diff options
| -rw-r--r-- | kernel/sched/core.c | 38 |
1 files changed, 15 insertions, 23 deletions
diff --git a/kernel/sched/core.c b/kernel/sched/core.c index b4935600cd85..1b69603c1d3e 100644 --- a/kernel/sched/core.c +++ b/kernel/sched/core.c @@ -2220,7 +2220,6 @@ prepare_task_switch(struct rq *rq, struct task_struct *prev, /** * finish_task_switch - clean up after a task-switch - * @rq: runqueue associated with task-switch * @prev: the thread we just switched away from. * * finish_task_switch must be called after the context switch, paired @@ -2232,10 +2231,16 @@ prepare_task_switch(struct rq *rq, struct task_struct *prev, * so, we finish that here outside of the runqueue lock. (Doing it * with the lock held can cause deadlocks; see schedule() for * details.) + * + * The context switch have flipped the stack from under us and restored the + * local variables which were saved when this task called schedule() in the + * past. prev == current is still correct but we need to recalculate this_rq + * because prev may have moved to another CPU. */ -static void finish_task_switch(struct rq *rq, struct task_struct *prev) +static struct rq *finish_task_switch(struct task_struct *prev) __releases(rq->lock) { + struct rq *rq = this_rq(); struct mm_struct *mm = rq->prev_mm; long prev_state; @@ -2275,6 +2280,7 @@ static void finish_task_switch(struct rq *rq, struct task_struct *prev) } tick_nohz_task_switch(current); + return rq; } #ifdef CONFIG_SMP @@ -2313,8 +2319,7 @@ asmlinkage __visible void schedule_tail(struct task_struct *prev) /* finish_task_switch() drops rq->lock and enables preemtion */ preempt_disable(); - rq = this_rq(); - finish_task_switch(rq, prev); + rq = finish_task_switch(prev); post_schedule(rq); preempt_enable(); @@ -2323,10 +2328,9 @@ asmlinkage __visible void schedule_tail(struct task_struct *prev) } /* - * context_switch - switch to the new MM and the new - * thread's register state. + * context_switch - switch to the new MM and the new thread's register state. */ -static inline void +static inline struct rq * context_switch(struct rq *rq, struct task_struct *prev, struct task_struct *next) { @@ -2365,14 +2369,9 @@ context_switch(struct rq *rq, struct task_struct *prev, context_tracking_task_switch(prev, next); /* Here we just switch the register state and the stack. */ switch_to(prev, next, prev); - barrier(); - /* - * this_rq must be evaluated again because prev may have moved - * CPUs since it called schedule(), thus the 'rq' on its stack - * frame will be invalid. - */ - finish_task_switch(this_rq(), prev); + + return finish_task_switch(prev); } /* @@ -2854,15 +2853,8 @@ need_resched: rq->curr = next; ++*switch_count; - context_switch(rq, prev, next); /* unlocks the rq */ - /* - * The context switch have flipped the stack from under us - * and restored the local variables which were saved when - * this task called schedule() in the past. prev == current - * is still correct, but it can be moved to another cpu/rq. - */ - cpu = smp_processor_id(); - rq = cpu_rq(cpu); + rq = context_switch(rq, prev, next); /* unlocks the rq */ + cpu = cpu_of(rq); } else raw_spin_unlock_irq(&rq->lock); |