rcu-tasks: Add a ->percpu_enqueue_lim to the rcu_tasks structure

This commit adds a ->percpu_enqueue_lim field to the rcu_tasks structure.
This field contains two to the power of the ->percpu_enqueue_shift
field, easing construction of iterators over the per-CPU queues that
might contain RCU Tasks callbacks.  Such iterators will be introduced
in later commits.

Reported-by: Martin Lau <kafai@fb.com>
Cc: Neeraj Upadhyay <neeraj.iitr10@gmail.com>
Signed-off-by: Paul E. McKenney <paulmck@kernel.org>
This commit is contained in:
Paul E. McKenney 2021-11-09 11:11:32 -08:00
parent 65b629e704
commit 8dd593fddd

View File

@ -52,6 +52,7 @@ struct rcu_tasks_percpu {
* @call_func: This flavor's call_rcu()-equivalent function.
* @rtpcpu: This flavor's rcu_tasks_percpu structure.
* @percpu_enqueue_shift: Shift down CPU ID this much when enqueuing callbacks.
* @percpu_enqueue_lim: Number of per-CPU callback queues in use.
* @name: This flavor's textual name.
* @kname: This flavor's kthread name.
*/
@ -76,6 +77,7 @@ struct rcu_tasks {
call_rcu_func_t call_func;
struct rcu_tasks_percpu __percpu *rtpcpu;
int percpu_enqueue_shift;
int percpu_enqueue_lim;
char *name;
char *kname;
};
@ -93,6 +95,7 @@ static struct rcu_tasks rt_name = \
.rtpcpu = &rt_name ## __percpu, \
.name = n, \
.percpu_enqueue_shift = ilog2(CONFIG_NR_CPUS), \
.percpu_enqueue_lim = 1, \
.kname = #rt_name, \
}
@ -172,6 +175,7 @@ static void cblist_init_generic(struct rcu_tasks *rtp)
raw_spin_lock_irqsave(&rtp->cbs_gbl_lock, flags);
rtp->percpu_enqueue_shift = ilog2(nr_cpu_ids);
rtp->percpu_enqueue_lim = 1;
for_each_possible_cpu(cpu) {
struct rcu_tasks_percpu *rtpcp = per_cpu_ptr(rtp->rtpcpu, cpu);