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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: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
This commit is contained in:
Paul E. McKenney 2017-02-10 14:32:54 -08:00
parent 15fecf89e4
commit 900b1028ec
5 changed files with 43 additions and 38 deletions
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6
include/linux/rcutiny.h
View File

@ -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)

9
kernel/rcu/tiny_plugin.h
View File

@ -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

2
kernel/rcu/tree.c
View File

@ -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)

12
kernel/rcu/tree_exp.h
View File

@ -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);

52
kernel/rcu/update.c
View File

@ -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
/*