sched/headers: Simplify and clean up header usage in the scheduler

Do the following cleanups and simplifications:

 - sched/sched.h already includes <asm/paravirt.h>, so no need to
   include it in sched/core.c again.

 - order the <linux/sched/*.h> headers alphabetically

 - add all <linux/sched/*.h> headers to kernel/sched/sched.h

 - remove all unnecessary includes from the .c files that
   are already included in kernel/sched/sched.h.

Finally, make all scheduler .c files use a single common header:

  #include "sched.h"

... which now contains a union of the relied upon headers.

This makes the various .c files easier to read and easier to handle.

Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Mike Galbraith <efault@gmx.de>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: linux-kernel@vger.kernel.org
Signed-off-by: Ingo Molnar <mingo@kernel.org>

include/linux/sched/deadline.h

@@ -1,8 +1,4 @@
 /* SPDX-License-Identifier: GPL-2.0 */
-#ifndef _LINUX_SCHED_DEADLINE_H
-#define _LINUX_SCHED_DEADLINE_H
-
-#include <linux/sched.h>
 
 /*
  * SCHED_DEADLINE tasks has negative priorities, reflecting
@@ -28,5 +24,3 @@ static inline bool dl_time_before(u64 a, u64 b)
 {
 	return (s64)(a - b) < 0;
 }
-
-#endif /* _LINUX_SCHED_DEADLINE_H */

kernel/sched/autogroup.c

@@ -1,10 +1,7 @@
 // SPDX-License-Identifier: GPL-2.0
-#include <linux/proc_fs.h>
-#include <linux/seq_file.h>
-#include <linux/utsname.h>
-#include <linux/security.h>
-#include <linux/export.h>
-
+/*
+ * Auto-group scheduling implementation:
+ */
 #include "sched.h"
 
 unsigned int __read_mostly sysctl_sched_autogroup_enabled = 1;

kernel/sched/autogroup.h

@@ -1,10 +1,6 @@
 /* SPDX-License-Identifier: GPL-2.0 */
 #ifdef CONFIG_SCHED_AUTOGROUP
 
-#include <linux/kref.h>
-#include <linux/rwsem.h>
-#include <linux/sched/autogroup.h>
-
 struct autogroup {
 	/*
 	 * Reference doesn't mean how many threads attach to this

kernel/sched/clock.c

@@ -52,19 +52,7 @@
  * that is otherwise invisible (TSC gets stopped).
  *
  */
-#include <linux/spinlock.h>
-#include <linux/hardirq.h>
-#include <linux/export.h>
-#include <linux/percpu.h>
-#include <linux/ktime.h>
-#include <linux/sched.h>
-#include <linux/nmi.h>
-#include <linux/sched/clock.h>
-#include <linux/static_key.h>
-#include <linux/workqueue.h>
-#include <linux/compiler.h>
-#include <linux/tick.h>
-#include <linux/init.h>
+#include "sched.h"
 
 /*
  * Scheduler clock - returns current time in nanosec units.

kernel/sched/completion.c

@@ -11,10 +11,7 @@
  * typically be used for exclusion which gives rise to priority inversion.
  * Waiting for completion is a typically sync point, but not an exclusion point.
  */
-
-#include <linux/sched/signal.h>
-#include <linux/sched/debug.h>
-#include <linux/completion.h>
+#include "sched.h"
 
 /**
  * complete: - signals a single thread waiting on this completion

kernel/sched/core.c

@@ -5,37 +5,11 @@
  *
  *  Copyright (C) 1991-2002  Linus Torvalds
  */
-#include <linux/sched.h>
-#include <linux/sched/clock.h>
-#include <uapi/linux/sched/types.h>
-#include <linux/sched/loadavg.h>
-#include <linux/sched/hotplug.h>
-#include <linux/wait_bit.h>
-#include <linux/cpuset.h>
-#include <linux/delayacct.h>
-#include <linux/init_task.h>
-#include <linux/context_tracking.h>
-#include <linux/rcupdate_wait.h>
-#include <linux/compat.h>
-
-#include <linux/blkdev.h>
-#include <linux/kprobes.h>
-#include <linux/mmu_context.h>
-#include <linux/module.h>
-#include <linux/nmi.h>
-#include <linux/prefetch.h>
-#include <linux/profile.h>
-#include <linux/security.h>
-#include <linux/syscalls.h>
-#include <linux/sched/isolation.h>
+#include "sched.h"
 
