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Commit 5dc31b57 authored by Linus Torvalds's avatar Linus Torvalds
Browse files

Merge branch 'core-urgent-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip 

Pull two small RCU fixlets from Ingo Molnar.

* 'core-urgent-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip:
  rcu: Make rcu_nocb_poll an early_param instead of module_param
  rcu: Prevent soft-lockup complaints about no-CBs CPUs
parents d92dd359 d36b7b96

Documentation/kernel-parameters.txt

+1 −1
Original line number Diff line number Diff line
@@ -2438,7 +2438,7 @@ bytes respectively. Such letter suffixes can also be entirely omitted. 
			real-time workloads.  It can also improve energy

			efficiency for asymmetric multiprocessors.



	rcu_nocbs_poll	[KNL,BOOT]

	rcu_nocb_poll	[KNL,BOOT]

			Rather than requiring that offloaded CPUs

			(specified by rcu_nocbs= above) explicitly

			awaken the corresponding "rcuoN" kthreads,

kernel/rcutree_plugin.h

+10 −3
Original line number Diff line number Diff line
@@ -40,8 +40,7 @@ 
#ifdef CONFIG_RCU_NOCB_CPU

static cpumask_var_t rcu_nocb_mask; /* CPUs to have callbacks offloaded. */

static bool have_rcu_nocb_mask;	    /* Was rcu_nocb_mask allocated? */

static bool rcu_nocb_poll;	    /* Offload kthread are to poll. */

module_param(rcu_nocb_poll, bool, 0444);

static bool __read_mostly rcu_nocb_poll;    /* Offload kthread are to poll. */

static char __initdata nocb_buf[NR_CPUS * 5];

#endif /* #ifdef CONFIG_RCU_NOCB_CPU */
@@ -2159,6 +2158,13 @@ static int __init rcu_nocb_setup(char *str) 
}

__setup("rcu_nocbs=", rcu_nocb_setup);



static int __init parse_rcu_nocb_poll(char *arg)

{

	rcu_nocb_poll = 1;

	return 0;

}

early_param("rcu_nocb_poll", parse_rcu_nocb_poll);



/* Is the specified CPU a no-CPUs CPU? */

static bool is_nocb_cpu(int cpu)

{
@@ -2366,10 +2372,11 @@ static int rcu_nocb_kthread(void *arg) 
	for (;;) {

		/* If not polling, wait for next batch of callbacks. */

		if (!rcu_nocb_poll)

			wait_event(rdp->nocb_wq, rdp->nocb_head);

			wait_event_interruptible(rdp->nocb_wq, rdp->nocb_head);

		list = ACCESS_ONCE(rdp->nocb_head);

		if (!list) {

			schedule_timeout_interruptible(1);

			flush_signals(current);

			continue;

		}