On 17-Mar 20:05, Leo Yan wrote:
Function select_energy_cpu_brute() can firstly handle for case 'next_cpu == prev_cpu', so can avoid big amount code indentation under the case 'next_cpu != prev_cpu'.
The existing code is still withing the 80 cols margin and also not so bad to read.
Thus I'm not in general a big fan of this kind of function-0-change patches... and I would really like to avoid them at least when they are not part of a functional refactoring.
Moreover...
Change-Id: Iac08b5f1e6072805c0bee22680bd0ecab411cdba Signed-off-by: Leo Yan leo.yan@linaro.org
kernel/sched/fair.c | 91 +++++++++++++++++++++++++---------------------------- 1 file changed, 42 insertions(+), 49 deletions(-)
diff --git a/kernel/sched/fair.c b/kernel/sched/fair.c index 0f0b307..b67999a 100644 --- a/kernel/sched/fair.c +++ b/kernel/sched/fair.c @@ -7060,6 +7060,8 @@ static int select_energy_cpu_brute(struct task_struct *p, int prev_cpu, int sync int target_cpu; int backup_cpu; int next_cpu;
int delta = 0;
struct energy_env eenv;
schedstat_inc(p->se.statistics.nr_wakeups_secb_attempts); schedstat_inc(this_rq()->eas_stats.secb_attempts);
@@ -7108,63 +7110,54 @@ static int select_energy_cpu_brute(struct task_struct *p, int prev_cpu, int sync }
target_cpu = prev_cpu;
- if (next_cpu != prev_cpu) {
int delta = 0;struct energy_env eenv = {.p = p,.util_delta = task_util(p),/* Task's previous CPU candidate */.cpu[EAS_CPU_PRV] = {.cpu_id = prev_cpu,},/* Main alternative CPU candidate */.cpu[EAS_CPU_NXT] = {.cpu_id = next_cpu,},/* Backup alternative CPU candidate */.cpu[EAS_CPU_BKP] = {.cpu_id = backup_cpu,},};
The block above exploits the designated initializers to ensure a zero initialization to all omitted members... for example eenv.energy which is used by the following code to sum track the estimated energy of a candidate to ensure a zero initialization to all omitted members... for example eenv.energy which is used by the following code to sum track the estimated energy of a candidate.
- if (next_cpu == prev_cpu) {
schedstat_inc(p->se.statistics.nr_wakeups_secb_count);schedstat_inc(this_rq()->eas_stats.secb_count);goto unlock;- }
- eenv.p = p;
- eenv.util_delta = task_util(p);
- /* Task's previous CPU candidate */
- eenv.cpu[EAS_CPU_PRV].cpu_id = prev_cpu;
- /* Main alternative CPU candidate */
- eenv.cpu[EAS_CPU_NXT].cpu_id = next_cpu;
- /* Backup alternative CPU candidate */
- eenv.cpu[EAS_CPU_BKP].cpu_id = backup_cpu;
... AFAIKS here we don't sure eenv.cpu[XXX].energy = 0
Thus don't we get whatever is on stack as initial energy value?
#ifdef CONFIG_SCHED_WALT
if (!walt_disabled && sysctl_sched_use_walt_cpu_util &&p->state == TASK_WAKING)delta = task_util(p);
- if (!walt_disabled && sysctl_sched_use_walt_cpu_util &&
p->state == TASK_WAKING)delta = task_util(p);#endif
/* Not enough spare capacity on previous cpu */if (__cpu_overutilized(prev_cpu, delta)) {schedstat_inc(p->se.statistics.nr_wakeups_secb_insuff_cap);schedstat_inc(this_rq()->eas_stats.secb_insuff_cap);target_cpu = next_cpu;goto unlock;}cpumask_clear(&eenv.cpus_mask);if (prev_cpu >= 0)cpumask_set_cpu(prev_cpu, &eenv.cpus_mask);if (next_cpu >= 0)cpumask_set_cpu(next_cpu, &eenv.cpus_mask);if (backup_cpu >= 0)cpumask_set_cpu(backup_cpu, &eenv.cpus_mask);
- /* Not enough spare capacity on previous cpu */
- if (__cpu_overutilized(prev_cpu, delta)) {
schedstat_inc(p->se.statistics.nr_wakeups_secb_insuff_cap);schedstat_inc(this_rq()->eas_stats.secb_insuff_cap);target_cpu = next_cpu;goto unlock;- }
select_energy_cpu_idx(&eenv);
- cpumask_clear(&eenv.cpus_mask);
- if (prev_cpu >= 0)
cpumask_set_cpu(prev_cpu, &eenv.cpus_mask);- if (next_cpu >= 0)
cpumask_set_cpu(next_cpu, &eenv.cpus_mask);- if (backup_cpu >= 0)
cpumask_set_cpu(backup_cpu, &eenv.cpus_mask);
/* Check if EAS_CPU_NXT is a more energy efficient CPU */if (eenv.next_idx != EAS_CPU_PRV) {schedstat_inc(p->se.statistics.nr_wakeups_secb_nrg_sav);schedstat_inc(this_rq()->eas_stats.secb_nrg_sav);} else {schedstat_inc(p->se.statistics.nr_wakeups_secb_no_nrg_sav);schedstat_inc(this_rq()->eas_stats.secb_no_nrg_sav);}
- select_energy_cpu_idx(&eenv);
target_cpu = eenv.cpu[eenv.next_idx].cpu_id;goto unlock;
- /* Check if EAS_CPU_NXT is a more energy efficient CPU */
- if (eenv.next_idx != EAS_CPU_PRV) {
schedstat_inc(p->se.statistics.nr_wakeups_secb_nrg_sav);schedstat_inc(this_rq()->eas_stats.secb_nrg_sav);- } else {
schedstat_inc(p->se.statistics.nr_wakeups_secb_no_nrg_sav);schedstat_inc(this_rq()->eas_stats.secb_no_nrg_sav);
- schedstat_inc(p->se.statistics.nr_wakeups_secb_count);
- schedstat_inc(this_rq()->eas_stats.secb_count);
- target_cpu = eenv.cpu[eenv.next_idx].cpu_id;
unlock: rcu_read_unlock(); -- 1.9.1
-- #include <best/regards.h>
Patrick Bellasi