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rcu: Replace the rcu_barrier enum with pointer to call_rcu*() function

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The rcu_barrier enum causes several problems:

  (1) you have to define the enum somewhere, and there is no
      convenient place,

  (2) the difference between TREE_RCU and TREE_PREEMPT_RCU causes
      problems when you need to map from rcu_barrier enum to struct
      rcu_state,

  (3) the switch statement are large, and

  (4) TINY_RCU really needs a different rcu_barrier() than do the
      treercu implementations.

So replace it with a functionally equivalent but cleaner function
pointer abstraction.

Signed-off-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
Acked-by: Mathieu Desnoyers <mathieu.desnoyers@polymtl.ca>
Cc: laijs@cn.fujitsu.com
Cc: dipankar@in.ibm.com
Cc: akpm@linux-foundation.org
Cc: josh@joshtriplett.org
Cc: dvhltc@us.ibm.com
Cc: niv@us.ibm.com
Cc: peterz@infradead.org
Cc: rostedt@goodmis.org
Cc: Valdis.Kletnieks@vt.edu
Cc: dhowells@redhat.com
LKML-Reference: <12541998232366-git-send-email->
Signed-off-by: Ingo Molnar <mingo@elte.hu>
This commit is contained in:
Paul E. McKenney 2009-09-28 21:50:21 -07:00 committed by Ingo Molnar
parent a0b6c9a78c
commit 135c8aea55
1 changed files with 10 additions and 22 deletions
Show stats Download patch file Download diff file Expand all files Collapse all files

32
kernel/rcupdate.c
View file

@ -53,12 +53,6 @@ struct lockdep_map rcu_lock_map =
EXPORT_SYMBOL_GPL(rcu_lock_map);
#endif
enum rcu_barrier {
RCU_BARRIER_STD,
RCU_BARRIER_BH,
RCU_BARRIER_SCHED,
};
static DEFINE_PER_CPU(struct rcu_head, rcu_barrier_head) = {NULL};
static atomic_t rcu_barrier_cpu_count;
static DEFINE_MUTEX(rcu_barrier_mutex);
@ -184,19 +178,12 @@ static void rcu_barrier_func(void *type)
{
int cpu = smp_processor_id();
struct rcu_head *head = &per_cpu(rcu_barrier_head, cpu);
void (*call_rcu_func)(struct rcu_head *head,
void (*func)(struct rcu_head *head));
atomic_inc(&rcu_barrier_cpu_count);
switch ((enum rcu_barrier)type) {
case RCU_BARRIER_STD:
call_rcu(head, rcu_barrier_callback);
break;
case RCU_BARRIER_BH:
call_rcu_bh(head, rcu_barrier_callback);
break;
case RCU_BARRIER_SCHED:
call_rcu_sched(head, rcu_barrier_callback);
break;
}
call_rcu_func = type;
call_rcu_func(head, rcu_barrier_callback);
}
static inline void wait_migrated_callbacks(void)
@ -209,7 +196,8 @@ static inline void wait_migrated_callbacks(void)
* Orchestrate the specified type of RCU barrier, waiting for all
* RCU callbacks of the specified type to complete.
*/
static void _rcu_barrier(enum rcu_barrier type)
static void _rcu_barrier(void (*call_rcu_func)(struct rcu_head *head,
void (*func)(struct rcu_head *head)))
{
BUG_ON(in_interrupt());
/* Take cpucontrol mutex to protect against CPU hotplug */
@ -225,7 +213,7 @@ static void _rcu_barrier(enum rcu_barrier type)
* early.
*/
atomic_set(&rcu_barrier_cpu_count, 1);
on_each_cpu(rcu_barrier_func, (void *)type, 1);
on_each_cpu(rcu_barrier_func, (void *)call_rcu_func, 1);
if (atomic_dec_and_test(&rcu_barrier_cpu_count))
complete(&rcu_barrier_completion);
wait_for_completion(&rcu_barrier_completion);
@ -238,7 +226,7 @@ static void _rcu_barrier(enum rcu_barrier type)
*/
void rcu_barrier(void)
{
_rcu_barrier(RCU_BARRIER_STD);
_rcu_barrier(call_rcu);
}
EXPORT_SYMBOL_GPL(rcu_barrier);
@ -247,7 +235,7 @@ EXPORT_SYMBOL_GPL(rcu_barrier);
*/
void rcu_barrier_bh(void)
{
_rcu_barrier(RCU_BARRIER_BH);
_rcu_barrier(call_rcu_bh);
}
EXPORT_SYMBOL_GPL(rcu_barrier_bh);
@ -256,7 +244,7 @@ EXPORT_SYMBOL_GPL(rcu_barrier_bh);
*/
void rcu_barrier_sched(void)
{
_rcu_barrier(RCU_BARRIER_SCHED);
_rcu_barrier(call_rcu_sched);
}
EXPORT_SYMBOL_GPL(rcu_barrier_sched);