* [PATCH] PM/runtime: Optimize pm_runtime_autosuspend_expiration()
@ 2019-01-30 21:40 Ladislav Michl
2019-02-06 10:34 ` Rafael J. Wysocki
0 siblings, 1 reply; 2+ messages in thread
From: Ladislav Michl @ 2019-01-30 21:40 UTC (permalink / raw)
To: Rafael J. Wysocki
Cc: Linux PM, Linux Kernel Mailing List, Linux ARM,
Linux OMAP Mailing List, Ulf Hansson, Biju Das,
Geert Uytterhoeven, Linux-Renesas, Vincent Guittot
pm_runtime_autosuspend_expiration calls ktime_get_mono_fast_ns
even when its returned value may be unused. Therefore get
current time later and remove gotos while there.
Signed-off-by: Ladislav Michl <ladis@linux-mips.org>
Acked-by: Tony Lindgren <tony@atomide.com>
Acked-by: Vincent Guittot <vincent.guittot@linaro.org>
---
This patch is based on top of bleeding-edge branch, where
"[PATCH v2 ] PM-runtime: fix deadlock with ktime" is sitting.
I expect v3 of that patch, which should not harm this one.
It is meant to replace "PM/runtime: Do not needlessly call ktime_get"
sent earlier.
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 65e2b5f48e0c..7bbe28faca8d 100644
--- a/drivers/base/power/runtime.c
+++ b/drivers/base/power/runtime.c
@@ -145,24 +145,21 @@ 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_get_mono_fast_ns();
+ 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_get_mono_fast_ns())
+ return expires; /* Expires in the future */
- out:
- return expires;
+ return 0;
}
EXPORT_SYMBOL_GPL(pm_runtime_autosuspend_expiration);
--
2.20.1
^ permalink raw reply related [flat|nested] 2+ messages in thread
* Re: [PATCH] PM/runtime: Optimize pm_runtime_autosuspend_expiration()
2019-01-30 21:40 [PATCH] PM/runtime: Optimize pm_runtime_autosuspend_expiration() Ladislav Michl
@ 2019-02-06 10:34 ` Rafael J. Wysocki
0 siblings, 0 replies; 2+ messages in thread
From: Rafael J. Wysocki @ 2019-02-06 10:34 UTC (permalink / raw)
To: Ladislav Michl
Cc: Rafael J. Wysocki, Linux PM, Linux Kernel Mailing List,
Linux ARM, Linux OMAP Mailing List, Ulf Hansson, Biju Das,
Geert Uytterhoeven, Linux-Renesas, Vincent Guittot
On Wednesday, January 30, 2019 10:40:17 PM CET Ladislav Michl wrote:
> pm_runtime_autosuspend_expiration calls ktime_get_mono_fast_ns
> even when its returned value may be unused. Therefore get
> current time later and remove gotos while there.
>
> Signed-off-by: Ladislav Michl <ladis@linux-mips.org>
> Acked-by: Tony Lindgren <tony@atomide.com>
> Acked-by: Vincent Guittot <vincent.guittot@linaro.org>
> ---
> This patch is based on top of bleeding-edge branch, where
> "[PATCH v2 ] PM-runtime: fix deadlock with ktime" is sitting.
> I expect v3 of that patch, which should not harm this one.
> It is meant to replace "PM/runtime: Do not needlessly call ktime_get"
> sent earlier.
>
> 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 65e2b5f48e0c..7bbe28faca8d 100644
> --- a/drivers/base/power/runtime.c
> +++ b/drivers/base/power/runtime.c
> @@ -145,24 +145,21 @@ 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_get_mono_fast_ns();
> + 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_get_mono_fast_ns())
> + return expires; /* Expires in the future */
>
> - out:
> - return expires;
> + return 0;
> }
> EXPORT_SYMBOL_GPL(pm_runtime_autosuspend_expiration);
>
>
Applied, thanks!
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2019-01-30 21:40 [PATCH] PM/runtime: Optimize pm_runtime_autosuspend_expiration() Ladislav Michl
2019-02-06 10:34 ` Rafael J. Wysocki
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