From: "Rafael J. Wysocki" <rjw@rjwysocki.net>
To: Ladislav Michl <ladis@linux-mips.org>
Cc: "Rafael J. Wysocki" <rafael@kernel.org>,
Linux PM <linux-pm@vger.kernel.org>,
Linux Kernel Mailing List <linux-kernel@vger.kernel.org>,
Linux ARM <linux-arm-kernel@lists.infradead.org>,
Linux OMAP Mailing List <linux-omap@vger.kernel.org>,
Ulf Hansson <ulf.hansson@linaro.org>,
Biju Das <biju.das@bp.renesas.com>,
Geert Uytterhoeven <geert@linux-m68k.org>,
Linux-Renesas <linux-renesas-soc@vger.kernel.org>,
Vincent Guittot <vincent.guittot@linaro.org>
Subject: Re: [PATCH] PM/runtime: Optimize pm_runtime_autosuspend_expiration()
Date: Wed, 06 Feb 2019 11:34:03 +0100 [thread overview]
Message-ID: <4091828.IqCJ3qcF9B@aspire.rjw.lan> (raw)
In-Reply-To: <20190130214017.GA5038@lenoch>
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!
prev parent reply other threads:[~2019-02-06 10:35 UTC|newest]
Thread overview: 2+ messages / expand[flat|nested] mbox.gz Atom feed top
2019-01-30 21:40 [PATCH] PM/runtime: Optimize pm_runtime_autosuspend_expiration() Ladislav Michl
2019-02-06 10:34 ` Rafael J. Wysocki [this message]
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