From 521c42990e9d561ed5ed9f501f07639d0512b3c9 Mon Sep 17 00:00:00 2001 From: Viresh Kumar Date: Tue, 15 Apr 2014 10:54:37 +0530 Subject: [PATCH 1/3] tick-common: Fix wrong check in tick_check_replacement() tick_check_replacement() returns if a replacement of clock_event_device is possible or not. It does this as the first check: if (tick_check_percpu(curdev, newdev, smp_processor_id())) return false; Thats wrong. tick_check_percpu() returns true when the device is useable. Check for false instead. [ tglx: Massaged changelog ] Signed-off-by: Viresh Kumar Cc: # v3.11+ Cc: linaro-kernel@lists.linaro.org Cc: fweisbec@gmail.com Cc: Arvind.Chauhan@arm.com Cc: linaro-networking@linaro.org Link: http://lkml.kernel.org/r/486a02efe0246635aaba786e24b42d316438bf3b.1397537987.git.viresh.kumar@linaro.org Signed-off-by: Thomas Gleixner --- kernel/time/tick-common.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) diff --git a/kernel/time/tick-common.c b/kernel/time/tick-common.c index 015661279b68..0a0608edeb26 100644 --- a/kernel/time/tick-common.c +++ b/kernel/time/tick-common.c @@ -276,7 +276,7 @@ static bool tick_check_preferred(struct clock_event_device *curdev, bool tick_check_replacement(struct clock_event_device *curdev, struct clock_event_device *newdev) { - if (tick_check_percpu(curdev, newdev, smp_processor_id())) + if (!tick_check_percpu(curdev, newdev, smp_processor_id())) return false; return tick_check_preferred(curdev, newdev); From 03e6bdc5c4d0fc166bfd5d3cf749a5a0c1b5b1bd Mon Sep 17 00:00:00 2001 From: Viresh Kumar Date: Tue, 15 Apr 2014 10:54:40 +0530 Subject: [PATCH 2/3] tick-sched: Don't call update_wall_time() when delta is lesser than tick_period 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 Cc: linaro-kernel@lists.linaro.org Cc: fweisbec@gmail.com Cc: Arvind.Chauhan@arm.com Cc: linaro-networking@linaro.org Cc: John Stultz Cc: # v3.14+ Link: http://lkml.kernel.org/r/80afb18a494b0bd9710975bcc4de134ae323c74f.1397537987.git.viresh.kumar@linaro.org Signed-off-by: Thomas Gleixner --- kernel/time/tick-sched.c | 3 +++ 1 file changed, 3 insertions(+) diff --git a/kernel/time/tick-sched.c b/kernel/time/tick-sched.c index 9f8af69c67ec..e947d968c5b5 100644 --- a/kernel/time/tick-sched.c +++ b/kernel/time/tick-sched.c @@ -84,6 +84,9 @@ static void tick_do_update_jiffies64(ktime_t now) /* 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(); From 27630532ef5ead28b98cfe28d8f95222ef91c2b7 Mon Sep 17 00:00:00 2001 From: Viresh Kumar Date: Tue, 15 Apr 2014 10:54:41 +0530 Subject: [PATCH 3/3] tick-sched: Check tick_nohz_enabled in tick_nohz_switch_to_nohz() Since commit d689fe222 (NOHZ: Check for nohz active instead of nohz enabled) the tick_nohz_switch_to_nohz() function returns because it checks for the tick_nohz_active flag. This can't be set, because the function itself sets it. Undo the change in tick_nohz_switch_to_nohz(). Signed-off-by: Viresh Kumar Cc: linaro-kernel@lists.linaro.org Cc: fweisbec@gmail.com Cc: Arvind.Chauhan@arm.com Cc: linaro-networking@linaro.org Cc: # 3.13+ Link: http://lkml.kernel.org/r/40939c05f2d65d781b92b20302b02243d0654224.1397537987.git.viresh.kumar@linaro.org Signed-off-by: Thomas Gleixner --- kernel/time/tick-sched.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) diff --git a/kernel/time/tick-sched.c b/kernel/time/tick-sched.c index e947d968c5b5..6558b7ac112d 100644 --- a/kernel/time/tick-sched.c +++ b/kernel/time/tick-sched.c @@ -970,7 +970,7 @@ static void tick_nohz_switch_to_nohz(void) struct tick_sched *ts = &__get_cpu_var(tick_cpu_sched); ktime_t next; - if (!tick_nohz_active) + if (!tick_nohz_enabled) return; local_irq_disable();