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sched/walt: guarantee result from energy efficient cpu

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It is possible that walt_find_energy_efficient_cpu will return
an error value, or a negative number for the cpu. In walt_lb_tick
this was called without checking the return value.

Update walt_find_energy_efficient_cpu to guarantee that it never
returns a bad value, and that in all cases it returns prev_cpu
if it cannot find an energy efficient cpu.

Change-Id: Ifc08bdf42b8d54923f8a4ecc3ca8b2c0dba11f4f
Signed-off-by: Stephen Dickey <quic_dickey@quicinc.com>
This commit is contained in:
Stephen Dickey 2022-02-19 14:17:14 -08:00 committed by Rishabh Bhatnagar
parent e8c7c38077
commit 53ef4e9eed
2 changed files with 9 additions and 11 deletions
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12
kernel/sched/walt/walt_cfs.c
View File

@ -1,6 +1,7 @@
// SPDX-License-Identifier: GPL-2.0-only
/*
* Copyright (c) 2020-2022, The Linux Foundation. All rights reserved.
* Copyright (c) 2020-2021, The Linux Foundation. All rights reserved.
* Copyright (c) 2022 Qualcomm Innovation Center, Inc. All rights reserved.
*/
#include <trace/hooks/sched.h>
@ -788,7 +789,7 @@ int walt_find_energy_efficient_cpu(struct task_struct *p, int prev_cpu,
return prev_cpu;
if (unlikely(!cpu_array))
return -EPERM;
return prev_cpu;
walt_get_indicies(p, &order_index, &end_index, task_boost, uclamp_boost,
&energy_eval_needed);
@ -926,6 +927,9 @@ int walt_find_energy_efficient_cpu(struct task_struct *p, int prev_cpu,
rcu_read_unlock();
done:
if (best_energy_cpu < 0 || best_energy_cpu >= WALT_NR_CPUS)
best_energy_cpu = prev_cpu;
trace_sched_task_util(p, cpumask_bits(candidates)[0], best_energy_cpu,
sync, fbt_env.need_idle, fbt_env.fastpath,
start_t, uclamp_boost, start_cpu);
@ -934,7 +938,7 @@ int walt_find_energy_efficient_cpu(struct task_struct *p, int prev_cpu,
fail:
rcu_read_unlock();
return -EPERM;
return prev_cpu;
}
static void
@ -952,8 +956,6 @@ walt_select_task_rq_fair(void *unused, struct task_struct *p, int prev_cpu,
p->wake_q_count = 0;
*target_cpu = walt_find_energy_efficient_cpu(p, prev_cpu, sync, sibling_count_hint);
if (unlikely(*target_cpu < 0))
*target_cpu = prev_cpu;
}
static void walt_binder_low_latency_set(void *unused, struct task_struct *task,

8
kernel/sched/walt/walt_lb.c
View File

@ -1,7 +1,7 @@
// SPDX-License-Identifier: GPL-2.0-only
/*
* Copyright (c) 2020-2021, The Linux Foundation. All rights reserved.
* Copyright (c) 2020-2021, Qualcomm Innovation Center, Inc. All rights reserved.
* Copyright (c) 2020-2022, Qualcomm Innovation Center, Inc. All rights reserved.
*/
#include <trace/hooks/sched.h>
@ -633,14 +633,10 @@ void walt_lb_tick(struct rq *rq)
new_cpu = walt_find_energy_efficient_cpu(p, prev_cpu, 0, 1);
rcu_read_unlock();
if (new_cpu < 0)
goto out_unlock;
new_wrq = (struct walt_rq *) cpu_rq(new_cpu)->android_vendor_data1;
/* prevent active task migration to busy or same/lower capacity CPU */
if (!available_idle_cpu(new_cpu) ||
new_wrq->cluster->id <= prev_wrq->cluster->id)
if (!available_idle_cpu(new_cpu) || new_wrq->cluster->id <= prev_wrq->cluster->id)
goto out_unlock;
raw_spin_lock(&rq->__lock);