diff options
Diffstat (limited to 'kernel/rcupdate.c')
-rw-r--r-- | kernel/rcupdate.c | 145 |
1 files changed, 26 insertions, 119 deletions
diff --git a/kernel/rcupdate.c b/kernel/rcupdate.c index 400183346ad2..f1125c1a6321 100644 --- a/kernel/rcupdate.c +++ b/kernel/rcupdate.c | |||
@@ -51,9 +51,35 @@ static struct lock_class_key rcu_lock_key; | |||
51 | struct lockdep_map rcu_lock_map = | 51 | struct lockdep_map rcu_lock_map = |
52 | STATIC_LOCKDEP_MAP_INIT("rcu_read_lock", &rcu_lock_key); | 52 | STATIC_LOCKDEP_MAP_INIT("rcu_read_lock", &rcu_lock_key); |
53 | EXPORT_SYMBOL_GPL(rcu_lock_map); | 53 | EXPORT_SYMBOL_GPL(rcu_lock_map); |
54 | |||
55 | static struct lock_class_key rcu_bh_lock_key; | ||
56 | struct lockdep_map rcu_bh_lock_map = | ||
57 | STATIC_LOCKDEP_MAP_INIT("rcu_read_lock_bh", &rcu_bh_lock_key); | ||
58 | EXPORT_SYMBOL_GPL(rcu_bh_lock_map); | ||
59 | |||
60 | static struct lock_class_key rcu_sched_lock_key; | ||
61 | struct lockdep_map rcu_sched_lock_map = | ||
62 | STATIC_LOCKDEP_MAP_INIT("rcu_read_lock_sched", &rcu_sched_lock_key); | ||
63 | EXPORT_SYMBOL_GPL(rcu_sched_lock_map); | ||
54 | #endif | 64 | #endif |
55 | 65 | ||
56 | int rcu_scheduler_active __read_mostly; | 66 | int rcu_scheduler_active __read_mostly; |
67 | EXPORT_SYMBOL_GPL(rcu_scheduler_active); | ||
68 | |||
69 | /* | ||
70 | * This function is invoked towards the end of the scheduler's initialization | ||
71 | * process. Before this is called, the idle task might contain | ||
72 | * RCU read-side critical sections (during which time, this idle | ||
73 | * task is booting the system). After this function is called, the | ||
74 | * idle tasks are prohibited from containing RCU read-side critical | ||
75 | * sections. | ||
76 | */ | ||
77 | void rcu_scheduler_starting(void) | ||
78 | { | ||
79 | WARN_ON(num_online_cpus() != 1); | ||
80 | WARN_ON(nr_context_switches() > 0); | ||
81 | rcu_scheduler_active = 1; | ||
82 | } | ||
57 | 83 | ||
58 | /* | 84 | /* |
59 | * Awaken the corresponding synchronize_rcu() instance now that a | 85 | * Awaken the corresponding synchronize_rcu() instance now that a |
@@ -66,122 +92,3 @@ void wakeme_after_rcu(struct rcu_head *head) | |||
66 | rcu = container_of(head, struct rcu_synchronize, head); | 92 | rcu = container_of(head, struct rcu_synchronize, head); |
67 | complete(&rcu->completion); | 93 | complete(&rcu->completion); |
68 | } | 94 | } |
69 | |||
70 | #ifdef CONFIG_TREE_PREEMPT_RCU | ||
71 | |||
72 | /** | ||
73 | * synchronize_rcu - wait until a grace period has elapsed. | ||
74 | * | ||
75 | * Control will return to the caller some time after a full grace | ||
76 | * period has elapsed, in other words after all currently executing RCU | ||
77 | * read-side critical sections have completed. RCU read-side critical | ||
78 | * sections are delimited by rcu_read_lock() and rcu_read_unlock(), | ||
79 | * and may be nested. | ||
80 | */ | ||
81 | void synchronize_rcu(void) | ||
82 | { | ||
83 | struct rcu_synchronize rcu; | ||
84 | |||
85 | if (!rcu_scheduler_active) | ||
86 | return; | ||
87 | |||
88 | init_completion(&rcu.completion); | ||
89 | /* Will wake me after RCU finished. */ | ||
90 | call_rcu(&rcu.head, wakeme_after_rcu); | ||
91 | /* Wait for it. */ | ||
92 | wait_for_completion(&rcu.completion); | ||
93 | } | ||
94 | EXPORT_SYMBOL_GPL(synchronize_rcu); | ||
95 | |||
96 | #endif /* #ifdef CONFIG_TREE_PREEMPT_RCU */ | ||
97 | |||
98 | /** | ||
99 | * synchronize_sched - wait until an rcu-sched grace period has elapsed. | ||
100 | * | ||
101 | * Control will return to the caller some time after a full rcu-sched | ||
