Commit 900b1028 authored by Paul E. McKenney's avatar Paul E. McKenney
Browse files

srcu: Allow SRCU to access rcu_scheduler_active 



This is primarily a code-movement commit in preparation for allowing
SRCU to handle early-boot SRCU grace periods.

Signed-off-by: default avatarPaul E. McKenney <paulmck@linux.vnet.ibm.com>
parent 15fecf89

include/linux/rcutiny.h

+3 −3
Original line number Diff line number Diff line
@@ -217,14 +217,14 @@ static inline void exit_rcu(void) 
{

}



#ifdef CONFIG_DEBUG_LOCK_ALLOC

#if defined(CONFIG_DEBUG_LOCK_ALLOC) || defined(CONFIG_SRCU)

extern int rcu_scheduler_active __read_mostly;

void rcu_scheduler_starting(void);

#else /* #ifdef CONFIG_DEBUG_LOCK_ALLOC */

#else /* #if defined(CONFIG_DEBUG_LOCK_ALLOC) || defined(CONFIG_SRCU) */

static inline void rcu_scheduler_starting(void)

{

}

#endif /* #else #ifdef CONFIG_DEBUG_LOCK_ALLOC */

#endif /* #else #if defined(CONFIG_DEBUG_LOCK_ALLOC) || defined(CONFIG_SRCU) */



#if defined(CONFIG_DEBUG_LOCK_ALLOC) || defined(CONFIG_RCU_TRACE)

kernel/rcu/tiny_plugin.h

+5 −4
Original line number Diff line number Diff line
@@ -52,7 +52,7 @@ static struct rcu_ctrlblk rcu_bh_ctrlblk = { 
	RCU_TRACE(.name = "rcu_bh")

};



#ifdef CONFIG_DEBUG_LOCK_ALLOC

#if defined(CONFIG_DEBUG_LOCK_ALLOC) || defined(CONFIG_SRCU)

#include <linux/kernel_stat.h>



int rcu_scheduler_active __read_mostly;
@@ -65,15 +65,16 @@ EXPORT_SYMBOL_GPL(rcu_scheduler_active); 
 * to RCU_SCHEDULER_RUNNING, skipping the RCU_SCHEDULER_INIT stage.

 * The reason for this is that Tiny RCU does not need kthreads, so does

 * not have to care about the fact that the scheduler is half-initialized

 * at a certain phase of the boot process.

 * at a certain phase of the boot process.  Unless SRCU is in the mix.

 */

void __init rcu_scheduler_starting(void)

{

	WARN_ON(nr_context_switches() > 0);

	rcu_scheduler_active = RCU_SCHEDULER_RUNNING;

	rcu_scheduler_active = IS_ENABLED(CONFIG_SRCU)

		? RCU_SCHEDULER_INIT : RCU_SCHEDULER_RUNNING;

}



#endif /* #ifdef CONFIG_DEBUG_LOCK_ALLOC */

#endif /* #if defined(CONFIG_DEBUG_LOCK_ALLOC) || defined(CONFIG_SRCU) */



#ifdef CONFIG_RCU_TRACE

kernel/rcu/tree.c

+1 −1
Original line number Diff line number Diff line
@@ -3974,7 +3974,7 @@ early_initcall(rcu_spawn_gp_kthread); 
 * task is booting the system, and such primitives are no-ops).  After this

 * function is called, any synchronous grace-period primitives are run as

 * expedited, with the requesting task driving the grace period forward.

 * A later core_initcall() rcu_exp_runtime_mode() will switch to full

 * A later core_initcall() rcu_set_runtime_mode() will switch to full

 * runtime RCU functionality.

 */

void rcu_scheduler_starting(void)

kernel/rcu/tree_exp.h

+0 −12
Original line number Diff line number Diff line
@@ -737,15 +737,3 @@ void synchronize_rcu_expedited(void) 
EXPORT_SYMBOL_GPL(synchronize_rcu_expedited);



#endif /* #else #ifdef CONFIG_PREEMPT_RCU */
 


/*

 * Switch to run-time mode once Tree RCU has fully initialized.

 */

static int __init rcu_exp_runtime_mode(void)

{

	rcu_test_sync_prims();

	rcu_scheduler_active = RCU_SCHEDULER_RUNNING;

	rcu_test_sync_prims();

	return 0;

}

core_initcall(rcu_exp_runtime_mode);

kernel/rcu/update.c

+34 −18
Original line number Diff line number Diff line
@@ -124,7 +124,7 @@ EXPORT_SYMBOL(rcu_read_lock_sched_held); 
 * non-expedited counterparts?  Intended for use within RCU.  Note

 * that if the user specifies both rcu_expedited and rcu_normal, then

 * rcu_normal wins.  (Except during the time period during boot from

 * when the first task is spawned until the rcu_exp_runtime_mode()

 * when the first task is spawned until the rcu_set_runtime_mode()

 * core_initcall() is invoked, at which point everything is expedited.)

 */

bool rcu_gp_is_normal(void)
@@ -190,6 +190,39 @@ void rcu_end_inkernel_boot(void) 


#endif /* #ifndef CONFIG_TINY_RCU */



/*

 * Test each non-SRCU synchronous grace-period wait API.  This is

 * useful just after a change in mode for these primitives, and

 * during early boot.

 */

void rcu_test_sync_prims(void)

{

	if (!IS_ENABLED(CONFIG_PROVE_RCU))

		return;

	synchronize_rcu();

	synchronize_rcu_bh();

	synchronize_sched();

	synchronize_rcu_expedited();

	synchronize_rcu_bh_expedited();

	synchronize_sched_expedited();

}



#if !defined(CONFIG_TINY_RCU) || defined(CONFIG_SRCU)



/*

 * Switch to run-time mode once RCU has fully initialized.

 */

static int __init rcu_set_runtime_mode(void)

{

	rcu_test_sync_prims();

	rcu_scheduler_active = RCU_SCHEDULER_RUNNING;

	rcu_test_sync_prims();

	return 0;

}

core_initcall(rcu_set_runtime_mode);



#endif /* #if !defined(CONFIG_TINY_RCU) || defined(CONFIG_SRCU) */



#ifdef CONFIG_PREEMPT_RCU



/*
@@ -817,23 +850,6 @@ static void rcu_spawn_tasks_kthread(void) 


#endif /* #ifdef CONFIG_TASKS_RCU */



/*

 * Test each non-SRCU synchronous grace-period wait API.  This is

 * useful just after a change in mode for these primitives, and

 * during early boot.

 */

void rcu_test_sync_prims(void)

{

	if (!IS_ENABLED(CONFIG_PROVE_RCU))

		return;

	synchronize_rcu();

	synchronize_rcu_bh();

	synchronize_sched();

	synchronize_rcu_expedited();

	synchronize_rcu_bh_expedited();

	synchronize_sched_expedited();

}



#ifdef CONFIG_PROVE_RCU



/*