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sched: Drop the rq argument to sched_class::select_task_rq()

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In preparation of calling select_task_rq() without rq->lock held, drop
the dependency on the rq argument.

Reviewed-by: Frank Rowand <frank.rowand@am.sony.com>
Signed-off-by: Peter Zijlstra <a.p.zijlstra@chello.nl>
Cc: Mike Galbraith <efault@gmx.de>
Cc: Nick Piggin <npiggin@kernel.dk>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Andrew Morton <akpm@linux-foundation.org>
Link: http://lkml.kernel.org/r/20110405152729.031077745@chello.nl
Signed-off-by: Ingo Molnar <mingo@elte.hu>
This commit is contained in:
Peter Zijlstra
2011-04-05 17:23:46 +02:00
committed by Ingo Molnar
parent 013fdb8086
commit 7608dec2ce
6 changed files with 43 additions and 29 deletions
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42
kernel/sched_rt.c
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@@ -977,13 +977,23 @@ static void yield_task_rt(struct rq *rq)
static int find_lowest_rq(struct task_struct *task);
static int
select_task_rq_rt(struct rq *rq, struct task_struct *p, int sd_flag, int flags)
select_task_rq_rt(struct task_struct *p, int sd_flag, int flags)
{
struct task_struct *curr;
struct rq *rq;
int cpu;
if (sd_flag != SD_BALANCE_WAKE)
return smp_processor_id();
cpu = task_cpu(p);
rq = cpu_rq(cpu);
rcu_read_lock();
curr = ACCESS_ONCE(rq->curr); /* unlocked access */
/*
* If the current task is an RT task, then
* If the current task on @p's runqueue is an RT task, then
* try to see if we can wake this RT task up on another
* runqueue. Otherwise simply start this RT task
* on its current runqueue.
@@ -997,21 +1007,25 @@ select_task_rq_rt(struct rq *rq, struct task_struct *p, int sd_flag, int flags)
* lock?
*
* For equal prio tasks, we just let the scheduler sort it out.
*/
if (unlikely(rt_task(rq->curr)) &&
(rq->curr->rt.nr_cpus_allowed < 2 ||
rq->curr->prio < p->prio) &&
(p->rt.nr_cpus_allowed > 1)) {
int cpu = find_lowest_rq(p);
return (cpu == -1) ? task_cpu(p) : cpu;
}
/*
*
* Otherwise, just let it ride on the affined RQ and the
* post-schedule router will push the preempted task away
*
* This test is optimistic, if we get it wrong the load-balancer
* will have to sort it out.
*/
return task_cpu(p);
if (curr && unlikely(rt_task(curr)) &&
(curr->rt.nr_cpus_allowed < 2 ||
curr->prio < p->prio) &&
(p->rt.nr_cpus_allowed > 1)) {
int target = find_lowest_rq(p);
if (target != -1)
cpu = target;
}
rcu_read_unlock();
return cpu;
}
static void check_preempt_equal_prio(struct rq *rq, struct task_struct *p)