 #include <asm/switch_to.h>
 #include <asm/tlb.h>
-#ifdef CONFIG_PARAVIRT
-#include <asm/paravirt.h>
-#endif
 
-#include "sched.h"
 #include "../workqueue_internal.h"
 #include "../smpboot.h"
 
@@ -2629,6 +2603,18 @@ static inline void finish_lock_switch(struct rq *rq)
 	raw_spin_unlock_irq(&rq->lock);
 }
 
+/*
+ * NOP if the arch has not defined these:
+ */
+
+#ifndef prepare_arch_switch
+# define prepare_arch_switch(next)	do { } while (0)
+#endif
+
+#ifndef finish_arch_post_lock_switch
+# define finish_arch_post_lock_switch()	do { } while (0)
+#endif
+
 /**
  * prepare_task_switch - prepare to switch tasks
  * @rq: the runqueue preparing to switch

kernel/sched/cpuacct.c

@@ -1,22 +1,11 @@
 // SPDX-License-Identifier: GPL-2.0
-#include <linux/cgroup.h>
-#include <linux/slab.h>
-#include <linux/percpu.h>
-#include <linux/spinlock.h>
-#include <linux/cpumask.h>
-#include <linux/seq_file.h>
-#include <linux/rcupdate.h>
-#include <linux/kernel_stat.h>
-#include <linux/err.h>
-
-#include "sched.h"
-
 /*
  * CPU accounting code for task groups.
  *
  * Based on the work by Paul Menage (menage@google.com) and Balbir Singh
  * (balbir@in.ibm.com).
  */
+#include "sched.h"
 
 /* Time spent by the tasks of the CPU accounting group executing in ... */
 enum cpuacct_stat_index {

kernel/sched/cpudeadline.c

@@ -10,10 +10,7 @@
  *  as published by the Free Software Foundation; version 2
  *  of the License.
  */
-#include <linux/gfp.h>
-#include <linux/kernel.h>
-#include <linux/slab.h>
-#include "cpudeadline.h"
+#include "sched.h"
 
 static inline int parent(int i)
 {

kernel/sched/cpudeadline.h

@@ -1,6 +1,4 @@
 /* SPDX-License-Identifier: GPL-2.0 */
-#include <linux/sched.h>
-#include <linux/sched/deadline.h>
 
 #define IDX_INVALID		-1
 

kernel/sched/cpufreq.c

@@ -8,7 +8,6 @@
  * it under the terms of the GNU General Public License version 2 as
  * published by the Free Software Foundation.
  */
-
 #include "sched.h"
 
 DEFINE_PER_CPU(struct update_util_data *, cpufreq_update_util_data);

kernel/sched/cpufreq_schedutil.c

@@ -11,14 +11,10 @@
 
 #define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
 
-#include <linux/cpufreq.h>
-#include <linux/kthread.h>
-#include <uapi/linux/sched/types.h>
-#include <linux/slab.h>
-#include <trace/events/power.h>
-
 #include "sched.h"
 
+#include <trace/events/power.h>
+
 struct sugov_tunables {
 	struct gov_attr_set	attr_set;
 	unsigned int		rate_limit_us;

kernel/sched/cpupri.c

@@ -26,11 +26,7 @@
  *  as published by the Free Software Foundation; version 2
  *  of the License.
  */
-#include <linux/gfp.h>
-#include <linux/sched.h>
-#include <linux/sched/rt.h>
-#include <linux/slab.h>
-#include "cpupri.h"
+#include "sched.h"
 
 /* Convert between a 140 based task->prio, and our 102 based cpupri */
 static int convert_prio(int prio)

kernel/sched/cpupri.h

@@ -1,5 +1,4 @@
 /* SPDX-License-Identifier: GPL-2.0 */
-#include <linux/sched.h>
 
