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From: Thomas Gleixner <tglx@linutronix.de>
To: Andrew Morton <akpm@osdl.org>
Cc: LKML <linux-kernel@vger.kernel.org>, Ingo Molnar <mingo@elte.hu>,
	John Stultz <johnstul@us.ibm.com>,
	Arjan van de Veen <arjan@infradead.org>,
	Roman Zippel <zippel@linux-m68k.org>
Subject: [patch 34/46] tick-management: core functionality
Date: Tue, 23 Jan 2007 22:01:30 -0000	[thread overview]
Message-ID: <20070123211208.231121000@localhost.localdomain> (raw)
In-Reply-To: <20070123211159.178138000@localhost.localdomain>

[-- Attachment #1: tick-management-core.patch --]
[-- Type: text/plain, Size: 8419 bytes --]

From: Thomas Gleixner <tglx@linutronix.de>
From: Ingo Molnar <mingo@elte.hu>

The tick-management code is the first user of the clockevents layer.
It takes clock event devices from the clock events core and uses them
to provide the periodic tick.

Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Signed-off-by: Ingo Molnar <mingo@elte.hu>

---
 include/linux/tick.h      |   25 ++++
 init/main.c               |    2 
 kernel/time/Makefile      |    3 
 kernel/time/tick-common.c |  273 ++++++++++++++++++++++++++++++++++++++++++++++
 4 files changed, 302 insertions(+), 1 deletion(-)

Index: linux-2.6.20-rc4-mm1-bo/include/linux/tick.h
===================================================================
--- /dev/null
+++ linux-2.6.20-rc4-mm1-bo/include/linux/tick.h
@@ -0,0 +1,25 @@
+/*  linux/include/linux/tick.h
+ *
+ *  This file contains the structure definitions for tick related functions
+ *
+ */
+#ifndef _LINUX_TICK_H
+#define _LINUX_TICK_H
+
+#include <linux/clockchips.h>
+
+#ifdef CONFIG_GENERIC_CLOCKEVENTS
+
+enum tick_device_mode {
+	TICKDEV_MODE_PERIODIC,
+	TICKDEV_MODE_ONESHOT,
+};
+
+struct tick_device {
+	struct clock_event_device *evtdev;
+	enum tick_device_mode mode;
+};
+
+extern void __init tick_init(void);
+
+#endif
Index: linux-2.6.20-rc4-mm1-bo/init/main.c
===================================================================
--- linux-2.6.20-rc4-mm1-bo.orig/init/main.c
+++ linux-2.6.20-rc4-mm1-bo/init/main.c
@@ -40,6 +40,7 @@
 #include <linux/cpu.h>
 #include <linux/cpuset.h>
 #include <linux/efi.h>
+#include <linux/tick.h>
 #include <linux/taskstats_kern.h>
 #include <linux/delayacct.h>
 #include <linux/unistd.h>
@@ -503,6 +504,7 @@ asmlinkage void __init start_kernel(void
  * enable them
  */
 	lock_kernel();
+	tick_init();
 	boot_cpu_init();
 	page_address_init();
 	printk(KERN_NOTICE);
Index: linux-2.6.20-rc4-mm1-bo/kernel/time/Makefile
===================================================================
--- linux-2.6.20-rc4-mm1-bo.orig/kernel/time/Makefile
+++ linux-2.6.20-rc4-mm1-bo/kernel/time/Makefile
@@ -1,3 +1,4 @@
 obj-y += ntp.o clocksource.o jiffies.o
 
