diff options
author | Linus Torvalds <torvalds@linux-foundation.org> | 2013-09-04 20:36:54 +0400 |
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committer | Linus Torvalds <torvalds@linux-foundation.org> | 2013-09-04 20:36:54 +0400 |
commit | 6832d9652f395f7d13003e3884942c40f52ac1fa (patch) | |
tree | 40555ad5eda9700cb973dac4db136ad97f5e8b19 /kernel/time | |
parent | 228abe73ad67665d71eacd6a8a347dd76b0115ae (diff) | |
parent | c2e7fcf53c3cb02b4ada1c66a9bc8a4d97d58aba (diff) |
Merge branch 'timers-nohz-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip
Pull timers/nohz changes from Ingo Molnar:
"It mostly contains fixes and full dynticks off-case optimizations, by
Frederic Weisbecker"
* 'timers-nohz-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip: (24 commits)
nohz: Include local CPU in full dynticks global kick
nohz: Optimize full dynticks's sched hooks with static keys
nohz: Optimize full dynticks state checks with static keys
nohz: Rename a few state variables
vtime: Always debug check snapshot source _before_ updating it
vtime: Always scale generic vtime accounting results
vtime: Optimize full dynticks accounting off case with static keys
vtime: Describe overriden functions in dedicated arch headers
m68k: hardirq_count() only need preempt_mask.h
hardirq: Split preempt count mask definitions
context_tracking: Split low level state headers
vtime: Fix racy cputime delta update
vtime: Remove a few unneeded generic vtime state checks
context_tracking: User/kernel broundary cross trace events
context_tracking: Optimize context switch off case with static keys
context_tracking: Optimize guest APIs off case with static key
context_tracking: Optimize main APIs off case with static key
context_tracking: Ground setup for static key use
context_tracking: Remove full dynticks' hacky dependency on wide context tracking
nohz: Only enable context tracking on full dynticks CPUs
...
Diffstat (limited to 'kernel/time')
-rw-r--r-- | kernel/time/Kconfig | 1 | ||||
-rw-r--r-- | kernel/time/tick-sched.c | 61 |
2 files changed, 29 insertions, 33 deletions
diff --git a/kernel/time/Kconfig b/kernel/time/Kconfig index 3381f098070f..2b62fe86f9ec 100644 --- a/kernel/time/Kconfig +++ b/kernel/time/Kconfig @@ -105,7 +105,6 @@ config NO_HZ_FULL select RCU_USER_QS select RCU_NOCB_CPU select VIRT_CPU_ACCOUNTING_GEN - select CONTEXT_TRACKING_FORCE select IRQ_WORK help Adaptively try to shutdown the tick whenever possible, even when diff --git a/kernel/time/tick-sched.c b/kernel/time/tick-sched.c index e8a1516cc0a3..3612fc77f834 100644 --- a/kernel/time/tick-sched.c +++ b/kernel/time/tick-sched.c @@ -23,6 +23,7 @@ #include <linux/irq_work.h> #include <linux/posix-timers.h> #include <linux/perf_event.h> +#include <linux/context_tracking.h> #include <asm/irq_regs.h> @@ -148,8 +149,8 @@ static void tick_sched_handle(struct tick_sched *ts, struct pt_regs *regs) } #ifdef CONFIG_NO_HZ_FULL -static cpumask_var_t nohz_full_mask; -bool have_nohz_full_mask; +cpumask_var_t tick_nohz_full_mask; +bool tick_nohz_full_running; static bool can_stop_full_tick(void) { @@ -182,7 +183,7 @@ static bool can_stop_full_tick(void) * Don't allow the user to think they can get * full NO_HZ with this machine. */ - WARN_ONCE(have_nohz_full_mask, + WARN_ONCE(tick_nohz_full_running, "NO_HZ FULL will not work with unstable sched clock"); return false; } @@ -197,7 +198,7 @@ static void tick_nohz_restart_sched_tick(struct tick_sched *ts, ktime_t now); * Re-evaluate the need for the tick on the current CPU * and restart it if necessary. */ -void tick_nohz_full_check(void) +void __tick_nohz_full_check(void) { struct tick_sched *ts = &__get_cpu_var(tick_cpu_sched); @@ -211,7 +212,7 @@ void tick_nohz_full_check(void) static void nohz_full_kick_work_func(struct irq_work *work) { - tick_nohz_full_check(); + __tick_nohz_full_check(); } static DEFINE_PER_CPU(struct irq_work, nohz_full_kick_work) = { @@ -230,7 +231,7 @@ void tick_nohz_full_kick(void) static void nohz_full_kick_ipi(void *info) { - tick_nohz_full_check(); + __tick_nohz_full_check(); } /* @@ -239,12 +240,13 @@ static void nohz_full_kick_ipi(void *info) */ void tick_nohz_full_kick_all(void) { - if (!have_nohz_full_mask) + if (!tick_nohz_full_running) return; preempt_disable(); - smp_call_function_many(nohz_full_mask, + smp_call_function_many(tick_nohz_full_mask, nohz_full_kick_ipi, NULL, false); + tick_nohz_full_kick(); preempt_enable(); } @@ -253,7 +255,7 @@ void tick_nohz_full_kick_all(void) * It might need the tick due to per task/process properties: * perf events, posix cpu timers, ... */ -void tick_nohz_task_switch(struct task_struct *tsk) +void __tick_nohz_task_switch(struct task_struct *tsk) { unsigned long flags; @@ -269,31 +271,23 @@ out: local_irq_restore(flags); } -int tick_nohz_full_cpu(int cpu) -{ - if (!have_nohz_full_mask) - return 0; - - return cpumask_test_cpu(cpu, nohz_full_mask); -} - /* Parse the boot-time nohz CPU list from the kernel parameters. */ static int __init tick_nohz_full_setup(char *str) { int cpu; - alloc_bootmem_cpumask_var(&nohz_full_mask); - if (cpulist_parse(str, nohz_full_mask) < 0) { + alloc_bootmem_cpumask_var(&tick_nohz_full_mask); + if (cpulist_parse(str, tick_nohz_full_mask) < 0) { pr_warning("NOHZ: Incorrect nohz_full cpumask\n"); return 1; } cpu = smp_processor_id(); - if (cpumask_test_cpu(cpu, nohz_full_mask)) { + if (cpumask_test_cpu(cpu, tick_nohz_full_mask)) { pr_warning("NO_HZ: Clearing %d from nohz_full range for timekeeping\n", cpu); - cpumask_clear_cpu(cpu, nohz_full_mask); + cpumask_clear_cpu(cpu, tick_nohz_full_mask); } - have_nohz_full_mask = true; + tick_nohz_full_running = true; return 1; } @@ -311,7 +305,7 @@ static int tick_nohz_cpu_down_callback(struct notifier_block *nfb, * If we handle the timekeeping duty for full dynticks CPUs, * we can't safely shutdown that CPU. */ - if (have_nohz_full_mask && tick_do_timer_cpu == cpu) + if (tick_nohz_full_running && tick_do_timer_cpu == cpu) return NOTIFY_BAD; break; } @@ -330,31 +324,34 @@ static int tick_nohz_init_all(void) int err = -1; #ifdef CONFIG_NO_HZ_FULL_ALL - if (!alloc_cpumask_var(&nohz_full_mask, GFP_KERNEL)) { + if (!alloc_cpumask_var(&tick_nohz_full_mask, GFP_KERNEL)) { pr_err("NO_HZ: Can't allocate full dynticks cpumask\n"); return err; } err = 0; - cpumask_setall(nohz_full_mask); - cpumask_clear_cpu(smp_processor_id(), nohz_full_mask); - have_nohz_full_mask = true; + cpumask_setall(tick_nohz_full_mask); + cpumask_clear_cpu(smp_processor_id(), tick_nohz_full_mask); + tick_nohz_full_running = true; #endif return err; } void __init tick_nohz_init(void) { - if (!have_nohz_full_mask) { + int cpu; + + if (!tick_nohz_full_running) { if (tick_nohz_init_all() < 0) return; } + for_each_cpu(cpu, tick_nohz_full_mask) + context_tracking_cpu_set(cpu); + cpu_notifier(tick_nohz_cpu_down_callback, 0); - cpulist_scnprintf(nohz_full_buf, sizeof(nohz_full_buf), nohz_full_mask); + cpulist_scnprintf(nohz_full_buf, sizeof(nohz_full_buf), tick_nohz_full_mask); pr_info("NO_HZ: Full dynticks CPUs: %s.\n", nohz_full_buf); } -#else -#define have_nohz_full_mask (0) #endif /* @@ -732,7 +729,7 @@ static bool can_stop_idle_tick(int cpu, struct tick_sched *ts) return false; } - if (have_nohz_full_mask) { + if (tick_nohz_full_enabled()) { /* * Keep the tick alive to guarantee timekeeping progression * if there are full dynticks CPUs around |