Release 4.7 kernel/softirq.c

Directory: kernel
/*
 *      linux/kernel/softirq.c
 *
 *      Copyright (C) 1992 Linus Torvalds
 *
 *      Distribute under GPLv2.
 *
 *      Rewritten. Old one was good in 2.2, but in 2.3 it was immoral. --ANK (990903)
 */


#define pr_fmt(fmt) KBUILD_MODNAME ": " fmt

#include <linux/export.h>
#include <linux/kernel_stat.h>
#include <linux/interrupt.h>
#include <linux/init.h>
#include <linux/mm.h>
#include <linux/notifier.h>
#include <linux/percpu.h>
#include <linux/cpu.h>
#include <linux/freezer.h>
#include <linux/kthread.h>
#include <linux/rcupdate.h>
#include <linux/ftrace.h>
#include <linux/smp.h>
#include <linux/smpboot.h>
#include <linux/tick.h>
#include <linux/irq.h>


#define CREATE_TRACE_POINTS
#include <trace/events/irq.h>

/*
   - No shared variables, all the data are CPU local.
   - If a softirq needs serialization, let it serialize itself
     by its own spinlocks.
   - Even if softirq is serialized, only local cpu is marked for
     execution. Hence, we get something sort of weak cpu binding.
     Though it is still not clear, will it result in better locality
     or will not.

   Examples:
   - NET RX softirq. It is multithreaded and does not require
     any global serialization.
   - NET TX softirq. It kicks software netdevice queues, hence
     it is logically serialized per device, but this serialization
     is invisible to common code.
   - Tasklets: serialized wrt itself.
 */

#ifndef __ARCH_IRQ_STAT

irq_cpustat_t irq_stat[NR_CPUS] ____cacheline_aligned;

EXPORT_SYMBOL(irq_stat);
#endif


static struct softirq_action softirq_vec[NR_SOFTIRQS] __cacheline_aligned_in_smp;

DEFINE_PER_CPU(struct task_struct *, ksoftirqd);


const char * const softirq_to_name[NR_SOFTIRQS] = {
	"HI", "TIMER", "NET_TX", "NET_RX", "BLOCK", "BLOCK_IOPOLL",
	"TASKLET", "SCHED", "HRTIMER", "RCU"
};

/*
 * we cannot loop indefinitely here to avoid userspace starvation,
 * but we also don't want to introduce a worst case 1/HZ latency
 * to the pending events, so lets the scheduler to balance
 * the softirq load for us.
 */


static void wakeup_softirqd(void)
{
	/* Interrupts are disabled: no need to stop preemption */
	struct task_struct *tsk = __this_cpu_read(ksoftirqd);

	if (tsk && tsk->state != TASK_RUNNING)
		wake_up_process(tsk);
}

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christoph lameter christoph lameter 1 2.94% 1 25.00%
Total 34 100.00% 4 100.00%

/*
 * preempt_count and SOFTIRQ_OFFSET usage:
 * - preempt_count is changed by SOFTIRQ_OFFSET on entering or leaving
 *   softirq processing.
 * - preempt_count is changed by SOFTIRQ_DISABLE_OFFSET (= 2 * SOFTIRQ_OFFSET)
 *   on local_bh_disable or local_bh_enable.
 * This lets us distinguish between whether we are currently processing
 * softirq and whether we just have bh disabled.
 */

/*
 * This one is for softirq.c-internal use,
 * where hardirqs are disabled legitimately:
 */
#ifdef CONFIG_TRACE_IRQFLAGS


void __local_bh_disable_ip(unsigned long ip, unsigned int cnt)
{
	unsigned long flags;

	WARN_ON_ONCE(in_irq());

	raw_local_irq_save(flags);
	/*
         * The preempt tracer hooks into preempt_count_add and will break
         * lockdep because it calls back into lockdep after SOFTIRQ_OFFSET
         * is set and before current->softirq_enabled is cleared.
         * We must manually increment preempt_count here and manually
         * call the trace_preempt_off later.
         */
	__preempt_count_add(cnt);
	/*
         * Were softirqs turned off above:
         */
	if (softirq_count() == (cnt & SOFTIRQ_MASK))
		trace_softirqs_off(ip);
	raw_local_irq_restore(flags);

	if (preempt_count() == cnt) {
#ifdef CONFIG_DEBUG_PREEMPT
		current->preempt_disable_ip = get_lock_parent_ip();
#endif
		trace_preempt_off(CALLER_ADDR0, get_lock_parent_ip());
	}
}
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peter zijlstra peter zijlstra 9 10.59% 4 44.44%
venkatesh pallipadi venkatesh pallipadi 7 8.24% 1 11.11%
sebastian andrzej siewior sebastian andrzej siewior 4 4.71% 1 11.11%
Total 85 100.00% 9 100.00%


