kernel/sched/core.c | 2 +- kernel/sched/deadline.c | 8 ++++++-- kernel/sched/ext/ext.c | 5 ++++- kernel/sched/fair.c | 15 ++++++++++----- kernel/sched/idle.c | 5 ++++- kernel/sched/rt.c | 7 +++++-- kernel/sched/sched.h | 16 ++++++++++++---- kernel/sched/stop_task.c | 5 ++++- 8 files changed, 46 insertions(+), 17 deletions(-)
Fair and DL hrticks are one-shot timers. After an hrtick expires, the
next preemption point must be explicitly armed for the task that remains
selected.
For fair, the missed path is:
hrtick()
-> rq->donor->sched_class->task_tick(rq, rq->donor, 1)
-> task_tick_fair(..., queued=1)
-> entity_tick()
-> resched_curr()
-> schedule()
-> pick_task_fair() selects the current task again
-> put_prev_set_next_task(rq, prev, next)
-> next == prev
-> return
put_prev_set_next_task() returns without calling
next->sched_class->set_next_task(). Consequently, set_next_task_fair()
is not called and does not invoke hrtick_start_fair() to arm the next
fair hrtick.
The same `next == prev` return skips set_next_task_dl() and
start_hrtick_dl() when a DL hrtick causes a reschedule that repicks the
current DL task.
Replace the `bool first` argument of set_next_task() with an enum.
SNT_NORMAL and SNT_PICK preserve the existing call sites, while
SNT_REPICK identifies the next == prev case. On `SNT_REPICK`, fair and DL
skip their normal task-transition work because the task is already
current, but restart their respective hrticks.
Calling the class-specific rearm from the repick path also preserves the
existing hrtick scheduling rules. The call occurs during schedule(), with
hrtick programming deferred by rq->hrtick_sched; hrtick_start()
records the new delay and hrtick_schedule_exit() rearms the hrtimer
after scheduling completes.
This replaces the fair specific rq state and runnable count checks with a
common scheduler core solution.
Signed-off-by: Shubhang Kaushik (Ampere) <sh@gentwo.org>
---
Testing:
- Built and booted baseline 08df884136f1 and v2 with
CONFIG_HIGH_RES_TIMERS=y and CONFIG_SCHED_HRTICK=y.
- Enabled HRTICK and DELAY_DEQUEUE, set base_slice_ns to 3000000, and
pinned two CPU-bound nice-0 fair-class tasks plus a periodic sleeper to
CPU 0.
- Collected five 10-second `perf sched` traces per kernel.
Across the CPU-bound fair-class tasks:
baseline: maximum runtime 5.227ms; 6 samples above 4ms.
v2: maximum runtime 3.386ms; no samples above 4ms.
---
Changes in v2:
- Replace the fair-specific hrtick rearm state with SNT_REPICK.
- Restart hrticks for both fair and SCHED_DEADLINE same-task repicks.
- Remove the delayed-dequeue runnable-count condition.
Link to v1: https://lore.kernel.org/r/20260813-sched-fair-hrtick-restart-v1-1-4230d1e18fbb@gentwo.org
---
kernel/sched/core.c | 2 +-
kernel/sched/deadline.c | 8 ++++++--
kernel/sched/ext/ext.c | 5 ++++-
kernel/sched/fair.c | 15 ++++++++++-----
kernel/sched/idle.c | 5 ++++-
kernel/sched/rt.c | 7 +++++--
kernel/sched/sched.h | 16 ++++++++++++----
kernel/sched/stop_task.c | 5 ++++-
8 files changed, 46 insertions(+), 17 deletions(-)
diff --git a/kernel/sched/core.c b/kernel/sched/core.c
index b998ef6b87af4fa60422fe86b3702c43103ea9aa..90607d2f3a93a59c2227ce9775ce3976054a0b96 100644
--- a/kernel/sched/core.c
+++ b/kernel/sched/core.c
@@ -7221,7 +7221,7 @@ static void __sched notrace __schedule(int sched_mode)
* on_cpu.