 #define CPUPRI_NR_PRIORITIES	(MAX_RT_PRIO + 2)
 

kernel/sched/cputime.c

@@ -1,10 +1,6 @@
-#include <linux/export.h>
-#include <linux/sched.h>
-#include <linux/tsacct_kern.h>
-#include <linux/kernel_stat.h>
-#include <linux/static_key.h>
-#include <linux/context_tracking.h>
-#include <linux/sched/cputime.h>
+/*
+ * Simple CPU accounting cgroup controller
+ */
 #include "sched.h"
 
 #ifdef CONFIG_IRQ_TIME_ACCOUNTING

kernel/sched/deadline.c

@@ -17,9 +17,6 @@
  */
 #include "sched.h"
 
-#include <linux/slab.h>
-#include <uapi/linux/sched/types.h>
-
 struct dl_bandwidth def_dl_bandwidth;
 
 static inline struct task_struct *dl_task_of(struct sched_dl_entity *dl_se)

kernel/sched/debug.c

@@ -1,7 +1,7 @@
 /*
  * kernel/sched/debug.c
  *
- * Print the CFS rbtree
+ * Print the CFS rbtree and other debugging details
  *
  * Copyright(C) 2007, Red Hat, Inc., Ingo Molnar
  *
@@ -9,15 +9,6 @@
  * it under the terms of the GNU General Public License version 2 as
  * published by the Free Software Foundation.
  */
-#include <linux/proc_fs.h>
-#include <linux/sched/mm.h>
-#include <linux/sched/task.h>
-#include <linux/seq_file.h>
-#include <linux/kallsyms.h>
-#include <linux/utsname.h>
-#include <linux/mempolicy.h>
-#include <linux/debugfs.h>
-
 #include "sched.h"
 
 static DEFINE_SPINLOCK(sched_debug_lock);

kernel/sched/fair.c

@@ -20,24 +20,10 @@
  *  Adaptive scheduling granularity, math enhancements by Peter Zijlstra
  *  Copyright (C) 2007 Red Hat, Inc., Peter Zijlstra
  */
-#include <linux/sched/mm.h>
-#include <linux/sched/topology.h>
-
-#include <linux/latencytop.h>
-#include <linux/cpumask.h>
-#include <linux/cpuidle.h>
-#include <linux/slab.h>
-#include <linux/profile.h>
-#include <linux/interrupt.h>
-#include <linux/mempolicy.h>
-#include <linux/migrate.h>
-#include <linux/task_work.h>
-#include <linux/sched/isolation.h>
+#include "sched.h"
 
 #include <trace/events/sched.h>
 
-#include "sched.h"
-
 /*
  * Targeted preemption latency for CPU-bound tasks:
  *

kernel/sched/idle.c

@@ -1,23 +1,10 @@
 /*
  * Generic entry points for the idle threads
  */
-#include <linux/sched.h>
-#include <linux/sched/idle.h>
-#include <linux/cpu.h>
-#include <linux/cpuidle.h>
-#include <linux/cpuhotplug.h>
-#include <linux/tick.h>
-#include <linux/mm.h>
-#include <linux/stackprotector.h>
-#include <linux/suspend.h>
-#include <linux/livepatch.h>
-
-#include <asm/tlb.h>
+#include "sched.h"
 
 #include <trace/events/power.h>
 
-#include "sched.h"
-
 /* Linker adds these: start and end of __cpuidle functions */
 extern char __cpuidle_text_start[], __cpuidle_text_end[];
 

kernel/sched/idle_task.c

@@ -1,12 +1,11 @@
 // SPDX-License-Identifier: GPL-2.0
-#include "sched.h"
-
 /*
  * idle-task scheduling class.
  *
- * (NOTE: these are not related to SCHED_IDLE tasks which are
+ * (NOTE: these are not related to SCHED_IDLE batch scheduling tasks which are
  *  handled in sched/fair.c)
  */
+#include "sched.h"
 