EXPORT_SYMBOL(__local_bh_disable_ip);
#endif /* CONFIG_TRACE_IRQFLAGS */



static void __local_bh_enable(unsigned int cnt)
{
	WARN_ON_ONCE(!irqs_disabled());

	if (softirq_count() == (cnt & SOFTIRQ_MASK))
		trace_softirqs_on(_RET_IP_);
	preempt_count_sub(cnt);
}

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davidlohr bueso davidlohr bueso 1 2.63% 1 20.00%
Total 38 100.00% 5 100.00%

/*
 * Special-case - softirqs can safely be enabled in
 * cond_resched_softirq(), or by __do_softirq(),
 * without processing still-pending softirqs:
 */


void _local_bh_enable(void)
{
	WARN_ON_ONCE(in_irq());
	__local_bh_enable(SOFTIRQ_DISABLE_OFFSET);
}
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Total 18 100.00% 3 100.00%


EXPORT_SYMBOL(_local_bh_enable);



void __local_bh_enable_ip(unsigned long ip, unsigned int cnt)
{
	WARN_ON_ONCE(in_irq() || irqs_disabled());
#ifdef CONFIG_TRACE_IRQFLAGS
	local_irq_disable();
#endif
	/*
         * Are softirqs going to be turned on now:
         */
	if (softirq_count() == SOFTIRQ_DISABLE_OFFSET)
		trace_softirqs_on(ip);
	/*
         * Keep preemption disabled until we are done with
         * softirq processing:
         */
	preempt_count_sub(cnt - 1);

	if (unlikely(!in_interrupt() && local_softirq_pending())) {
		/*
                 * Run softirq if any pending. And do it in its own stack
                 * as we may be calling this deep in a task call stack already.
                 */
		do_softirq();
	}

	preempt_count_dec();
#ifdef CONFIG_TRACE_IRQFLAGS
	local_irq_enable();
#endif
	preempt_check_resched();
}
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peter zijlstra peter zijlstra 8 9.64% 2 25.00%
frederic weisbecker frederic weisbecker 3 3.61% 1 12.50%
joe perches joe perches 1 1.20% 1 12.50%
venkatesh pallipadi venkatesh pallipadi 1 1.20% 1 12.50%
Total 83 100.00% 8 100.00%


EXPORT_SYMBOL(__local_bh_enable_ip);

/*
 * We restart softirq processing for at most MAX_SOFTIRQ_RESTART times,
 * but break the loop if need_resched() is set or after 2 ms.
 * The MAX_SOFTIRQ_TIME provides a nice upper bound in most cases, but in
 * certain cases, such as stop_machine(), jiffies may cease to
 * increment and so we need the MAX_SOFTIRQ_RESTART limit as
 * well to make sure we eventually return from this method.
 *
 * These limits have been established via experimentation.
 * The two things to balance is latency against fairness -
 * we want to handle softirqs as soon as possible, but they
 * should not be able to lock up the box.
 */

#define MAX_SOFTIRQ_TIME  msecs_to_jiffies(2)

#define MAX_SOFTIRQ_RESTART 10

#ifdef CONFIG_TRACE_IRQFLAGS
/*
 * When we run softirqs from irq_exit() and thus on the hardirq stack we need
 * to keep the lockdep irq context tracking as tight as possible in order to
 * not miss-qualify lock contexts and miss possible deadlocks.
 */



static inline bool lockdep_softirq_start(void)
{
	bool in_hardirq = false;

	if (trace_hardirq_context(current)) {
		in_hardirq = true;
		trace_hardirq_exit();
	}

	lockdep_softirq_enter();

	return in_hardirq;
}

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static inline void lockdep_softirq_end(bool in_hardirq)
{
	lockdep_softirq_exit();

	if (in_hardirq)
		trace_hardirq_enter();
}
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Total 20 100.00% 2 100.00%

