4 files changed, 39 insertions, 2 deletions

diff --git a/Documentation/power/freezing-of-tasks.txt b/Documentation/power/freezing-of-tasks.txt
index 6ec291ea1c78..85894d83b352 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 e4238ceaa4d6..e70df40d84f6 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 freeze_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 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
@@ -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 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();