 #ifdef CONFIG_SMP
 static int

kernel/sched/isolation.c

@@ -6,13 +6,6 @@
  * Copyright (C) 2017-2018 SUSE, Frederic Weisbecker
  *
  */
-#include <linux/sched/isolation.h>
-#include <linux/tick.h>
-#include <linux/init.h>
-#include <linux/kernel.h>
-#include <linux/static_key.h>
-#include <linux/ctype.h>
-
 #include "sched.h"
 
 DEFINE_STATIC_KEY_FALSE(housekeeping_overriden);

kernel/sched/loadavg.c

@@ -6,10 +6,6 @@
  * figure. Its a silly number but people think its important. We go through
  * great pains to make it work on big machines and tickless kernels.
  */
-
-#include <linux/export.h>
-#include <linux/sched/loadavg.h>
-
 #include "sched.h"
 
 /*

kernel/sched/membarrier.c

@@ -13,14 +13,7 @@
  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  * GNU General Public License for more details.
  */
-
-#include <linux/syscalls.h>
-#include <linux/membarrier.h>
-#include <linux/tick.h>
-#include <linux/cpumask.h>
-#include <linux/atomic.h>
-
-#include "sched.h"	/* for cpu_rq(). */
+#include "sched.h"
 
 /*
  * Bitmask made from a "or" of all commands within enum membarrier_cmd,

kernel/sched/rt.c

@@ -3,12 +3,8 @@
  * Real-Time Scheduling Class (mapped to the SCHED_FIFO and SCHED_RR
  * policies)
  */
-
 #include "sched.h"
 
-#include <linux/slab.h>
-#include <linux/irq_work.h>
-
 int sched_rr_timeslice = RR_TIMESLICE;
 int sysctl_sched_rr_timeslice = (MSEC_PER_SEC / HZ) * RR_TIMESLICE;
 

kernel/sched/sched.h

@@ -3,39 +3,71 @@
  * Scheduler internal types and methods:
  */
 #include <linux/sched.h>
+
 #include <linux/sched/autogroup.h>
-#include <linux/sched/sysctl.h>
-#include <linux/sched/topology.h>
-#include <linux/sched/rt.h>
-#include <linux/sched/deadline.h>
 #include <linux/sched/clock.h>
-#include <linux/sched/wake_q.h>
-#include <linux/sched/signal.h>
-#include <linux/sched/numa_balancing.h>
-#include <linux/sched/mm.h>
+#include <linux/sched/coredump.h>
 #include <linux/sched/cpufreq.h>
-#include <linux/sched/stat.h>
-#include <linux/sched/nohz.h>
+#include <linux/sched/cputime.h>
+#include <linux/sched/deadline.h>
 #include <linux/sched/debug.h>
 #include <linux/sched/hotplug.h>
+#include <linux/sched/idle.h>
+#include <linux/sched/init.h>
+#include <linux/sched/isolation.h>
+#include <linux/sched/jobctl.h>
+#include <linux/sched/loadavg.h>
+#include <linux/sched/mm.h>
+#include <linux/sched/nohz.h>
+#include <linux/sched/numa_balancing.h>
+#include <linux/sched/prio.h>
+#include <linux/sched/rt.h>
+#include <linux/sched/signal.h>
+#include <linux/sched/stat.h>
+#include <linux/sched/sysctl.h>
 #include <linux/sched/task.h>
 #include <linux/sched/task_stack.h>
-#include <linux/sched/cputime.h>
-#include <linux/sched/init.h>
+#include <linux/sched/topology.h>
+#include <linux/sched/user.h>
+#include <linux/sched/wake_q.h>
+#include <linux/sched/xacct.h>
+
+#include <uapi/linux/sched/types.h>
 