#else


static inline bool lockdep_softirq_start(void) { return false; }
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static inline void lockdep_softirq_end(bool in_hardirq) { }
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#endif



asmlinkage __visible void __softirq_entry __do_softirq(void)
{
	unsigned long end = jiffies + MAX_SOFTIRQ_TIME;
	unsigned long old_flags = current->flags;
	int max_restart = MAX_SOFTIRQ_RESTART;
	struct softirq_action *h;
	bool in_hardirq;
	__u32 pending;
	int softirq_bit;

	/*
         * Mask out PF_MEMALLOC s current task context is borrowed for the
         * softirq. A softirq handled such as network RX might set PF_MEMALLOC
         * again if the socket is related to swap
         */
	current->flags &= ~PF_MEMALLOC;

	pending = local_softirq_pending();
	account_irq_enter_time(current);

	__local_bh_disable_ip(_RET_IP_, SOFTIRQ_OFFSET);
	in_hardirq = lockdep_softirq_start();

restart:
	/* Reset the pending bitmask before enabling irqs */
	set_softirq_pending(0);

	local_irq_enable();

	h = softirq_vec;

	while ((softirq_bit = ffs(pending))) {
		unsigned int vec_nr;
		int prev_count;

		h += softirq_bit - 1;

		vec_nr = h - softirq_vec;
		prev_count = preempt_count();

		kstat_incr_softirqs_this_cpu(vec_nr);

		trace_softirq_entry(vec_nr);
		h->action(h);
		trace_softirq_exit(vec_nr);
		if (unlikely(prev_count != preempt_count())) {
			pr_err("huh, entered softirq %u %s %p with preempt_count %08x, exited with %08x?\n",
			       vec_nr, softirq_to_name[vec_nr], h->action,
			       prev_count, preempt_count());
			preempt_count_set(prev_count);
		}
		h++;
		pending >>= softirq_bit;
	}

	rcu_bh_qs();
	local_irq_disable();

	pending = local_softirq_pending();
	if (pending) {
		if (time_before(jiffies, end) && !need_resched() &&
		    --max_restart)
			goto restart;

		wakeup_softirqd();
	}

	lockdep_softirq_end(in_hardirq);
	account_irq_exit_time(current);
	__local_bh_enable(SOFTIRQ_OFFSET);
	WARN_ON_ONCE(in_interrupt());
	tsk_restore_flags(current, old_flags, PF_MEMALLOC);
}

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frederic weisbecker frederic weisbecker 16 6.08% 3 8.11%
linus torvalds linus torvalds 16 6.08% 3 8.11%
peter zijlstra peter zijlstra 15 5.70% 3 8.11%
jason baron jason baron 12 4.56% 2 5.41%
andrew morton andrew morton 10 3.80% 3 8.11%
ben greear ben greear 8 3.04% 1 2.70%
paul mackerras paul mackerras 8 3.04% 1 2.70%
venkatesh pallipadi venkatesh pallipadi 6 2.28% 1 2.70%
david s. miller david s. miller 5 1.90% 1 2.70%
ingo molnar ingo molnar 5 1.90% 2 5.41%
keika kobayashi keika kobayashi 4 1.52% 1 2.70%
andi kleen andi kleen 4 1.52% 2 5.41%
dipankar sarma dipankar sarma 1 0.38% 1 2.70%
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alexander potapenko alexander potapenko 1 0.38% 1 2.70%
Total 263 100.00% 37 100.00%



asmlinkage __visible void do_softirq(void)
{
	__u32 pending;
	unsigned long flags;

	if (in_interrupt())
		return;

	local_irq_save(flags);

	pending = local_softirq_pending();

	if (pending)
		do_softirq_own_stack();

	local_irq_restore(flags);
}

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andi kleen andi kleen 1 2.27% 1 25.00%
Total 44 100.00% 4 100.00%

/*
 * Enter an interrupt context.
 */


void irq_enter(void)
{
	rcu_irq_enter();
	if (is_idle_task(current) && !in_interrupt()) {
		/*
                 * Prevent raise_softirq from needlessly waking up ksoftirqd
                 * here, as softirq will be serviced on return from interrupt.
                 */
		local_bh_disable();
		tick_irq_enter();
		_local_bh_enable();
	}

	__irq_enter();
}

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frederic weisbecker frederic weisbecker 4 11.11% 3 33.33%
paul e. mckenney paul e. mckenney 3 8.33% 1 11.11%
Total 36 100.00% 9 100.00%



static inline void invoke_softirq(void)
{
	if (!force_irqthreads) {
#ifdef CONFIG_HAVE_IRQ_EXIT_ON_IRQ_STACK
		/*
                 * We can safely execute softirq on the current stack if
                 * it is the irq stack, because it should be near empty
                 * at this stage.
                 */
		__do_softirq();
#else
		/*
                 * Otherwise, irq_exit() is called on the task stack that can
                 * be potentially deep already. So call softirq in its own stack
                 * to prevent from any overrun.
                 */
		do_softirq_own_stack();
#endif
	} else {
		wakeup_softirqd();
	}
}