102 | * grace period has elapsed, in other words after all currently executing | ||
103 | * rcu-sched read-side critical sections have completed. These read-side | ||
104 | * critical sections are delimited by rcu_read_lock_sched() and | ||
105 | * rcu_read_unlock_sched(), and may be nested. Note that preempt_disable(), | ||
106 | * local_irq_disable(), and so on may be used in place of | ||
107 | * rcu_read_lock_sched(). | ||
108 | * | ||
109 | * This means that all preempt_disable code sequences, including NMI and | ||
110 | * hardware-interrupt handlers, in progress on entry will have completed | ||
111 | * before this primitive returns. However, this does not guarantee that | ||
112 | * softirq handlers will have completed, since in some kernels, these | ||
113 | * handlers can run in process context, and can block. | ||
114 | * | ||
115 | * This primitive provides the guarantees made by the (now removed) | ||
116 | * synchronize_kernel() API. In contrast, synchronize_rcu() only | ||
117 | * guarantees that rcu_read_lock() sections will have completed. | ||
118 | * In "classic RCU", these two guarantees happen to be one and | ||
119 | * the same, but can differ in realtime RCU implementations. | ||
120 | */ | ||
121 | void synchronize_sched(void) | ||
122 | { | ||
123 | struct rcu_synchronize rcu; | ||
124 | |||
125 | if (rcu_blocking_is_gp()) | ||
126 | return; | ||
127 | |||
128 | init_completion(&rcu.completion); | ||
129 | /* Will wake me after RCU finished. */ | ||
130 | call_rcu_sched(&rcu.head, wakeme_after_rcu); | ||
131 | /* Wait for it. */ | ||
132 | wait_for_completion(&rcu.completion); | ||
133 | } | ||
134 | EXPORT_SYMBOL_GPL(synchronize_sched); | ||
135 | |||
136 | /** | ||
137 | * synchronize_rcu_bh - wait until an rcu_bh grace period has elapsed. | ||
138 | * | ||
139 | * Control will return to the caller some time after a full rcu_bh grace | ||
140 | * period has elapsed, in other words after all currently executing rcu_bh | ||
141 | * read-side critical sections have completed. RCU read-side critical | ||
142 | * sections are delimited by rcu_read_lock_bh() and rcu_read_unlock_bh(), | ||
143 | * and may be nested. | ||
144 | */ | ||
145 | void synchronize_rcu_bh(void) | ||
146 | { | ||
147 | struct rcu_synchronize rcu; | ||
148 | |||
149 | if (rcu_blocking_is_gp()) | ||
150 | return; | ||
151 | |||
152 | init_completion(&rcu.completion); | ||
153 | /* Will wake me after RCU finished. */ | ||
154 | call_rcu_bh(&rcu.head, wakeme_after_rcu); | ||
155 | /* Wait for it. */ | ||
156 | wait_for_completion(&rcu.completion); | ||
157 | } | ||
158 | EXPORT_SYMBOL_GPL(synchronize_rcu_bh); | ||
159 | |||
160 | static int __cpuinit rcu_barrier_cpu_hotplug(struct notifier_block *self, | ||
161 | unsigned long action, void *hcpu) | ||
162 | { | ||
163 | return rcu_cpu_notify(self, action, hcpu); | ||
164 | } | ||
165 | |||
166 | void __init rcu_init(void) | ||
167 | { | ||
168 | int i; | ||
169 | |||
170 | __rcu_init(); | ||
171 | cpu_notifier(rcu_barrier_cpu_hotplug, 0); | ||
172 | |||
173 | /* | ||
174 | * We don't need protection against CPU-hotplug here because | ||
175 | * this is called early in boot, before either interrupts | ||
176 | * or the scheduler are operational. | ||
177 | */ | ||
178 | for_each_online_cpu(i) | ||
179 | rcu_barrier_cpu_hotplug(NULL, CPU_UP_PREPARE, (void *)(long)i); | ||
180 | } | ||
181 | |||
182 | void rcu_scheduler_starting(void) | ||
183 | { | ||
184 | WARN_ON(num_online_cpus() != 1); | ||
185 | WARN_ON(nr_context_switches() > 0); | ||
186 | rcu_scheduler_active = 1; | ||
187 | } | ||