*/
donor->sched_class->put_prev_task(rq, donor, donor);
- donor->sched_class->set_next_task(rq, donor, true);
+ donor->sched_class->set_next_task(rq, donor, SNT_PICK);
}
} else {
rq_set_donor(rq, next);
diff --git a/kernel/sched/deadline.c b/kernel/sched/deadline.c
index 0663c00c41c04213fda2ebaf16a0bdf34e0849a8..6c17563f42a1d22bae5fc9f85b75497b6b4faccb 100644
--- a/kernel/sched/deadline.c
+++ b/kernel/sched/deadline.c
@@ -2773,11 +2773,14 @@ static void start_hrtick_dl(struct rq *rq, struct sched_dl_entity *dl_se)
* DL keeps current in tree, because ->deadline is not typically changed while
* a task is runnable.
*/
-static void set_next_task_dl(struct rq *rq, struct task_struct *p, bool first)
+static void set_next_task_dl(struct rq *rq, struct task_struct *p, enum snt_e type)
{
struct sched_dl_entity *dl_se = &p->dl;
struct dl_rq *dl_rq = &rq->dl;
+ if (type == SNT_REPICK)
+ goto repick;
+
p->se.exec_start = rq_clock_task(rq);
if (on_dl_rq(&p->dl))
update_stats_wait_end_dl(dl_rq, dl_se);
@@ -2788,7 +2791,7 @@ static void set_next_task_dl(struct rq *rq, struct task_struct *p, bool first)
WARN_ON_ONCE(dl_rq->curr);
dl_rq->curr = dl_se;
- if (!first)
+ if (type != SNT_PICK)
return;
if (rq->donor->sched_class != &dl_sched_class)
@@ -2796,6 +2799,7 @@ static void set_next_task_dl(struct rq *rq, struct task_struct *p, bool first)
deadline_queue_push_tasks(rq);
+repick:
if (hrtick_enabled_dl(rq))
start_hrtick_dl(rq, &p->dl);
}
diff --git a/kernel/sched/ext/ext.c b/kernel/sched/ext/ext.c
index 51de1d8b72a1ede6d16c07b58defb1284285b8a6..31a300f2d3b202d588ca666d6b8f6d4705ee6c79 100644
--- a/kernel/sched/ext/ext.c
+++ b/kernel/sched/ext/ext.c
@@ -3003,10 +3003,13 @@ static enum scx_dsp_verdict dispatch_one(struct rq *rq, struct task_struct *prev
return verdict;
}
-static void set_next_task_scx(struct rq *rq, struct task_struct *p, bool first)
+static void set_next_task_scx(struct rq *rq, struct task_struct *p, enum snt_e type)
{
struct scx_sched *sch = scx_task_sched(p);
+ if (type == SNT_REPICK)
+ return;
+
if (p->scx.flags & SCX_TASK_QUEUED) {
/*
* Core-sched might decide to execute @p before it is
diff --git a/kernel/sched/fair.c b/kernel/sched/fair.c
index ade1eceb39b806e60e44efe54e33a7097d01d1df..4a83ad97544675d52ca6b296a5e57356da537293 100644
--- a/kernel/sched/fair.c
+++ b/kernel/sched/fair.c
@@ -15245,14 +15245,18 @@ static void switched_to_fair(struct rq *rq, struct task_struct *p)
}
}
-static void set_next_task_fair(struct rq *rq, struct task_struct *p, bool first)
+static void set_next_task_fair(struct rq *rq, struct task_struct *p, enum snt_e type)
{
struct sched_entity *se = &p->se;
- bool throttled = false;
struct cfs_rq *cfs_rq = &rq->cfs;
unsigned long weight = NICE_0_LOAD;
+ bool first = type == SNT_PICK;
+ bool throttled = false;
bool on_rq = se->on_rq;
+ if (type == SNT_REPICK)
+ goto repick;
+
clear_buddies(cfs_rq, se);
if (on_rq)
@@ -15296,11 +15300,12 @@ static void set_next_task_fair(struct rq *rq, struct task_struct *p, bool first)
WARN_ON_ONCE(se->sched_delayed);
- if (hrtick_enabled_fair(rq))
- hrtick_start_fair(rq, p);
-
update_misfit_status(p, rq);
sched_fair_update_stop_tick(rq, p);
+
+repick:
+ if (hrtick_enabled_fair(rq))
