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authorLinus Torvalds <torvalds@linux-foundation.org>2013-09-04 09:36:54 -0700
committerLinus Torvalds <torvalds@linux-foundation.org>2013-09-04 09:36:54 -0700
commit6832d9652f395f7d13003e3884942c40f52ac1fa (patch)
tree40555ad5eda9700cb973dac4db136ad97f5e8b19 /kernel/time
parent228abe73ad67665d71eacd6a8a347dd76b0115ae (diff)
parentc2e7fcf53c3cb02b4ada1c66a9bc8a4d97d58aba (diff)
downloadlinux-6832d9652f395f7d13003e3884942c40f52ac1fa.tar.bz2
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/Kconfig1
-rw-r--r--kernel/time/tick-sched.c61
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