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rcu: Optimize rcu_is_nocb_cpu() for RCU_NOCB_CPU_ALL 

If CONFIG_RCU_NOCB_CPU_ALL=y, then rcu_is_nocb_cpu() will always
return true, however, the current version nevertheless checks
rcu_nocb_mask.  This commit therefore creates a static inline
implementation of rcu_is_nocb_cpu() that unconditionally returns
true 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>
This commit is contained in:
Paul E. McKenney 2013-11-17 18:25:48 -08:00
parent 6d0abeca32
commit 2f33b512a5
2 changed files with 6 additions and 2 deletions
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6
include/linux/rcupdate.h
View File

@ -1015,11 +1015,13 @@ static inline notrace void rcu_read_unlock_sched_notrace(void)
#define kfree_rcu(ptr, rcu_head) \
__kfree_rcu(&((ptr)->rcu_head), offsetof(typeof(*(ptr)), rcu_head))
#ifdef CONFIG_RCU_NOCB_CPU
#if defined(CONFIG_RCU_NOCB_CPU_ALL)
static inline bool rcu_is_nocb_cpu(int cpu) { return true; }
#elif defined(CONFIG_RCU_NOCB_CPU)
bool rcu_is_nocb_cpu(int cpu);
#else
static inline bool rcu_is_nocb_cpu(int cpu) { return false; }
#endif /* #else #ifdef CONFIG_RCU_NOCB_CPU */
#endif
/* Only for use by adaptive-ticks code. */

2
kernel/rcu/tree_plugin.h
View File

@ -2101,6 +2101,7 @@ static void rcu_init_one_nocb(struct rcu_node *rnp)
init_waitqueue_head(&rnp->nocb_gp_wq[1]);
}
#ifndef CONFIG_RCU_NOCB_CPU_ALL
/* Is the specified CPU a no-CPUs CPU? */
bool rcu_is_nocb_cpu(int cpu)
{
@ -2108,6 +2109,7 @@ bool rcu_is_nocb_cpu(int cpu)
return cpumask_test_cpu(cpu, rcu_nocb_mask);
return false;
}
#endif /* #ifndef CONFIG_RCU_NOCB_CPU_ALL */
/*
* Enqueue the specified string of rcu_head structures onto the specified