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Total 37 100.00% 5 100.00%



static inline void tick_irq_exit(void)
{
#ifdef CONFIG_NO_HZ_COMMON
	int cpu = smp_processor_id();

	/* Make sure that timer wheel updates are propagated */
	if ((idle_cpu(cpu) && !need_resched()) || tick_nohz_full_cpu(cpu)) {
		if (!in_interrupt())
			tick_nohz_irq_exit();
	}
#endif
}

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/*
 * Exit an interrupt context. Process softirqs if needed and possible:
 */


void irq_exit(void)
{
#ifndef __ARCH_IRQ_EXIT_IRQS_DISABLED
	local_irq_disable();
#else
	WARN_ON_ONCE(!irqs_disabled());
#endif

	account_irq_exit_time(current);
	preempt_count_sub(HARDIRQ_OFFSET);
	if (!in_interrupt() && local_softirq_pending())
		invoke_softirq();

	tick_irq_exit();
	rcu_irq_exit();
	trace_hardirq_exit(); /* must be last! */
}

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peter zijlstra peter zijlstra 5 8.93% 2 15.38%
martin schwidefsky martin schwidefsky 4 7.14% 1 7.69%
ingo molnar ingo molnar 2 3.57% 1 7.69%
Total 56 100.00% 13 100.00%

/*
 * This function must run with irqs disabled!
 */


inline void raise_softirq_irqoff(unsigned int nr)
{
	__raise_softirq_irqoff(nr);

	/*
         * If we're in an interrupt or softirq, we're done
         * (this also catches softirq-disabled code). We will
         * actually run the softirq once we return from
         * the irq or softirq.
         *
         * Otherwise we wake up ksoftirqd to make sure we
         * schedule the softirq soon.
         */
	if (!in_interrupt())
		wakeup_softirqd();
}

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Total 25 100.00% 5 100.00%



void raise_softirq(unsigned int nr)
{
	unsigned long flags;

	local_irq_save(flags);
	raise_softirq_irqoff(nr);
	local_irq_restore(flags);
}

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Total 28 100.00% 6 100.00%



void __raise_softirq_irqoff(unsigned int nr)
{
	trace_softirq_raise(nr);
	or_softirq_pending(1UL << nr);
}

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void open_softirq(int nr, void (*action)(struct softirq_action *))
{
	softirq_vec[nr].action = action;
}

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/*
 * Tasklets
 */

struct tasklet_head {
	
struct tasklet_struct *head;
	
struct tasklet_struct **tail;
};

static DEFINE_PER_CPU(struct tasklet_head, tasklet_vec);
static DEFINE_PER_CPU(struct tasklet_head, tasklet_hi_vec);



void __tasklet_schedule(struct tasklet_struct *t)
{
	unsigned long flags;

	local_irq_save(flags);
	t->next = NULL;
	*__this_cpu_read(tasklet_vec.tail) = t;
	__this_cpu_write(tasklet_vec.tail, &(t->next));
	raise_softirq_irqoff(TASKLET_SOFTIRQ);
	local_irq_restore(flags);
}
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Total 59 100.00% 6 100.00%


EXPORT_SYMBOL(__tasklet_schedule);



void __tasklet_hi_schedule(struct tasklet_struct *t)
{
	unsigned long flags;

	local_irq_save(flags);
	t->next = NULL;
	*__this_cpu_read(tasklet_hi_vec.tail) = t;
	__this_cpu_write(tasklet_hi_vec.tail,  &(t->next));
	raise_softirq_irqoff(HI_SOFTIRQ);
	local_irq_restore(flags);
}
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Total 59 100.00% 6 100.00%


