| From 03e6bdc5c4d0fc166bfd5d3cf749a5a0c1b5b1bd Mon Sep 17 00:00:00 2001 |
| From: Viresh Kumar <viresh.kumar@linaro.org> |
| Date: Tue, 15 Apr 2014 10:54:40 +0530 |
| Subject: tick-sched: Don't call update_wall_time() when delta is lesser than tick_period |
| |
| From: Viresh Kumar <viresh.kumar@linaro.org> |
| |
| commit 03e6bdc5c4d0fc166bfd5d3cf749a5a0c1b5b1bd upstream. |
| |
| In tick_do_update_jiffies64() we are processing ticks only if delta is |
| greater than tick_period. This is what we are supposed to do here and |
| it broke a bit with this patch: |
| |
| commit 47a1b796 (tick/timekeeping: Call update_wall_time outside the |
| jiffies lock) |
| |
| With above patch, we might end up calling update_wall_time() even if |
| delta is found to be smaller that tick_period. Fix this by returning |
| when the delta is less than tick period. |
| |
| [ tglx: Made it a 3 liner and massaged changelog ] |
| |
| Signed-off-by: Viresh Kumar <viresh.kumar@linaro.org> |
| Cc: linaro-kernel@lists.linaro.org |
| Cc: fweisbec@gmail.com |
| Cc: Arvind.Chauhan@arm.com |
| Cc: linaro-networking@linaro.org |
| Cc: John Stultz <john.stultz@linaro.org> |
| Link: http://lkml.kernel.org/r/80afb18a494b0bd9710975bcc4de134ae323c74f.1397537987.git.viresh.kumar@linaro.org |
| Signed-off-by: Thomas Gleixner <tglx@linutronix.de> |
| Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org> |
| |
| --- |
| kernel/time/tick-sched.c | 3 +++ |
| 1 file changed, 3 insertions(+) |
| |
| --- a/kernel/time/tick-sched.c |
| +++ b/kernel/time/tick-sched.c |
| @@ -84,6 +84,9 @@ static void tick_do_update_jiffies64(kti |
| |
| /* Keep the tick_next_period variable up to date */ |
| tick_next_period = ktime_add(last_jiffies_update, tick_period); |
| + } else { |
| + write_sequnlock(&jiffies_lock); |
| + return; |
| } |
| write_sequnlock(&jiffies_lock); |
| update_wall_time(); |