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Commit 2f33b512 authored by Paul E. McKenney's avatar Paul E. McKenney
Browse files

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: default avatarPaul E. McKenney <paulmck@linux.vnet.ibm.com>
Reviewed-by: default avatarJosh Triplett <josh@joshtriplett.org>
parent 6d0abeca

include/linux/rcupdate.h

+4 −2
Original line number Diff line number Diff line
@@ -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. */

kernel/rcu/tree_plugin.h

+2 −0
Original line number Diff line number Diff line
@@ -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