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authorLinus Torvalds <torvalds@linux-foundation.org>2025-07-06 11:17:47 -0700
committerLinus Torvalds <torvalds@linux-foundation.org>2025-07-06 11:17:47 -0700
commit772b78c2abd85586bb90b23adff89f7303c704c7 (patch)
treef18df282d7751b06f315a6b107b7d7384ec9aa17
parent95eb0d389b4a518a2630b18fbc5916a008f519f1 (diff)
parentfc975cfb36393db1db517fbbe366e550bcdcff14 (diff)
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
-rw-r--r--kernel/sched/core.c7
-rw-r--r--kernel/sched/deadline.c10
-rw-r--r--kernel/stop_machine.c20
3 files changed, 21 insertions, 16 deletions
diff --git a/kernel/sched/core.c b/kernel/sched/core.c
index 8988d38d46a3..ec68fc686bd7 100644
--- a/kernel/sched/core.c
+++ b/kernel/sched/core.c
@@ -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);
diff --git a/kernel/sched/deadline.c b/kernel/sched/deadline.c
index ad45a8fea245..89019a140826 100644
--- a/kernel/sched/deadline.c
+++ b/kernel/sched/deadline.c
@@ -1504,7 +1504,9 @@ 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 = dl_scaled_delta_exec(rq, dl_se, delta_exec);
+ 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 @@ throttle:
*/
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;
diff --git a/kernel/stop_machine.c b/kernel/stop_machine.c
index 5d2d0562115b..3fe6b0c99f3d 100644
--- a/kernel/stop_machine.c
+++ b/kernel/stop_machine.c
@@ -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 @@ retry:
}
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 @@ unlock:
goto retry;
}
- wake_up_q(&wakeq);
+ if (!err) {
+ wake_up_process(stopper1->thread);
+ wake_up_process(stopper2->thread);
+ }
preempt_enable();
return err;