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Commit 26845c28 authored by Paul E. McKenney's avatar Paul E. McKenney
Browse files

rcu: print boot-time console messages if RCU configs out of ordinary 



Print boot-time messages if tracing is enabled, if fanout is set
to non-default values, if exact fanout is specified, if accelerated
dyntick-idle grace periods have been enabled, if RCU-lockdep is enabled,
if rcutorture has been boot-time enabled, if the CPU stall detector has
been disabled, or if four-level hierarchy has been enabled.

This is all for TREE_RCU and TREE_PREEMPT_RCU.  TINY_RCU will be handled
separately, if at all.

Suggested-by: default avatarJosh Triplett <josh@joshtriplett.org>
Signed-off-by: default avatarPaul E. McKenney <paulmck@linux.vnet.ibm.com>
parent c68de209

kernel/rcutree.c

+0 −6
Original line number Diff line number Diff line
@@ -1938,12 +1938,6 @@ void __init rcu_init(void) 
	int cpu;



	rcu_bootup_announce();

#ifdef CONFIG_RCU_CPU_STALL_DETECTOR

	printk(KERN_INFO "RCU-based detection of stalled CPUs is enabled.\n");

#endif /* #ifdef CONFIG_RCU_CPU_STALL_DETECTOR */

#if NUM_RCU_LVL_4 != 0

	printk(KERN_INFO "Experimental four-level hierarchy is enabled.\n");

#endif /* #if NUM_RCU_LVL_4 != 0 */

	RCU_INIT_FLAVOR(&rcu_sched_state, rcu_sched_data);

	RCU_INIT_FLAVOR(&rcu_bh_state, rcu_bh_data);

	__rcu_init_preempt();

kernel/rcutree_plugin.h

+42 −2
Original line number Diff line number Diff line
@@ -26,6 +26,45 @@ 


#include <linux/delay.h>



/*

 * Check the RCU kernel configuration parameters and print informative

 * messages about anything out of the ordinary.  If you like #ifdef, you

 * will love this function.

 */

static void __init rcu_bootup_announce_oddness(void)

{

#ifdef CONFIG_RCU_TRACE

	printk(KERN_INFO "\tRCU debugfs-based tracing is enabled.\n");

#endif

#if (defined(CONFIG_64BIT) && CONFIG_RCU_FANOUT != 64) || (!defined(CONFIG_64BIT) && CONFIG_RCU_FANOUT != 32)

	printk(KERN_INFO "\tCONFIG_RCU_FANOUT set to non-default value of %d\n",

	       CONFIG_RCU_FANOUT);

#endif

#ifdef CONFIG_RCU_FANOUT_EXACT

	printk(KERN_INFO "\tHierarchical RCU autobalancing is disabled.\n");

#endif

#ifdef CONFIG_RCU_FAST_NO_HZ

	printk(KERN_INFO

	       "\tRCU dyntick-idle grace-period acceleration is enabled.\n");

#endif

#ifdef CONFIG_PROVE_RCU

	printk(KERN_INFO "\tRCU lockdep checking is enabled.\n");

#endif

#ifdef CONFIG_RCU_TORTURE_TEST_RUNNABLE

	printk(KERN_INFO "\tRCU torture testing starts during boot.\n");

#endif

#ifndef CONFIG_RCU_CPU_STALL_DETECTOR

	printk(KERN_INFO

	       "\tRCU-based detection of stalled CPUs is disabled.\n");

#endif

#ifndef CONFIG_RCU_CPU_STALL_VERBOSE

	printk(KERN_INFO "\tVerbose stalled-CPUs detection is disabled.\n");

#endif

#if NUM_RCU_LVL_4 != 0

	printk(KERN_INFO "\tExperimental four-level hierarchy is enabled.\n");

#endif

}



#ifdef CONFIG_TREE_PREEMPT_RCU



struct rcu_state rcu_preempt_state = RCU_STATE_INITIALIZER(rcu_preempt_state);
@@ -38,8 +77,8 @@ static int rcu_preempted_readers_exp(struct rcu_node *rnp); 
 */

static void __init rcu_bootup_announce(void)

{

	printk(KERN_INFO

	       "Experimental preemptable hierarchical RCU implementation.\n");

	printk(KERN_INFO "Preemptable hierarchical RCU implementation.\n");

	rcu_bootup_announce_oddness();

}



/*
@@ -757,6 +796,7 @@ void exit_rcu(void) 
static void __init rcu_bootup_announce(void)

{

	printk(KERN_INFO "Hierarchical RCU implementation.\n");

	rcu_bootup_announce_oddness();

}



/*