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sched: Move code around

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In preparation to reworking set_cpus_allowed_ptr() move some code
around. This also removes some superfluous #ifdefs and adds comments
to some #endifs.

   text    data     bss     dec     hex filename
12211532        1738144 1081344 15031020         e55aec defconfig-build/vmlinux.pre
12211532        1738144 1081344 15031020         e55aec defconfig-build/vmlinux.post

Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Cc: ktkhai@parallels.com
Cc: rostedt@goodmis.org
Cc: juri.lelli@gmail.com
Cc: pang.xunlei@linaro.org
Cc: oleg@redhat.com
Cc: wanpeng.li@linux.intel.com
Cc: umgwanakikbuti@gmail.com
Link: http://lkml.kernel.org/r/20150611124743.662086684@infradead.org
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
This commit is contained in:
Peter Zijlstra 2015-06-11 14:46:50 +02:00 committed by Thomas Gleixner
parent a649f237db
commit 5cc389bcee
1 changed files with 178 additions and 186 deletions
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364
kernel/sched/core.c
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@ -1046,6 +1046,180 @@ void check_preempt_curr(struct rq *rq, struct task_struct *p, int flags)
}
#ifdef CONFIG_SMP
/*
* This is how migration works:
*
* 1) we invoke migration_cpu_stop() on the target CPU using
* stop_one_cpu().
* 2) stopper starts to run (implicitly forcing the migrated thread
* off the CPU)
* 3) it checks whether the migrated task is still in the wrong runqueue.
* 4) if it's in the wrong runqueue then the migration thread removes
* it and puts it into the right queue.
* 5) stopper completes and stop_one_cpu() returns and the migration
* is done.
*/
/*
* move_queued_task - move a queued task to new rq.
*
* Returns (locked) new rq. Old rq's lock is released.
*/
static struct rq *move_queued_task(struct task_struct *p, int new_cpu)
{
struct rq *rq = task_rq(p);
lockdep_assert_held(&rq->lock);
dequeue_task(rq, p, 0);
p->on_rq = TASK_ON_RQ_MIGRATING;
set_task_cpu(p, new_cpu);
raw_spin_unlock(&rq->lock);
rq = cpu_rq(new_cpu);
raw_spin_lock(&rq->lock);
BUG_ON(task_cpu(p) != new_cpu);
p->on_rq = TASK_ON_RQ_QUEUED;
enqueue_task(rq, p, 0);
check_preempt_curr(rq, p, 0);
return rq;
}
struct migration_arg {
struct task_struct *task;
int dest_cpu;
};
/*
* Move (not current) task off this cpu, onto dest cpu. We're doing
* this because either it can't run here any more (set_cpus_allowed()
* away from this CPU, or CPU going down), or because we're
* attempting to rebalance this task on exec (sched_exec).
*
* So we race with normal scheduler movements, but that's OK, as long
* as the task is no longer on this CPU.
*
* Returns non-zero if task was successfully migrated.
*/
static int __migrate_task(struct task_struct *p, int src_cpu, int dest_cpu)
{
struct rq *rq;
int ret = 0;
if (unlikely(!cpu_active(dest_cpu)))
return ret;
rq = cpu_rq(src_cpu);
raw_spin_lock(&p->pi_lock);
raw_spin_lock(&rq->lock);
/* Already moved. */
if (task_cpu(p) != src_cpu)
goto done;
/* Affinity changed (again). */
if (!cpumask_test_cpu(dest_cpu, tsk_cpus_allowed(p)))
goto fail;
/*
* If we're not on a rq, the next wake-up will ensure we're
* placed properly.
*/
if (task_on_rq_queued(p))
rq = move_queued_task(p, dest_cpu);
done:
ret = 1;
fail:
raw_spin_unlock(&rq->lock);
raw_spin_unlock(&p->pi_lock);
return ret;
}
/*
* migration_cpu_stop - this will be executed by a highprio stopper thread
* and performs thread migration by bumping thread off CPU then
* 'pushing' onto another runqueue.
*/
static int migration_cpu_stop(void *data)
{
struct migration_arg *arg = data;
/*
* The original target cpu might have gone down and we might
* be on another cpu but it doesn't matter.
*/
local_irq_disable();
/*
* We need to explicitly wake pending tasks before running
* __migrate_task() such that we will not miss enforcing cpus_allowed
* during wakeups, see set_cpus_allowed_ptr()'s TASK_WAKING test.
*/
sched_ttwu_pending();
__migrate_task(arg->task, raw_smp_processor_id(), arg->dest_cpu);
local_irq_enable();
return 0;
}
void do_set_cpus_allowed(struct task_struct *p, const struct cpumask *new_mask)
{
if (p->sched_class->set_cpus_allowed)
p->sched_class->set_cpus_allowed(p, new_mask);
cpumask_copy(&p->cpus_allowed, new_mask);
p->nr_cpus_allowed = cpumask_weight(new_mask);
}
/*
* Change a given task's CPU affinity. Migrate the thread to a
* proper CPU and schedule it away if the CPU it's executing on
* is removed from the allowed bitmask.
