/*
 * linux/kernel/time/tick-oneshot.c
 *
 * This file contains functions which manage high resolution 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/interrupt.h>
#include <linux/percpu.h>
#include <linux/profile.h>
#include <linux/sched.h>

#include "tick-internal.h"

/**
 * tick_program_event
 */
int tick_program_event(ktime_t expires, int force)
{
	struct clock_event_device *dev = __this_cpu_read(tick_cpu_device.evtdev);

	if (unlikely(expires == KTIME_MAX)) {
		/*
		 * We don't need the clock event device any more, stop it.
		 */
		clockevents_switch_state(dev, CLOCK_EVT_STATE_ONESHOT_STOPPED);
		return 0;
	}

	if (unlikely(clockevent_state_oneshot_stopped(dev))) {
		/*
		 * We need the clock event again, configure it in ONESHOT mode
		 * before using it.
		 */
		clockevents_switch_state(dev, CLOCK_EVT_STATE_ONESHOT);
	}

	return clockevents_program_event(dev, expires, force);
}

/**
 * tick_resume_onshot - resume oneshot mode
 */
void tick_resume_oneshot(void)
{
	struct clock_event_device *dev = __this_cpu_read(tick_cpu_device.evtdev);

	clockevents_switch_state(dev, CLOCK_EVT_STATE_ONESHOT);
	clockevents_program_event(dev, ktime_get(), true);
}

/**
 * tick_setup_oneshot - setup the event device for oneshot mode (hres or nohz)
 */
void tick_setup_oneshot(struct clock_event_device *newdev,
			void (*handler)(struct clock_event_device *),
			ktime_t next_event)
{
	newdev->event_handler = handler;
	clockevents_switch_state(newdev, CLOCK_EVT_STATE_ONESHOT);
	clockevents_program_event(newdev, next_event, true);
}

/**
 * tick_switch_to_oneshot - switch to oneshot mode
 */
int tick_switch_to_oneshot(void (*handler)(struct clock_event_device *))
{
	struct tick_device *td = this_cpu_ptr(&tick_cpu_device);
	struct clock_event_device *dev = td->evtdev;

	if (!dev || !(dev->features & CLOCK_EVT_FEAT_ONESHOT) ||
		    !tick_device_is_functional(dev)) {

		printk(KERN_INFO "Clockevents: "
		       "could not switch to one-shot mode:");
		if (!dev) {
			printk(" no tick device\n");
		} else {
			if (!tick_device_is_functional(dev))
				printk(" %s is not functional.\n", dev->name);
			else
				printk(" %s does not support one-shot mode.\n",
				       dev->name);
		}
		return -EINVAL;
	}

	td->mode = TICKDEV_MODE_ONESHOT;
	dev->event_handler = handler;
	clockevents_switch_state(dev, CLOCK_EVT_STATE_ONESHOT);
	tick_broadcast_switch_to_oneshot();
	return 0;
}

/**
 * tick_check_oneshot_mode - check whether the system is in oneshot mode
 *
 * returns 1 when either nohz or highres are enabled. otherwise 0.
 */
int tick_oneshot_mode_active(void)
{
	unsigned long flags;
	int ret;

	local_irq_save(flags);
	ret = __this_cpu_read(tick_cpu_device.mode) == TICKDEV_MODE_ONESHOT;
	local_irq_restore(flags);