EXPORT_SYMBOL(__tasklet_hi_schedule);



void __tasklet_hi_schedule_first(struct tasklet_struct *t)
{
	BUG_ON(!irqs_disabled());

	t->next = __this_cpu_read(tasklet_hi_vec.head);
	__this_cpu_write(tasklet_hi_vec.head, t);
	__raise_softirq_irqoff(HI_SOFTIRQ);
}
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EXPORT_SYMBOL(__tasklet_hi_schedule_first);



static void tasklet_action(struct softirq_action *a)
{
	struct tasklet_struct *list;

	local_irq_disable();
	list = __this_cpu_read(tasklet_vec.head);
	__this_cpu_write(tasklet_vec.head, NULL);
	__this_cpu_write(tasklet_vec.tail, this_cpu_ptr(&tasklet_vec.head));
	local_irq_enable();

	while (list) {
		struct tasklet_struct *t = list;

		list = list->next;

		if (tasklet_trylock(t)) {
			if (!atomic_read(&t->count)) {
				if (!test_and_clear_bit(TASKLET_STATE_SCHED,
							&t->state))
					BUG();
				t->func(t->data);
				tasklet_unlock(t);
				continue;
			}
			tasklet_unlock(t);
		}

		local_irq_disable();
		t->next = NULL;
		*__this_cpu_read(tasklet_vec.tail) = t;
		__this_cpu_write(tasklet_vec.tail, &(t->next));
		__raise_softirq_irqoff(TASKLET_SOFTIRQ);
		local_irq_enable();
	}
}

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Total 173 100.00% 14 100.00%



static void tasklet_hi_action(struct softirq_action *a)
{
	struct tasklet_struct *list;

	local_irq_disable();
	list = __this_cpu_read(tasklet_hi_vec.head);
	__this_cpu_write(tasklet_hi_vec.head, NULL);
	__this_cpu_write(tasklet_hi_vec.tail, this_cpu_ptr(&tasklet_hi_vec.head));
	local_irq_enable();

	while (list) {
		struct tasklet_struct *t = list;

		list = list->next;

		if (tasklet_trylock(t)) {
			if (!atomic_read(&t->count)) {
				if (!test_and_clear_bit(TASKLET_STATE_SCHED,
							&t->state))
					BUG();
				t->func(t->data);
				tasklet_unlock(t);
				continue;
			}
			tasklet_unlock(t);
		}

		local_irq_disable();
		t->next = NULL;
		*__this_cpu_read(tasklet_hi_vec.tail) = t;
		__this_cpu_write(tasklet_hi_vec.tail, &(t->next));
		__raise_softirq_irqoff(HI_SOFTIRQ);
		local_irq_enable();
	}
}

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pre-git pre-git 89 51.45% 3 25.00%
linus torvalds linus torvalds 40 23.12% 4 33.33%
olof johansson olof johansson 23 13.29% 1 8.33%
christoph lameter christoph lameter 16 9.25% 2 16.67%
rusty russell rusty russell 5 2.89% 2 16.67%
Total 173 100.00% 12 100.00%



void tasklet_init(struct tasklet_struct *t,
		  void (*func)(unsigned long), unsigned long data)
{
	t->next = NULL;
	t->state = 0;
	atomic_set(&t->count, 0);
	t->func = func;
	t->data = data;
}
Contributors
Person Tokens Prop Commits CommitProp
pre-git pre-git 44 75.86% 1 50.00%
linus torvalds linus torvalds 14 24.14% 1 50.00%
Total 58 100.00% 2 100.00%


EXPORT_SYMBOL(tasklet_init);



void tasklet_kill(struct tasklet_struct *t)
{
	if (in_interrupt())
		pr_notice("Attempt to kill tasklet from interrupt\n");

	while (test_and_set_bit(TASKLET_STATE_SCHED, &t->state)) {
		do {
			yield();
		} while (test_bit(TASKLET_STATE_SCHED, &t->state));
	}
	tasklet_unlock_wait(t);
	clear_bit(TASKLET_STATE_SCHED, &t->state);
}
Contributors
Person Tokens Prop Commits CommitProp
pre-git pre-git 64 94.12% 5 62.50%
h hartley sweeten h hartley sweeten 2 2.94% 1 12.50%
joe perches joe perches 1 1.47% 1 12.50%
linus torvalds linus torvalds 1 1.47% 1 12.50%
Total 68 100.00% 8 100.00%


EXPORT_SYMBOL(tasklet_kill);

/*
 * tasklet_hrtimer
 */

/*
 * The trampoline is called when the hrtimer expires. It schedules a tasklet
 * to run __tasklet_hrtimer_trampoline() which in turn will call the intended
 * hrtimer callback, but from softirq context.
 */


static enum hrtimer_restart __hrtimer_tasklet_trampoline(struct hrtimer *timer)
{
	struct tasklet_hrtimer *ttimer =
		container_of(timer, struct tasklet_hrtimer, timer);

	tasklet_hi_schedule(&ttimer->tasklet);
	return HRTIMER_NORESTART;
}

Contributors
Person Tokens Prop Commits CommitProp
peter zijlstra peter zijlstra 38 100.00% 1 100.00%
Total 38 100.00% 1 100.00%

