[PATCH 6.6 1/5] sched/core: Remove ifdeffery for saved_state

From: Chen Ridong
Date: Sun Jul 27 2025 - 22:56:16 EST


From: Elliot Berman <quic_eberman@xxxxxxxxxxx>

[ Upstream commit fbaa6a181a4b1886cbf4214abdf9a2df68471510 ]

In preparation for freezer to also use saved_state, remove the
CONFIG_PREEMPT_RT compilation guard around saved_state.

On the arm64 platform I tested which did not have CONFIG_PREEMPT_RT,
there was no statistically significant deviation by applying this patch.

Test methodology:

perf bench sched message -g 40 -l 40

Signed-off-by: Elliot Berman <quic_eberman@xxxxxxxxxxx>
Signed-off-by: Peter Zijlstra (Intel) <peterz@xxxxxxxxxxxxx>
Signed-off-by: Ingo Molnar <mingo@xxxxxxxxxx>
Signed-off-by: Chen Ridong <chenridong@xxxxxxxxxx>
---
include/linux/sched.h | 2 --
kernel/sched/core.c | 10 ++--------
2 files changed, 2 insertions(+), 10 deletions(-)

diff --git a/include/linux/sched.h b/include/linux/sched.h
index 393c300347de..cb38eee732fd 100644
--- a/include/linux/sched.h
+++ b/include/linux/sched.h
@@ -753,10 +753,8 @@ struct task_struct {
#endif
unsigned int __state;

-#ifdef CONFIG_PREEMPT_RT
/* saved state for "spinlock sleepers" */
unsigned int saved_state;
-#endif

/*
* This begins the randomizable portion of task_struct. Only
diff --git a/kernel/sched/core.c b/kernel/sched/core.c
index 760a6c3781cb..ab6550fadecd 100644
--- a/kernel/sched/core.c
+++ b/kernel/sched/core.c
@@ -2238,17 +2238,15 @@ int __task_state_match(struct task_struct *p, unsigned int state)
if (READ_ONCE(p->__state) & state)
return 1;

-#ifdef CONFIG_PREEMPT_RT
if (READ_ONCE(p->saved_state) & state)
return -1;
-#endif
+
return 0;
}

static __always_inline
int task_state_match(struct task_struct *p, unsigned int state)
{
-#ifdef CONFIG_PREEMPT_RT
int match;

/*
@@ -2260,9 +2258,6 @@ int task_state_match(struct task_struct *p, unsigned int state)
raw_spin_unlock_irq(&p->pi_lock);

return match;
-#else
- return __task_state_match(p, state);
-#endif
}

/*
@@ -4059,7 +4054,6 @@ bool ttwu_state_match(struct task_struct *p, unsigned int state, int *success)

*success = !!(match = __task_state_match(p, state));

-#ifdef CONFIG_PREEMPT_RT
/*
* Saved state preserves the task state across blocking on
* an RT lock. If the state matches, set p::saved_state to
@@ -4075,7 +4069,7 @@ bool ttwu_state_match(struct task_struct *p, unsigned int state, int *success)
*/
if (match < 0)
p->saved_state = TASK_RUNNING;
-#endif
+
return match > 0;
}

--
2.34.1