rcu: Clean up flavor-related definitions and comments in update.c

Signed-off-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
This commit is contained in:
Paul E. McKenney 2018-07-08 10:58:37 -07:00
parent 0ae86a2726
commit 06462efc80

View File

@ -332,7 +332,7 @@ void __wait_rcu_gp(bool checktiny, int n, call_rcu_func_t *crcu_array,
int i;
int j;
/* Initialize and register callbacks for each flavor specified. */
/* Initialize and register callbacks for each crcu_array element. */
for (i = 0; i < n; i++) {
if (checktiny &&
(crcu_array[i] == call_rcu ||
@ -697,19 +697,19 @@ static int __noreturn rcu_tasks_kthread(void *arg)
/*
* Wait for all pre-existing t->on_rq and t->nvcsw
* transitions to complete. Invoking synchronize_sched()
* transitions to complete. Invoking synchronize_rcu()
* suffices because all these transitions occur with
* interrupts disabled. Without this synchronize_sched(),
* interrupts disabled. Without this synchronize_rcu(),
* a read-side critical section that started before the
* grace period might be incorrectly seen as having started
* after the grace period.
*
* This synchronize_sched() also dispenses with the
* This synchronize_rcu() also dispenses with the
* need for a memory barrier on the first store to
* ->rcu_tasks_holdout, as it forces the store to happen
* after the beginning of the grace period.
*/
synchronize_sched();
synchronize_rcu();
/*
* There were callbacks, so we need to wait for an
@ -736,7 +736,7 @@ static int __noreturn rcu_tasks_kthread(void *arg)
* This does only part of the job, ensuring that all
* tasks that were previously exiting reach the point
* where they have disabled preemption, allowing the
* later synchronize_sched() to finish the job.
* later synchronize_rcu() to finish the job.
*/
synchronize_srcu(&tasks_rcu_exit_srcu);
@ -786,20 +786,20 @@ static int __noreturn rcu_tasks_kthread(void *arg)
* cause their RCU-tasks read-side critical sections to
* extend past the end of the grace period. However,
* because these ->nvcsw updates are carried out with
* interrupts disabled, we can use synchronize_sched()
* interrupts disabled, we can use synchronize_rcu()
* to force the needed ordering on all such CPUs.
*
* This synchronize_sched() also confines all
* This synchronize_rcu() also confines all
* ->rcu_tasks_holdout accesses to be within the grace
* period, avoiding the need for memory barriers for
* ->rcu_tasks_holdout accesses.
*
* In addition, this synchronize_sched() waits for exiting
* In addition, this synchronize_rcu() waits for exiting
* tasks to complete their final preempt_disable() region
* of execution, cleaning up after the synchronize_srcu()
* above.
*/
synchronize_sched();
synchronize_rcu();
/* Invoke the callbacks. */
while (list) {