
+	cpus_read_unlock();
+	free_cpumask_var(new_mask);
+}
+
+static int
+__sched_setaffinity(struct task_struct *p, const struct cpumask *mask);
+
+/*
+ * Restore the affinity of a task @p which was previously restricted by a
+ * call to force_compatible_cpus_allowed_ptr(). This will clear (and free)
+ * @p->user_cpus_ptr.
+ *
+ * It is the caller's responsibility to serialise this with any calls to
+ * force_compatible_cpus_allowed_ptr(@p).
+ */
+void relax_compatible_cpus_allowed_ptr(struct task_struct *p)
+{
+	struct cpumask *user_mask = p->user_cpus_ptr;
+	unsigned long flags;
+
+	/*
+	 * Try to restore the old affinity mask. If this fails, then
+	 * we free the mask explicitly to avoid it being inherited across
+	 * a subsequent fork().
+	 */
+	if (!user_mask || !__sched_setaffinity(p, user_mask))
+		return;
+
+	raw_spin_lock_irqsave(&p->pi_lock, flags);
+	user_mask = clear_user_cpus_ptr(p);
+	raw_spin_unlock_irqrestore(&p->pi_lock, flags);
+
+	kfree(user_mask);
+}
+
 void set_task_cpu(struct task_struct *p, unsigned int new_cpu)
 {
 #ifdef CONFIG_SCHED_DEBUG
@@ -3112,9 +3316,7 @@ static int select_fallback_rq(int cpu, struct task_struct *p)
 
 		/* Look for allowed, online CPU in same node. */
 		for_each_cpu(dest_cpu, nodemask) {
-			if (!cpu_active(dest_cpu))
-				continue;
-			if (cpumask_test_cpu(dest_cpu, p->cpus_ptr))
+			if (is_cpu_allowed(p, dest_cpu))
 				return dest_cpu;
 		}
 	}
@@ -3131,8 +3333,7 @@ static int select_fallback_rq(int cpu, struct task_struct *p)
 		/* No more Mr. Nice Guy. */
 		switch (state) {
 		case cpuset:
-			if (IS_ENABLED(CONFIG_CPUSETS)) {
-				cpuset_cpus_allowed_fallback(p);
+			if (cpuset_cpus_allowed_fallback(p)) {
 				state = possible;
 				break;
 			}
@@ -3144,10 +3345,9 @@ static int select_fallback_rq(int cpu, struct task_struct *p)
 			 *
 			 * More yuck to audit.
 			 */
-			do_set_cpus_allowed(p, cpu_possible_mask);
+			do_set_cpus_allowed(p, task_cpu_possible_mask(p));
 			state = fail;
 			break;
-
 		case fail:
 			BUG();
 			break;
@@ -5660,11 +5860,9 @@ static bool try_steal_cookie(int this, int that)
 		if (p->core_occupation > dst->idle->core_occupation)
 			goto next;
 
-		p->on_rq = TASK_ON_RQ_MIGRATING;
 		deactivate_task(src, p, 0);
 		set_task_cpu(p, this);
 		activate_task(dst, p, 0);
-		p->on_rq = TASK_ON_RQ_QUEUED;
 
 		resched_curr(dst);
 
@@ -7300,6 +7498,16 @@ err_size:
 	return -E2BIG;
 }
 
+static void get_params(struct task_struct *p, struct sched_attr *attr)
+{
+	if (task_has_dl_policy(p))
+		__getparam_dl(p, attr);
+	else if (task_has_rt_policy(p))
+		attr->sched_priority = p->rt_priority;
+	else
+		attr->sched_nice = task_nice(p);
+}
+
 /**
  * sys_sched_setscheduler - set/change the scheduler policy and RT priority
  * @pid: the pid in question.
@@ -7361,6 +7569,8 @@ SYSCALL_DEFINE3(sched_setattr, pid_t, pid, struct sched_attr __user *, uattr,
 	rcu_read_unlock();
 
 	if (likely(p)) {
+		if (attr.sched_flags & SCHED_FLAG_KEEP_PARAMS)
+			get_params(p, &attr);
 		retval = sched_setattr(p, &attr);
 		put_task_struct(p);
 	}
@@ -7509,12 +7719,8 @@ SYSCALL_DEFINE4(sched_getattr, pid_t, pid, struct sched_attr __user *, uattr,
 	kattr.sched_policy = p->policy;
 	if (p->sched_reset_on_fork)
 		kattr.sched_flags |= SCHED_FLAG_RESET_ON_FORK;
-	if (task_has_dl_policy(p))
-		__getparam_dl(p, &kattr);
-	else if (task_has_rt_policy(p))
-		kattr.sched_priority = p->rt_priority;
-	else
-		kattr.sched_nice = task_nice(p);
+	get_params(p, &kattr);
+	kattr.sched_flags &= SCHED_FLAG_ALL;
 
