From 5acac1be499d979e3aa463ea73a498888faefcbe Mon Sep 17 00:00:00 2001 From: Frederic Weisbecker Date: Wed, 4 Dec 2013 18:28:20 +0100 Subject: tick: Rename tick_check_idle() to tick_irq_enter() This makes the code more symetric against the existing tick functions called on irq exit: tick_irq_exit() and tick_nohz_irq_exit(). These function are also symetric as they mirror each other's action: we start to account idle time on irq exit and we stop this accounting on irq entry. Also the tick is stopped on irq exit and timekeeping catches up with the tickless time elapsed until we reach irq entry. This rename was suggested by Peter Zijlstra a long while ago but it got forgotten in the mass. Cc: Thomas Gleixner Cc: Ingo Molnar Cc: Peter Zijlstra Cc: Alex Shi Cc: Steven Rostedt Cc: Paul E. McKenney Cc: John Stultz Cc: Kevin Hilman Link: http://lkml.kernel.org/r/1387320692-28460-2-git-send-email-fweisbec@gmail.com Signed-off-by: Frederic Weisbecker --- kernel/time/tick-sched.c | 8 ++++---- 1 file changed, 4 insertions(+), 4 deletions(-) (limited to 'kernel/time/tick-sched.c') diff --git a/kernel/time/tick-sched.c b/kernel/time/tick-sched.c index 0ddd020bbaf2..e4d0f093061f 100644 --- a/kernel/time/tick-sched.c +++ b/kernel/time/tick-sched.c @@ -1023,7 +1023,7 @@ static void tick_nohz_kick_tick(struct tick_sched *ts, ktime_t now) #endif } -static inline void tick_check_nohz_this_cpu(void) +static inline void tick_nohz_irq_enter(void) { struct tick_sched *ts = &__get_cpu_var(tick_cpu_sched); ktime_t now; @@ -1042,17 +1042,17 @@ static inline void tick_check_nohz_this_cpu(void) #else static inline void tick_nohz_switch_to_nohz(void) { } -static inline void tick_check_nohz_this_cpu(void) { } +static inline void tick_nohz_irq_enter(void) { } #endif /* CONFIG_NO_HZ_COMMON */ /* * Called from irq_enter to notify about the possible interruption of idle() */ -void tick_check_idle(void) +void tick_irq_enter(void) { tick_check_oneshot_broadcast_this_cpu(); - tick_check_nohz_this_cpu(); + tick_nohz_irq_enter(); } /* -- cgit v1.2.3-55-g7522 From 855a0fc30b70d6ae681badd24d6625f9a9abb787 Mon Sep 17 00:00:00 2001 From: Frederic Weisbecker Date: Tue, 17 Dec 2013 00:16:37 +0100 Subject: nohz: Get timekeeping max deferment outside jiffies_lock We don't need to fetch the timekeeping max deferment under the jiffies_lock seqlock. If the clocksource is updated concurrently while we stop the tick, stop machine is called and the tick will be reevaluated again along with uptodate jiffies and its related values. Cc: Thomas Gleixner Cc: Ingo Molnar Cc: Peter Zijlstra Cc: Alex Shi Cc: Steven Rostedt Cc: Paul E. McKenney Cc: John Stultz Cc: Kevin Hilman Link: http://lkml.kernel.org/r/1387320692-28460-9-git-send-email-fweisbec@gmail.com Signed-off-by: Frederic Weisbecker --- kernel/time/tick-sched.c | 3 ++- 1 file changed, 2 insertions(+), 1 deletion(-) (limited to 'kernel/time/tick-sched.c') diff --git a/kernel/time/tick-sched.c b/kernel/time/tick-sched.c index e4d0f093061f..68331d16b4ed 100644 --- a/kernel/time/tick-sched.c +++ b/kernel/time/tick-sched.c @@ -533,12 +533,13 @@ static ktime_t tick_nohz_stop_sched_tick(struct tick_sched *ts, struct clock_event_device *dev = __get_cpu_var(tick_cpu_device).evtdev; u64 time_delta; + time_delta = timekeeping_max_deferment(); + /* Read jiffies and the time when jiffies were updated last */ do { seq = read_seqbegin(&jiffies_lock); last_update = last_jiffies_update; last_jiffies = jiffies; - time_delta = timekeeping_max_deferment(); } while (read_seqretry(&jiffies_lock, seq)); if (rcu_needs_cpu(cpu, &rcu_delta_jiffies) || -- cgit v1.2.3-55-g7522 From e9a2eb403bd953788cd2abfd0d2646d43bd22671 Mon Sep 17 00:00:00 2001 From: Alex Shi Date: Thu, 28 Nov 2013 14:27:11 +0800 Subject: nohz_full: fix code style issue of tick_nohz_full_stop_tick Code usually starts with 'tab' instead of 7 'space' in kernel Signed-off-by: Alex Shi Cc: Thomas Gleixner Cc: Ingo Molnar Cc: Peter Zijlstra Cc: Alex Shi Cc: Steven Rostedt Cc: Paul E. McKenney Cc: John Stultz Cc: Kevin Hilman Link: http://lkml.kernel.org/r/1386074112-30754-2-git-send-email-alex.shi@linaro.org Signed-off-by: Frederic Weisbecker --- kernel/time/tick-sched.c | 16 ++++++++-------- 1 file changed, 8 insertions(+), 8 deletions(-) (limited to 'kernel/time/tick-sched.c') diff --git a/kernel/time/tick-sched.c b/kernel/time/tick-sched.c index 68331d16b4ed..d603baddd52d 100644 --- a/kernel/time/tick-sched.c +++ b/kernel/time/tick-sched.c @@ -679,18 +679,18 @@ out: static void tick_nohz_full_stop_tick(struct tick_sched *ts) { #ifdef CONFIG_NO_HZ_FULL - int cpu = smp_processor_id(); + int cpu = smp_processor_id(); - if (!tick_nohz_full_cpu(cpu) || is_idle_task(current)) - return; + if (!tick_nohz_full_cpu(cpu) || is_idle_task(current)) + return; - if (!ts->tick_stopped && ts->nohz_mode == NOHZ_MODE_INACTIVE) - return; + if (!ts->tick_stopped && ts->nohz_mode == NOHZ_MODE_INACTIVE) + return; - if (!can_stop_full_tick()) - return; + if (!can_stop_full_tick()) + return; - tick_nohz_stop_sched_tick(ts, ktime_get(), cpu); + tick_nohz_stop_sched_tick(ts, ktime_get(), cpu); #endif } -- cgit v1.2.3-55-g7522