+ hrtick_start_fair(rq, p);
}
void init_cfs_rq(struct cfs_rq *cfs_rq)
diff --git a/kernel/sched/idle.c b/kernel/sched/idle.c
index eb73b65ce6c4714db1e07066c86a8cf39adbc328..76f3c84ca6846afc30609fdc512553c6797e9557 100644
--- a/kernel/sched/idle.c
+++ b/kernel/sched/idle.c
@@ -487,8 +487,11 @@ static void put_prev_task_idle(struct rq *rq, struct task_struct *prev, struct t
update_rq_avg_idle(rq);
}
-static void set_next_task_idle(struct rq *rq, struct task_struct *next, bool first)
+static void set_next_task_idle(struct rq *rq, struct task_struct *next, enum snt_e type)
{
+ if (type == SNT_REPICK)
+ return;
+
update_idle_core(rq);
scx_update_idle(rq, true, true);
schedstat_inc(rq->sched_goidle);
diff --git a/kernel/sched/rt.c b/kernel/sched/rt.c
index 85303add726df4c2da846c427aab2d627fca9589..1535046a23ffa0705d90dce301fa4c5b015703a1 100644
--- a/kernel/sched/rt.c
+++ b/kernel/sched/rt.c
@@ -1654,11 +1654,14 @@ static void wakeup_preempt_rt(struct rq *rq, struct task_struct *p, int flags)
check_preempt_equal_prio(rq, p);
}
-static inline void set_next_task_rt(struct rq *rq, struct task_struct *p, bool first)
+static inline void set_next_task_rt(struct rq *rq, struct task_struct *p, enum snt_e type)
{
struct sched_rt_entity *rt_se = &p->rt;
struct rt_rq *rt_rq = &rq->rt;
+ if (type == SNT_REPICK)
+ return;
+
p->se.exec_start = rq_clock_task(rq);
if (on_rt_rq(&p->rt))
update_stats_wait_end_rt(rt_rq, rt_se);
@@ -1666,7 +1669,7 @@ static inline void set_next_task_rt(struct rq *rq, struct task_struct *p, bool f
/* The running task is never eligible for pushing */
dequeue_pushable_task(rq, p);
- if (!first)
+ if (type != SNT_PICK)
return;
/*
diff --git a/kernel/sched/sched.h b/kernel/sched/sched.h
index e656c7059bf864d1ed91d4ec3d4624850aded7e0..defcf7fd023fa5bb3c34c3c29f99afe3c42a87de 100644
--- a/kernel/sched/sched.h
+++ b/kernel/sched/sched.h
@@ -2621,6 +2621,12 @@ struct affinity_context {
extern s64 update_curr_common(struct rq *rq);
+enum snt_e {
+ SNT_NORMAL,
+ SNT_PICK,
+ SNT_REPICK,
+};
+
struct sched_class {
#ifdef CONFIG_UCLAMP_TASK
@@ -2678,7 +2684,7 @@ struct sched_class {
* __schedule: rq->lock
*/
void (*put_prev_task)(struct rq *rq, struct task_struct *p, struct task_struct *next);
- void (*set_next_task)(struct rq *rq, struct task_struct *p, bool first);
+ void (*set_next_task)(struct rq *rq, struct task_struct *p, enum snt_e type);
/*
* select_task_rq: p->pi_lock
@@ -2781,7 +2787,7 @@ static inline void put_prev_task(struct rq *rq, struct task_struct *prev)
static inline void set_next_task(struct rq *rq, struct task_struct *next)
{
- next->sched_class->set_next_task(rq, next, false);
+ next->sched_class->set_next_task(rq, next, SNT_NORMAL);
}
static inline void
@@ -2802,11 +2808,13 @@ static inline void put_prev_set_next_task(struct rq *rq,
__put_prev_set_next_dl_server(rq, prev, next);
- if (next == prev)
+ if (next == prev) {
+ next->sched_class->set_next_task(rq, next, SNT_REPICK);
return;
+ }
prev->sched_class->put_prev_task(rq, prev, next);
- next->sched_class->set_next_task(rq, next, true);
+ next->sched_class->set_next_task(rq, next, SNT_PICK);
}
/*
diff --git a/kernel/sched/stop_task.c b/kernel/sched/stop_task.c
