rcu: Renamings to increase RCU clarity
Make RCU-sched, RCU-bh, and RCU-preempt be underlying
implementations, with "RCU" defined in terms of one of the
three. Update the outdated rcu_qsctr_inc() names, as these
functions no longer increment anything.
Signed-off-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
Cc: laijs@cn.fujitsu.com
Cc: dipankar@in.ibm.com
Cc: akpm@linux-foundation.org
Cc: mathieu.desnoyers@polymtl.ca
Cc: josht@linux.vnet.ibm.com
Cc: dvhltc@us.ibm.com
Cc: niv@us.ibm.com
Cc: peterz@infradead.org
Cc: rostedt@goodmis.org
LKML-Reference: <12509746132696-git-send-email->
Signed-off-by: Ingo Molnar <mingo@elte.hu>
diff --git a/kernel/rcutree.c b/kernel/rcutree.c
index a162f85..4d71d4e 100644
--- a/kernel/rcutree.c
+++ b/kernel/rcutree.c
@@ -74,26 +74,25 @@
.n_force_qs_ngp = 0, \
}
-struct rcu_state rcu_state = RCU_STATE_INITIALIZER(rcu_state);
-DEFINE_PER_CPU(struct rcu_data, rcu_data);
+struct rcu_state rcu_sched_state = RCU_STATE_INITIALIZER(rcu_sched_state);
+DEFINE_PER_CPU(struct rcu_data, rcu_sched_data);
struct rcu_state rcu_bh_state = RCU_STATE_INITIALIZER(rcu_bh_state);
DEFINE_PER_CPU(struct rcu_data, rcu_bh_data);
/*
- * Increment the quiescent state counter.
- * The counter is a bit degenerated: We do not need to know
+ * Note a quiescent state. Because we do not need to know
* how many quiescent states passed, just if there was at least
- * one since the start of the grace period. Thus just a flag.
+ * one since the start of the grace period, this just sets a flag.
*/
-void rcu_qsctr_inc(int cpu)
+void rcu_sched_qs(int cpu)
{
- struct rcu_data *rdp = &per_cpu(rcu_data, cpu);
+ struct rcu_data *rdp = &per_cpu(rcu_sched_data, cpu);
rdp->passed_quiesc = 1;
rdp->passed_quiesc_completed = rdp->completed;
}
-void rcu_bh_qsctr_inc(int cpu)
+void rcu_bh_qs(int cpu)
{
struct rcu_data *rdp = &per_cpu(rcu_bh_data, cpu);
rdp->passed_quiesc = 1;
@@ -114,11 +113,21 @@
static void force_quiescent_state(struct rcu_state *rsp, int relaxed);
/*
+ * Return the number of RCU-sched batches processed thus far for debug & stats.
+ */
+long rcu_batches_completed_sched(void)
+{
+ return rcu_sched_state.completed;
+}
+EXPORT_SYMBOL_GPL(rcu_batches_completed_sched);
+
+/*
* Return the number of RCU batches processed thus far for debug & stats.
+ * @@@ placeholder, maps to rcu_batches_completed_sched().
*/
long rcu_batches_completed(void)
{
- return rcu_state.completed;
+ return rcu_batches_completed_sched();
}
EXPORT_SYMBOL_GPL(rcu_batches_completed);
@@ -310,7 +319,7 @@
WARN_ON_RATELIMIT(rdtp->dynticks & 0x1, &rcu_rs);
/* If the interrupt queued a callback, get out of dyntick mode. */
- if (__get_cpu_var(rcu_data).nxtlist ||
+ if (__get_cpu_var(rcu_sched_data).nxtlist ||
__get_cpu_var(rcu_bh_data).nxtlist)
set_need_resched();
}
@@ -847,7 +856,7 @@
/*
* Move callbacks from the outgoing CPU to the running CPU.
* Note that the outgoing CPU is now quiscent, so it is now
- * (uncharacteristically) safe to access it rcu_data structure.
+ * (uncharacteristically) safe to access its rcu_data structure.
* Note also that we must carefully retain the order of the
* outgoing CPU's callbacks in order for rcu_barrier() to work
* correctly. Finally, note that we start all the callbacks
@@ -878,7 +887,7 @@
*/
static void rcu_offline_cpu(int cpu)
{
- __rcu_offline_cpu(cpu, &rcu_state);
+ __rcu_offline_cpu(cpu, &rcu_sched_state);
__rcu_offline_cpu(cpu, &rcu_bh_state);
}
@@ -973,17 +982,16 @@
* Get here if this CPU took its interrupt from user
* mode or from the idle loop, and if this is not a
* nested interrupt. In this case, the CPU is in
- * a quiescent state, so count it.