-obj-$(CONFIG_GENERIC_CLOCKEVENTS) += clockevents.o
+obj-$(CONFIG_GENERIC_CLOCKEVENTS)	+= clockevents.o
+obj-$(CONFIG_GENERIC_CLOCKEVENTS)	+= tick-common.o
Index: linux-2.6.20-rc4-mm1-bo/kernel/time/tick-common.c
===================================================================
--- /dev/null
+++ linux-2.6.20-rc4-mm1-bo/kernel/time/tick-common.c
@@ -0,0 +1,273 @@
+/*
+ * linux/kernel/time/tick-common.c
+ *
+ * This file contains the base functions to manage periodic tick
+ * related events.
+ *
+ * Copyright(C) 2005-2006, Thomas Gleixner <tglx@linutronix.de>
+ * Copyright(C) 2005-2007, Red Hat, Inc., Ingo Molnar
+ * Copyright(C) 2006-2007, Timesys Corp., Thomas Gleixner
+ *
+ * This code is licenced under the GPL version 2. For details see
+ * kernel-base/COPYING.
+ */
+#include <linux/cpu.h>
+#include <linux/err.h>
+#include <linux/hrtimer.h>
+#include <linux/irq.h>
+#include <linux/percpu.h>
+#include <linux/profile.h>
+#include <linux/sched.h>
+#include <linux/tick.h>
+
+/*
+ * Tick devices
+ */
+static DEFINE_PER_CPU(struct tick_device, tick_cpu_device);
+/*
+ * Tick next event: keeps track of the tick time
+ */
+static ktime_t tick_next_period;
+static ktime_t tick_period;
+static int tick_do_timer_cpu = -1;
+static DEFINE_SPINLOCK(tick_device_lock);
+
+/*
+ * Periodic tick
+ */
+static void tick_periodic(int cpu)
+{
+	if (tick_do_timer_cpu == cpu) {
+		write_seqlock(&xtime_lock);
+
+		/* Keep track of the next tick event */
+		tick_next_period = ktime_add(tick_next_period, tick_period);
+
+		do_timer(1);
+		write_sequnlock(&xtime_lock);
+	}
+
+	update_process_times(user_mode(get_irq_regs()));
+	profile_tick(CPU_PROFILING);
+}
+
+/*
+ * Event handler for periodic ticks
+ */
+void tick_handle_periodic(struct clock_event_device *dev)
+{
+	int cpu = smp_processor_id();
+
+	tick_periodic(cpu);
+
+	if (dev->mode != CLOCK_EVT_MODE_ONESHOT)
+		return;
+	/*
+	 * Setup the next period for devices, which do not have
+	 * periodic mode:
+	 */
+	for (;;) {
+		ktime_t next = ktime_add(dev->next_event, tick_period);
+
+		if (!clockevents_program_event(dev, next))
+			return;
+		tick_periodic(cpu);
+	}
+}
+
+/*
+ * Setup the device for a periodic tick
+ */
+void tick_setup_periodic(struct clock_event_device *dev)
+{
+	dev->event_handler = tick_handle_periodic;
+
+	if (dev->features & CLOCK_EVT_FEAT_PERIODIC) {
+		clockevents_set_mode(dev, CLOCK_EVT_MODE_PERIODIC);
+	} else {
+		unsigned long seq;
+		ktime_t next;
+
+		do {
+			seq = read_seqbegin(&xtime_lock);
+			next = tick_next_period;
+		} while (read_seqretry(&xtime_lock, seq));
+
+		clockevents_set_mode(dev, CLOCK_EVT_MODE_ONESHOT);
+
+		for (;;) {
+			if (!clockevents_program_event(dev, next))
+				return;
+			next = ktime_add(next, tick_period);
+		}
+	}
+}
+
+/*
+ * Setup the tick device
+ */
+static void tick_setup_device(struct tick_device *td,
+			      struct clock_event_device *newdev, int cpu,
+			      cpumask_t cpumask)
+{
+	ktime_t next_event;
+	void (*handler)(struct clock_event_device *) = NULL;
+
+	/*
+	 * First device setup ?
+	 */
+	if (!td->evtdev) {
+		/*
+		 * If no cpu took the do_timer update, assign it to
+		 * this cpu:
