diff options
| author | Viresh Kumar <viresh.kumar@linaro.org> | 2018-04-26 16:00:50 +0530 |
|---|---|---|
| committer | Ingo Molnar <mingo@kernel.org> | 2018-05-04 10:00:07 +0200 |
| commit | f1d88b4468188ddcd2620b8d612068faf6662a62 (patch) | |
| tree | 7f9ee18eb9d6e7974e608112a151a37837e42e17 /kernel/sched | |
| parent | b5bf9a90bbebffba888c9144c5a8a10317b04064 (diff) | |
sched/fair: Rearrange select_task_rq_fair() to optimize it
Rearrange select_task_rq_fair() a bit to avoid executing some
conditional statements in few specific code-paths. That gets rid of the
goto as well.
This shouldn't result in any functional changes.
Tested-by: Rohit Jain <rohit.k.jain@oracle.com>
Signed-off-by: Viresh Kumar <viresh.kumar@linaro.org>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Reviewed-by: Valentin Schneider <valentin.schneider@arm.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Vincent Guittot <vincent.guittot@linaro.org>
Link: http://lkml.kernel.org/r/20831b8d237bf3a20e4e328286f678b425ff04c9.1524738578.git.viresh.kumar@linaro.org
Signed-off-by: Ingo Molnar <mingo@kernel.org>
Diffstat (limited to 'kernel/sched')
| -rw-r--r-- | kernel/sched/fair.c | 37 |
1 files changed, 16 insertions, 21 deletions
diff --git a/kernel/sched/fair.c b/kernel/sched/fair.c index e3002e5ada31..4b346f358005 100644 --- a/kernel/sched/fair.c +++ b/kernel/sched/fair.c @@ -6613,7 +6613,7 @@ static int wake_cap(struct task_struct *p, int cpu, int prev_cpu) static int select_task_rq_fair(struct task_struct *p, int prev_cpu, int sd_flag, int wake_flags) { - struct sched_domain *tmp, *affine_sd = NULL, *sd = NULL; + struct sched_domain *tmp, *sd = NULL; int cpu = smp_processor_id(); int new_cpu = prev_cpu; int want_affine = 0; @@ -6636,7 +6636,10 @@ select_task_rq_fair(struct task_struct *p, int prev_cpu, int sd_flag, int wake_f */ if (want_affine && (tmp->flags & SD_WAKE_AFFINE) && cpumask_test_cpu(prev_cpu, sched_domain_span(tmp))) { - affine_sd = tmp; + if (cpu != prev_cpu) + new_cpu = wake_affine(tmp, p, cpu, prev_cpu, sync); + + sd = NULL; /* Prefer wake_affine over balance flags */ break; } @@ -6646,33 +6649,25 @@ select_task_rq_fair(struct task_struct *p, int prev_cpu, int sd_flag, int wake_f break; } - if (affine_sd) { - sd = NULL; /* Prefer wake_affine over balance flags */ - if (cpu == prev_cpu) - goto pick_cpu; - - new_cpu = wake_affine(affine_sd, p, cpu, prev_cpu, sync); - } + if (unlikely(sd)) { + /* Slow path */ - if (sd && !(sd_flag & SD_BALANCE_FORK)) { /* * We're going to need the task's util for capacity_spare_wake * in find_idlest_group. Sync it up to prev_cpu's * last_update_time. */ - sync_entity_load_avg(&p->se); - } - - if (!sd) { -pick_cpu: - if (sd_flag & SD_BALANCE_WAKE) { /* XXX always ? */ - new_cpu = select_idle_sibling(p, prev_cpu, new_cpu); + if (!(sd_flag & SD_BALANCE_FORK)) + sync_entity_load_avg(&p->se); - if (want_affine) - current->recent_used_cpu = cpu; - } - } else { new_cpu = find_idlest_cpu(sd, p, cpu, prev_cpu, sd_flag); + } else if (sd_flag & SD_BALANCE_WAKE) { /* XXX always ? */ + /* Fast path */ + + new_cpu = select_idle_sibling(p, prev_cpu, new_cpu); + + if (want_affine) + current->recent_used_cpu = cpu; } rcu_read_unlock(); |