linux-kernel - [PATCH tip/core/rcu 08/15] sched: Cleanup PREEMPT

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Date:   Mon, 28 Sep 2020 16:30:55 -0700
From:   paulmck@...nel.org
To:     rcu@...r.kernel.org
Cc:     linux-kernel@...r.kernel.org, kernel-team@...com, mingo@...nel.org,
        jiangshanlai@...il.com, akpm@...ux-foundation.org,
        mathieu.desnoyers@...icios.com, josh@...htriplett.org,
        tglx@...utronix.de, peterz@...radead.org, rostedt@...dmis.org,
        dhowells@...hat.com, edumazet@...gle.com, fweisbec@...il.com,
        oleg@...hat.com, joel@...lfernandes.org, mhocko@...nel.org,
        mgorman@...hsingularity.net, torvalds@...ux-foundation.org,
        Ingo Molnar <mingo@...hat.com>,
        Juri Lelli <juri.lelli@...hat.com>,
        Vincent Guittot <vincent.guittot@...aro.org>,
        Dietmar Eggemann <dietmar.eggemann@....com>,
        Ben Segall <bsegall@...gle.com>, Mel Gorman <mgorman@...e.de>,
        Daniel Bristot de Oliveira <bristot@...hat.com>,
        "Paul E . McKenney" <paulmck@...nel.org>
Subject: [PATCH tip/core/rcu 08/15] sched: Cleanup PREEMPT_COUNT leftovers

From: Thomas Gleixner <tglx@...utronix.de>

CONFIG_PREEMPT_COUNT is now unconditionally enabled and will be
removed. Cleanup the leftovers before doing so.

Signed-off-by: Thomas Gleixner <tglx@...utronix.de>
Cc: Ingo Molnar <mingo@...hat.com>
Cc: Peter Zijlstra <peterz@...radead.org>
Cc: Juri Lelli <juri.lelli@...hat.com>
Cc: Vincent Guittot <vincent.guittot@...aro.org>
Cc: Dietmar Eggemann <dietmar.eggemann@....com>
Cc: Steven Rostedt <rostedt@...dmis.org>
Cc: Ben Segall <bsegall@...gle.com>
Cc: Mel Gorman <mgorman@...e.de>
Cc: Daniel Bristot de Oliveira <bristot@...hat.com>
Signed-off-by: Paul E. McKenney <paulmck@...nel.org>
---
 kernel/sched/core.c | 6 +-----
 lib/Kconfig.debug   | 1 -
 2 files changed, 1 insertion(+), 6 deletions(-)

diff --git a/kernel/sched/core.c b/kernel/sched/core.c
index 2d95dc3..1c304a1 100644
--- a/kernel/sched/core.c
+++ b/kernel/sched/core.c
@@ -3706,8 +3706,7 @@ asmlinkage __visible void schedule_tail(struct task_struct *prev)
 	 * finish_task_switch() for details.
 	 *
 	 * finish_task_switch() will drop rq->lock() and lower preempt_count
-	 * and the preempt_enable() will end up enabling preemption (on
-	 * PREEMPT_COUNT kernels).
+	 * and the preempt_enable() will end up enabling preemption.
 	 */
 
 	rq = finish_task_switch(prev);
@@ -7308,9 +7307,6 @@ void __cant_sleep(const char *file, int line, int preempt_offset)
 	if (irqs_disabled())
 		return;
 
-	if (!IS_ENABLED(CONFIG_PREEMPT_COUNT))
-		return;
-
 	if (preempt_count() > preempt_offset)
 		return;
 
diff --git a/lib/Kconfig.debug b/lib/Kconfig.debug
index d4d0574..52af6ad 100644
--- a/lib/Kconfig.debug
+++ b/lib/Kconfig.debug
@@ -1320,7 +1320,6 @@ config DEBUG_LOCKDEP
 
 config DEBUG_ATOMIC_SLEEP
 	bool "Sleep inside atomic section checking"
-	select PREEMPT_COUNT
 	depends on DEBUG_KERNEL
 	help
 	  If you say Y here, various routines which may sleep will become very
-- 
2.9.5