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sched/walt: Kick newidle balance after unhalting

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When a cpu is unhalted currently, it will attempt to perform
a balance through the normal ipi kick interface. However, this
can fail because a balance might have happened in the current
4mS tick, while the cpu was still halted. The next kick as a
result of unhalting, fails to execute (min 1 tick between kicks).

Instead, use walt_newidle_balance() to ensure that this cpu can
take a task. Perform an smp async function call to the target
cpu, invoke newidle balance, and allow the cpu to pull tasks
immediately after unhalting.

Change-Id: Ide1bb51f80dc8c4eba079588ffb6a7ed341e8628
Signed-off-by: Stephen Dickey <quic_dickey@quicinc.com>
This commit is contained in:
Stephen Dickey 2022-05-05 11:08:38 -07:00 committed by Rishabh Bhatnagar
parent 549ffdbf7a
commit 86a2dd10da
3 changed files with 39 additions and 1 deletions
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1
kernel/sched/walt/walt.h
View File

@ -163,6 +163,7 @@ extern void walt_boost_init(void);
extern int sched_pause_cpus(struct cpumask *pause_cpus);
extern int sched_unpause_cpus(struct cpumask *unpause_cpus);
extern void walt_kick_cpu(int cpu);
extern void walt_smp_call_newidle_balance(int cpu);
extern unsigned int sched_get_cpu_util_pct(int cpu);
extern void sched_update_hyst_times(void);

2
kernel/sched/walt/walt_halt.c
View File

@ -325,7 +325,7 @@ static int start_cpus(struct cpumask *cpus)
/* kick the cpu so it can pull tasks
* after the mask has been cleared.
*/
walt_kick_cpu(cpu);
walt_smp_call_newidle_balance(cpu);
}
trace_halt_cpus(cpus, start_time, 0, 0);

37
kernel/sched/walt/walt_lb.c
View File

@ -918,6 +918,34 @@ static void walt_newidle_balance(void *unused, struct rq *this_rq,
help_min_cap, enough_idle);
}
/* run newidle balance as a result of an unhalt operation */
void walt_smp_newidle_balance(void *ignored)
{
int cpu = raw_smp_processor_id();
struct rq *rq = cpu_rq(cpu);
struct rq_flags rf;
int pulled_task;
int done = 0;
rq_lock(rq, &rf);
update_rq_clock(rq);
walt_newidle_balance(NULL, rq, &rf, &pulled_task, &done);
resched_curr(rq);
rq_unlock(rq, &rf);
}
static DEFINE_PER_CPU(call_single_data_t, nib_csd);
void walt_smp_call_newidle_balance(int cpu)
{
call_single_data_t *csd = &per_cpu(nib_csd, cpu);
if (unlikely(walt_disabled))
return;
smp_call_function_single_async(cpu, csd);
}
static void walt_find_busiest_queue(void *unused, int dst_cpu,
struct sched_group *group,
struct cpumask *env_cpus,
@ -1028,6 +1056,8 @@ static void walt_can_migrate_task(void *unused, struct task_struct *p,
void walt_lb_init(void)
{
int cpu;
walt_lb_rotate_work_init();
register_trace_android_rvh_migrate_queued_task(walt_migrate_queued_task, NULL);
@ -1035,4 +1065,11 @@ void walt_lb_init(void)
register_trace_android_rvh_can_migrate_task(walt_can_migrate_task, NULL);
register_trace_android_rvh_find_busiest_queue(walt_find_busiest_queue, NULL);
register_trace_android_rvh_sched_newidle_balance(walt_newidle_balance, NULL);
for_each_cpu(cpu, cpu_possible_mask) {
call_single_data_t *csd;
csd = &per_cpu(nib_csd, cpu);
INIT_CSD(csd, walt_smp_newidle_balance, (void *)(unsigned long)cpu);
}
}