+		 */
+		if (tick_do_timer_cpu == -1) {
+			tick_do_timer_cpu = cpu;
+			tick_next_period = ktime_get();
+			tick_period = ktime_set(0, NSEC_PER_SEC / HZ);
+		}
+
+		/*
+		 * Startup in periodic mode first.
+		 */
+		td->mode = TICKDEV_MODE_PERIODIC;
+	} else {
+		handler = td->evtdev->event_handler;
+		next_event = td->evtdev->next_event;
+	}
+
+	td->evtdev = newdev;
+
+	/*
+	 * When the device is not per cpu, pin the interrupt to the
+	 * current cpu:
+	 */
+	if (!cpus_equal(newdev->cpumask, cpumask))
+		irq_set_affinity(newdev->irq, cpumask);
+
+	if (td->mode == TICKDEV_MODE_PERIODIC)
+		tick_setup_periodic(newdev, 0);
+}
+
+/*
+ * Check, if the new registered device should be used.
+ */
+static int tick_check_new_device(struct clock_event_device *newdev)
+{
+	struct clock_event_device *curdev;
+	struct tick_device *td;
+	int cpu, ret = NOTIFY_OK;
+	unsigned long flags;
+	cpumask_t cpumask;
+
+	spin_lock_irqsave(&tick_device_lock, flags);
+
+	cpu = smp_processor_id();
+	if (!cpu_isset(cpu, newdev->cpumask))
+		goto out;
+
+	td = &per_cpu(tick_cpu_device, cpu);
+	curdev = td->evtdev;
+	cpumask = cpumask_of_cpu(cpu);
+
+	/* cpu local device ? */
+	if (!cpus_equal(newdev->cpumask, cpumask)) {
+
+		/*
+		 * If the cpu affinity of the device interrupt can not
+		 * be set, ignore it.
+		 */
+		if (!irq_can_set_affinity(newdev->irq))
+			goto out_bc;
+
+		/*
+		 * If we have a cpu local device already, do not replace it
+		 * by a non cpu local device
+		 */
+		if (curdev && cpus_equal(curdev->cpumask, cpumask))
+			goto out_bc;
+	}
+
+	/*
+	 * If we have an active device, then check the rating and the oneshot
+	 * feature.
+	 */
+	if (curdev) {
+		/*
+		 * Check the rating
+		 */
+		if (curdev->rating >= newdev->rating)
+			goto out;
+	}
+
+	/*
+	 * Replace the eventually existing device by the new
+	 * device.
+	 */
+	clockevents_exchange_device(curdev, newdev);
+	tick_setup_device(td, newdev, cpu, cpumask);
+	ret = NOTIFY_STOP;
+
+out:
+	spin_unlock_irqrestore(&tick_device_lock, flags);
+	return ret;
+}
+
+/*
+ * Called with irqs disabled
+ */
+static inline void tick_do_resume(int cpu)
+{
+	struct tick_device *td = &per_cpu(tick_cpu_device, cpu);
+
+	if (td->mode == TICKDEV_MODE_PERIODIC)
+		tick_setup_periodic(td->evtdev, 0);
+}
+
+/*
+ * Resume tick devices
+ */
+static void tick_resume(void)
+{
+	unsigned long flags;
+
+	spin_lock_irqsave(&tick_device_lock, flags);
+	tick_do_resume(smp_processor_id());
+	spin_unlock_irqrestore(&tick_device_lock, flags);
+}
+
+/*
+ * Notification about clock event devices
+ */
+static int tick_notify(struct notifier_block *nb, unsigned long reason,
+			       void *dev)
+{
+	switch (reason) {
+
+	case CLOCK_EVT_NOTIFY_ADD:
+		return tick_check_new_device(dev);
+
+	case CLOCK_EVT_NOTIFY_RESUME:
+		tick_resume();
+		break;
+
+	default:
+		break;
+	}
+
+	return NOTIFY_OK;
+}
+
+static struct notifier_block tick_notifier = {
+	.notifier_call = tick_notify,
+};
+
+/**
+ * tick_init - initialize the tick control
+ *
+ * Register the notifier with the clockevents framework
+ */
+void __init tick_init(void)
+{
+	clockevents_register_notifier(&tick_notifier);
+}

