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Commit 825c5bd2 authored by Paul E. McKenney's avatar Paul E. McKenney
Browse files

srcu: Move rcu_scheduler_starting() from Tiny RCU to Tiny SRCU 



Other than lockdep support, Tiny RCU has no need for the
scheduler status.  However, Tiny SRCU will need this to control
boot-time behavior independent of lockdep.  Therefore, this commit
moves rcu_scheduler_starting() from kernel/rcu/tiny_plugin.h to
kernel/rcu/srcutiny.c.  This in turn allows the complete removal of
kernel/rcu/tiny_plugin.h.

Signed-off-by: default avatarPaul E. McKenney <paulmck@linux.vnet.ibm.com>
parent 520eccdf

include/linux/rcupdate.h

+1 −0
Original line number Diff line number Diff line
@@ -105,6 +105,7 @@ static inline int rcu_preempt_depth(void) 


/* Internal to kernel */

void rcu_init(void);

extern int rcu_scheduler_active __read_mostly;

void rcu_sched_qs(void);

void rcu_bh_qs(void);

void rcu_check_callbacks(int user);

include/linux/rcutiny.h

+3 −5
Original line number Diff line number Diff line
@@ -116,13 +116,11 @@ static inline void rcu_irq_exit_irqson(void) { } 
static inline void rcu_irq_enter_irqson(void) { }

static inline void rcu_irq_exit(void) { }

static inline void exit_rcu(void) { }



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

extern int rcu_scheduler_active __read_mostly;

#ifdef CONFIG_SRCU

void rcu_scheduler_starting(void);

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

#else /* #ifndef CONFIG_SRCU */

static inline void rcu_scheduler_starting(void) { }

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

#endif /* #else #ifndef CONFIG_SRCU */

static inline void rcu_end_inkernel_boot(void) { }

static inline bool rcu_is_watching(void) { return true; }

kernel/rcu/srcutiny.c

+8 −0
Original line number Diff line number Diff line
@@ -33,6 +33,8 @@ 
#include "rcu_segcblist.h"

#include "rcu.h"



int rcu_scheduler_active __read_mostly;



static int init_srcu_struct_fields(struct srcu_struct *sp)

{

	sp->srcu_lock_nesting[0] = 0;
@@ -193,3 +195,9 @@ void synchronize_srcu(struct srcu_struct *sp) 
	destroy_rcu_head_on_stack(&rs.head);

}

EXPORT_SYMBOL_GPL(synchronize_srcu);



/* Lockdep diagnostics.  */

void __init rcu_scheduler_starting(void)

{

	rcu_scheduler_active = RCU_SCHEDULER_RUNNING;

}

kernel/rcu/tiny.c

+0 −2
Original line number Diff line number Diff line
@@ -56,8 +56,6 @@ static struct rcu_ctrlblk rcu_bh_ctrlblk = { 
	.curtail	= &rcu_bh_ctrlblk.rcucblist,

};



#include "tiny_plugin.h"



void rcu_barrier_bh(void)

{

	wait_rcu_gp(call_rcu_bh);

kernel/rcu/tiny_plugin.h

deleted100644 → 0
+0 −47
Original line number Diff line number Diff line 
/*

 * Read-Copy Update mechanism for mutual exclusion, the Bloatwatch edition

 * Internal non-public definitions that provide either classic

 * or preemptible semantics.

 *

 * This program is free software; you can redistribute it and/or modify

 * it under the terms of the GNU General Public License as published by

 * the Free Software Foundation; either version 2 of the License, or

 * (at your option) any later version.

 *

 * This program is distributed in the hope that it will be useful,

 * but WITHOUT ANY WARRANTY; without even the implied warranty of

 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the

 * GNU General Public License for more details.

 *

 * You should have received a copy of the GNU General Public License

 * along with this program; if not, you can access it online at

 * http://www.gnu.org/licenses/gpl-2.0.html.

 *

 * Copyright (c) 2010 Linaro

 *

 * Author: Paul E. McKenney <paulmck@linux.vnet.ibm.com>

 */



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

#include <linux/kernel_stat.h>



int rcu_scheduler_active __read_mostly;

EXPORT_SYMBOL_GPL(rcu_scheduler_active);



/*

 * During boot, we forgive RCU lockdep issues.  After this function is

 * invoked, we start taking RCU lockdep issues seriously.  Note that unlike

 * Tree RCU, Tiny RCU transitions directly from RCU_SCHEDULER_INACTIVE

 * 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.  Unless SRCU is in the mix.

 */

void __init rcu_scheduler_starting(void)

{

	WARN_ON(nr_context_switches() > 0);

	rcu_scheduler_active = IS_ENABLED(CONFIG_SRCU)

		? RCU_SCHEDULER_INIT : RCU_SCHEDULER_RUNNING;

}



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