 #ifdef CONFIG_UCLAMP_TASK
 	/*
@@ -7535,9 +7741,76 @@ out_unlock:
 	return retval;
 }
 
-long sched_setaffinity(pid_t pid, const struct cpumask *in_mask)
+#ifdef CONFIG_SMP
+int dl_task_check_affinity(struct task_struct *p, const struct cpumask *mask)
 {
+	int ret = 0;
+
+	/*
+	 * If the task isn't a deadline task or admission control is
+	 * disabled then we don't care about affinity changes.
+	 */
+	if (!task_has_dl_policy(p) || !dl_bandwidth_enabled())
+		return 0;
+
+	/*
+	 * Since bandwidth control happens on root_domain basis,
+	 * if admission test is enabled, we only admit -deadline
+	 * tasks allowed to run on all the CPUs in the task's
+	 * root_domain.
+	 */
+	rcu_read_lock();
+	if (!cpumask_subset(task_rq(p)->rd->span, mask))
+		ret = -EBUSY;
+	rcu_read_unlock();
+	return ret;
+}
+#endif
+
+static int
+__sched_setaffinity(struct task_struct *p, const struct cpumask *mask)
+{
+	int retval;
 	cpumask_var_t cpus_allowed, new_mask;
+
+	if (!alloc_cpumask_var(&cpus_allowed, GFP_KERNEL))
+		return -ENOMEM;
+
+	if (!alloc_cpumask_var(&new_mask, GFP_KERNEL)) {
+		retval = -ENOMEM;
+		goto out_free_cpus_allowed;
+	}
+
+	cpuset_cpus_allowed(p, cpus_allowed);
+	cpumask_and(new_mask, mask, cpus_allowed);
+
+	retval = dl_task_check_affinity(p, new_mask);
+	if (retval)
+		goto out_free_new_mask;
+again:
+	retval = __set_cpus_allowed_ptr(p, new_mask, SCA_CHECK | SCA_USER);
+	if (retval)
+		goto out_free_new_mask;
+
+	cpuset_cpus_allowed(p, cpus_allowed);
+	if (!cpumask_subset(new_mask, cpus_allowed)) {
+		/*
+		 * We must have raced with a concurrent cpuset update.
+		 * Just reset the cpumask to the cpuset's cpus_allowed.
+		 */
+		cpumask_copy(new_mask, cpus_allowed);
+		goto again;
+	}
+
+out_free_new_mask:
+	free_cpumask_var(new_mask);
+out_free_cpus_allowed:
+	free_cpumask_var(cpus_allowed);
+	return retval;
+}
+
+long sched_setaffinity(pid_t pid, const struct cpumask *in_mask)
+{
 	struct task_struct *p;
 	int retval;
 
@@ -7557,68 +7830,22 @@ long sched_setaffinity(pid_t pid, const struct cpumask *in_mask)
 		retval = -EINVAL;
 		goto out_put_task;
 	}
-	if (!alloc_cpumask_var(&cpus_allowed, GFP_KERNEL)) {
-		retval = -ENOMEM;
-		goto out_put_task;
-	}
-	if (!alloc_cpumask_var(&new_mask, GFP_KERNEL)) {
-		retval = -ENOMEM;
-		goto out_free_cpus_allowed;
-	}
-	retval = -EPERM;
+
 	if (!check_same_owner(p)) {
 		rcu_read_lock();
 		if (!ns_capable(__task_cred(p)->user_ns, CAP_SYS_NICE)) {
 			rcu_read_unlock();
-			goto out_free_new_mask;
+			retval = -EPERM;
+			goto out_put_task;
 		}
 		rcu_read_unlock();
 	}
 