--


  parent reply	other threads:[~2007-01-23 22:08 UTC|newest]

Thread overview: 78+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2007-01-23 22:00 [patch 00/46] High resolution timer / dynamic tick update Thomas Gleixner
2007-01-23 22:00 ` [patch 01/46] Add irq flag to disable balancing for an interrupt Thomas Gleixner
2007-01-23 22:00 ` [patch 02/46] Add a functions to handle interrupt affinity setting Thomas Gleixner
2007-01-23 22:00 ` [patch 03/46] [RFC] HZ free ntp Thomas Gleixner
2007-01-23 22:00 ` [patch 04/46] Uninline jiffies.h functions Thomas Gleixner
2007-01-23 22:01 ` [patch 05/46] Thomas Gleixner
2007-01-23 22:01 ` [patch 06/46] Fix timeout overflow with jiffies Thomas Gleixner
2007-01-23 22:01 ` [patch 07/46] GTOD: persistent clock support Thomas Gleixner
2007-01-23 22:01 ` [patch 08/46] i386: use GTOD " Thomas Gleixner
2007-01-23 22:01 ` [patch 09/46] i386 Remove useless code in tsc.c Thomas Gleixner
2007-01-23 22:01 ` [patch 10/46] Simplify the registration of clocksources Thomas Gleixner
2007-01-23 22:01 ` [patch 11/46] x86: rewrite SMP TSC sync code Thomas Gleixner
2007-01-23 22:01 ` [patch 12/46] clocksource: replace is_continuous by a flag field Thomas Gleixner
2007-01-24 11:23   ` [patch] clocksource: fixup is_continous changes in vmitime.c Ingo Molnar
2007-01-24 11:53     ` Thomas Gleixner
2007-01-23 22:01 ` [patch 13/46] clocksource: fixup is_continous changes on ARM Thomas Gleixner
2007-01-23 22:01 ` [patch 14/46] clocksource: fixup is_continous changes on AVR32 Thomas Gleixner
2007-01-23 22:01 ` [patch 15/46] clocksource: fixup is_continous changes on S390 Thomas Gleixner
2007-01-23 22:01 ` [patch 16/46] clocksource: fixup is_continous changes on MIPS Thomas Gleixner
2007-01-23 22:01 ` [patch 17/46] clocksource: Remove the update callback Thomas Gleixner
2007-01-23 22:01 ` [patch 18/46] clocksource: Add verification (watchdog) helper Thomas Gleixner
2007-01-24 15:42   ` [patch] clocksource: add verification (watchdog) helper, fix Ingo Molnar
2007-01-23 22:01 ` [patch 19/46] Mark TSC on GeodeLX reliable Thomas Gleixner
2007-01-23 22:01 ` [patch 20/46] uninline irq_enter() Thomas Gleixner
2007-01-23 22:01 ` [patch 21/46] Fix cascade lookup of next_timer_interrupt Thomas Gleixner
2007-01-23 22:01 ` [patch 22/46] Extend next_timer_interrupt() to use a reference jiffie Thomas Gleixner
2007-01-23 22:01 ` [patch 23/46] hrtimers: namespace and enum cleanup Thomas Gleixner
2007-01-23 22:01 ` [patch 24/46] hrtimers: namespace and enum cleanup vs. git-input Thomas Gleixner
2007-01-23 22:01 ` [patch 25/46] hrtimers: cleanup locking Thomas Gleixner
2007-01-23 22:01 ` [patch 26/46] hrtimers; add state tracking Thomas Gleixner
2007-01-23 22:01 ` [patch 27/46] hrtimers: clean up callback tracking Thomas Gleixner
2007-01-23 22:01 ` [patch 28/46] hrtimers: move and add documentation Thomas Gleixner
2007-01-23 22:01 ` [patch 29/46] ACPI: fix missing include for UP Thomas Gleixner