index c909ca0d8c87c1055ad5ffe58ae9f044194ee358..1e0109ec36b3f9b84f6f7290e584e38257db701c 100644
--- a/kernel/sched/stop_task.c
+++ b/kernel/sched/stop_task.c
@@ -27,8 +27,11 @@ wakeup_preempt_stop(struct rq *rq, struct task_struct *p, int flags)
/* we're never preempted */
}
-static void set_next_task_stop(struct rq *rq, struct task_struct *stop, bool first)
+static void set_next_task_stop(struct rq *rq, struct task_struct *stop, enum snt_e type)
{
+ if (type == SNT_REPICK)
+ return;
+
stop->se.exec_start = rq_clock_task(rq);
}
---
base-commit: 08df884136f1c1197bab2a27814404fd329d9aac
change-id: 20260813-sched-fair-hrtick-restart-ab9d3d47ef78
Best regards,
--
Shubhang Kaushik (Ampere) <sh@gentwo.org>Hi all,
There seems to be an issue with the DL rearm in v2.
On a non-tick reschedule that repicks the running SCHED_DEADLINE task,
`next == prev` skips put_prev_task_dl(). Therefore
update_curr_dl() may not have charged execution since exec_start.
The v2 SNT_REPICK path then calls start_hrtick_dl() using stale
dl_se->runtime, which can arm the next hrtick too late and delay
SCHED_DEADLINE runtime enforcement.
Unless there is a DL case that requires this rearm and accounts current
beforehand, I will drop the DL SNT_REPICK rearm in the next revision.
So for now, please disregard the DL portion of v2 for review.
Thanks,
Shubhang Kaushik
On Fri, 11 Sep 2026, Shubhang Kaushik (Ampere) wrote:
> Fair and DL hrticks are one-shot timers. After an hrtick expires, the
> next preemption point must be explicitly armed for the task that remains
> selected.
>
> For fair, the missed path is:
>
> hrtick()
> -> rq->donor->sched_class->task_tick(rq, rq->donor, 1)
> -> task_tick_fair(..., queued=1)
> -> entity_tick()
> -> resched_curr()
> -> schedule()
> -> pick_task_fair() selects the current task again
> -> put_prev_set_next_task(rq, prev, next)
> -> next == prev
> -> return
>
> put_prev_set_next_task() returns without calling
> next->sched_class->set_next_task(). Consequently, set_next_task_fair()
> is not called and does not invoke hrtick_start_fair() to arm the next
> fair hrtick.
>
> The same `next == prev` return skips set_next_task_dl() and
> start_hrtick_dl() when a DL hrtick causes a reschedule that repicks the
> current DL task.
>
> Replace the `bool first` argument of set_next_task() with an enum.
> SNT_NORMAL and SNT_PICK preserve the existing call sites, while
> SNT_REPICK identifies the next == prev case. On `SNT_REPICK`, fair and DL
> skip their normal task-transition work because the task is already
> current, but restart their respective hrticks.
>
> Calling the class-specific rearm from the repick path also preserves the
> existing hrtick scheduling rules. The call occurs during schedule(), with
> hrtick programming deferred by rq->hrtick_sched; hrtick_start()
> records the new delay and hrtick_schedule_exit() rearms the hrtimer
> after scheduling completes.
>
> This replaces the fair specific rq state and runnable count checks with a
> common scheduler core solution.
>
> Signed-off-by: Shubhang Kaushik (Ampere) <sh@gentwo.org>
> ---
> Testing:
> - Built and booted baseline 08df884136f1 and v2 with
> CONFIG_HIGH_RES_TIMERS=y and CONFIG_SCHED_HRTICK=y.
