Re: [PATCH v3 5/5] PM / sleep: Asynchronous threads for suspend_late

From: Rafael J. Wysocki
Date: Mon Feb 17 2014 - 12:13:06 EST


On Monday, February 17, 2014 02:19:14 PM Chuansheng Liu wrote:
> In analogy with commits 5af84b82701a and 97df8c12995, using
> asynchronous threads can improve the overall suspend_late
> time significantly.
>
> This patch is for suspend_late phase.
>
> Signed-off-by: Chuansheng Liu <chuansheng.liu@xxxxxxxxx>
> ---
> drivers/base/power/main.c | 66 ++++++++++++++++++++++++++++++++++++++---------
> 1 file changed, 54 insertions(+), 12 deletions(-)
>
> diff --git a/drivers/base/power/main.c b/drivers/base/power/main.c
> index 72b4c9c..c031050 100644
> --- a/drivers/base/power/main.c
> +++ b/drivers/base/power/main.c
> @@ -1127,16 +1127,26 @@ static int dpm_suspend_noirq(pm_message_t state)
> *
> * Runtime PM is disabled for @dev while this function is being executed.
> */
> -static int device_suspend_late(struct device *dev, pm_message_t state)
> +static int __device_suspend_late(struct device *dev, pm_message_t state, bool async)
> {
> pm_callback_t callback = NULL;
> char *info = NULL;
> - int error;
> + int error = 0;
> +
> + dpm_wait_for_children(dev, async);
>

Like in patch [4/5], all of the "goto Complete" statements can go before
the waiting.

> __pm_runtime_disable(dev, false);
>
> + if (async_error)
> + goto Complete;
> +
> + if (pm_wakeup_pending()) {
> + async_error = -EBUSY;
> + goto Complete;
> + }
> +
> if (dev->power.syscore)
> - return 0;
> + goto Complete;
>
> if (dev->pm_domain) {
> info = "late power domain ";
> @@ -1160,10 +1170,40 @@ static int device_suspend_late(struct device *dev, pm_message_t state)
> error = dpm_run_callback(callback, dev, state, info);
> if (!error)
> dev->power.is_late_suspended = true;
> + else
> + async_error = error;
>
> +Complete:
> + complete_all(&dev->power.completion);
> return error;
> }
>
> +static void async_suspend_late(void *data, async_cookie_t cookie)
> +{
> + struct device *dev = (struct device *)data;
> + int error;
> +
> + error = __device_suspend_late(dev, pm_transition, true);
> + if (error) {
> + dpm_save_failed_dev(dev_name(dev));
> + pm_dev_err(dev, pm_transition, " async", error);
> + }
> + put_device(dev);
> +}
> +
> +static int device_suspend_late(struct device *dev)
> +{
> + reinit_completion(&dev->power.completion);
> +
> + if (pm_async_enabled && dev->power.async_suspend) {
> + get_device(dev);
> + async_schedule(async_suspend_late, dev);
> + return 0;
> + }
> +
> + return __device_suspend_late(dev, pm_transition, false);
> +}
> +
> /**
> * dpm_suspend_late - Execute "late suspend" callbacks for all devices.
> * @state: PM transition of the system being carried out.
> @@ -1174,19 +1214,20 @@ static int dpm_suspend_late(pm_message_t state)
> int error = 0;
>
> mutex_lock(&dpm_list_mtx);
> + pm_transition = state;
> + async_error = 0;
> +
> while (!list_empty(&dpm_suspended_list)) {
> struct device *dev = to_device(dpm_suspended_list.prev);
>
> get_device(dev);
> mutex_unlock(&dpm_list_mtx);
>
> - error = device_suspend_late(dev, state);
> + error = device_suspend_late(dev);
>
> mutex_lock(&dpm_list_mtx);
> if (error) {
> pm_dev_err(dev, state, " late", error);
> - suspend_stats.failed_suspend_late++;
> - dpm_save_failed_step(SUSPEND_SUSPEND_LATE);
> dpm_save_failed_dev(dev_name(dev));
> put_device(dev);
> break;
> @@ -1195,17 +1236,18 @@ static int dpm_suspend_late(pm_message_t state)
> list_move(&dev->power.entry, &dpm_late_early_list);
> put_device(dev);
>
> - if (pm_wakeup_pending()) {
> - error = -EBUSY;
> + if (async_error)
> break;
> - }
> }
> mutex_unlock(&dpm_list_mtx);
> - if (error)
> + async_synchronize_full();
> + if (error) {
> + suspend_stats.failed_suspend_late++;
> + dpm_save_failed_step(SUSPEND_SUSPEND_LATE);
> dpm_resume_early(resume_event(state));
> - else
> + } else {
> dpm_show_time(starttime, state, "late");
> -
> + }
> return error;
> }
>
>

--
I speak only for myself.
Rafael J. Wysocki, Intel Open Source Technology Center.
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