	return ret;
}

#ifdef CONFIG_HIGH_RES_TIMERS
/**
 * tick_init_highres - switch to high resolution mode
 *
 * Called with interrupts disabled.
 */
int tick_init_highres(void)
{
	return tick_switch_to_oneshot(hrtimer_interrupt);
}
#endif
x/net-next.git/commit/include/dt-bindings/mfd?h=nds-private-remove&amp;id=79c6f448c8b79c321e4a1f31f98194e4f6b6cae7'>mfd</a></div><div class='content'><div class='cgit-panel'><b>diff options</b><form method='get'><input type='hidden' name='h' value='nds-private-remove'/><input type='hidden' name='id' value='79c6f448c8b79c321e4a1f31f98194e4f6b6cae7'/><table><tr><td colspan='2'/></tr><tr><td class='label'>context:</td><td class='ctrl'><select name='context' onchange='this.form.submit();'><option value='1'>1</option><option value='2'>2</option><option value='3' selected='selected'>3</option><option value='4'>4</option><option value='5'>5</option><option value='6'>6</option><option value='7'>7</option><option value='8'>8</option><option value='9'>9</option><option value='10'>10</option><option value='15'>15</option><option value='20'>20</option><option value='25'>25</option><option value='30'>30</option><option value='35'>35</option><option value='40'>40</option></select></td></tr><tr><td class='label'>space:</td><td class='ctrl'><select name='ignorews' onchange='this.form.submit();'><option value='0' selected='selected'>include</option><option value='1'>ignore</option></select></td></tr><tr><td class='label'>mode:</td><td class='ctrl'><select name='dt' onchange='this.form.submit();'><option value='0' selected='selected'>unified</option><option value='1'>ssdiff</option><option value='2'>stat only</option></select></td></tr><tr><td/><td class='ctrl'><noscript><input type='submit' value='reload'/></noscript></td></tr></table></form></div><table summary='commit info' class='commit-info'>
<tr><th>author</th><td>Steven Rostedt (VMware) &lt;rostedt@goodmis.org&gt;</td><td class='right'>2017-01-30 19:27:10 -0500</td></tr>
<tr><th>committer</th><td>Steven Rostedt (VMware) &lt;rostedt@goodmis.org&gt;</td><td class='right'>2017-01-31 09:13:49 -0500</td></tr>
<tr><th>commit</th><td colspan='2' class='oid'><a href='/cgit.cgi/linux/net-next.git/commit/include/dt-bindings/mfd?h=nds-private-remove&amp;id=79c6f448c8b79c321e4a1f31f98194e4f6b6cae7'>79c6f448c8b79c321e4a1f31f98194e4f6b6cae7</a> (<a href='/cgit.cgi/linux/net-next.git/patch/include/dt-bindings/mfd?id=79c6f448c8b79c321e4a1f31f98194e4f6b6cae7'>patch</a>)</td></tr>
<tr><th>tree</th><td colspan='2' class='oid'><a href='/cgit.cgi/linux/net-next.git/tree/?h=nds-private-remove&amp;id=79c6f448c8b79c321e4a1f31f98194e4f6b6cae7'>370efda701f03cccf21e02bb1fdd3b852547d75c</a> /<a href='/cgit.cgi/linux/net-next.git/tree/include/dt-bindings/mfd?h=nds-private-remove&amp;id=79c6f448c8b79c321e4a1f31f98194e4f6b6cae7'>include/dt-bindings/mfd</a></td></tr>
<tr><th>parent</th><td colspan='2' class='oid'><a href='/cgit.cgi/linux/net-next.git/commit/include/dt-bindings/mfd?h=nds-private-remove&amp;id=0c744ea4f77d72b3dcebb7a8f2684633ec79be88'>0c744ea4f77d72b3dcebb7a8f2684633ec79be88</a> (<a href='/cgit.cgi/linux/net-next.git/diff/include/dt-bindings/mfd?h=nds-private-remove&amp;id=79c6f448c8b79c321e4a1f31f98194e4f6b6cae7&amp;id2=0c744ea4f77d72b3dcebb7a8f2684633ec79be88'>diff</a>)</td></tr></table>
<div class='commit-subject'>tracing: Fix hwlat kthread migration</div><div class='commit-msg'>The hwlat tracer creates a kernel thread at start of the tracer. It is
pinned to a single CPU and will move to the next CPU after each period of
running. If the user modifies the migration thread's affinity, it will not
change after that happens.

The original code created the thread at the first instance it was called,
but later was changed to destroy the thread after the tracer was finished,
and would not be created until the next instance of the tracer was
established. The code that initialized the affinity was only called on the
initial instantiation of the tracer. After that, it was not initialized, and
the previous affinity did not match the current newly created one, making
it appear that the user modified the thread's affinity when it did not, and
the thread failed to migrate again.

Cc: stable@vger.kernel.org
Fixes: 0330f7aa8ee6 ("tracing: Have hwlat trace migrate across tracing_cpumask CPUs")
Signed-off-by: Steven Rostedt (VMware) &lt;rostedt@goodmis.org&gt;
</div><div class='diffstat-header'><a href='/cgit.cgi/linux/net-next.git/diff/?h=nds-private-remove&amp;id=79c6f448c8b79c321e4a1f31f98194e4f6b6cae7'>Diffstat</a> (limited to 'include/dt-bindings/mfd')</div><table summary='diffstat' class='diffstat'>