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Subject[PATCH] PM: Enable asynchronous noirq resume threads to save the resuming time
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Currently, the dpm_resume_noirq() is done synchronously, and for PCI devices
pci_pm_resume_noirq():

pci_pm_resume_noirq()
pci_pm_default_resume_early()
pci_power_up()
pci_raw_set_power_state()
Which set the device from D3hot to D0 mostly, for every device, there will
be one 10ms(pci_pm_d3_delay) to wait.

Hence normally dpm_resume_noirq() will cost > 100ms, which is bigger for mobile
platform.

Here implementing it with asynchronous way which will reduce much.

For example below, The 80% time is saved.
With synchronous way:
[ 1411.272218] PM: noirq resume of devices complete after 92.223 msecs
With asynchronous way:
[ 110.616735] PM: noirq resume of devices complete after 10.544 msecs

Signed-off-by: Liu, Chuansheng <chuansheng.liu@intel.com>
---
drivers/base/power/main.c | 42 +++++++++++++++++++++++++++++++++---------
1 file changed, 33 insertions(+), 9 deletions(-)

diff --git a/drivers/base/power/main.c b/drivers/base/power/main.c
index 1b41fca..1b9d774 100644
--- a/drivers/base/power/main.c
+++ b/drivers/base/power/main.c
@@ -505,6 +505,19 @@ static int device_resume_noirq(struct device *dev, pm_message_t state)
return error;
}

+static bool is_async(struct device *dev);
+
+static void async_resume_noirq(void *data, async_cookie_t cookie)
+{
+ struct device *dev = (struct device *)data;
+ int error;
+
+ error = device_resume_noirq(dev, pm_transition);
+ if (error)
+ pm_dev_err(dev, pm_transition, " noirq", error);
+ put_device(dev);
+}
+
/**
* dpm_resume_noirq - Execute "noirq resume" callbacks for all devices.
* @state: PM transition of the system being carried out.
@@ -514,29 +527,40 @@ static int device_resume_noirq(struct device *dev, pm_message_t state)
*/
static void dpm_resume_noirq(pm_message_t state)
{
+ struct device *dev;
ktime_t starttime = ktime_get();
+ pm_transition = state;
+
+ list_for_each_entry(dev, &dpm_noirq_list, power.entry) {
+ if (is_async(dev)) {
+ get_device(dev);
+ async_schedule(async_resume_noirq, dev);
+ }
+ }

mutex_lock(&dpm_list_mtx);
while (!list_empty(&dpm_noirq_list)) {
- struct device *dev = to_device(dpm_noirq_list.next);
- int error;
+ dev = to_device(dpm_noirq_list.next);

get_device(dev);
list_move_tail(&dev->power.entry, &dpm_late_early_list);
mutex_unlock(&dpm_list_mtx);

- error = device_resume_noirq(dev, state);
- if (error) {
- suspend_stats.failed_resume_noirq++;
- dpm_save_failed_step(SUSPEND_RESUME_NOIRQ);
- dpm_save_failed_dev(dev_name(dev));
- pm_dev_err(dev, state, " noirq", error);
+ if (!is_async(dev)) {
+ int error;
+ error = device_resume_noirq(dev, state);
+ if (error) {
+ suspend_stats.failed_resume_noirq++;
+ dpm_save_failed_step(SUSPEND_RESUME_NOIRQ);
+ dpm_save_failed_dev(dev_name(dev));
+ pm_dev_err(dev, state, " noirq", error);
+ }
}
-
mutex_lock(&dpm_list_mtx);
put_device(dev);
}
mutex_unlock(&dpm_list_mtx);
+ async_synchronize_full();
dpm_show_time(starttime, state, "noirq");
resume_device_irqs();
cpuidle_resume();
--
1.7.9.5




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