From 5bb76f1ddf2a7dd98f5a89d7755600ed1b4a7fcd Mon Sep 17 00:00:00 2001 From: Peter Zijlstra Date: Tue, 1 Aug 2023 22:41:24 +0200 Subject: [PATCH] sched: Simplify: migrate_swap_stop() Use guards to reduce gotos and simplify control flow. Signed-off-by: Peter Zijlstra (Intel) Reviewed-by: Valentin Schneider Link: https://lore.kernel.org/r/20230801211811.964370836@infradead.org --- kernel/sched/core.c | 23 +++++++---------------- kernel/sched/sched.h | 20 ++++++++++++++++++++ 2 files changed, 27 insertions(+), 16 deletions(-) diff --git a/kernel/sched/core.c b/kernel/sched/core.c index 6e8a8e9..66478a6 100644 --- a/kernel/sched/core.c +++ b/kernel/sched/core.c @@ -3433,7 +3433,6 @@ static int migrate_swap_stop(void *data) { struct migration_swap_arg *arg = data; struct rq *src_rq, *dst_rq; - int ret = -EAGAIN; if (!cpu_active(arg->src_cpu) || !cpu_active(arg->dst_cpu)) return -EAGAIN; @@ -3441,33 +3440,25 @@ static int migrate_swap_stop(void *data) src_rq = cpu_rq(arg->src_cpu); dst_rq = cpu_rq(arg->dst_cpu); - double_raw_lock(&arg->src_task->pi_lock, - &arg->dst_task->pi_lock); - double_rq_lock(src_rq, dst_rq); + guard(double_raw_spinlock)(&arg->src_task->pi_lock, &arg->dst_task->pi_lock); + guard(double_rq_lock)(src_rq, dst_rq); if (task_cpu(arg->dst_task) != arg->dst_cpu) - goto unlock; + return -EAGAIN; if (task_cpu(arg->src_task) != arg->src_cpu) - goto unlock; + return -EAGAIN; if (!cpumask_test_cpu(arg->dst_cpu, arg->src_task->cpus_ptr)) - goto unlock; + return -EAGAIN; if (!cpumask_test_cpu(arg->src_cpu, arg->dst_task->cpus_ptr)) - goto unlock; + return -EAGAIN; __migrate_swap_task(arg->src_task, arg->dst_cpu); __migrate_swap_task(arg->dst_task, arg->src_cpu); - ret = 0; - -unlock: - double_rq_unlock(src_rq, dst_rq); - raw_spin_unlock(&arg->dst_task->pi_lock); - raw_spin_unlock(&arg->src_task->pi_lock); - - return ret; + return 0; } /* diff --git a/kernel/sched/sched.h b/kernel/sched/sched.h index 9c5035c..c299a58 100644 --- a/kernel/sched/sched.h +++ b/kernel/sched/sched.h @@ -2614,6 +2614,12 @@ static inline void double_rq_clock_clear_update(struct rq *rq1, struct rq *rq2) static inline void double_rq_clock_clear_update(struct rq *rq1, struct rq *rq2) {} #endif +#define DEFINE_LOCK_GUARD_2(name, type, _lock, _unlock, ...) \ +__DEFINE_UNLOCK_GUARD(name, type, _unlock, type *lock2; __VA_ARGS__) \ +static inline class_##name##_t class_##name##_constructor(type *lock, type *lock2) \ +{ class_##name##_t _t = { .lock = lock, .lock2 = lock2 }, *_T = &_t; \ + _lock; return _t; } + #ifdef CONFIG_SMP static inline bool rq_order_less(struct rq *rq1, struct rq *rq2) @@ -2743,6 +2749,16 @@ static inline void double_raw_lock(raw_spinlock_t *l1, raw_spinlock_t *l2) raw_spin_lock_nested(l2, SINGLE_DEPTH_NESTING); } +static inline void double_raw_unlock(raw_spinlock_t *l1, raw_spinlock_t *l2) +{ + raw_spin_unlock(l1); + raw_spin_unlock(l2); +} + +DEFINE_LOCK_GUARD_2(double_raw_spinlock, raw_spinlock_t, + double_raw_lock(_T->lock, _T->lock2), + double_raw_unlock(_T->lock, _T->lock2)) + /* * double_rq_unlock - safely unlock two runqueues * @@ -2800,6 +2816,10 @@ static inline void double_rq_unlock(struct rq *rq1, struct rq *rq2) #endif +DEFINE_LOCK_GUARD_2(double_rq_lock, struct rq, + double_rq_lock(_T->lock, _T->lock2), + double_rq_unlock(_T->lock, _T->lock2)) + extern struct sched_entity *__pick_first_entity(struct cfs_rq *cfs_rq); extern struct sched_entity *__pick_last_entity(struct cfs_rq *cfs_rq); -- 2.7.4