/*
 * Helper function which calls the hrtimer callback from
 * tasklet/softirq context
 */


static void __tasklet_hrtimer_trampoline(unsigned long data)
{
	struct tasklet_hrtimer *ttimer = (void *)data;
	enum hrtimer_restart restart;

	restart = ttimer->function(&ttimer->timer);
	if (restart != HRTIMER_NORESTART)
		hrtimer_restart(&ttimer->timer);
}

Contributors
Person Tokens Prop Commits CommitProp
peter zijlstra peter zijlstra 51 100.00% 1 100.00%
Total 51 100.00% 1 100.00%

/**
 * tasklet_hrtimer_init - Init a tasklet/hrtimer combo for softirq callbacks
 * @ttimer:      tasklet_hrtimer which is initialized
 * @function:    hrtimer callback function which gets called from softirq context
 * @which_clock: clock id (CLOCK_MONOTONIC/CLOCK_REALTIME)
 * @mode:        hrtimer mode (HRTIMER_MODE_ABS/HRTIMER_MODE_REL)
 */

void tasklet_hrtimer_init(struct tasklet_hrtimer *ttimer,
			  enum hrtimer_restart (*function)(struct hrtimer *),
			  clockid_t which_clock, enum hrtimer_mode mode)
{
	hrtimer_init(&ttimer->timer, which_clock, mode);
	ttimer->timer.function = __hrtimer_tasklet_trampoline;
	tasklet_init(&ttimer->tasklet, __tasklet_hrtimer_trampoline,
		     (unsigned long)ttimer);
	ttimer->function = function;
}

EXPORT_SYMBOL_GPL(tasklet_hrtimer_init);



void __init softirq_init(void)
{
	int cpu;

	for_each_possible_cpu(cpu) {
		per_cpu(tasklet_vec, cpu).tail =
			&per_cpu(tasklet_vec, cpu).head;
		per_cpu(tasklet_hi_vec, cpu).tail =
			&per_cpu(tasklet_hi_vec, cpu).head;
	}

	open_softirq(TASKLET_SOFTIRQ, tasklet_action);
	open_softirq(HI_SOFTIRQ, tasklet_hi_action);
}

Contributors
Person Tokens Prop Commits CommitProp
olof johansson olof johansson 47 68.12% 1 25.00%
pre-git pre-git 19 27.54% 2 50.00%
linus torvalds linus torvalds 3 4.35% 1 25.00%
Total 69 100.00% 4 100.00%



static int ksoftirqd_should_run(unsigned int cpu)
{
	return local_softirq_pending();
}

Contributors
Person Tokens Prop Commits CommitProp
thomas gleixner thomas gleixner 6 42.86% 1 25.00%
linus torvalds linus torvalds 5 35.71% 1 25.00%
david s. miller david s. miller 2 14.29% 1 25.00%
zwane mwaikambo zwane mwaikambo 1 7.14% 1 25.00%
Total 14 100.00% 4 100.00%



static void run_ksoftirqd(unsigned int cpu)
{
	local_irq_disable();
	if (local_softirq_pending()) {
		/*
                 * We can safely run softirq on inline stack, as we are not deep
                 * in the task stack here.
                 */
		__do_softirq();
		local_irq_enable();
		cond_resched_rcu_qs();
		return;
	}
	local_irq_enable();
}

Contributors
Person Tokens Prop Commits CommitProp
thomas gleixner thomas gleixner 24 70.59% 2 28.57%
rusty russell rusty russell 5 14.71% 1 14.29%
linus torvalds linus torvalds 2 5.88% 1 14.29%
paul e. mckenney paul e. mckenney 1 2.94% 1 14.29%
calvin owens calvin owens 1 2.94% 1 14.29%
frederic weisbecker frederic weisbecker 1 2.94% 1 14.29%
Total 34 100.00% 7 100.00%

