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Message-ID: <3154303.fma7bByNVc@vostro.rjw.lan>
Date: Sat, 16 May 2015 02:45:42 +0200
From: "Rafael J. Wysocki" <rjw@...ysocki.net>
To: "Fu, Zhonghui" <zhonghui.fu@...ux.intel.com>
Cc: len.brown@...el.com, pavel@....cz,
Greg Kroah-Hartman <gregkh@...uxfoundation.org>,
linux-pm@...r.kernel.org,
"linux-kernel@...r.kernel.org" <linux-kernel@...r.kernel.org>
Subject: Re: [PATCH] PM / sleep: cancel the synchronous restriction of pm-trace
On Wednesday, May 06, 2015 10:47:24 PM Fu, Zhonghui wrote:
> Some system-hang occur only when multiple device PM methods
> are running asynchronously. So should cancel the synchronization
> of pm-trace, and make it suitable for asynchronous PM environment.
>
> Signed-off-by: Zhonghui Fu <zhonghui.fu@...ux.intel.com>
> ---
> drivers/base/power/main.c | 53 +++++++++++++++++++++-----------------------
> include/linux/pm-trace.h | 24 ++++++++++++--------
> kernel/power/main.c | 2 +
> 3 files changed, 41 insertions(+), 38 deletions(-)
>
> diff --git a/drivers/base/power/main.c b/drivers/base/power/main.c
> index 3d874ec..40daf48 100644
> --- a/drivers/base/power/main.c
> +++ b/drivers/base/power/main.c
> @@ -476,9 +476,6 @@ static int device_resume_noirq(struct device *dev, pm_message_t state, bool asyn
> char *info = NULL;
> int error = 0;
>
> - TRACE_DEVICE(dev);
> - TRACE_RESUME(0);
> -
> if (dev->power.syscore || dev->power.direct_complete)
> goto Out;
>
> @@ -506,19 +503,21 @@ static int device_resume_noirq(struct device *dev, pm_message_t state, bool asyn
> callback = pm_noirq_op(dev->driver->pm, state);
> }
>
> + TRACE_DEVICE_START(dev);
> + TRACE_RESUME(0);
> +
> error = dpm_run_callback(callback, dev, state, info);
> dev->power.is_noirq_suspended = false;
>
> + TRACE_DEVICE_END();
> 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();
> + return dev->power.async_suspend && pm_async_enabled;
> }
>
> static void async_resume_noirq(void *data, async_cookie_t cookie)
> @@ -605,9 +604,6 @@ static int device_resume_early(struct device *dev, pm_message_t state, bool asyn
> char *info = NULL;
> int error = 0;
>
> - TRACE_DEVICE(dev);
> - TRACE_RESUME(0);
> -
> if (dev->power.syscore || dev->power.direct_complete)
> goto Out;
>
> @@ -635,12 +631,14 @@ static int device_resume_early(struct device *dev, pm_message_t state, bool asyn
> callback = pm_late_early_op(dev->driver->pm, state);
> }
>
> + TRACE_DEVICE_START(dev);
> + TRACE_RESUME(0);
> +
> error = dpm_run_callback(callback, dev, state, info);
> dev->power.is_late_suspended = false;
>
> + TRACE_DEVICE_END();
> Out:
> - TRACE_RESUME(error);
> -
> pm_runtime_enable(dev);
> complete_all(&dev->power.completion);
> return error;
> @@ -734,9 +732,6 @@ static int device_resume(struct device *dev, pm_message_t state, bool async)
> int error = 0;
> DECLARE_DPM_WATCHDOG_ON_STACK(wd);
>
> - TRACE_DEVICE(dev);
> - TRACE_RESUME(0);
> -
> if (dev->power.syscore)
> goto Complete;
>
> @@ -801,9 +796,13 @@ static int device_resume(struct device *dev, pm_message_t state, bool async)
> }
>
> End:
> + TRACE_DEVICE_START(dev);
> + TRACE_RESUME(0);
> +
> error = dpm_run_callback(callback, dev, state, info);
> dev->power.is_suspended = false;
>
> + TRACE_DEVICE_END();
> Unlock:
> device_unlock(dev);
> dpm_watchdog_clear(&wd);
> @@ -811,8 +810,6 @@ static int device_resume(struct device *dev, pm_message_t state, bool async)
> Complete:
> complete_all(&dev->power.completion);
>
> - TRACE_RESUME(error);
> -
> return error;
> }
>
> @@ -1017,9 +1014,6 @@ static int __device_suspend_noirq(struct device *dev, pm_message_t state, bool a
> char *info = NULL;
> int error = 0;
>
> - TRACE_DEVICE(dev);
> - TRACE_SUSPEND(0);
> -
> if (async_error)
> goto Complete;
>
> @@ -1052,15 +1046,18 @@ static int __device_suspend_noirq(struct device *dev, pm_message_t state, bool a
> callback = pm_noirq_op(dev->driver->pm, state);
> }
>
> + TRACE_DEVICE_START(dev);
> + TRACE_SUSPEND(0);
> +
> error = dpm_run_callback(callback, dev, state, info);