*
* NOTE: the caller must have a valid reference to the task, the
* task must not exit() & deallocate itself prematurely. The
* call is not atomic; no spinlocks may be held.
*/
int set_cpus_allowed_ptr(struct task_struct *p, const struct cpumask *new_mask)
{
unsigned long flags;
struct rq *rq;
unsigned int dest_cpu;
int ret = 0;
rq = task_rq_lock(p, &flags);
if (cpumask_equal(&p->cpus_allowed, new_mask))
goto out;
if (!cpumask_intersects(new_mask, cpu_active_mask)) {
ret = -EINVAL;
goto out;
}
do_set_cpus_allowed(p, new_mask);
/* Can the task run on the task's current CPU? If so, we're done */
if (cpumask_test_cpu(task_cpu(p), new_mask))
goto out;
dest_cpu = cpumask_any_and(cpu_active_mask, new_mask);
if (task_running(rq, p) || p->state == TASK_WAKING) {
struct migration_arg arg = { p, dest_cpu };
/* Need help from migration thread: drop lock and wait. */
task_rq_unlock(rq, p, &flags);
stop_one_cpu(cpu_of(rq), migration_cpu_stop, &arg);
tlb_migrate_finish(p->mm);
return 0;
} else if (task_on_rq_queued(p))
rq = move_queued_task(p, dest_cpu);
out:
task_rq_unlock(rq, p, &flags);
return ret;
}
EXPORT_SYMBOL_GPL(set_cpus_allowed_ptr);
void set_task_cpu(struct task_struct *p, unsigned int new_cpu)
{
#ifdef CONFIG_SCHED_DEBUG
@ -1186,13 +1360,6 @@ int migrate_swap(struct task_struct *cur, struct task_struct *p)
return ret;
}
struct migration_arg {
struct task_struct *task;
int dest_cpu;
};
static int migration_cpu_stop(void *data);
/*
* wait_task_inactive - wait for a thread to unschedule.
*
@ -1325,9 +1492,7 @@ void kick_process(struct task_struct *p)
preempt_enable();
}
EXPORT_SYMBOL_GPL(kick_process);
#endif /* CONFIG_SMP */
#ifdef CONFIG_SMP
/*
* ->cpus_allowed is protected by both rq->lock and p->pi_lock
*/
@ -1432,7 +1597,7 @@ static void update_avg(u64 *avg, u64 sample)
s64 diff = sample - *avg;
*avg += diff >> 3;
}
#endif
#endif /* CONFIG_SMP */
static void
ttwu_stat(struct task_struct *p, int cpu, int wake_flags)
@ -4773,149 +4938,6 @@ int task_can_attach(struct task_struct *p,
}
#ifdef CONFIG_SMP
/*
* move_queued_task - move a queued task to new rq.
*
* Returns (locked) new rq. Old rq's lock is released.
*/
static struct rq *move_queued_task(struct task_struct *p, int new_cpu)
{
struct rq *rq = task_rq(p);
lockdep_assert_held(&rq->lock);
dequeue_task(rq, p, 0);
p->on_rq = TASK_ON_RQ_MIGRATING;
set_task_cpu(p, new_cpu);
raw_spin_unlock(&rq->lock);
rq = cpu_rq(new_cpu);
raw_spin_lock(&rq->lock);
BUG_ON(task_cpu(p) != new_cpu);
p->on_rq = TASK_ON_RQ_QUEUED;
enqueue_task(rq, p, 0);
check_preempt_curr(rq, p, 0);
return rq;
}
void do_set_cpus_allowed(struct task_struct *p, const struct cpumask *new_mask)
{
if (p->sched_class->set_cpus_allowed)
p->sched_class->set_cpus_allowed(p, new_mask);
cpumask_copy(&p->cpus_allowed, new_mask);
p->nr_cpus_allowed = cpumask_weight(new_mask);
}
/*
* This is how migration works:
*
* 1) we invoke migration_cpu_stop() on the target CPU using
* stop_one_cpu().
* 2) stopper starts to run (implicitly forcing the migrated thread
* off the CPU)
* 3) it checks whether the migrated task is still in the wrong runqueue.
* 4) if it's in the wrong runqueue then the migration thread removes
* it and puts it into the right queue.
* 5) stopper completes and stop_one_cpu() returns and the migration
* is done.
*/
/*
* Change a given task's CPU affinity. Migrate the thread to a
* proper CPU and schedule it away if the CPU it's executing on
* is removed from the allowed bitmask.
*
* NOTE: the caller must have a valid reference to the task, the
* task must not exit() & deallocate itself prematurely. The
* call is not atomic; no spinlocks may be held.