 	retval = security_task_setscheduler(p);
 	if (retval)
-		goto out_free_new_mask;
-
-
-	cpuset_cpus_allowed(p, cpus_allowed);
-	cpumask_and(new_mask, in_mask, cpus_allowed);
-
-	/*
-	 * Since bandwidth control happens on root_domain basis,
-	 * if admission test is enabled, we only admit -deadline
-	 * tasks allowed to run on all the CPUs in the task's
-	 * root_domain.
-	 */
-#ifdef CONFIG_SMP
-	if (task_has_dl_policy(p) && dl_bandwidth_enabled()) {
-		rcu_read_lock();
-		if (!cpumask_subset(task_rq(p)->rd->span, new_mask)) {
-			retval = -EBUSY;
-			rcu_read_unlock();
-			goto out_free_new_mask;
-		}
-		rcu_read_unlock();
-	}
-#endif
-again:
-	retval = __set_cpus_allowed_ptr(p, new_mask, SCA_CHECK);
+		goto out_put_task;
 
-	if (!retval) {
-		cpuset_cpus_allowed(p, cpus_allowed);
-		if (!cpumask_subset(new_mask, cpus_allowed)) {
-			/*
-			 * We must have raced with a concurrent cpuset
-			 * update. Just reset the cpus_allowed to the
-			 * cpuset's cpus_allowed
-			 */
-			cpumask_copy(new_mask, cpus_allowed);
-			goto again;
-		}
-	}
-out_free_new_mask:
-	free_cpumask_var(new_mask);
-out_free_cpus_allowed:
-	free_cpumask_var(cpus_allowed);
+	retval = __sched_setaffinity(p, in_mask);
 out_put_task:
 	put_task_struct(p);
 	return retval;
@@ -9804,7 +10031,7 @@ static int tg_set_cfs_bandwidth(struct task_group *tg, u64 period, u64 quota,
 	 * Prevent race between setting of cfs_rq->runtime_enabled and
 	 * unthrottle_offline_cfs_rqs().
 	 */
-	get_online_cpus();
+	cpus_read_lock();
 	mutex_lock(&cfs_constraints_mutex);
 	ret = __cfs_schedulable(tg, period, quota);
 	if (ret)
@@ -9848,7 +10075,7 @@ static int tg_set_cfs_bandwidth(struct task_group *tg, u64 period, u64 quota,
 		cfs_bandwidth_usage_dec();
 out_unlock:
 	mutex_unlock(&cfs_constraints_mutex);
-	put_online_cpus();
+	cpus_read_unlock();
 
 	return ret;
 }
@@ -10099,6 +10326,20 @@ static u64 cpu_rt_period_read_uint(struct cgroup_subsys_state *css,
 }
 #endif /* CONFIG_RT_GROUP_SCHED */
 
+#ifdef CONFIG_FAIR_GROUP_SCHED
+static s64 cpu_idle_read_s64(struct cgroup_subsys_state *css,
+			       struct cftype *cft)
+{
+	return css_tg(css)->idle;
+}
+
+static int cpu_idle_write_s64(struct cgroup_subsys_state *css,
+				struct cftype *cft, s64 idle)
+{
+	return sched_group_set_idle(css_tg(css), idle);
+}
+#endif
+
 static struct cftype cpu_legacy_files[] = {
 #ifdef CONFIG_FAIR_GROUP_SCHED
 	{
@@ -10106,6 +10347,11 @@ static struct cftype cpu_legacy_files[] = {
 		.read_u64 = cpu_shares_read_u64,
 		.write_u64 = cpu_shares_write_u64,
 	},
+	{
+		.name = "idle",
+		.read_s64 = cpu_idle_read_s64,
+		.write_s64 = cpu_idle_write_s64,
+	},
 #endif
 #ifdef CONFIG_CFS_BANDWIDTH
 	{
@@ -10313,6 +10559,12 @@ static struct cftype cpu_files[] = {
 		.read_s64 = cpu_weight_nice_read_s64,
 		.write_s64 = cpu_weight_nice_write_s64,
 	},
+	{
+		.name = "idle",
+		.flags = CFTYPE_NOT_ON_ROOT,
+		.read_s64 = cpu_idle_read_s64,
+		.write_s64 = cpu_idle_write_s64,
+	},
 #endif
 #ifdef CONFIG_CFS_BANDWIDTH
 	{