#ifdef CONFIG_HOTPLUG_CPU
/*
 * tasklet_kill_immediate is called to remove a tasklet which can already be
 * scheduled for execution on @cpu.
 *
 * Unlike tasklet_kill, this function removes the tasklet
 * _immediately_, even if the tasklet is in TASKLET_STATE_SCHED state.
 *
 * When this function is called, @cpu must be in the CPU_DEAD state.
 */


void tasklet_kill_immediate(struct tasklet_struct *t, unsigned int cpu)
{
	struct tasklet_struct **i;

	BUG_ON(cpu_online(cpu));
	BUG_ON(test_bit(TASKLET_STATE_RUN, &t->state));

	if (!test_bit(TASKLET_STATE_SCHED, &t->state))
		return;

	/* CPU is dead, so no lock needed. */
	for (i = &per_cpu(tasklet_vec, cpu).head; *i; i = &(*i)->next) {
		if (*i == t) {
			*i = t->next;
			/* If this was the tail element, move the tail ptr */
			if (*i == NULL)
				per_cpu(tasklet_vec, cpu).tail = i;
			return;
		}
	}
	BUG();
}

Contributors
Person Tokens Prop Commits CommitProp
rusty russell rusty russell 104 83.87% 1 50.00%
olof johansson olof johansson 20 16.13% 1 50.00%
Total 124 100.00% 2 100.00%



static void takeover_tasklets(unsigned int cpu)
{
	/* CPU is dead, so no lock needed. */
	local_irq_disable();

	/* Find end, append list for that CPU. */
	if (&per_cpu(tasklet_vec, cpu).head != per_cpu(tasklet_vec, cpu).tail) {
		*__this_cpu_read(tasklet_vec.tail) = per_cpu(tasklet_vec, cpu).head;
		this_cpu_write(tasklet_vec.tail, per_cpu(tasklet_vec, cpu).tail);
		per_cpu(tasklet_vec, cpu).head = NULL;
		per_cpu(tasklet_vec, cpu).tail = &per_cpu(tasklet_vec, cpu).head;
	}
	raise_softirq_irqoff(TASKLET_SOFTIRQ);

	if (&per_cpu(tasklet_hi_vec, cpu).head != per_cpu(tasklet_hi_vec, cpu).tail) {
		*__this_cpu_read(tasklet_hi_vec.tail) = per_cpu(tasklet_hi_vec, cpu).head;
		__this_cpu_write(tasklet_hi_vec.tail, per_cpu(tasklet_hi_vec, cpu).tail);
		per_cpu(tasklet_hi_vec, cpu).head = NULL;
		per_cpu(tasklet_hi_vec, cpu).tail = &per_cpu(tasklet_hi_vec, cpu).head;
	}
	raise_softirq_irqoff(HI_SOFTIRQ);

	local_irq_enable();
}
Contributors
Person Tokens Prop Commits CommitProp
olof johansson olof johansson 72 36.00% 1 25.00%
rusty russell rusty russell 72 36.00% 1 25.00%
christian borntraeger christian borntraeger 46 23.00% 1 25.00%
christoph lameter christoph lameter 10 5.00% 1 25.00%
Total 200 100.00% 4 100.00%

#endif /* CONFIG_HOTPLUG_CPU */



static int cpu_callback(struct notifier_block *nfb, unsigned long action,
			void *hcpu)
{
	switch (action) {
#ifdef CONFIG_HOTPLUG_CPU
	case CPU_DEAD:
	case CPU_DEAD_FROZEN:
		takeover_tasklets((unsigned long)hcpu);
		break;
#endif /* CONFIG_HOTPLUG_CPU */
	}
	return NOTIFY_OK;
}

Contributors
Person Tokens Prop Commits CommitProp
rusty russell rusty russell 30 60.00% 3 33.33%
linus torvalds linus torvalds 7 14.00% 1 11.11%
thomas gleixner thomas gleixner 5 10.00% 1 11.11%
andrew morton andrew morton 5 10.00% 3 33.33%
rafael j. wysocki rafael j. wysocki 3 6.00% 1 11.11%
Total 50 100.00% 9 100.00%


static struct notifier_block cpu_nfb = {
	.notifier_call = cpu_callback
};


static struct smp_hotplug_thread softirq_threads = {
	.store			= &ksoftirqd,
	.thread_should_run	= ksoftirqd_should_run,
	.thread_fn		= run_ksoftirqd,
	.thread_comm		= "ksoftirqd/%u",
};



static __init int spawn_ksoftirqd(void)
{
	register_cpu_notifier(&cpu_nfb);