+ * a quiescent state, so note it.
*
* No memory barrier is required here because both
- * rcu_qsctr_inc() and rcu_bh_qsctr_inc() reference
- * only CPU-local variables that other CPUs neither
- * access nor modify, at least not while the corresponding
- * CPU is online.
+ * rcu_sched_qs() and rcu_bh_qs() reference only CPU-local
+ * variables that other CPUs neither access nor modify,
+ * at least not while the corresponding CPU is online.
*/
- rcu_qsctr_inc(cpu);
- rcu_bh_qsctr_inc(cpu);
+ rcu_sched_qs(cpu);
+ rcu_bh_qs(cpu);
} else if (!in_softirq()) {
@@ -991,10 +999,10 @@
* Get here if this CPU did not take its interrupt from
* softirq, in other words, if it is not interrupting
* a rcu_bh read-side critical section. This is an _bh
- * critical section, so count it.
+ * critical section, so note it.
*/
- rcu_bh_qsctr_inc(cpu);
+ rcu_bh_qs(cpu);
}
raise_softirq(RCU_SOFTIRQ);
}
@@ -1174,7 +1182,8 @@
*/
smp_mb(); /* See above block comment. */
- __rcu_process_callbacks(&rcu_state, &__get_cpu_var(rcu_data));
+ __rcu_process_callbacks(&rcu_sched_state,
+ &__get_cpu_var(rcu_sched_data));
__rcu_process_callbacks(&rcu_bh_state, &__get_cpu_var(rcu_bh_data));
/*
@@ -1231,14 +1240,25 @@
}
/*
- * Queue an RCU callback for invocation after a grace period.
+ * Queue an RCU-sched callback for invocation after a grace period.
+ */
+void call_rcu_sched(struct rcu_head *head, void (*func)(struct rcu_head *rcu))
+{
+ __call_rcu(head, func, &rcu_sched_state);
+}
+EXPORT_SYMBOL_GPL(call_rcu_sched);
+
+/*
+ * @@@ Queue an RCU callback for invocation after a grace period.
+ * @@@ Placeholder pending rcutree_plugin.h.
*/
void call_rcu(struct rcu_head *head, void (*func)(struct rcu_head *rcu))
{
- __call_rcu(head, func, &rcu_state);
+ call_rcu_sched(head, func);
}
EXPORT_SYMBOL_GPL(call_rcu);
+
/*
* Queue an RCU for invocation after a quicker grace period.
*/
@@ -1311,7 +1331,7 @@
*/
int rcu_pending(int cpu)
{
- return __rcu_pending(&rcu_state, &per_cpu(rcu_data, cpu)) ||
+ return __rcu_pending(&rcu_sched_state, &per_cpu(rcu_sched_data, cpu)) ||
__rcu_pending(&rcu_bh_state, &per_cpu(rcu_bh_data, cpu));
}
@@ -1324,7 +1344,7 @@
int rcu_needs_cpu(int cpu)
{
/* RCU callbacks either ready or pending? */
- return per_cpu(rcu_data, cpu).nxtlist ||
+ return per_cpu(rcu_sched_data, cpu).nxtlist ||
per_cpu(rcu_bh_data, cpu).nxtlist;
}
@@ -1418,7 +1438,7 @@
static void __cpuinit rcu_online_cpu(int cpu)
{
- rcu_init_percpu_data(cpu, &rcu_state);
+ rcu_init_percpu_data(cpu, &rcu_sched_state);
rcu_init_percpu_data(cpu, &rcu_bh_state);
}
@@ -1545,10 +1565,10 @@
#ifdef CONFIG_RCU_CPU_STALL_DETECTOR
printk(KERN_INFO "RCU-based detection of stalled CPUs is enabled.\n");
#endif /* #ifdef CONFIG_RCU_CPU_STALL_DETECTOR */
- rcu_init_one(&rcu_state);
- RCU_DATA_PTR_INIT(&rcu_state, rcu_data);
+ rcu_init_one(&rcu_sched_state);
+ RCU_DATA_PTR_INIT(&rcu_sched_state, rcu_sched_data);
for_each_possible_cpu(i)
- rcu_boot_init_percpu_data(i, &rcu_state);
+ rcu_boot_init_percpu_data(i, &rcu_sched_state);
rcu_init_one(&rcu_bh_state);
RCU_DATA_PTR_INIT(&rcu_bh_state, rcu_bh_data);
for_each_possible_cpu(i)
