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authorPaul E. McKenney <paul.mckenney@linaro.org>2011-02-07 21:47:15 +0100
committerPaul E. McKenney <paulmck@linux.vnet.ibm.com>2011-05-06 08:16:55 +0200
commit27f4d28057adf98750cf863c40baefb12f5b6d21 (patch)
treea66584d2cb68cebda327313f78b8f4eb602ed4ef /kernel/rcutree.h
parentrcu: move TREE_RCU from softirq to kthread (diff)
downloadlinux-27f4d28057adf98750cf863c40baefb12f5b6d21.tar.xz
linux-27f4d28057adf98750cf863c40baefb12f5b6d21.zip
rcu: priority boosting for TREE_PREEMPT_RCU
Add priority boosting for TREE_PREEMPT_RCU, similar to that for TINY_PREEMPT_RCU. This is enabled by the default-off RCU_BOOST kernel parameter. The priority to which to boost preempted RCU readers is controlled by the RCU_BOOST_PRIO kernel parameter (defaulting to real-time priority 1) and the time to wait before boosting the readers who are blocking a given grace period is controlled by the RCU_BOOST_DELAY kernel parameter (defaulting to 500 milliseconds). Signed-off-by: Paul E. McKenney <paul.mckenney@linaro.org> Signed-off-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com> Reviewed-by: Josh Triplett <josh@joshtriplett.org>
Diffstat (limited to 'kernel/rcutree.h')
-rw-r--r--kernel/rcutree.h31
1 files changed, 30 insertions, 1 deletions
diff --git a/kernel/rcutree.h b/kernel/rcutree.h
index c0213802d164..8db0cdc7f450 100644
--- a/kernel/rcutree.h
+++ b/kernel/rcutree.h
@@ -135,6 +135,24 @@ struct rcu_node {
/* if there is no such task. If there */
/* is no current expedited grace period, */
/* then there can cannot be any such task. */
+#ifdef CONFIG_RCU_BOOST
+ struct list_head *boost_tasks;
+ /* Pointer to first task that needs to be */
+ /* priority boosted, or NULL if no priority */
+ /* boosting is needed for this rcu_node */
+ /* structure. If there are no tasks */
+ /* queued on this rcu_node structure that */
+ /* are blocking the current grace period, */
+ /* there can be no such task. */
+ unsigned long boost_time;
+ /* When to start boosting (jiffies). */
+ struct task_struct *boost_kthread_task;
+ /* kthread that takes care of priority */
+ /* boosting for this rcu_node structure. */
+ wait_queue_head_t boost_wq;
+ /* Wait queue on which to park the boost */
+ /* kthread. */
+#endif /* #ifdef CONFIG_RCU_BOOST */
struct task_struct *node_kthread_task;
/* kthread that takes care of this rcu_node */
/* structure, for example, awakening the */
@@ -365,7 +383,7 @@ DECLARE_PER_CPU(struct rcu_data, rcu_preempt_data);
static void rcu_bootup_announce(void);
long rcu_batches_completed(void);
static void rcu_preempt_note_context_switch(int cpu);
-static int rcu_preempted_readers(struct rcu_node *rnp);
+static int rcu_preempt_blocked_readers_cgp(struct rcu_node *rnp);
#ifdef CONFIG_HOTPLUG_CPU
static void rcu_report_unblock_qs_rnp(struct rcu_node *rnp,
unsigned long flags);
@@ -392,5 +410,16 @@ static void __cpuinit rcu_preempt_init_percpu_data(int cpu);
static void rcu_preempt_send_cbs_to_online(void);
static void __init __rcu_init_preempt(void);
static void rcu_needs_cpu_flush(void);
+static void __init rcu_init_boost_waitqueue(struct rcu_node *rnp);
+static void rcu_initiate_boost(struct rcu_node *rnp);
+static void rcu_boost_kthread_setaffinity(struct rcu_node *rnp,
+ cpumask_var_t cm);
+static void rcu_preempt_boost_start_gp(struct rcu_node *rnp);
+static int __cpuinit rcu_spawn_one_boost_kthread(struct rcu_state *rsp,
+ struct rcu_node *rnp,
+ int rnp_index);
+#ifdef CONFIG_HOTPLUG_CPU
+static void rcu_stop_boost_kthread(struct rcu_node *rnp);
+#endif /* #ifdef CONFIG_HOTPLUG_CPU */
#endif /* #ifndef RCU_TREE_NONCORE */