> - Enabled HRTICK and DELAY_DEQUEUE, set base_slice_ns to 3000000, and
> pinned two CPU-bound nice-0 fair-class tasks plus a periodic sleeper to
> CPU 0.
> - Collected five 10-second `perf sched` traces per kernel.
>
> Across the CPU-bound fair-class tasks:
>
> baseline: maximum runtime 5.227ms; 6 samples above 4ms.
> v2: maximum runtime 3.386ms; no samples above 4ms.
> ---
> Changes in v2:
>
> - Replace the fair-specific hrtick rearm state with SNT_REPICK.
> - Restart hrticks for both fair and SCHED_DEADLINE same-task repicks.
> - Remove the delayed-dequeue runnable-count condition.
>
> Link to v1: https://lore.kernel.org/r/20260813-sched-fair-hrtick-restart-v1-1-4230d1e18fbb@gentwo.org
> ---
> kernel/sched/core.c | 2 +-
> kernel/sched/deadline.c | 8 ++++++--
> kernel/sched/ext/ext.c | 5 ++++-
> kernel/sched/fair.c | 15 ++++++++++-----
> kernel/sched/idle.c | 5 ++++-
> kernel/sched/rt.c | 7 +++++--
> kernel/sched/sched.h | 16 ++++++++++++----
> kernel/sched/stop_task.c | 5 ++++-
> 8 files changed, 46 insertions(+), 17 deletions(-)
>
> diff --git a/kernel/sched/core.c b/kernel/sched/core.c
> index b998ef6b87af4fa60422fe86b3702c43103ea9aa..90607d2f3a93a59c2227ce9775ce3976054a0b96 100644
> --- a/kernel/sched/core.c
> +++ b/kernel/sched/core.c
> @@ -7221,7 +7221,7 @@ static void __sched notrace __schedule(int sched_mode)
> * on_cpu.
> */
> donor->sched_class->put_prev_task(rq, donor, donor);
> - donor->sched_class->set_next_task(rq, donor, true);
> + donor->sched_class->set_next_task(rq, donor, SNT_PICK);
> }
> } else {
> rq_set_donor(rq, next);
> diff --git a/kernel/sched/deadline.c b/kernel/sched/deadline.c
> index 0663c00c41c04213fda2ebaf16a0bdf34e0849a8..6c17563f42a1d22bae5fc9f85b75497b6b4faccb 100644
> --- a/kernel/sched/deadline.c
> +++ b/kernel/sched/deadline.c
> @@ -2773,11 +2773,14 @@ static void start_hrtick_dl(struct rq *rq, struct sched_dl_entity *dl_se)
> * DL keeps current in tree, because ->deadline is not typically changed while
> * a task is runnable.
> */
> -static void set_next_task_dl(struct rq *rq, struct task_struct *p, bool first)
> +static void set_next_task_dl(struct rq *rq, struct task_struct *p, enum snt_e type)
> {
> struct sched_dl_entity *dl_se = &p->dl;
> struct dl_rq *dl_rq = &rq->dl;
>
> + if (type == SNT_REPICK)
> + goto repick;
> +
> p->se.exec_start = rq_clock_task(rq);
> if (on_dl_rq(&p->dl))
> update_stats_wait_end_dl(dl_rq, dl_se);
> @@ -2788,7 +2791,7 @@ static void set_next_task_dl(struct rq *rq, struct task_struct *p, bool first)
> WARN_ON_ONCE(dl_rq->curr);
> dl_rq->curr = dl_se;
>
> - if (!first)
> + if (type != SNT_PICK)
> return;
>
> if (rq->donor->sched_class != &dl_sched_class)
> @@ -2796,6 +2799,7 @@ static void set_next_task_dl(struct rq *rq, struct task_struct *p, bool first)
>
> deadline_queue_push_tasks(rq);
>
> +repick:
> if (hrtick_enabled_dl(rq))
> start_hrtick_dl(rq, &p->dl);
> }
> diff --git a/kernel/sched/ext/ext.c b/kernel/sched/ext/ext.c
