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Commit c68de209 authored by Paul E. McKenney's avatar Paul E. McKenney
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rcu: disable CPU stall warnings upon panic 



The current RCU CPU stall warnings remain enabled even after a panic
occurs, which some people have found to be a bit counterproductive.
This patch therefore uses a notifier to disable stall warnings once a
panic occurs.

Signed-off-by: default avatarPaul E. McKenney <paulmck@linux.vnet.ibm.com>
parent 55ec936f

kernel/rcutree.c

+24 −0
Original line number Diff line number Diff line
@@ -449,6 +449,8 @@ static int rcu_implicit_dynticks_qs(struct rcu_data *rdp) 


#ifdef CONFIG_RCU_CPU_STALL_DETECTOR



int rcu_cpu_stall_panicking __read_mostly;



static void record_gp_stall_check_time(struct rcu_state *rsp)

{

	rsp->gp_start = jiffies;
@@ -526,6 +528,8 @@ static void check_cpu_stall(struct rcu_state *rsp, struct rcu_data *rdp) 
	long delta;

	struct rcu_node *rnp;



	if (rcu_cpu_stall_panicking)

		return;

	delta = jiffies - rsp->jiffies_stall;

	rnp = rdp->mynode;

	if ((rnp->qsmask & rdp->grpmask) && delta >= 0) {
@@ -540,6 +544,21 @@ static void check_cpu_stall(struct rcu_state *rsp, struct rcu_data *rdp) 
	}

}



static int rcu_panic(struct notifier_block *this, unsigned long ev, void *ptr)

{

	rcu_cpu_stall_panicking = 1;

	return NOTIFY_DONE;

}



static struct notifier_block rcu_panic_block = {

	.notifier_call = rcu_panic,

};



static void __init check_cpu_stall_init(void)

{

	atomic_notifier_chain_register(&panic_notifier_list, &rcu_panic_block);

}



#else /* #ifdef CONFIG_RCU_CPU_STALL_DETECTOR */



static void record_gp_stall_check_time(struct rcu_state *rsp)
@@ -550,6 +569,10 @@ static void check_cpu_stall(struct rcu_state *rsp, struct rcu_data *rdp) 
{

}



static void __init check_cpu_stall_init(void)

{

}



#endif /* #else #ifdef CONFIG_RCU_CPU_STALL_DETECTOR */



/*
@@ -1934,6 +1957,7 @@ void __init rcu_init(void) 
	cpu_notifier(rcu_cpu_notify, 0);

	for_each_online_cpu(cpu)

		rcu_cpu_notify(NULL, CPU_UP_PREPARE, (void *)(long)cpu);

	check_cpu_stall_init();

}



#include "rcutree_plugin.h"