From 957d1282bb8c07e682e142b9237cd9fcb8348a0b Mon Sep 17 00:00:00 2001 From: Li Fei Date: Fri, 1 Feb 2013 08:56:03 +0000 Subject: suspend: enable freeze timeout configuration through sys At present, the value of timeout for freezing is 20s, which is meaningless in case that one thread is frozen with mutex locked and another thread is trying to lock the mutex, as this time of freezing will fail unavoidably. And if there is no new wakeup event registered, the system will waste at most 20s for such meaningless trying of freezing. With this patch, the value of timeout can be configured to smaller value, so such meaningless trying of freezing will be aborted in earlier time, and later freezing can be also triggered in earlier time. And more power will be saved. In normal case on mobile phone, it costs real little time to freeze processes. On some platform, it only costs about 20ms to freeze user space processes and 10ms to freeze kernel freezable threads. Signed-off-by: Liu Chuansheng Signed-off-by: Li Fei Signed-off-by: Rafael J. Wysocki --- kernel/power/main.c | 27 +++++++++++++++++++++++++++ kernel/power/process.c | 4 ++-- 2 files changed, 29 insertions(+), 2 deletions(-) (limited to 'kernel') diff --git a/kernel/power/main.c b/kernel/power/main.c index b1c26a92ca9f..d77663bfedeb 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", freeze_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; + + freeze_timeout_msecs = val; + return n; +} + +power_attr(pm_freeze_timeout); + +#endif /* CONFIG_FREEZER*/ + static struct attribute * g[] = { &state_attr.attr, #ifdef CONFIG_PM_TRACE @@ -575,6 +599,9 @@ static struct attribute * g[] = { #ifdef CONFIG_PM_SLEEP_DEBUG &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 d5a258b60c6f..98088e0e71e8 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 freeze_timeout_msecs = 20 * MSEC_PER_SEC; 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(freeze_timeout_msecs); if (!user_only) freeze_workqueues_begin(); -- cgit v1.2.3