Messages in this thread Patch in this message | | | From | Chen Yu <> | Subject | [PATCH 2/2][RFC] PM-runtime: add tracepoints to cover all usage_count changes | Date | Sat, 6 Jun 2020 03:05:52 +0800 |
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Commit d229290689ae ("PM-runtime: add tracepoints for usage_count changes") has added some tracepoints to monitor the change of runtime usage, and there is something to improve: 1. There are some places that adjust the usage count have not been traced yet. For example, pm_runtime_get_noresume() and pm_runtime_put_noidle() 2. The change of the usage count will not be tracked if decreased from 1 to 0.
This patch address above issues by tracking the usage count whenever it has been modified. And these changes has helped track down the e1000e runtime issue.
Signed-off-by: Chen Yu <yu.c.chen@intel.com> --- drivers/base/power/runtime.c | 37 ++++++++++++++++++++++-------------- 1 file changed, 23 insertions(+), 14 deletions(-)
diff --git a/drivers/base/power/runtime.c b/drivers/base/power/runtime.c index 85a248e196ca..4aa2b5aa0bb8 100644 --- a/drivers/base/power/runtime.c +++ b/drivers/base/power/runtime.c @@ -1004,10 +1004,11 @@ int __pm_runtime_idle(struct device *dev, int rpmflags) int retval; if (rpmflags & RPM_GET_PUT) { - if (!atomic_dec_and_test(&dev->power.usage_count)) { - trace_rpm_usage_rcuidle(dev, rpmflags); + bool non_zero = !atomic_dec_and_test(&dev->power.usage_count); + + trace_rpm_usage_rcuidle(dev, rpmflags); + if (non_zero) return 0; - } } might_sleep_if(!(rpmflags & RPM_ASYNC) && !dev->power.irq_safe); @@ -1038,10 +1039,12 @@ int __pm_runtime_suspend(struct device *dev, int rpmflags) int retval; if (rpmflags & RPM_GET_PUT) { - if (!atomic_dec_and_test(&dev->power.usage_count)) { - trace_rpm_usage_rcuidle(dev, rpmflags); + bool non_zero = !atomic_dec_and_test(&dev->power.usage_count); + + trace_rpm_usage_rcuidle(dev, rpmflags); + if (non_zero) return 0; - } + } might_sleep_if(!(rpmflags & RPM_ASYNC) && !dev->power.irq_safe); @@ -1073,8 +1076,10 @@ int __pm_runtime_resume(struct device *dev, int rpmflags) might_sleep_if(!(rpmflags & RPM_ASYNC) && !dev->power.irq_safe && dev->power.runtime_status != RPM_ACTIVE); - if (rpmflags & RPM_GET_PUT) + if (rpmflags & RPM_GET_PUT) { atomic_inc(&dev->power.usage_count); + trace_rpm_usage_rcuidle(dev, rpmflags); + } spin_lock_irqsave(&dev->power.lock, flags); retval = rpm_resume(dev, rpmflags); @@ -1448,16 +1453,17 @@ EXPORT_SYMBOL_GPL(pm_runtime_forbid); */ void pm_runtime_allow(struct device *dev) { + bool is_zero; + spin_lock_irq(&dev->power.lock); if (dev->power.runtime_auto) goto out; dev->power.runtime_auto = true; - if (atomic_dec_and_test(&dev->power.usage_count)) + is_zero = atomic_dec_and_test(&dev->power.usage_count); + trace_rpm_usage_rcuidle(dev, RPM_AUTO | RPM_ASYNC); + if (is_zero) rpm_idle(dev, RPM_AUTO | RPM_ASYNC); - else - trace_rpm_usage_rcuidle(dev, RPM_AUTO | RPM_ASYNC); - out: spin_unlock_irq(&dev->power.lock); } @@ -1523,9 +1529,8 @@ static void update_autosuspend(struct device *dev, int old_delay, int old_use) /* If it used to be allowed then prevent it. */ if (!old_use || old_delay >= 0) { atomic_inc(&dev->power.usage_count); - rpm_resume(dev, 0); - } else { trace_rpm_usage_rcuidle(dev, 0); + rpm_resume(dev, 0); } } @@ -1533,8 +1538,10 @@ static void update_autosuspend(struct device *dev, int old_delay, int old_use) else { /* If it used to be prevented then allow it. */ - if (old_use && old_delay < 0) + if (old_use && old_delay < 0) { atomic_dec(&dev->power.usage_count); + trace_rpm_usage_rcuidle(dev, 0); + } /* Maybe we can autosuspend now. */ rpm_idle(dev, RPM_AUTO); @@ -1741,12 +1748,14 @@ void pm_runtime_drop_link(struct device *dev) void pm_runtime_get_noresume(struct device *dev) { atomic_inc(&dev->power.usage_count); + trace_rpm_usage_rcuidle(dev, 0); } EXPORT_SYMBOL_GPL(pm_runtime_get_noresume); void pm_runtime_put_noidle(struct device *dev) { atomic_add_unless(&dev->power.usage_count, -1, 0); + trace_rpm_usage_rcuidle(dev, 0); } EXPORT_SYMBOL_GPL(pm_runtime_put_noidle); -- 2.20.1
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