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linux-next/include/linux/rcutiny.h
Paul E. McKenney ffa83fb565 rcu: Optimize rcu_needs_cpu() for RCU_NOCB_CPU_ALL
If CONFIG_RCU_NOCB_CPU_ALL=y, then rcu_needs_cpu() will always
return false, however, the current version nevertheless checks
for RCU callbacks.  This commit therefore creates a static inline
implementation of rcu_needs_cpu() that unconditionally returns false
when CONFIG_RCU_NOCB_CPU_ALL=y.

Signed-off-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
Reviewed-by: Josh Triplett <josh@joshtriplett.org>
2014-02-17 16:03:09 -08:00

147 lines
3.2 KiB
C

/*
* Read-Copy Update mechanism for mutual exclusion, the Bloatwatch edition.
*
* 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, write to the Free Software
* Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA.
*
* Copyright IBM Corporation, 2008
*
* Author: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
*
* For detailed explanation of Read-Copy Update mechanism see -
* Documentation/RCU
*/
#ifndef __LINUX_TINY_H
#define __LINUX_TINY_H
#include <linux/cache.h>
static inline void rcu_barrier_bh(void)
{
wait_rcu_gp(call_rcu_bh);
}
static inline void rcu_barrier_sched(void)
{
wait_rcu_gp(call_rcu_sched);
}
static inline void synchronize_rcu_expedited(void)
{
synchronize_sched(); /* Only one CPU, so pretty fast anyway!!! */
}
static inline void rcu_barrier(void)
{
rcu_barrier_sched(); /* Only one CPU, so only one list of callbacks! */
}
static inline void synchronize_rcu_bh(void)
{
synchronize_sched();
}
static inline void synchronize_rcu_bh_expedited(void)
{
synchronize_sched();
}
static inline void synchronize_sched_expedited(void)
{
synchronize_sched();
}
static inline void kfree_call_rcu(struct rcu_head *head,
void (*func)(struct rcu_head *rcu))
{
call_rcu(head, func);
}
static inline void rcu_note_context_switch(int cpu)
{
rcu_sched_qs(cpu);
}
/*
* Take advantage of the fact that there is only one CPU, which
* allows us to ignore virtualization-based context switches.
*/
static inline void rcu_virt_note_context_switch(int cpu)
{
}
/*
* Return the number of grace periods.
*/
static inline long rcu_batches_completed(void)
{
return 0;
}
/*
* Return the number of bottom-half grace periods.
*/
static inline long rcu_batches_completed_bh(void)
{
return 0;
}
static inline void rcu_force_quiescent_state(void)
{
}
static inline void rcu_bh_force_quiescent_state(void)
{
}
static inline void rcu_sched_force_quiescent_state(void)
{
}
static inline void rcu_cpu_stall_reset(void)
{
}
static inline void exit_rcu(void)
{
}
#ifdef CONFIG_DEBUG_LOCK_ALLOC
extern int rcu_scheduler_active __read_mostly;
void rcu_scheduler_starting(void);
#else /* #ifdef CONFIG_DEBUG_LOCK_ALLOC */
static inline void rcu_scheduler_starting(void)
{
}
#endif /* #else #ifdef CONFIG_DEBUG_LOCK_ALLOC */
#if defined(CONFIG_DEBUG_LOCK_ALLOC) || defined(CONFIG_RCU_TRACE)
static inline bool rcu_is_watching(void)
{
return __rcu_is_watching();
}
#else /* defined(CONFIG_DEBUG_LOCK_ALLOC) || defined(CONFIG_RCU_TRACE) */
static inline bool rcu_is_watching(void)
{
return true;
}
#endif /* #else defined(CONFIG_DEBUG_LOCK_ALLOC) || defined(CONFIG_RCU_TRACE) */
#endif /* __LINUX_RCUTINY_H */