Commit-ID: 63928384faefba1b31c3bb77361965715a9fc71c
Gitweb: https://git.kernel.org/tip/63928384faefba1b31c3bb77361965715a9fc71c
Author: Peter Zijlstra <peterz@xxxxxxxxxxxxx>
AuthorDate: Tue, 13 Feb 2018 16:54:17 +0100
Committer: Ingo Molnar <mingo@xxxxxxxxxx>
CommitDate: Fri, 9 Mar 2018 07:59:22 +0100
sched/nohz: Optimize nohz_idle_balance()
Avoid calling update_blocked_averages() when it does not in fact have
any by re-using/extending update_nohz_stats().
Signed-off-by: Peter Zijlstra (Intel) <peterz@xxxxxxxxxxxxx>
Cc: Frederic Weisbecker <fweisbec@xxxxxxxxx>
Cc: Linus Torvalds <torvalds@xxxxxxxxxxxxxxxxxxxx>
Cc: Peter Zijlstra <peterz@xxxxxxxxxxxxx>
Cc: Thomas Gleixner <tglx@xxxxxxxxxxxxx>
Cc: linux-kernel@xxxxxxxxxxxxxxx
Signed-off-by: Ingo Molnar <mingo@xxxxxxxxxx>
---
kernel/sched/fair.c | 9 ++++-----
1 file changed, 4 insertions(+), 5 deletions(-)
diff --git a/kernel/sched/fair.c b/kernel/sched/fair.c
index aad7c03dbad8..5c357561db5d 100644
--- a/kernel/sched/fair.c
+++ b/kernel/sched/fair.c
@@ -7898,7 +7898,7 @@ group_type group_classify(struct sched_group *group,
return group_other;
}
-static bool update_nohz_stats(struct rq *rq)
+static bool update_nohz_stats(struct rq *rq, bool force)
{
#ifdef CONFIG_NO_HZ_COMMON
unsigned int cpu = rq->cpu;
@@ -7909,7 +7909,7 @@ static bool update_nohz_stats(struct rq *rq)
if (!cpumask_test_cpu(cpu, nohz.idle_cpus_mask))
return false;
- if (!time_after(jiffies, rq->last_blocked_load_update_tick))
+ if (!force && !time_after(jiffies, rq->last_blocked_load_update_tick))
return true;
update_blocked_averages(cpu);
@@ -7942,7 +7942,7 @@ static inline void update_sg_lb_stats(struct lb_env *env,
for_each_cpu_and(i, sched_group_span(group), env->cpus) {
struct rq *rq = cpu_rq(i);
- if ((env->flags & LBF_NOHZ_STATS) && update_nohz_stats(rq))
+ if ((env->flags & LBF_NOHZ_STATS) && update_nohz_stats(rq, false))
env->flags |= LBF_NOHZ_AGAIN;
/* Bias balancing toward CPUs of our domain: */
@@ -9552,8 +9552,7 @@ static bool nohz_idle_balance(struct rq *this_rq, enum cpu_idle_type idle)
rq = cpu_rq(balance_cpu);
- update_blocked_averages(rq->cpu);
- has_blocked_load |= rq->has_blocked_load;
+ has_blocked_load |= update_nohz_stats(rq, true);
/*
* If time for next balance is due,
--
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