[PATCH v3 2/5] PM / sleep: Asynchronous threads for resume_noirq

From: Chuansheng Liu
Date: Mon Feb 17 2014 - 01:31:57 EST


In analogy with commits 5af84b82701a and 97df8c12995, using
asynchronous threads can improve the overall resume_noirq time
significantly.

One typical case is:
In resume_noirq phase and for the PCI devices, the function
pci_pm_resume_noirq() will be called, and there is one d3_delay
(10ms) at least.

With the way of asynchronous threads, we just need wait d3_delay
time once in parallel for each calling, which saves much time to
resume quickly.

Signed-off-by: Chuansheng Liu <chuansheng.liu@xxxxxxxxx>
---
drivers/base/power/main.c | 66 +++++++++++++++++++++++++++++++++++------------
1 file changed, 50 insertions(+), 16 deletions(-)

diff --git a/drivers/base/power/main.c b/drivers/base/power/main.c
index 00c53eb..89172aa 100644
--- a/drivers/base/power/main.c
+++ b/drivers/base/power/main.c
@@ -469,7 +469,7 @@ static void dpm_watchdog_clear(struct dpm_watchdog *wd)
* The driver of @dev will not receive interrupts while this function is being
* executed.
*/
-static int device_resume_noirq(struct device *dev, pm_message_t state)
+static int device_resume_noirq(struct device *dev, pm_message_t state, bool async)
{
pm_callback_t callback = NULL;
char *info = NULL;
@@ -481,6 +481,8 @@ static int device_resume_noirq(struct device *dev, pm_message_t state)
if (dev->power.syscore)
goto Out;

+ dpm_wait(dev->parent, async);
+
if (!dev->power.is_noirq_suspended)
goto Out;

@@ -507,10 +509,29 @@ static int device_resume_noirq(struct device *dev, pm_message_t state)
dev->power.is_noirq_suspended = false;

Out:
+ complete_all(&dev->power.completion);
TRACE_RESUME(error);
return error;
}

+static bool is_async(struct device *dev)
+{
+ return dev->power.async_suspend && pm_async_enabled
+ && !pm_trace_is_enabled();
+}
+
+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, true);
+ if (error)
+ pm_dev_err(dev, pm_transition, " async", error);
+
+ put_device(dev);
+}
+
/**
* dpm_resume_noirq - Execute "noirq resume" callbacks for all devices.
* @state: PM transition of the system being carried out.
@@ -520,29 +541,48 @@ 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();

mutex_lock(&dpm_list_mtx);
- while (!list_empty(&dpm_noirq_list)) {
- struct device *dev = to_device(dpm_noirq_list.next);
- int error;
+ pm_transition = state;
+
+ /*
+ * Advanced the async threads upfront,
+ * in case the starting of async threads is
+ * delayed by non-async resuming devices.
+ */
+ list_for_each_entry(dev, &dpm_noirq_list, power.entry) {
+ reinit_completion(&dev->power.completion);
+ if (is_async(dev)) {
+ get_device(dev);
+ async_schedule(async_resume_noirq, dev);
+ }
+ }

+ while (!list_empty(&dpm_noirq_list)) {
+ 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, false);
+ 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();
@@ -742,12 +782,6 @@ static void async_resume(void *data, async_cookie_t cookie)
put_device(dev);
}

-static bool is_async(struct device *dev)
-{
- return dev->power.async_suspend && pm_async_enabled
- && !pm_trace_is_enabled();
-}
-
/**
* dpm_resume - Execute "resume" callbacks for non-sysdev devices.
* @state: PM transition of the system being carried out.
--
1.9.rc0

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