> index 51de1d8b72a1ede6d16c07b58defb1284285b8a6..31a300f2d3b202d588ca666d6b8f6d4705ee6c79 100644
> --- a/kernel/sched/ext/ext.c
> +++ b/kernel/sched/ext/ext.c
> @@ -3003,10 +3003,13 @@ static enum scx_dsp_verdict dispatch_one(struct rq *rq, struct task_struct *prev
> return verdict;
> }
>
> -static void set_next_task_scx(struct rq *rq, struct task_struct *p, bool first)
> +static void set_next_task_scx(struct rq *rq, struct task_struct *p, enum snt_e type)
> {
> struct scx_sched *sch = scx_task_sched(p);
>
> + if (type == SNT_REPICK)
> + return;
> +
> if (p->scx.flags & SCX_TASK_QUEUED) {
> /*
> * Core-sched might decide to execute @p before it is
> diff --git a/kernel/sched/fair.c b/kernel/sched/fair.c
> index ade1eceb39b806e60e44efe54e33a7097d01d1df..4a83ad97544675d52ca6b296a5e57356da537293 100644
> --- a/kernel/sched/fair.c
> +++ b/kernel/sched/fair.c
> @@ -15245,14 +15245,18 @@ static void switched_to_fair(struct rq *rq, struct task_struct *p)
> }
> }
>
> -static void set_next_task_fair(struct rq *rq, struct task_struct *p, bool first)
> +static void set_next_task_fair(struct rq *rq, struct task_struct *p, enum snt_e type)
> {
> struct sched_entity *se = &p->se;
> - bool throttled = false;
> struct cfs_rq *cfs_rq = &rq->cfs;
> unsigned long weight = NICE_0_LOAD;
> + bool first = type == SNT_PICK;
> + bool throttled = false;
> bool on_rq = se->on_rq;
>
> + if (type == SNT_REPICK)
> + goto repick;
> +
> clear_buddies(cfs_rq, se);
>
> if (on_rq)
> @@ -15296,11 +15300,12 @@ static void set_next_task_fair(struct rq *rq, struct task_struct *p, bool first)
>
> WARN_ON_ONCE(se->sched_delayed);
>
> - if (hrtick_enabled_fair(rq))
> - hrtick_start_fair(rq, p);
> -
> update_misfit_status(p, rq);
> sched_fair_update_stop_tick(rq, p);
> +
> +repick:
> + if (hrtick_enabled_fair(rq))
> + hrtick_start_fair(rq, p);
> }
>
> void init_cfs_rq(struct cfs_rq *cfs_rq)
> diff --git a/kernel/sched/idle.c b/kernel/sched/idle.c
> index eb73b65ce6c4714db1e07066c86a8cf39adbc328..76f3c84ca6846afc30609fdc512553c6797e9557 100644
> --- a/kernel/sched/idle.c
> +++ b/kernel/sched/idle.c
> @@ -487,8 +487,11 @@ static void put_prev_task_idle(struct rq *rq, struct task_struct *prev, struct t
> update_rq_avg_idle(rq);
> }
>
> -static void set_next_task_idle(struct rq *rq, struct task_struct *next, bool first)
> +static void set_next_task_idle(struct rq *rq, struct task_struct *next, enum snt_e type)
> {
> + if (type == SNT_REPICK)
> + return;
> +
> update_idle_core(rq);
> scx_update_idle(rq, true, true);
> schedstat_inc(rq->sched_goidle);
> diff --git a/kernel/sched/rt.c b/kernel/sched/rt.c
> index 85303add726df4c2da846c427aab2d627fca9589..1535046a23ffa0705d90dce301fa4c5b015703a1 100644
> --- a/kernel/sched/rt.c
> +++ b/kernel/sched/rt.c
> @@ -1654,11 +1654,14 @@ static void wakeup_preempt_rt(struct rq *rq, struct task_struct *p, int flags)
> check_preempt_equal_prio(rq, p);
> }
>
> -static inline void set_next_task_rt(struct rq *rq, struct task_struct *p, bool first)
