sched_clock: prevent scd->clock from moving backwards, take #2
Redo:
5b7dba4: sched_clock: prevent scd->clock from moving backwards
which had to be reverted due to s2ram hangs:
ca7e716: Revert "sched_clock: prevent scd->clock from moving backwards"
... this time with resume restoring GTOD later in the sequence
taken into account as well.
The "timekeeping_suspended" flag is not very nice but we cannot call into
GTOD before it has been properly resumed and the scheduler will run very
early in the resume sequence.
Cc: <stable@kernel.org>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
diff --git a/kernel/sched_clock.c b/kernel/sched_clock.c
index e8ab096..a0b0852 100644
--- a/kernel/sched_clock.c
+++ b/kernel/sched_clock.c
@@ -124,7 +124,7 @@
clock = scd->tick_gtod + delta;
min_clock = wrap_max(scd->tick_gtod, scd->clock);
- max_clock = scd->tick_gtod + TICK_NSEC;
+ max_clock = wrap_max(scd->clock, scd->tick_gtod + TICK_NSEC);
clock = wrap_max(clock, min_clock);
clock = wrap_min(clock, max_clock);
@@ -227,6 +227,9 @@
*/
void sched_clock_idle_wakeup_event(u64 delta_ns)
{
+ if (timekeeping_suspended)
+ return;
+
sched_clock_tick();
touch_softlockup_watchdog();
}
diff --git a/kernel/time/timekeeping.c b/kernel/time/timekeeping.c
index fa05e88..900f1b6 100644
--- a/kernel/time/timekeeping.c
+++ b/kernel/time/timekeeping.c
@@ -46,6 +46,9 @@
struct timespec wall_to_monotonic __attribute__ ((aligned (16)));
static unsigned long total_sleep_time; /* seconds */
+/* flag for if timekeeping is suspended */
+int __read_mostly timekeeping_suspended;
+
static struct timespec xtime_cache __attribute__ ((aligned (16)));
void update_xtime_cache(u64 nsec)
{
@@ -92,6 +95,8 @@
unsigned long seq;
s64 nsecs;
+ WARN_ON(timekeeping_suspended);
+
do {
seq = read_seqbegin(&xtime_lock);
@@ -299,8 +304,6 @@
write_sequnlock_irqrestore(&xtime_lock, flags);
}
-/* flag for if timekeeping is suspended */
-static int timekeeping_suspended;
/* time in seconds when suspend began */
static unsigned long timekeeping_suspend_time;