diff options
| -rw-r--r-- | kernel/sched/core.c | 6 | ||||
| -rw-r--r-- | kernel/sched/sched.h | 14 | ||||
| -rw-r--r-- | kernel/sched/syscalls.c | 2 |
3 files changed, 18 insertions, 4 deletions
diff --git a/kernel/sched/core.c b/kernel/sched/core.c index 45daa41ab0b8..03d7b63dc3e5 100644 --- a/kernel/sched/core.c +++ b/kernel/sched/core.c @@ -1941,12 +1941,12 @@ static int sysctl_sched_uclamp_handler(const struct ctl_table *table, int write, } if (update_root_tg) { - static_branch_enable(&sched_uclamp_used); + sched_uclamp_enable(); uclamp_update_root_tg(); } if (old_min_rt != sysctl_sched_uclamp_util_min_rt_default) { - static_branch_enable(&sched_uclamp_used); + sched_uclamp_enable(); uclamp_sync_util_min_rt_default(); } @@ -9294,7 +9294,7 @@ static ssize_t cpu_uclamp_write(struct kernfs_open_file *of, char *buf, if (req.ret) return req.ret; - static_branch_enable(&sched_uclamp_used); + sched_uclamp_enable(); guard(mutex)(&uclamp_mutex); guard(rcu)(); diff --git a/kernel/sched/sched.h b/kernel/sched/sched.h index 8d42d3cd1cb8..0212a0c5534a 100644 --- a/kernel/sched/sched.h +++ b/kernel/sched/sched.h @@ -3407,6 +3407,18 @@ static inline bool uclamp_is_used(void) return static_branch_likely(&sched_uclamp_used); } +/* + * Enabling static branches would get the cpus_read_lock(), + * check whether uclamp_is_used before enable it to avoid always + * calling cpus_read_lock(). Because we never disable this + * static key once enable it. + */ +static inline void sched_uclamp_enable(void) +{ + if (!uclamp_is_used()) + static_branch_enable(&sched_uclamp_used); +} + static inline unsigned long uclamp_rq_get(struct rq *rq, enum uclamp_id clamp_id) { @@ -3486,6 +3498,8 @@ static inline bool uclamp_is_used(void) return false; } +static inline void sched_uclamp_enable(void) {} + static inline unsigned long uclamp_rq_get(struct rq *rq, enum uclamp_id clamp_id) { diff --git a/kernel/sched/syscalls.c b/kernel/sched/syscalls.c index 9f40348f1dc7..c326de1344fb 100644 --- a/kernel/sched/syscalls.c +++ b/kernel/sched/syscalls.c @@ -368,7 +368,7 @@ static int uclamp_validate(struct task_struct *p, * blocking operation which obviously cannot be done while holding * scheduler locks. */ - static_branch_enable(&sched_uclamp_used); + sched_uclamp_enable(); return 0; } |