-#include <linux/u64_stats_sync.h>
-#include <linux/kernel_stat.h>
 #include <linux/binfmts.h>
-#include <linux/mutex.h>
-#include <linux/spinlock.h>
+#include <linux/blkdev.h>
+#include <linux/compat.h>
+#include <linux/context_tracking.h>
+#include <linux/cpufreq.h>
+#include <linux/cpuidle.h>
+#include <linux/cpuset.h>
+#include <linux/ctype.h>
+#include <linux/debugfs.h>
+#include <linux/delayacct.h>
+#include <linux/init_task.h>
+#include <linux/kprobes.h>
+#include <linux/kthread.h>
+#include <linux/membarrier.h>
+#include <linux/migrate.h>
+#include <linux/mmu_context.h>
+#include <linux/nmi.h>
+#include <linux/proc_fs.h>
+#include <linux/prefetch.h>
+#include <linux/profile.h>
+#include <linux/rcupdate_wait.h>
+#include <linux/security.h>
+#include <linux/stackprotector.h>
 #include <linux/stop_machine.h>
-#include <linux/irq_work.h>
-#include <linux/tick.h>
-#include <linux/slab.h>
-#include <linux/cgroup.h>
+#include <linux/suspend.h>
+#include <linux/swait.h>
+#include <linux/syscalls.h>
+#include <linux/task_work.h>
+#include <linux/tsacct_kern.h>
+
+#include <asm/tlb.h>
 
 #ifdef CONFIG_PARAVIRT
-#include <asm/paravirt.h>
+# include <asm/paravirt.h>
 #endif
 
 #include "cpupri.h"
@@ -1357,13 +1389,6 @@ static inline int task_on_rq_migrating(struct task_struct *p)
 	return p->on_rq == TASK_ON_RQ_MIGRATING;
 }
 
-#ifndef prepare_arch_switch
-# define prepare_arch_switch(next)	do { } while (0)
-#endif
-#ifndef finish_arch_post_lock_switch
-# define finish_arch_post_lock_switch()	do { } while (0)
-#endif
-
 /*
  * wake flags
  */

kernel/sched/stats.c

@@ -1,14 +1,13 @@
 // SPDX-License-Identifier: GPL-2.0
-
-#include <linux/slab.h>
-#include <linux/fs.h>
-#include <linux/seq_file.h>
-#include <linux/proc_fs.h>
-
+/*
+ * /proc/schedstat implementation
+ */
 #include "sched.h"
 
 /*
- * bump this up when changing the output format or the meaning of an existing
+ * Current schedstat API version.
+ *
+ * Bump this up when changing the output format or the meaning of an existing
  * format, so that tools can adapt (or abort)
  */
 #define SCHEDSTAT_VERSION 15

kernel/sched/swait.c

@@ -2,8 +2,7 @@
 /*
  * <linux/swait.h> (simple wait queues ) implementation:
  */
-#include <linux/sched/signal.h>
-#include <linux/swait.h>
+#include "sched.h"
 
 void __init_swait_queue_head(struct swait_queue_head *q, const char *name,
 			     struct lock_class_key *key)

kernel/sched/topology.c

@@ -2,10 +2,6 @@
 /*
  * Scheduler topology setup/handling methods
  */
-#include <linux/sched.h>
-#include <linux/mutex.h>
-#include <linux/sched/isolation.h>
-
 #include "sched.h"
 
 DEFINE_MUTEX(sched_domains_mutex);

kernel/sched/wait.c

@@ -3,14 +3,7 @@
  *
  * (C) 2004 Nadia Yvette Chambers, Oracle
  */
-#include <linux/init.h>
-#include <linux/export.h>
-#include <linux/sched/signal.h>
-#include <linux/sched/debug.h>
-#include <linux/mm.h>
-#include <linux/wait.h>
-#include <linux/hash.h>
-#include <linux/kthread.h>
+#include "sched.h"
 
 void __init_waitqueue_head(struct wait_queue_head *wq_head, const char *name, struct lock_class_key *key)
 {

kernel/sched/wait_bit.c

@@ -1,10 +1,7 @@
 /*
  * The implementation of the wait_bit*() and related waiting APIs:
  */
-#include <linux/wait_bit.h>
-#include <linux/sched/signal.h>
-#include <linux/sched/debug.h>
-#include <linux/hash.h>
+#include "sched.h"
 
 #define WAIT_TABLE_BITS 8
 #define WAIT_TABLE_SIZE (1 << WAIT_TABLE_BITS)