Commit 772b78c2 authored by Linus Torvalds's avatar Linus Torvalds
Browse files

Merge tag 'sched_urgent_for_v6.16_rc5' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip 

Pull scheduler fixes from Borislav Petkov:

 - Fix the calculation of the deadline server task's runtime as this
   mishap was preventing realtime tasks from running

 - Avoid a race condition during migrate-swapping two tasks

 - Fix the string reported for the "none" dynamic preemption option

* tag 'sched_urgent_for_v6.16_rc5' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip:
  sched/deadline: Fix dl_server runtime calculation formula
  sched/core: Fix migrate_swap() vs. hotplug
  sched: Fix preemption string of preempt_dynamic_none
parents 95eb0d38 fc975cfb

kernel/sched/core.c

+6 −1
Original line number Diff line number Diff line
@@ -3943,6 +3943,11 @@ static inline bool ttwu_queue_cond(struct task_struct *p, int cpu) 
	if (!scx_allow_ttwu_queue(p))

		return false;



#ifdef CONFIG_SMP

	if (p->sched_class == &stop_sched_class)

		return false;

#endif



	/*

	 * Do not complicate things with the async wake_list while the CPU is

	 * in hotplug state.
@@ -7663,7 +7668,7 @@ const char *preempt_model_str(void) 


		if (IS_ENABLED(CONFIG_PREEMPT_DYNAMIC)) {

			seq_buf_printf(&s, "(%s)%s",

				       preempt_dynamic_mode > 0 ?

				       preempt_dynamic_mode >= 0 ?

				       preempt_modes[preempt_dynamic_mode] : "undef",

				       brace ? "}" : "");

			return seq_buf_str(&s);

kernel/sched/deadline.c

+5 −5
Original line number Diff line number Diff line
@@ -1504,6 +1504,8 @@ static void update_curr_dl_se(struct rq *rq, struct sched_dl_entity *dl_se, s64 
	if (dl_entity_is_special(dl_se))

		return;



	scaled_delta_exec = delta_exec;

	if (!dl_server(dl_se))

		scaled_delta_exec = dl_scaled_delta_exec(rq, dl_se, delta_exec);



	dl_se->runtime -= scaled_delta_exec;
@@ -1611,7 +1613,7 @@ static void update_curr_dl_se(struct rq *rq, struct sched_dl_entity *dl_se, s64 
 */

void dl_server_update_idle_time(struct rq *rq, struct task_struct *p)

{

	s64 delta_exec, scaled_delta_exec;

	s64 delta_exec;



	if (!rq->fair_server.dl_defer)

		return;
@@ -1624,9 +1626,7 @@ void dl_server_update_idle_time(struct rq *rq, struct task_struct *p) 
	if (delta_exec < 0)

		return;



	scaled_delta_exec = dl_scaled_delta_exec(rq, &rq->fair_server, delta_exec);



	rq->fair_server.runtime -= scaled_delta_exec;

	rq->fair_server.runtime -= delta_exec;



	if (rq->fair_server.runtime < 0) {

		rq->fair_server.dl_defer_running = 0;

kernel/stop_machine.c

+10 −10
Original line number Diff line number Diff line
@@ -82,18 +82,15 @@ static void cpu_stop_signal_done(struct cpu_stop_done *done) 
}



static void __cpu_stop_queue_work(struct cpu_stopper *stopper,

					struct cpu_stop_work *work,

					struct wake_q_head *wakeq)

				  struct cpu_stop_work *work)

{

	list_add_tail(&work->list, &stopper->works);

	wake_q_add(wakeq, stopper->thread);

}



/* queue @work to @stopper.  if offline, @work is completed immediately */

static bool cpu_stop_queue_work(unsigned int cpu, struct cpu_stop_work *work)

{

	struct cpu_stopper *stopper = &per_cpu(cpu_stopper, cpu);

	DEFINE_WAKE_Q(wakeq);

	unsigned long flags;

	bool enabled;
@@ -101,12 +98,13 @@ static bool cpu_stop_queue_work(unsigned int cpu, struct cpu_stop_work *work) 
	raw_spin_lock_irqsave(&stopper->lock, flags);

	enabled = stopper->enabled;

	if (enabled)

		__cpu_stop_queue_work(stopper, work, &wakeq);

		__cpu_stop_queue_work(stopper, work);

	else if (work->done)

		cpu_stop_signal_done(work->done);

	raw_spin_unlock_irqrestore(&stopper->lock, flags);



	wake_up_q(&wakeq);

	if (enabled)

		wake_up_process(stopper->thread);

	preempt_enable();



	return enabled;
@@ -264,7 +262,6 @@ static int cpu_stop_queue_two_works(int cpu1, struct cpu_stop_work *work1, 
{

	struct cpu_stopper *stopper1 = per_cpu_ptr(&cpu_stopper, cpu1);

	struct cpu_stopper *stopper2 = per_cpu_ptr(&cpu_stopper, cpu2);

	DEFINE_WAKE_Q(wakeq);

	int err;



retry:
@@ -300,8 +297,8 @@ static int cpu_stop_queue_two_works(int cpu1, struct cpu_stop_work *work1, 
	}



	err = 0;

	__cpu_stop_queue_work(stopper1, work1, &wakeq);

	__cpu_stop_queue_work(stopper2, work2, &wakeq);

	__cpu_stop_queue_work(stopper1, work1);

	__cpu_stop_queue_work(stopper2, work2);



unlock:

	raw_spin_unlock(&stopper2->lock);
@@ -316,7 +313,10 @@ static int cpu_stop_queue_two_works(int cpu1, struct cpu_stop_work *work1, 
		goto retry;

	}



	wake_up_q(&wakeq);

	if (!err) {

		wake_up_process(stopper1->thread);

		wake_up_process(stopper2->thread);

	}

	preempt_enable();



	return err;