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authorQais Yousef <qais.yousef@arm.com>2020-06-30 12:21:22 +0100
committerPeter Zijlstra <peterz@infradead.org>2020-07-08 11:39:01 +0200
commitd81ae8aac85ca2e307d273f6dc7863a721bf054e (patch)
tree30358d803f92a87ecf910ac67f9f947cace500c2 /kernel/sched
parent85c2ce9104eb93517db2037699471c517e81f9b4 (diff)
sched/uclamp: Fix initialization of struct uclamp_rq
struct uclamp_rq was zeroed out entirely in assumption that in the first call to uclamp_rq_inc() they'd be initialized correctly in accordance to default settings. But when next patch introduces a static key to skip uclamp_rq_{inc,dec}() until userspace opts in to use uclamp, schedutil will fail to perform any frequency changes because the rq->uclamp[UCLAMP_MAX].value is zeroed at init and stays as such. Which means all rqs are capped to 0 by default. Fix it by making sure we do proper initialization at init without relying on uclamp_rq_inc() doing it later. Fixes: 69842cba9ace ("sched/uclamp: Add CPU's clamp buckets refcounting") Signed-off-by: Qais Yousef <qais.yousef@arm.com> Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org> Reviewed-by: Valentin Schneider <valentin.schneider@arm.com> Tested-by: Lukasz Luba <lukasz.luba@arm.com> Link: https://lkml.kernel.org/r/20200630112123.12076-2-qais.yousef@arm.com
Diffstat (limited to 'kernel/sched')
-rw-r--r--kernel/sched/core.c21
1 files changed, 16 insertions, 5 deletions
diff --git a/kernel/sched/core.c b/kernel/sched/core.c
index 15c980af63db..9605db70e671 100644
--- a/kernel/sched/core.c
+++ b/kernel/sched/core.c
@@ -1239,6 +1239,20 @@ static void uclamp_fork(struct task_struct *p)
}
}
+static void __init init_uclamp_rq(struct rq *rq)
+{
+ enum uclamp_id clamp_id;
+ struct uclamp_rq *uc_rq = rq->uclamp;
+
+ for_each_clamp_id(clamp_id) {
+ uc_rq[clamp_id] = (struct uclamp_rq) {
+ .value = uclamp_none(clamp_id)
+ };
+ }
+
+ rq->uclamp_flags = 0;
+}
+
static void __init init_uclamp(void)
{
struct uclamp_se uc_max = {};
@@ -1247,11 +1261,8 @@ static void __init init_uclamp(void)
mutex_init(&uclamp_mutex);
- for_each_possible_cpu(cpu) {
- memset(&cpu_rq(cpu)->uclamp, 0,
- sizeof(struct uclamp_rq)*UCLAMP_CNT);
- cpu_rq(cpu)->uclamp_flags = 0;
- }
+ for_each_possible_cpu(cpu)
+ init_uclamp_rq(cpu_rq(cpu));
for_each_clamp_id(clamp_id) {
uclamp_se_set(&init_task.uclamp_req[clamp_id],