From: Rafael J. Wysocki <rjw@xxxxxxx>
Subject: PM: Allow wakeup events to abort freezing of tasks
If there is a wakeup event during the freezing of tasks, suspend or
hibernation will fail anyway. Since try_to_freeze_tasks() can take
up to 20 seconds to complete or fail, aborting it as soon as a wakeup
event is detected improves the worst case wakeup latency.
Based on a patch from Arve HjÃnnevÃg.
Signed-off-by: Rafael J. Wysocki <rjw@xxxxxxx>
---
kernel/power/process.c | 11 +++++++++--
1 file changed, 9 insertions(+), 2 deletions(-)
Index: linux-2.6/kernel/power/process.c
===================================================================
--- linux-2.6.orig/kernel/power/process.c
+++ linux-2.6/kernel/power/process.c
@@ -40,6 +40,7 @@ static int try_to_freeze_tasks(bool sig_
struct timeval start, end;
u64 elapsed_csecs64;
unsigned int elapsed_csecs;
+ bool wakeup = false;
do_gettimeofday(&start);
@@ -78,6 +79,11 @@ static int try_to_freeze_tasks(bool sig_
if (!todo || time_after(jiffies, end_time))
break;
+ if (!pm_check_wakeup_events()) {
+ wakeup = true;
+ break;
+ }
+
/*
* We need to retry, but first give the freezing tasks some
* time to enter the regrigerator.
@@ -97,8 +103,9 @@ static int try_to_freeze_tasks(bool sig_
* but it cleans up leftover PF_FREEZE requests.
*/
printk("\n");
- printk(KERN_ERR "Freezing of tasks failed after %d.%02d seconds "
+ printk(KERN_ERR "Freezing of tasks %s after %d.%02d seconds "
"(%d tasks refusing to freeze, wq_busy=%d):\n",
+ wakeup ? "aborted" : "failed",
elapsed_csecs / 100, elapsed_csecs % 100,
todo - wq_busy, wq_busy);
@@ -107,7 +114,7 @@ static int try_to_freeze_tasks(bool sig_
read_lock(&tasklist_lock);
do_each_thread(g, p) {
task_lock(p);
- if (freezing(p) && !freezer_should_skip(p))
+ if (!wakeup && freezing(p) && !freezer_should_skip(p))
sched_show_task(p);
cancel_freezing(p);
task_unlock(p);
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