On Wednesday, January 30, 2013 02:23:39 PM fli24 wrote:
>
> At present, the timeout value for freezing tasks is fixed as 20s,
> which is too long for handheld device usage, especially for mobile
> phone.
>
> In order to improve user experience, we enable freeze timeout
> configuration through sys, so that we can tune the value easily
> for concrete usage, such as smaller value for handheld device such
> as mobile phone.
As I said, I'd like to know what's the exact problem you need to work around
using this.
Thanks,
Rafael
> Signed-off-by: Liu Chuansheng <chuansheng....@intel.com>
> Signed-off-by: Li Fei <fei...@intel.com>
> ---
> Documentation/power/freezing-of-tasks.txt | 5 +++++
> include/linux/freezer.h | 5 +++++
> kernel/power/main.c | 27 +++++++++++++++++++++++++++
> kernel/power/process.c | 4 ++--
> 4 files changed, 39 insertions(+), 2 deletions(-)
>
> diff --git a/Documentation/power/freezing-of-tasks.txt
> b/Documentation/power/freezing-of-tasks.txt
> index 6ec291e..85894d8 100644
> --- a/Documentation/power/freezing-of-tasks.txt
> +++ b/Documentation/power/freezing-of-tasks.txt
> @@ -223,3 +223,8 @@ since they ask the freezer to skip freezing this task,
> since it is anyway
> only after the entire suspend/hibernation sequence is complete.
> So, to summarize, use [un]lock_system_sleep() instead of directly using
> mutex_[un]lock(&pm_mutex). That would prevent freezing failures.
> +
> +V. Miscellaneous
> +/sys/power/pm_freeze_timeout controls how long it will cost at most to freeze
> +all user space processes or all freezable kernel threads, in unit of
> millisecond.
> +The default value is 20000, with range of unsigned integer.
> diff --git a/include/linux/freezer.h b/include/linux/freezer.h
> index e4238ce..5a24a33 100644
> --- a/include/linux/freezer.h
> +++ b/include/linux/freezer.h
> @@ -13,6 +13,11 @@ extern bool pm_freezing; /* PM freezing in
> effect */
> extern bool pm_nosig_freezing; /* PM nosig freezing in effect
> */
>
> /*
> + * Timeout for stopping processes
> + */
> +extern unsigned int sys_freeze_process_timeout_msecs;
> +
> +/*
> * Check if a process has been frozen
> */
> static inline bool frozen(struct task_struct *p)
> diff --git a/kernel/power/main.c b/kernel/power/main.c
> index 1c16f91..453ead1 100644
> --- a/kernel/power/main.c
> +++ b/kernel/power/main.c
> @@ -553,6 +553,30 @@ power_attr(pm_trace_dev_match);
>
> #endif /* CONFIG_PM_TRACE */
>
> +#ifdef CONFIG_FREEZER
> +static ssize_t pm_freeze_timeout_show(struct kobject *kobj,
> + struct kobj_attribute *attr, char *buf)
> +{
> + return sprintf(buf, "%u\n", sys_freeze_process_timeout_msecs);
> +}
> +
> +static ssize_t pm_freeze_timeout_store(struct kobject *kobj,
> + struct kobj_attribute *attr,
> + const char *buf, size_t n)
> +{
> + unsigned long val;
> +
> + if (kstrtoul(buf, 10, &val))
> + return -EINVAL;
> +
> + sys_freeze_process_timeout_msecs = val;
> + return n;
> +}
> +
> +power_attr(pm_freeze_timeout);
> +
> +#endif /* CONFIG_FREEZER*/
> +
> static struct attribute * g[] = {
> &state_attr.attr,
> #ifdef CONFIG_PM_TRACE
> @@ -576,6 +600,9 @@ static struct attribute * g[] = {
> &pm_print_times_attr.attr,
> #endif
> #endif
> +#ifdef CONFIG_FREEZER
> + &pm_freeze_timeout_attr.attr,
> +#endif
> NULL,
> };
>
> diff --git a/kernel/power/process.c b/kernel/power/process.c
> index d5a258b..ba45a26 100644
> --- a/kernel/power/process.c
> +++ b/kernel/power/process.c
> @@ -21,7 +21,7 @@
> /*
> * Timeout for stopping processes
> */
> -#define TIMEOUT (20 * HZ)
> +unsigned int __read_mostly sys_freeze_process_timeout_msecs = 20000;
>
> static int try_to_freeze_tasks(bool user_only)
> {
> @@ -36,7 +36,7 @@ static int try_to_freeze_tasks(bool user_only)
>
> do_gettimeofday(&start);
>
> - end_time = jiffies + TIMEOUT;
> + end_time = jiffies + msecs_to_jiffies(sys_freeze_process_timeout_msecs);
>
> if (!user_only)
> freeze_workqueues_begin();
>
--
I speak only for myself.
Rafael J. Wysocki, Intel Open Source Technology Center.
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