*/
int set_cpus_allowed_ptr(struct task_struct *p, const struct cpumask *new_mask)
{
unsigned long flags;
struct rq *rq;
unsigned int dest_cpu;
int ret = 0;
rq = task_rq_lock(p, &flags);
if (cpumask_equal(&p->cpus_allowed, new_mask))
goto out;
if (!cpumask_intersects(new_mask, cpu_active_mask)) {
ret = -EINVAL;
goto out;
}
do_set_cpus_allowed(p, new_mask);
/* Can the task run on the task's current CPU? If so, we're done */
if (cpumask_test_cpu(task_cpu(p), new_mask))
goto out;
dest_cpu = cpumask_any_and(cpu_active_mask, new_mask);
if (task_running(rq, p) || p->state == TASK_WAKING) {
struct migration_arg arg = { p, dest_cpu };
/* Need help from migration thread: drop lock and wait. */
task_rq_unlock(rq, p, &flags);
stop_one_cpu(cpu_of(rq), migration_cpu_stop, &arg);
tlb_migrate_finish(p->mm);
return 0;
} else if (task_on_rq_queued(p))
rq = move_queued_task(p, dest_cpu);
out:
task_rq_unlock(rq, p, &flags);
return ret;
}
EXPORT_SYMBOL_GPL(set_cpus_allowed_ptr);
/*
* Move (not current) task off this cpu, onto dest cpu. We're doing
* this because either it can't run here any more (set_cpus_allowed()
* away from this CPU, or CPU going down), or because we're
* attempting to rebalance this task on exec (sched_exec).
*
* So we race with normal scheduler movements, but that's OK, as long
* as the task is no longer on this CPU.
*
* Returns non-zero if task was successfully migrated.
*/
static int __migrate_task(struct task_struct *p, int src_cpu, int dest_cpu)
{
struct rq *rq;
int ret = 0;
if (unlikely(!cpu_active(dest_cpu)))
return ret;
rq = cpu_rq(src_cpu);
raw_spin_lock(&p->pi_lock);
raw_spin_lock(&rq->lock);
/* Already moved. */
if (task_cpu(p) != src_cpu)
goto done;
/* Affinity changed (again). */
if (!cpumask_test_cpu(dest_cpu, tsk_cpus_allowed(p)))
goto fail;
/*
* If we're not on a rq, the next wake-up will ensure we're
* placed properly.
*/
if (task_on_rq_queued(p))
rq = move_queued_task(p, dest_cpu);
done:
ret = 1;
fail:
raw_spin_unlock(&rq->lock);
raw_spin_unlock(&p->pi_lock);
return ret;
}
#ifdef CONFIG_NUMA_BALANCING
/* Migrate current task p to target_cpu */
@ -4963,35 +4985,9 @@ void sched_setnuma(struct task_struct *p, int nid)
enqueue_task(rq, p, 0);
task_rq_unlock(rq, p, &flags);
}
#endif
/*
* migration_cpu_stop - this will be executed by a highprio stopper thread
* and performs thread migration by bumping thread off CPU then
* 'pushing' onto another runqueue.
*/
static int migration_cpu_stop(void *data)
{
struct migration_arg *arg = data;
/*
* The original target cpu might have gone down and we might
* be on another cpu but it doesn't matter.
*/
local_irq_disable();
/*
* We need to explicitly wake pending tasks before running
* __migrate_task() such that we will not miss enforcing cpus_allowed
* during wakeups, see set_cpus_allowed_ptr()'s TASK_WAKING test.
*/
sched_ttwu_pending();
__migrate_task(arg->task, raw_smp_processor_id(), arg->dest_cpu);
local_irq_enable();
return 0;
}
#endif /* CONFIG_NUMA_BALANCING */
#ifdef CONFIG_HOTPLUG_CPU
/*
* Ensures that the idle task is using init_mm right before its cpu goes
* offline.
@ -5094,7 +5090,6 @@ static void migrate_tasks(unsigned int dead_cpu)
rq->stop = stop;
}
#endif /* CONFIG_HOTPLUG_CPU */
#if defined(CONFIG_SCHED_DEBUG) && defined(CONFIG_SYSCTL)
@ -5273,7 +5268,7 @@ static void register_sched_domain_sysctl(void)
static void unregister_sched_domain_sysctl(void)
{
}
#endif
#endif /* CONFIG_SCHED_DEBUG && CONFIG_SYSCTL */
static void set_rq_online(struct rq *rq)
{
@ -5420,9 +5415,6 @@ static int __init migration_init(void)
return 0;
}
early_initcall(migration_init);
#endif
#ifdef CONFIG_SMP
static cpumask_var_t sched_domains_tmpmask; /* sched_domains_mutex */
@ -6648,7 +6640,7 @@ static int __sdt_alloc(const struct cpumask *cpu_map)
struct sched_group *sg;
struct sched_group_capacity *sgc;
sd = kzalloc_node(sizeof(struct sched_domain) + cpumask_size(),
sd = kzalloc_node(sizeof(struct sched_domain) + cpumask_size(),
GFP_KERNEL, cpu_to_node(j));
if (!sd)
return -ENOMEM;