linux-kernel - [tip: sched/core] sched/core: Remove ifdeffery for saved

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Date:   Mon, 18 Sep 2023 06:21:23 -0000
From:   "tip-bot2 for Elliot Berman" <tip-bot2@...utronix.de>
To:     linux-tip-commits@...r.kernel.org
Cc:     Elliot Berman <quic_eberman@...cinc.com>,
        "Peter Zijlstra (Intel)" <peterz@...radead.org>,
        Ingo Molnar <mingo@...nel.org>, x86@...nel.org,
        linux-kernel@...r.kernel.org
Subject: [tip: sched/core] sched/core: Remove ifdeffery for saved_state

The following commit has been merged into the sched/core branch of tip:

Commit-ID:     fbaa6a181a4b1886cbf4214abdf9a2df68471510
Gitweb:        https://git.kernel.org/tip/fbaa6a181a4b1886cbf4214abdf9a2df68471510
Author:        Elliot Berman <quic_eberman@...cinc.com>
AuthorDate:    Fri, 08 Sep 2023 15:49:15 -07:00
Committer:     Ingo Molnar <mingo@...nel.org>
CommitterDate: Mon, 18 Sep 2023 08:13:57 +02:00

sched/core: Remove ifdeffery for saved_state

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@...cinc.com>
Signed-off-by: Peter Zijlstra (Intel) <peterz@...radead.org>
Signed-off-by: Ingo Molnar <mingo@...nel.org>
---
 include/linux/sched.h | 2 --
 kernel/sched/core.c   | 8 ++------
 2 files changed, 2 insertions(+), 8 deletions(-)

diff --git a/include/linux/sched.h b/include/linux/sched.h
index 77f01ac..dc37ae7 100644
--- a/include/linux/sched.h
+++ b/include/linux/sched.h
@@ -750,10 +750,8 @@ 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 f39482d..49541e3 100644
--- a/kernel/sched/core.c
+++ b/kernel/sched/core.c
@@ -2232,23 +2232,20 @@ 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
 	/*
 	 * Serialize against current_save_and_set_rtlock_wait_state() and
 	 * current_restore_rtlock_saved_state().
 	 */
 	guard(raw_spinlock_irq)(&p->pi_lock);
-#endif
 	return __task_state_match(p, state);
 }
 
@@ -4038,7 +4035,6 @@ 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
@@ -4054,7 +4050,7 @@ 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;
 }