> if (!error)
> dev->power.is_noirq_suspended = true;
> else
> async_error = error;
>
> + TRACE_DEVICE_END();
> Complete:
> complete_all(&dev->power.completion);
> - TRACE_SUSPEND(error);
> return error;
> }
>
> @@ -1161,9 +1158,6 @@ static int __device_suspend_late(struct device *dev, pm_message_t state, bool as
> char *info = NULL;
> int error = 0;
>
> - TRACE_DEVICE(dev);
> - TRACE_SUSPEND(0);
> -
> __pm_runtime_disable(dev, false);
>
> if (async_error)
> @@ -1198,14 +1192,17 @@ static int __device_suspend_late(struct device *dev, pm_message_t state, bool as
> callback = pm_late_early_op(dev->driver->pm, state);
> }
>
> + TRACE_DEVICE_START(dev);
> + TRACE_SUSPEND(0);
> +
> error = dpm_run_callback(callback, dev, state, info);
> if (!error)
> dev->power.is_late_suspended = true;
> else
> async_error = error;
>
> + TRACE_DEVICE_END();
> Complete:
> - TRACE_SUSPEND(error);
> complete_all(&dev->power.completion);
> return error;
> }
> @@ -1346,9 +1343,6 @@ static int __device_suspend(struct device *dev, pm_message_t state, bool async)
> int error = 0;
> DECLARE_DPM_WATCHDOG_ON_STACK(wd);
>
> - TRACE_DEVICE(dev);
> - TRACE_SUSPEND(0);
> -
> dpm_wait_for_children(dev, async);
>
> if (async_error)
> @@ -1428,8 +1422,12 @@ static int __device_suspend(struct device *dev, pm_message_t state, bool async)
> callback = pm_op(dev->driver->pm, state);
> }
>
> + TRACE_DEVICE_START(dev);
> + TRACE_SUSPEND(0);
> +
> error = dpm_run_callback(callback, dev, state, info);
>
> + TRACE_DEVICE_END();
> End:
> if (!error) {
> struct device *parent = dev->parent;
> @@ -1455,7 +1453,6 @@ static int __device_suspend(struct device *dev, pm_message_t state, bool async)
> if (error)
> async_error = error;
>
> - TRACE_SUSPEND(error);
> return error;
> }
>
> diff --git a/include/linux/pm-trace.h b/include/linux/pm-trace.h
> index ecbde7a..aa480b1 100644
> --- a/include/linux/pm-trace.h
> +++ b/include/linux/pm-trace.h
> @@ -6,29 +6,33 @@
> #include <linux/types.h>
>
> extern int pm_trace_enabled;
> -
> -static inline int pm_trace_is_enabled(void)
> -{
> - return pm_trace_enabled;
> -}
> +extern struct mutex pt_mutex;
>
> struct device;
> extern void set_trace_device(struct device *);
> extern void generate_pm_trace(const void *tracedata, unsigned int user);
> extern int show_trace_dev_match(char *buf, size_t size);
>
> -#define TRACE_DEVICE(dev) do { \
> +#define TRACE_DEVICE_START(dev) do { \
> if (pm_trace_enabled) \
> + mutex_lock(&pt_mutex); \
> set_trace_device(dev); \
> } while(0)
>
> +#define TRACE_DEVICE_END() \
> +do { \
> + if (pm_trace_enabled) { \
> + mutex_unlock(&pt_mutex); \
> + } \
> +} while (0)
> +
Won't this serialize the whole thing again?
> #else
>
> -static inline int pm_trace_is_enabled(void) { return 0; }
> +#define TRACE_DEVICE_START(dev) do { } while (0)
> +#define TRACE_DEVICE_END() do { } while (0)
>
> -#define TRACE_DEVICE(dev) do { } while (0)
> -#define TRACE_RESUME(dev) do { } while (0)
> -#define TRACE_SUSPEND(dev) do { } while (0)
> +#define TRACE_RESUME(user) do { } while (0)
> +#define TRACE_SUSPEND(user) do { } while (0)
>
> #endif
>
> diff --git a/kernel/power/main.c b/kernel/power/main.c
> index 86e8157..ffd5145 100644
> --- a/kernel/power/main.c
> +++ b/kernel/power/main.c
> @@ -515,6 +515,7 @@ power_attr(wake_unlock);
>
> #ifdef CONFIG_PM_TRACE
> int pm_trace_enabled;
> +struct mutex pt_mutex;
>
> static ssize_t pm_trace_show(struct kobject *kobj, struct kobj_attribute *attr,
> char *buf)
> @@ -533,6 +534,7 @@ pm_trace_store(struct kobject *kobj, struct kobj_attribute *attr,
> if (pm_trace_enabled) {
> pr_warn("PM: Enabling pm_trace changes system date and time during resume.\n"
> "PM: Correct system time has to be restored manually after resume.\n");
> + mutex_init(&pt_mutex);
> }
> return n;
> }
> -- 1.7.1
>
> --
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--
I speak only for myself.
Rafael J. Wysocki, Intel Open Source Technology Center.
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