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authorValentin Schneider <valentin.schneider@arm.com>2020-04-15 22:05:06 +0100
committerPeter Zijlstra <peterz@infradead.org>2020-04-30 20:14:39 +0200
commite669ac8ab952df2f07dee1e1efbf40647d6de332 (patch)
tree19a14e3cb10525a7552d77d4927d531fe2d86dd3 /kernel/sched/fair.c
parent9818427c6270a9ce8c52c8621026fe9cebae0f92 (diff)
downloadlinux-e669ac8ab952df2f07dee1e1efbf40647d6de332.tar.gz
sched: Remove checks against SD_LOAD_BALANCE
The SD_LOAD_BALANCE flag is set unconditionally for all domains in sd_init(). By making the sched_domain->flags syctl interface read-only, we have removed the last piece of code that could clear that flag - as such, it will now be always present. Rather than to keep carrying it along, we can work towards getting rid of it entirely. cpusets don't need it because they can make CPUs be attached to the NULL domain (e.g. cpuset with sched_load_balance=0), or to a partitioned root_domain, i.e. a sched_domain hierarchy that doesn't span the entire system (e.g. root cpuset with sched_load_balance=0 and sibling cpusets with sched_load_balance=1). isolcpus apply the same "trick": isolated CPUs are explicitly taken out of the sched_domain rebuild (using housekeeping_cpumask()), so they get the NULL domain treatment as well. Remove the checks against SD_LOAD_BALANCE. Signed-off-by: Valentin Schneider <valentin.schneider@arm.com> Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org> Link: https://lkml.kernel.org/r/20200415210512.805-4-valentin.schneider@arm.com
Diffstat (limited to 'kernel/sched/fair.c')
-rw-r--r--kernel/sched/fair.c14
1 files changed, 2 insertions, 12 deletions
diff --git a/kernel/sched/fair.c b/kernel/sched/fair.c
index 617ca44ed61b..4b959c0a7d7b 100644
--- a/kernel/sched/fair.c
+++ b/kernel/sched/fair.c
@@ -6649,9 +6649,6 @@ select_task_rq_fair(struct task_struct *p, int prev_cpu, int sd_flag, int wake_f
rcu_read_lock();
for_each_domain(cpu, tmp) {
- if (!(tmp->flags & SD_LOAD_BALANCE))
- break;
-
/*
* If both 'cpu' and 'prev_cpu' are part of this domain,
* cpu is a valid SD_WAKE_AFFINE target.
@@ -9790,9 +9787,8 @@ static int active_load_balance_cpu_stop(void *data)
/* Search for an sd spanning us and the target CPU. */
rcu_read_lock();
for_each_domain(target_cpu, sd) {
- if ((sd->flags & SD_LOAD_BALANCE) &&
- cpumask_test_cpu(busiest_cpu, sched_domain_span(sd)))
- break;
+ if (cpumask_test_cpu(busiest_cpu, sched_domain_span(sd)))
+ break;
}
if (likely(sd)) {
@@ -9881,9 +9877,6 @@ static void rebalance_domains(struct rq *rq, enum cpu_idle_type idle)
}
max_cost += sd->max_newidle_lb_cost;
- if (!(sd->flags & SD_LOAD_BALANCE))
- continue;
-
/*
* Stop the load balance at this level. There is another
* CPU in our sched group which is doing load balancing more
@@ -10472,9 +10465,6 @@ int newidle_balance(struct rq *this_rq, struct rq_flags *rf)
int continue_balancing = 1;
u64 t0, domain_cost;
- if (!(sd->flags & SD_LOAD_BALANCE))
- continue;
-
if (this_rq->avg_idle < curr_cost + sd->max_newidle_lb_cost) {
update_next_balance(sd, &next_balance);
break;