2019-01-10 10:11:43

by Ladislav Michl

Subject: [PATCH] PM/runtime: Do not needlessly call ktime_get

pm_runtime_autosuspend_expiration calls ktime_get even when
its returned value may be unused. Therefore get current time
later and remove gotos while there.

Signed-off-by: Ladislav Michl <[email protected]>
---
NOTE: Depends on Vincent's "[PATCH v2] PM/runtime: Fix autosuspend_delay
on 32bits arch"!

drivers/base/power/runtime.c | 19 ++++++++-----------
1 file changed, 8 insertions(+), 11 deletions(-)

diff --git a/drivers/base/power/runtime.c b/drivers/base/power/runtime.c
index 457be03b744d..836b1b8784eb 100644
--- a/drivers/base/power/runtime.c
+++ b/drivers/base/power/runtime.c
@@ -129,24 +129,21 @@ static void pm_runtime_cancel_pending(struct device *dev)
u64 pm_runtime_autosuspend_expiration(struct device *dev)
{
int autosuspend_delay;
- u64 last_busy, expires = 0;
- u64 now = ktime_to_ns(ktime_get());
+ u64 expires;

if (!dev->power.use_autosuspend)
- goto out;
+ return 0;

autosuspend_delay = READ_ONCE(dev->power.autosuspend_delay);
if (autosuspend_delay < 0)
- goto out;
-
- last_busy = READ_ONCE(dev->power.last_busy);
+ return 0;

- expires = last_busy + (u64)autosuspend_delay * NSEC_PER_MSEC;
- if (expires <= now)
- expires = 0; /* Already expired. */
+ expires = READ_ONCE(dev->power.last_busy);
+ expires += (u64)autosuspend_delay * NSEC_PER_MSEC;
+ if (expires > ktime_to_ns(ktime_get()))
+ return expires; /* Expires in the future */

- out:
- return expires;
+ return 0;
}
EXPORT_SYMBOL_GPL(pm_runtime_autosuspend_expiration);

--
2.20.1

2019-01-10 16:46:52

by Tony Lindgren

Subject: Re: [PATCH] PM/runtime: Do not needlessly call ktime_get

* Ladislav Michl <[email protected]> [190110 09:51]:
> pm_runtime_autosuspend_expiration calls ktime_get even when
> its returned value may be unused. Therefore get current time
> later and remove gotos while there.

Acked-by: Tony Lindgren <[email protected]>

2019-01-10 18:58:24

by Vincent Guittot

Subject: Re: [PATCH] PM/runtime: Do not needlessly call ktime_get

On Thu, 10 Jan 2019 at 10:51, Ladislav Michl <[email protected]> wrote:
>
> pm_runtime_autosuspend_expiration calls ktime_get even when
> its returned value may be unused. Therefore get current time
> later and remove gotos while there.
>
> Signed-off-by: Ladislav Michl <[email protected]>

Acked-by: Vincent Guittot <[email protected]>

> ---
> NOTE: Depends on Vincent's "[PATCH v2] PM/runtime: Fix autosuspend_delay
> on 32bits arch"!
>
> drivers/base/power/runtime.c | 19 ++++++++-----------
> 1 file changed, 8 insertions(+), 11 deletions(-)
>
> diff --git a/drivers/base/power/runtime.c b/drivers/base/power/runtime.c
> index 457be03b744d..836b1b8784eb 100644
> --- a/drivers/base/power/runtime.c
> +++ b/drivers/base/power/runtime.c
> @@ -129,24 +129,21 @@ static void pm_runtime_cancel_pending(struct device *dev)
> u64 pm_runtime_autosuspend_expiration(struct device *dev)
> {
> int autosuspend_delay;
> - u64 last_busy, expires = 0;
> - u64 now = ktime_to_ns(ktime_get());
> + u64 expires;
>
> if (!dev->power.use_autosuspend)
> - goto out;
> + return 0;
>
> autosuspend_delay = READ_ONCE(dev->power.autosuspend_delay);
> if (autosuspend_delay < 0)
> - goto out;
> -
> - last_busy = READ_ONCE(dev->power.last_busy);
> + return 0;
>
> - expires = last_busy + (u64)autosuspend_delay * NSEC_PER_MSEC;
> - if (expires <= now)
> - expires = 0; /* Already expired. */
> + expires = READ_ONCE(dev->power.last_busy);
> + expires += (u64)autosuspend_delay * NSEC_PER_MSEC;
> + if (expires > ktime_to_ns(ktime_get()))
> + return expires; /* Expires in the future */
>
> - out:
> - return expires;
> + return 0;
> }
> EXPORT_SYMBOL_GPL(pm_runtime_autosuspend_expiration);
>
> --
> 2.20.1
>

2019-01-16 20:06:32

by Rafael J. Wysocki

Subject: Re: [PATCH] PM/runtime: Do not needlessly call ktime_get

On Thursday, January 10, 2019 7:56:19 PM CET Vincent Guittot wrote:
> On Thu, 10 Jan 2019 at 10:51, Ladislav Michl <[email protected]> wrote:
> >
> > pm_runtime_autosuspend_expiration calls ktime_get even when
> > its returned value may be unused. Therefore get current time
> > later and remove gotos while there.
> >
> > Signed-off-by: Ladislav Michl <[email protected]>
>
> Acked-by: Vincent Guittot <[email protected]>

Patch applied, thanks!