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sched/walt: implement select_task_rq_rt trace hook

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Implement select_task_rq_rt trace hook to be able to find suitable
CPU for the RT tasks from wake-up path.

Change-Id: Id1e8a4529d7391bf39a2a069ae37c146fb8a55c9
Signed-off-by: Satya Durga Srinivasu Prabhala <satyap@codeaurora.org>
Signed-off-by: Sai Harshini Nimmala <snimmala@codeaurora.org>
This commit is contained in:
Sai Harshini Nimmala 2021-10-26 17:41:44 -07:00 committed by Rishabh Bhatnagar
parent cc2a0e6b28
commit b9df052aa2
1 changed files with 101 additions and 2 deletions
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103
kernel/sched/walt/walt_rt.c
View File

@ -8,7 +8,9 @@
#include "walt.h"
#include "trace.h"
static void rt_energy_aware_wake_cpu(void *unused, struct task_struct *task,
static DEFINE_PER_CPU(cpumask_var_t, walt_local_cpu_mask);
static void walt_rt_energy_aware_wake_cpu(void *unused, struct task_struct *task,
struct cpumask *lowest_mask, int ret, int *best_cpu)
{
int cpu;
@ -24,6 +26,7 @@ static void rt_energy_aware_wake_cpu(void *unused, struct task_struct *task,
if (static_branch_unlikely(&walt_disabled))
return;
if (!ret)
return; /* No targets found */
@ -86,7 +89,103 @@ static void rt_energy_aware_wake_cpu(void *unused, struct task_struct *task,
rcu_read_unlock();
}
#ifdef CONFIG_UCLAMP_TASK
static inline bool walt_rt_task_fits_capacity(struct task_struct *p, int cpu)
{
unsigned int min_cap;
unsigned int max_cap;
unsigned int cpu_cap;
min_cap = uclamp_eff_value(p, UCLAMP_MIN);
max_cap = uclamp_eff_value(p, UCLAMP_MAX);
cpu_cap = capacity_orig_of(cpu);
return cpu_cap >= min(min_cap, max_cap);
}
#else
static inline bool walt_rt_task_fits_capacity(struct task_struct *p, int cpu)
{
return true;
}
#endif
static void walt_select_task_rq_rt(void *unused, struct task_struct *task, int cpu,
int sd_flag, int wake_flags, int *new_cpu)
{
struct task_struct *curr;
struct rq *rq;
bool may_not_preempt;
int ret, target = -1;
struct cpumask *lowest_mask;
if (static_branch_unlikely(&walt_disabled))
return;
/* For anything but wake ups, just return the task_cpu */
if (sd_flag != SD_BALANCE_WAKE && sd_flag != SD_BALANCE_FORK)
return;
*new_cpu = cpu; /* previous CPU as back up */
rq = cpu_rq(cpu);
rcu_read_lock();
curr = READ_ONCE(rq->curr); /* unlocked access */
/*
* If the current task on @p's runqueue is a softirq task,
* it may run without preemption for a time that is
* ill-suited for a waiting RT task. Therefore, try to
* wake this RT task on another runqueue.
*
* Otherwise, just let it ride on the affined RQ and the
* post-schedule router will push the preempted task away
*
* This test is optimistic, if we get it wrong the load-balancer
* will have to sort it out.
*
* We take into account the capacity of the CPU to ensure it fits the
* requirement of the task - which is only important on heterogeneous
* systems like big.LITTLE.
*/
may_not_preempt = task_may_not_preempt(curr, cpu);
lowest_mask = this_cpu_cpumask_var_ptr(walt_local_cpu_mask);
/*
* If we're on asym system ensure we consider the different capacities
* of the CPUs when searching for the lowest_mask.
*/
ret = cpupri_find_fitness(&task_rq(task)->rd->cpupri, task,
lowest_mask, walt_rt_task_fits_capacity);
walt_rt_energy_aware_wake_cpu(NULL, task, lowest_mask, ret, &target);
/*
* If cpu is non-preemptible, prefer remote cpu
* even if it's running a higher-prio task.
* Otherwise: Don't bother moving it if the destination CPU is
* not running a lower priority task.
*/
if (target != -1 &&
(may_not_preempt || task->prio < cpu_rq(target)->rt.highest_prio.curr))
*new_cpu = target;
rcu_read_unlock();
}
void walt_rt_init(void)
{
register_trace_android_rvh_find_lowest_rq(rt_energy_aware_wake_cpu, NULL);
unsigned int i;
for_each_possible_cpu(i) {
if(!(zalloc_cpumask_var_node(&per_cpu(walt_local_cpu_mask, i),
GFP_KERNEL, cpu_to_node(i)))) {
pr_err("walt_local_cpu_mask alloc failed for cpu%d\n", i);
return;
}
}
register_trace_android_rvh_select_task_rq_rt(walt_select_task_rq_rt, NULL);
register_trace_android_rvh_find_lowest_rq(walt_rt_energy_aware_wake_cpu, NULL);
}