From: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
Date: Tue, 16 Sep 2014 17:08:34 +0000 (-0700)
Subject: Merge branches 'doc.2014.09.07a', 'fixes.2014.09.10a', 'nocb-nohz.2014.09.16b' and... 
X-Git-Tag: firefly_0821_release~176^2~3065^2~1^2~16
X-Git-Url: http://demsky.eecs.uci.edu/git/?a=commitdiff_plain;h=e98d06dd6cd791b5138b0fc6c14a9c0b4d1f2e72;p=firefly-linux-kernel-4.4.55.git

Merge branches 'doc.2014.09.07a', 'fixes.2014.09.10a', 'nocb-nohz.2014.09.16b' and 'torture.2014.09.07a' into HEAD

doc.2014.09.07a: Documentation updates.
fixes.2014.09.10a: Miscellaneous fixes.
nocb-nohz.2014.09.16b: No-CBs CPUs and NO_HZ_FULL updates.
torture.2014.09.07a: Torture-test updates.
---

e98d06dd6cd791b5138b0fc6c14a9c0b4d1f2e72
diff --cc kernel/rcu/tree.h
index 6a86eb7bac45,e33562f2a655,a9a226d2e80a,6a86eb7bac45..ffedcb9d42dc
--- a/kernel/rcu/tree.h
+++ b/kernel/rcu/tree.h
@@@@@ -589,10 -594,10 -590,14 -589,10 +595,14 @@@@@ static bool __call_rcu_nocb(struct rcu_
    static bool rcu_nocb_adopt_orphan_cbs(struct rcu_state *rsp,
    				      struct rcu_data *rdp,
    				      unsigned long flags);
- --static bool rcu_nocb_need_deferred_wakeup(struct rcu_data *rdp);
+ ++static int rcu_nocb_need_deferred_wakeup(struct rcu_data *rdp);
    static void do_nocb_deferred_wakeup(struct rcu_data *rdp);
    static void rcu_boot_init_nocb_percpu_data(struct rcu_data *rdp);
-- -static void rcu_spawn_nocb_kthreads(struct rcu_state *rsp);
++ +static void rcu_spawn_all_nocb_kthreads(int cpu);
++ +static void __init rcu_spawn_nocb_kthreads(void);
++ +#ifdef CONFIG_RCU_NOCB_CPU
++ +static void __init rcu_organize_nocb_kthreads(struct rcu_state *rsp);
++ +#endif /* #ifdef CONFIG_RCU_NOCB_CPU */
    static void __maybe_unused rcu_kick_nohz_cpu(int cpu);
    static bool init_nocb_callback_list(struct rcu_data *rdp);
    static void rcu_sysidle_enter(struct rcu_dynticks *rdtp, int irq);
diff --cc kernel/rcu/tree_plugin.h
index a7997e272564,bbb0a0cd091b,c554accfc5f5,a7997e272564..59318ea32bc8
--- a/kernel/rcu/tree_plugin.h
+++ b/kernel/rcu/tree_plugin.h
@@@@@ -2444,13 -2453,16 -2424,78 -2444,13 +2433,81 @@@@@ static int rcu_nocb_need_deferred_wakeu
    /* Do a deferred wakeup of rcu_nocb_kthread(). */
    static void do_nocb_deferred_wakeup(struct rcu_data *rdp)
    {
+ ++	int ndw;
+ ++
    	if (!rcu_nocb_need_deferred_wakeup(rdp))
    		return;
- --	ACCESS_ONCE(rdp->nocb_defer_wakeup) = false;
- --	wake_nocb_leader(rdp, false);
- --	trace_rcu_nocb_wake(rdp->rsp->name, rdp->cpu, TPS("DeferredWakeEmpty"));
+ ++	ndw = ACCESS_ONCE(rdp->nocb_defer_wakeup);
