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Subject[tip:sched/core] sched/fair: Use non-atomic cpumask_{set,clear}_cpu()
Commit-ID:  c89d92eddfad11e912fb506f85e1796064a9f9d2
Gitweb: https://git.kernel.org/tip/c89d92eddfad11e912fb506f85e1796064a9f9d2
Author: Viresh Kumar <viresh.kumar@linaro.org>
AuthorDate: Tue, 12 Feb 2019 14:57:01 +0530
Committer: Ingo Molnar <mingo@kernel.org>
CommitDate: Wed, 13 Feb 2019 08:34:13 +0100

sched/fair: Use non-atomic cpumask_{set,clear}_cpu()

The cpumasks updated here are not subject to concurrency and using
atomic bitops for them is pointless and expensive. Use the non-atomic
variants instead.

Suggested-by: Peter Zijlstra <peterz@infradead.org>
Signed-off-by: Viresh Kumar <viresh.kumar@linaro.org>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Vincent Guittot <vincent.guittot@linaro.org>
Link: http://lkml.kernel.org/r/2e2a10f84b9049a81eef94ed6d5989447c21e34a.1549963617.git.viresh.kumar@linaro.org
Signed-off-by: Ingo Molnar <mingo@kernel.org>
---
kernel/sched/fair.c | 6 +++---
kernel/sched/isolation.c | 2 +-
2 files changed, 4 insertions(+), 4 deletions(-)

diff --git a/kernel/sched/fair.c b/kernel/sched/fair.c
index 8abd1c271499..8213ff6e365d 100644
--- a/kernel/sched/fair.c
+++ b/kernel/sched/fair.c
@@ -6097,7 +6097,7 @@ static int select_idle_core(struct task_struct *p, struct sched_domain *sd, int
bool idle = true;

for_each_cpu(cpu, cpu_smt_mask(core)) {
- cpumask_clear_cpu(cpu, cpus);
+ __cpumask_clear_cpu(cpu, cpus);
if (!available_idle_cpu(cpu))
idle = false;
}
@@ -9105,7 +9105,7 @@ more_balance:
if ((env.flags & LBF_DST_PINNED) && env.imbalance > 0) {

/* Prevent to re-select dst_cpu via env's CPUs */
- cpumask_clear_cpu(env.dst_cpu, env.cpus);
+ __cpumask_clear_cpu(env.dst_cpu, env.cpus);

env.dst_rq = cpu_rq(env.new_dst_cpu);
env.dst_cpu = env.new_dst_cpu;
@@ -9132,7 +9132,7 @@ more_balance:

/* All tasks on this runqueue were pinned by CPU affinity */
if (unlikely(env.flags & LBF_ALL_PINNED)) {
- cpumask_clear_cpu(cpu_of(busiest), cpus);
+ __cpumask_clear_cpu(cpu_of(busiest), cpus);
/*
* Attempting to continue load balancing at the current
* sched_domain level only makes sense if there are
diff --git a/kernel/sched/isolation.c b/kernel/sched/isolation.c
index 81faddba9e20..b02d148e7672 100644
--- a/kernel/sched/isolation.c
+++ b/kernel/sched/isolation.c
@@ -80,7 +80,7 @@ static int __init housekeeping_setup(char *str, enum hk_flags flags)
cpumask_andnot(housekeeping_mask,
cpu_possible_mask, non_housekeeping_mask);
if (cpumask_empty(housekeeping_mask))
- cpumask_set_cpu(smp_processor_id(), housekeeping_mask);
+ __cpumask_set_cpu(smp_processor_id(), housekeeping_mask);
} else {
cpumask_var_t tmp;

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