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sched: Allow sched_core_put() from atomic context

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Stuff the meat of sched_core_put() into a work such that we can use
sched_core_put() from atomic context.

Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Tested-by: Don Hiatt <dhiatt@digitalocean.com>
Tested-by: Hongyu Ning <hongyu.ning@linux.intel.com>
Tested-by: Vincent Guittot <vincent.guittot@linaro.org>
Link: https://lkml.kernel.org/r/20210422123308.377455632@infradead.org
This commit is contained in:
Peter Zijlstra 2021-03-29 10:08:58 +02:00
parent 9ef7e7e33b
commit 875feb41fd
1 changed files with 27 additions and 6 deletions
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33
kernel/sched/core.c
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@ -102,7 +102,7 @@ DEFINE_STATIC_KEY_FALSE(__sched_core_enabled);
*/
static DEFINE_MUTEX(sched_core_mutex);
static int sched_core_count;
static atomic_t sched_core_count;
static struct cpumask sched_core_mask;
static void __sched_core_flip(bool enabled)
@ -170,18 +170,39 @@ static void __sched_core_disable(void)
void sched_core_get(void)
{
if (atomic_inc_not_zero(&sched_core_count))
return;
mutex_lock(&sched_core_mutex);
if (!sched_core_count++)
if (!atomic_read(&sched_core_count))
__sched_core_enable();
smp_mb__before_atomic();
atomic_inc(&sched_core_count);
mutex_unlock(&sched_core_mutex);
}
static void __sched_core_put(struct work_struct *work)
{
if (atomic_dec_and_mutex_lock(&sched_core_count, &sched_core_mutex)) {
__sched_core_disable();
mutex_unlock(&sched_core_mutex);
}
}
void sched_core_put(void)
{
mutex_lock(&sched_core_mutex);
if (!--sched_core_count)
__sched_core_disable();
mutex_unlock(&sched_core_mutex);
static DECLARE_WORK(_work, __sched_core_put);
/*
* "There can be only one"
*
* Either this is the last one, or we don't actually need to do any
* 'work'. If it is the last *again*, we rely on
* WORK_STRUCT_PENDING_BIT.
*/
if (!atomic_add_unless(&sched_core_count, -1, 1))
schedule_work(&_work);
}
#endif /* CONFIG_SCHED_CORE */