[PATCH v3 08/57] sched: Simplify wake_up_if_idle()
From: Peter Zijlstra <peterz@infradead.org>
Date: 2023-06-12 09:57:25
Also in:
dmaengine, linux-kbuild, linux-perf-users, lkml, llvm, rcu
Use guards to reduce gotos and simplify control flow. Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org> --- kernel/sched/core.c | 20 ++++++-------------- kernel/sched/sched.h | 15 +++++++++++++++ 2 files changed, 21 insertions(+), 14 deletions(-)
--- a/kernel/sched/core.c
+++ b/kernel/sched/core.c@@ -3872,21 +3872,13 @@ static void __ttwu_queue_wakelist(struct void wake_up_if_idle(int cpu) { struct rq *rq = cpu_rq(cpu); - struct rq_flags rf; - rcu_read_lock(); - - if (!is_idle_task(rcu_dereference(rq->curr))) - goto out; - - rq_lock_irqsave(rq, &rf); - if (is_idle_task(rq->curr)) - resched_curr(rq); - /* Else CPU is not idle, do nothing here: */ - rq_unlock_irqrestore(rq, &rf); - -out: - rcu_read_unlock(); + guard(rcu)(); + if (is_idle_task(rcu_dereference(rq->curr))) { + guard(rq_lock)(rq); + if (is_idle_task(rq->curr)) + resched_curr(rq); + } } bool cpus_share_cache(int this_cpu, int that_cpu) --- a/kernel/sched/sched.h +++ b/kernel/sched/sched.h
@@ -1678,6 +1678,21 @@ rq_unlock(struct rq *rq, struct rq_flags raw_spin_rq_unlock(rq); } +DEFINE_LOCK_GUARD_1(rq_lock, struct rq, + rq_lock(_T->lock, &_T->rf), + rq_unlock(_T->lock, &_T->rf), + struct rq_flags rf) + +DEFINE_LOCK_GUARD_1(rq_lock_irq, struct rq, + rq_lock_irq(_T->lock, &_T->rf), + rq_unlock_irq(_T->lock, &_T->rf), + struct rq_flags rf) + +DEFINE_LOCK_GUARD_1(rq_lock_irqsave, struct rq, + rq_lock_irqsave(_T->lock, &_T->rf), + rq_unlock_irqrestore(_T->lock, &_T->rf), + struct rq_flags rf) + static inline struct rq * this_rq_lock_irq(struct rq_flags *rf) __acquires(rq->lock)