[removing close lustre-devel list as requested, adding assorted Lustre individuals]
On Fri, Dec 22 2017, Peter Zijlstra wrote:
> On Fri, Dec 22, 2017 at 02:11:04PM +1100, NeilBrown wrote:
>> The new TASK_IDLE state (TASK_UNINTERRUPTIBLE | __TASK_NOLOAD)
>> is not much used. One way to make it easier to use is to
>> add wait_event*() family functions that make use of it.
>> This patch adds:
>> wait_event_idle()
>> wait_event_idle_timeout()
>> wait_event_idle_exclusive()
>>
>> This set were chosen because lustre needs them before
>> it can discard its own l_wait_event() macro.
>
> Seems sane enough; please take through the tree that introduces the
> first users of this.
Will do.
>
> Acked-by: Peter Zijlstra (Intel) <pet...@infradead.org>
Thanks,
NeilBrown
>
>> Signed-off-by: NeilBrown <ne...@suse.com>
>> ---
>> include/linux/wait.h | 77
>> ++++++++++++++++++++++++++++++++++++++++++++++++++
>> 1 file changed, 77 insertions(+)
>>
>> diff --git a/include/linux/wait.h b/include/linux/wait.h
>> index 158715445ffb..3aea0780c9d0 100644
>> --- a/include/linux/wait.h
>> +++ b/include/linux/wait.h
>> @@ -597,6 +597,83 @@ do {
>> \
>> __ret;
>> \
>> })
>>
>> +/**
>> + * wait_event_idle - wait for a condition with contributing to system load
>> + * @wq_head: the waitqueue to wait on
>> + * @condition: a C expression for the event to wait for
>> + *
>> + * The process is put to sleep (TASK_IDLE) until the
>> + * @condition evaluates to true.
>> + * The @condition is checked each time the waitqueue @wq_head is woken up.
>> + *
>> + * wake_up() has to be called after changing any variable that could
>> + * change the result of the wait condition.
>> + *
>> + */
>> +#define wait_event_idle(wq_head, condition)
>> \
>> +do {
>> \
>> + might_sleep();
>> \
>> + if (!(condition))
>> \
>> + ___wait_event(wq_head, condition, TASK_IDLE, 0, 0, schedule());
>> \
>> +} while (0)
>> +
>> +/**
>> + * wait_event_idle_exclusive - wait for a condition with contributing to
>> system load
>> + * @wq_head: the waitqueue to wait on
>> + * @condition: a C expression for the event to wait for
>> + *
>> + * The process is put to sleep (TASK_IDLE) until the
>> + * @condition evaluates to true.
>> + * The @condition is checked each time the waitqueue @wq_head is woken up.
>> + *
>> + * The process is put on the wait queue with an WQ_FLAG_EXCLUSIVE flag
>> + * set thus when other process waits process on the list if this
>> + * process is awaken further processes are not considered.
>> + *
>> + * wake_up() has to be called after changing any variable that could
>> + * change the result of the wait condition.
>> + *
>> + */
>> +#define wait_event_idle_exclusive(wq_head, condition)
>> \
>> +do {
>> \
>> + might_sleep();
>> \
>> + if (!(condition))
>> \
>> + ___wait_event(wq_head, condition, TASK_IDLE, 1, 0, schedule());
>> \
>> +} while (0)
>> +
>> +#define __wait_event_idle_timeout(wq_head, condition, timeout)
>> \
>> + ___wait_event(wq_head, ___wait_cond_timeout(condition),
>> \
>> + TASK_IDLE, 0, timeout,
>> \
>> + __ret = schedule_timeout(__ret))
>> +
>> +/**
>> + * wait_event_idle_timeout - sleep without load until a condition gets true
>> or a timeout elapses
>> + * @wq_head: the waitqueue to wait on
>> + * @condition: a C expression for the event to wait for
>> + * @timeout: timeout, in jiffies
>> + *
>> + * The process is put to sleep (TASK_IDLE) until the
>> + * @condition evaluates to true. The @condition is checked each time
>> + * the waitqueue @wq_head is woken up.
>> + *
>> + * wake_up() has to be called after changing any variable that could
>> + * change the result of the wait condition.
>> + *
>> + * Returns:
>> + * 0 if the @condition evaluated to %false after the @timeout elapsed,
>> + * 1 if the @condition evaluated to %true after the @timeout elapsed,
>> + * or the remaining jiffies (at least 1) if the @condition evaluated
>> + * to %true before the @timeout elapsed.
>> + */
>> +#define wait_event_idle_timeout(wq_head, condition, timeout)
>> \
>> +({
>> \
>> + long __ret = timeout;
>> \
>> + might_sleep();
>> \
>> + if (!___wait_cond_timeout(condition))
>> \
>> + __ret = __wait_event_timeout(wq_head, condition, timeout);
>> \
>> + __ret;
>> \
>> +})
>> +
>> extern int do_wait_intr(wait_queue_head_t *, wait_queue_entry_t *);
>> extern int do_wait_intr_irq(wait_queue_head_t *, wait_queue_entry_t *);
>>
>>
>>
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