From: Frederic Weisbecker <fweisbec@gmail.com>
To: Ingo Molnar <mingo@kernel.org>
Cc: LKML <linux-kernel@vger.kernel.org>,
Frederic Weisbecker <fweisbec@gmail.com>,
Peter Zijlstra <peterz@infradead.org>,
Thomas Gleixner <tglx@linutronix.de>,
Andrew Morton <akpm@linux-foundation.org>,
Steven Rostedt <rostedt@goodmis.org>,
Paul Gortmaker <paul.gortmaker@windriver.com>
Subject: [PATCH 4/7] nohz: Add API to check tick state
Date: Wed, 14 Nov 2012 21:37:34 +0100 [thread overview]
Message-ID: <1352925457-15700-5-git-send-email-fweisbec@gmail.com> (raw)
In-Reply-To: <1352925457-15700-1-git-send-email-fweisbec@gmail.com>
We need some quick way to check if the CPU has stopped
its tick. This will be useful to implement the printk tick
using the irq work subsystem.
Signed-off-by: Frederic Weisbecker <fweisbec@gmail.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Ingo Molnar <mingo@kernel.org>
Cc: Andrew Morton <akpm@linux-foundation.org>
Cc: Steven Rostedt <rostedt@goodmis.org>
Cc: Paul Gortmaker <paul.gortmaker@windriver.com>
---
include/linux/tick.h | 17 ++++++++++++++++-
kernel/time/tick-sched.c | 2 +-
2 files changed, 17 insertions(+), 2 deletions(-)
diff --git a/include/linux/tick.h b/include/linux/tick.h
index f37fceb..2307dd3 100644
--- a/include/linux/tick.h
+++ b/include/linux/tick.h
@@ -8,6 +8,8 @@
#include <linux/clockchips.h>
#include <linux/irqflags.h>
+#include <linux/percpu.h>
+#include <linux/hrtimer.h>
#ifdef CONFIG_GENERIC_CLOCKEVENTS
@@ -122,13 +124,26 @@ static inline int tick_oneshot_mode_active(void) { return 0; }
#endif /* !CONFIG_GENERIC_CLOCKEVENTS */
# ifdef CONFIG_NO_HZ
+DECLARE_PER_CPU(struct tick_sched, tick_cpu_sched);
+
+static inline int tick_nohz_tick_stopped(void)
+{
+ return __this_cpu_read(tick_cpu_sched.tick_stopped);
+}
+
extern void tick_nohz_idle_enter(void);
extern void tick_nohz_idle_exit(void);
extern void tick_nohz_irq_exit(void);
extern ktime_t tick_nohz_get_sleep_length(void);
extern u64 get_cpu_idle_time_us(int cpu, u64 *last_update_time);
extern u64 get_cpu_iowait_time_us(int cpu, u64 *last_update_time);
-# else
+
+# else /* !CONFIG_NO_HZ */
+static inline int tick_nohz_tick_stopped(void)
+{
+ return 0;
+}
+
static inline void tick_nohz_idle_enter(void) { }
static inline void tick_nohz_idle_exit(void) { }
diff --git a/kernel/time/tick-sched.c b/kernel/time/tick-sched.c
index a402608..9e945aa 100644
--- a/kernel/time/tick-sched.c
+++ b/kernel/time/tick-sched.c
@@ -28,7 +28,7 @@
/*
* Per cpu nohz control structure
*/
-static DEFINE_PER_CPU(struct tick_sched, tick_cpu_sched);
+DEFINE_PER_CPU(struct tick_sched, tick_cpu_sched);
/*
* The time, when the last jiffy update happened. Protected by xtime_lock.
--
1.7.5.4
next prev parent reply other threads:[~2012-11-14 20:38 UTC|newest]
Thread overview: 21+ messages / expand[flat|nested] mbox.gz Atom feed top
2012-11-14 20:37 [GIT PULL] printk: Make it usable on nohz cpus Frederic Weisbecker
2012-11-14 20:37 ` [PATCH 1/7] irq_work: Fix racy IRQ_WORK_BUSY flag setting Frederic Weisbecker
2012-11-14 20:37 ` [PATCH 2/7] irq_work: Fix racy check on work pending flag Frederic Weisbecker
2012-11-14 20:37 ` [PATCH 3/7] irq_work: Remove CONFIG_HAVE_IRQ_WORK Frederic Weisbecker
2012-11-14 20:37 ` Frederic Weisbecker [this message]
2012-11-14 20:37 ` [PATCH 5/7] irq_work: Don't stop the tick with pending works Frederic Weisbecker
2012-11-15 3:59 ` Steven Rostedt
2012-11-15 15:38 ` Frederic Weisbecker
2012-11-14 20:37 ` [PATCH 6/7] irq_work: Make self-IPIs optable Frederic Weisbecker
2012-11-14 20:37 ` [PATCH 7/7] printk: Wake up klogd using irq_work Frederic Weisbecker
2012-11-15 4:26 ` Steven Rostedt
2012-11-15 15:25 ` Frederic Weisbecker
2012-11-15 15:33 ` Frederic Weisbecker
2012-11-15 16:34 ` [PATCH RFC] irq_work: Flush work on CPU_DYING (was: Re: [PATCH 7/7] printk: Wake up klogd using irq_work) Steven Rostedt
2012-11-15 17:52 ` [PATCH RFC] irq_work: Warn if there's still work on cpu_down Steven Rostedt
2012-11-15 18:12 ` Frederic Weisbecker
2012-11-15 18:56 ` Steven Rostedt
2012-11-15 18:08 ` [PATCH RFC] irq_work: Flush work on CPU_DYING (was: Re: [PATCH 7/7] printk: Wake up klogd using irq_work) Frederic Weisbecker
2012-11-15 18:13 ` Steven Rostedt
2012-11-15 18:16 ` Steven Rostedt
-- strict thread matches above, loose matches on Subject: below --
2012-11-08 13:14 [PATCH 0/7] printk: Make it usable on nohz CPUs v4 Frederic Weisbecker
2012-11-08 13:14 ` [PATCH 4/7] nohz: Add API to check tick state Frederic Weisbecker
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