+ ++	ACCESS_ONCE(rdp->nocb_defer_wakeup) = RCU_NOGP_WAKE_NOT;
+ ++	wake_nocb_leader(rdp, ndw == RCU_NOGP_WAKE_FORCE);
+ ++	trace_rcu_nocb_wake(rdp->rsp->name, rdp->cpu, TPS("DeferredWake"));
+  +}
+  +
++ +void __init rcu_init_nohz(void)
++ +{
++ +	int cpu;
++ +	bool need_rcu_nocb_mask = true;
++ +	struct rcu_state *rsp;
++ +
++ +#ifdef CONFIG_RCU_NOCB_CPU_NONE
++ +	need_rcu_nocb_mask = false;
++ +#endif /* #ifndef CONFIG_RCU_NOCB_CPU_NONE */
++ +
++ +#if defined(CONFIG_NO_HZ_FULL)
++ +	if (tick_nohz_full_running && cpumask_weight(tick_nohz_full_mask))
++ +		need_rcu_nocb_mask = true;
++ +#endif /* #if defined(CONFIG_NO_HZ_FULL) */
++ +
++ +	if (!have_rcu_nocb_mask && need_rcu_nocb_mask) {
++ +		if (!zalloc_cpumask_var(&rcu_nocb_mask, GFP_KERNEL)) {
++ +			pr_info("rcu_nocb_mask allocation failed, callback offloading disabled.\n");
++ +			return;
++ +		}
++ +		have_rcu_nocb_mask = true;
++ +	}
++ +	if (!have_rcu_nocb_mask)
++ +		return;
++ +
++ +#ifdef CONFIG_RCU_NOCB_CPU_ZERO
++ +	pr_info("\tOffload RCU callbacks from CPU 0\n");
++ +	cpumask_set_cpu(0, rcu_nocb_mask);
++ +#endif /* #ifdef CONFIG_RCU_NOCB_CPU_ZERO */
++ +#ifdef CONFIG_RCU_NOCB_CPU_ALL
++ +	pr_info("\tOffload RCU callbacks from all CPUs\n");
++ +	cpumask_copy(rcu_nocb_mask, cpu_possible_mask);
++ +#endif /* #ifdef CONFIG_RCU_NOCB_CPU_ALL */
++ +#if defined(CONFIG_NO_HZ_FULL)
++ +	if (tick_nohz_full_running)
++ +		cpumask_or(rcu_nocb_mask, rcu_nocb_mask, tick_nohz_full_mask);
++ +#endif /* #if defined(CONFIG_NO_HZ_FULL) */
++ +
++ +	if (!cpumask_subset(rcu_nocb_mask, cpu_possible_mask)) {
++ +		pr_info("\tNote: kernel parameter 'rcu_nocbs=' contains nonexistent CPUs.\n");
++ +		cpumask_and(rcu_nocb_mask, cpu_possible_mask,
++ +			    rcu_nocb_mask);
++ +	}
++ +	cpulist_scnprintf(nocb_buf, sizeof(nocb_buf), rcu_nocb_mask);
++ +	pr_info("\tOffload RCU callbacks from CPUs: %s.\n", nocb_buf);
++ +	if (rcu_nocb_poll)
++ +		pr_info("\tPoll for callbacks from no-CBs CPUs.\n");
++ +
++ +	for_each_rcu_flavor(rsp) {
++ +		for_each_cpu(cpu, rcu_nocb_mask) {
++ +			struct rcu_data *rdp = per_cpu_ptr(rsp->rda, cpu);
++ +
++ +			/*
++ +			 * If there are early callbacks, they will need
++ +			 * to be moved to the nocb lists.
++ +			 */
++ +			WARN_ON_ONCE(rdp->nxttail[RCU_NEXT_TAIL] !=
++ +				     &rdp->nxtlist &&
++ +				     rdp->nxttail[RCU_NEXT_TAIL] != NULL);
++ +			init_nocb_callback_list(rdp);
++ +		}
++ +		rcu_organize_nocb_kthreads(rsp);
++ +	}
 +  }
 +  
    /* Initialize per-rcu_data variables for no-CBs CPUs. */
    static void __init rcu_boot_init_nocb_percpu_data(struct rcu_data *rdp)
    {