> +static inline void set_next_task_rt(struct rq *rq, struct task_struct *p, enum snt_e type)
> {
> struct sched_rt_entity *rt_se = &p->rt;
> struct rt_rq *rt_rq = &rq->rt;
>
> + if (type == SNT_REPICK)
> + return;
> +
> p->se.exec_start = rq_clock_task(rq);
> if (on_rt_rq(&p->rt))
> update_stats_wait_end_rt(rt_rq, rt_se);
> @@ -1666,7 +1669,7 @@ static inline void set_next_task_rt(struct rq *rq, struct task_struct *p, bool f
> /* The running task is never eligible for pushing */
> dequeue_pushable_task(rq, p);
>
> - if (!first)
> + if (type != SNT_PICK)
> return;
>
> /*
> diff --git a/kernel/sched/sched.h b/kernel/sched/sched.h
> index e656c7059bf864d1ed91d4ec3d4624850aded7e0..defcf7fd023fa5bb3c34c3c29f99afe3c42a87de 100644
> --- a/kernel/sched/sched.h
> +++ b/kernel/sched/sched.h
> @@ -2621,6 +2621,12 @@ struct affinity_context {
>
> extern s64 update_curr_common(struct rq *rq);
>
> +enum snt_e {
> + SNT_NORMAL,
> + SNT_PICK,
> + SNT_REPICK,
> +};
> +
> struct sched_class {
>
> #ifdef CONFIG_UCLAMP_TASK
> @@ -2678,7 +2684,7 @@ struct sched_class {
> * __schedule: rq->lock
> */
> void (*put_prev_task)(struct rq *rq, struct task_struct *p, struct task_struct *next);
> - void (*set_next_task)(struct rq *rq, struct task_struct *p, bool first);
> + void (*set_next_task)(struct rq *rq, struct task_struct *p, enum snt_e type);
>
> /*
> * select_task_rq: p->pi_lock
> @@ -2781,7 +2787,7 @@ static inline void put_prev_task(struct rq *rq, struct task_struct *prev)
>
> static inline void set_next_task(struct rq *rq, struct task_struct *next)
> {
> - next->sched_class->set_next_task(rq, next, false);
> + next->sched_class->set_next_task(rq, next, SNT_NORMAL);
> }
>
> static inline void
> @@ -2802,11 +2808,13 @@ static inline void put_prev_set_next_task(struct rq *rq,
>
> __put_prev_set_next_dl_server(rq, prev, next);
>
> - if (next == prev)
> + if (next == prev) {
> + next->sched_class->set_next_task(rq, next, SNT_REPICK);
> return;
> + }
>
> prev->sched_class->put_prev_task(rq, prev, next);
> - next->sched_class->set_next_task(rq, next, true);
> + next->sched_class->set_next_task(rq, next, SNT_PICK);
> }
>
> /*
> diff --git a/kernel/sched/stop_task.c b/kernel/sched/stop_task.c
> index c909ca0d8c87c1055ad5ffe58ae9f044194ee358..1e0109ec36b3f9b84f6f7290e584e38257db701c 100644
> --- a/kernel/sched/stop_task.c
> +++ b/kernel/sched/stop_task.c
> @@ -27,8 +27,11 @@ wakeup_preempt_stop(struct rq *rq, struct task_struct *p, int flags)
> /* we're never preempted */
> }
>
> -static void set_next_task_stop(struct rq *rq, struct task_struct *stop, bool first)
> +static void set_next_task_stop(struct rq *rq, struct task_struct *stop, enum snt_e type)
> {
> + if (type == SNT_REPICK)
> + return;
> +
> stop->se.exec_start = rq_clock_task(rq);
> }
>
>
> ---
> base-commit: 08df884136f1c1197bab2a27814404fd329d9aac
> change-id: 20260813-sched-fair-hrtick-restart-ab9d3d47ef78
>
> Best regards,
> --
> Shubhang Kaushik (Ampere) <sh@gentwo.org>
>
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