2007-01-23 22:01 ` [patch 30/46] ACPI keep track of timer broadcasting Thomas Gleixner
2007-01-23 22:01 ` [patch 31/46] Allow early access to the power management timer Thomas Gleixner
2007-01-23 22:01 ` [patch 32/46] i386, apic: clean up the APIC code Thomas Gleixner
2007-01-23 22:01 ` [patch 33/46] clockevents: add core functionality Thomas Gleixner
2007-01-23 22:01 ` Thomas Gleixner [this message]
2007-01-23 22:01 ` [patch 35/46] tick-management: broadcast functionality Thomas Gleixner
2007-01-23 22:01 ` [patch 36/46] tick-management: dyntick / highres functionality Thomas Gleixner
2007-01-28  2:03   ` [PATCH] high_res_timers: precisely update_process_times; " Karsten Wiese
2007-01-23 22:01 ` [patch 37/46] clockevents: i383 drivers Thomas Gleixner
2007-01-23 22:01 ` [patch 38/46] i386 rework local apic timer calibration Thomas Gleixner
2007-01-23 22:01 ` [patch 39/46] i386 prepare for dyntick Thomas Gleixner
2007-01-23 22:01 ` [patch 40/46] i386 prepare nmi watchdog for dynticks Thomas Gleixner
2007-01-23 22:01 ` [patch 41/46] i386: enable dynticks in kconfig Thomas Gleixner
2007-01-23 22:01 ` [patch 42/46] hrtimers: add high resolution timer support Thomas Gleixner
2007-01-23 22:01 ` [patch 43/46] hrtimers: prevent possible itimer DoS Thomas Gleixner
2007-01-23 22:01 ` [patch 44/46] Add debugging feature /proc/timer_stat Thomas Gleixner
2007-01-23 22:01 ` [patch 45/46] Add debugging feature /proc/timer_list Thomas Gleixner
2007-01-23 22:01 ` [patch 46/46] Add SysRq-Q to print timer_list debug info Thomas Gleixner
2007-01-24  2:16 ` [patch 00/46] High resolution timer / dynamic tick update Daniel Walker
2007-01-24  2:23   ` Andrew Morton
2007-01-24  3:25     ` Daniel Walker
2007-01-24  7:07   ` Ingo Molnar
2007-01-24  9:30     ` Daniel Walker
2007-01-24  9:51       ` Ingo Molnar
2007-01-24 10:23         ` Daniel Walker
2007-01-24 10:29           ` Ingo Molnar
2007-01-24 10:53             ` Daniel Walker
2007-01-24 11:04               ` Ingo Molnar
2007-01-24 11:13           ` Thomas Gleixner
2007-01-24 15:53             ` Daniel Walker
     [not found]               ` <20070124160046.GA24798@elte.hu>
2007-01-24 17:21                 ` Daniel Walker
     [not found]                 ` <1169655076.19471.241.camel@imap.mvista.com>
2007-01-24 19:38                   ` Ingo Molnar
2007-01-24 20:09                     ` Daniel Walker
2007-01-24 20:13                       ` Ingo Molnar
2007-01-24 19:57       ` john stultz
2007-01-24 20:51         ` Daniel Walker
2007-01-24 21:23           ` john stultz
2007-01-24 21:37             ` Daniel Walker
2007-01-25  6:10           ` Ingo Molnar
2007-01-25  6:37           ` Ingo Molnar
2007-01-25  6:32         ` Ingo Molnar
2007-01-25 16:38           ` Daniel Walker
2007-01-28  2:17 ` Andrew Morton
2007-01-29 21:31   ` john stultz
2007-01-29 21:45     ` john stultz

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