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sched/walt/halt: cleaup issues post-review

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Minor cleanup including renaming of the drain functions and
commenting the update_halt_cpus function and usage.

Change-Id: I44502cde850af8fc6124e7b8ae014c562b21d0d9
Signed-off-by: Stephen Dickey <quic_dickey@quicinc.com>
This commit is contained in:
Stephen Dickey 2021-12-17 16:57:55 -08:00 committed by Rishabh Bhatnagar
parent 4a531492c9
commit 229e297c1a
1 changed files with 12 additions and 14 deletions
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26
kernel/sched/walt/walt_halt.c
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@ -61,9 +61,9 @@ void attach_tasks_core(struct list_head *tasks, struct rq *rq)
* there's no concurrency possible, we hold the required locks anyway
* because of lock validation efforts.
*
* force: if false, the function will skip CPU pinned kthreads.
* The function will skip CPU pinned kthreads.
*/
static void migrate_tasks(struct rq *dead_rq, struct rq_flags *rf, bool force)
static void migrate_tasks(struct rq *dead_rq, struct rq_flags *rf)
{
struct rq *rq = dead_rq;
struct task_struct *next, *stop = rq->stop;
@ -110,7 +110,7 @@ static void migrate_tasks(struct rq *dead_rq, struct rq_flags *rf, bool force)
* kthread from the run-queue to continue.
*/
if (!force && is_per_cpu_kthread(next)) {
if (is_per_cpu_kthread(next)) {
detach_one_task_core(next, rq, &percpu_kthreads);
num_pinned_kthreads += 1;
continue;
@ -135,18 +135,11 @@ static void migrate_tasks(struct rq *dead_rq, struct rq_flags *rf, bool force)
* that case the above rq->__lock drop is a fail too.
*/
if (task_rq(next) != rq || !task_on_rq_queued(next)) {
/*
* In the !force case, there is a hole between
* rq_unlock() and rq_relock(), where another CPU might
* not observe an up to date cpu_active_mask and try to
* move tasks around.
*/
WARN_ON(force);
raw_spin_unlock(&next->pi_lock);
continue;
}
/* Find suitable destination for @next, with force if needed. */
/* Find suitable destination for @next */
dest_cpu = select_fallback_rq(dead_rq->cpu, next);
rq = __migrate_task(rq, rf, next, dest_cpu);
if (rq != dead_rq) {
@ -170,13 +163,13 @@ static int drain_rq_cpu_stop(void *data)
struct rq_flags rf;
rq_lock_irqsave(rq, &rf);
migrate_tasks(rq, &rf, false);
migrate_tasks(rq, &rf);
rq_unlock_irqrestore(rq, &rf);
return 0;
}
static int sched_cpu_drain_rq(unsigned int cpu)
static int cpu_drain_rq(unsigned int cpu)
{
if (available_idle_cpu(cpu))
return 0;
@ -205,7 +198,7 @@ static int halt_cpus(struct cpumask *cpus)
/* only drain online cpus */
if (cpu_online(cpu)) {
/* drain the online CPU */
ret = sched_cpu_drain_rq(cpu);
ret = cpu_drain_rq(cpu);
}
if (ret < 0) {
@ -257,6 +250,7 @@ static void update_ref_counts(struct cpumask *cpus, bool halt)
}
}
/* remove cpus that are already halted */
static void update_halt_cpus(struct cpumask *cpus)
{
int cpu;
@ -278,6 +272,8 @@ int walt_halt_cpus(struct cpumask *cpus)
mutex_lock(&halt_lock);
cpumask_copy(&requested_cpus, cpus);
/* remove cpus that are already halted */
update_halt_cpus(cpus);
if (cpumask_empty(cpus)) {
@ -314,6 +310,8 @@ int walt_start_cpus(struct cpumask *cpus)
mutex_lock(&halt_lock);
cpumask_copy(&requested_cpus, cpus);
update_ref_counts(&requested_cpus, false);
/* remove cpus that should still be halted, due to ref-counts */
update_halt_cpus(cpus);
ret = start_cpus(cpus);