	BUG_ON(smpboot_register_percpu_thread(&softirq_threads));

	return 0;
}
Contributors
Person Tokens Prop Commits CommitProp
rusty russell rusty russell 10 37.04% 1 16.67%
andrew morton andrew morton 6 22.22% 1 16.67%
linus torvalds linus torvalds 4 14.81% 1 16.67%
thomas gleixner thomas gleixner 4 14.81% 1 16.67%
akinobu mita akinobu mita 2 7.41% 1 16.67%
eduard gabriel munteanu eduard gabriel munteanu 1 3.70% 1 16.67%
Total 27 100.00% 6 100.00%


early_initcall(spawn_ksoftirqd);

/*
 * [ These __weak aliases are kept in a separate compilation unit, so that
 *   GCC does not inline them incorrectly. ]
 */



int __init __weak early_irq_init(void)
{
	return 0;
}

Contributors
Person Tokens Prop Commits CommitProp
yinghai lu yinghai lu 12 100.00% 1 100.00%
Total 12 100.00% 1 100.00%



int __init __weak arch_probe_nr_irqs(void)
{
	return NR_IRQS_LEGACY;
}

Contributors
Person Tokens Prop Commits CommitProp
yinghai lu yinghai lu 11 91.67% 1 50.00%
thomas gleixner thomas gleixner 1 8.33% 1 50.00%
Total 12 100.00% 2 100.00%



int __init __weak arch_early_irq_init(void)
{
	return 0;
}

Contributors
Person Tokens Prop Commits CommitProp
yinghai lu yinghai lu 12 100.00% 1 100.00%
Total 12 100.00% 1 100.00%



unsigned int __weak arch_dynirq_lower_bound(unsigned int from)
{
	return from;
}
Contributors
Person Tokens Prop Commits CommitProp
thomas gleixner thomas gleixner 14 100.00% 1 100.00%
Total 14 100.00% 1 100.00%

Overall Contributors
Person Tokens Prop Commits CommitProp
pre-git pre-git 391 15.16% 10 7.46%
rusty russell rusty russell 300 11.63% 9 6.72%
linus torvalds linus torvalds 293 11.36% 8 5.97%
peter zijlstra peter zijlstra 270 10.47% 7 5.22%
olof johansson olof johansson 216 8.38% 1 0.75%
thomas gleixner thomas gleixner 174 6.75% 12 8.96%
ingo molnar ingo molnar 150 5.82% 6 4.48%
frederic weisbecker frederic weisbecker 136 5.27% 16 11.94%
andrew morton andrew morton 83 3.22% 9 6.72%
christoph lameter christoph lameter 58 2.25% 2 1.49%
venkatesh pallipadi venkatesh pallipadi 50 1.94% 3 2.24%
christian borntraeger christian borntraeger 46 1.78% 1 0.75%
steven rostedt steven rostedt 45 1.74% 4 2.99%
vegard nossum vegard nossum 42 1.63% 1 0.75%
joe perches joe perches 39 1.51% 3 2.24%
yinghai lu yinghai lu 36 1.40% 2 1.49%
jason baron jason baron 29 1.12% 2 1.49%
mel gorman mel gorman 25 0.97% 1 0.75%
eric dumazet eric dumazet 25 0.97% 2 1.49%
christoph hellwig christoph hellwig 23 0.89% 2 1.49%
arnaldo carvalho de melo arnaldo carvalho de melo 20 0.78% 1 0.75%
tim chen tim chen 19 0.74% 1 0.75%
heiko carstens heiko carstens 15 0.58% 2 1.49%
ben greear ben greear 13 0.50% 1 0.75%
johannes berg johannes berg 9 0.35% 1 0.75%
david s. miller david s. miller 9 0.35% 2 1.49%
paul mackerras paul mackerras 8 0.31% 1 0.75%
rafael j. wysocki rafael j. wysocki 6 0.23% 2 1.49%
eduard gabriel munteanu eduard gabriel munteanu 6 0.23% 1 0.75%
andi kleen andi kleen 5 0.19% 2 1.49%
sebastian andrzej siewior sebastian andrzej siewior 4 0.16% 1 0.75%
paul e. mckenney paul e. mckenney 4 0.16% 2 1.49%
dipankar sarma dipankar sarma 4 0.16% 1 0.75%
keika kobayashi keika kobayashi 4 0.16% 1 0.75%
martin schwidefsky martin schwidefsky 4 0.16% 1 0.75%
li zefan li zefan 2 0.08% 1 0.75%
akinobu mita akinobu mita 2 0.08% 1 0.75%
davidlohr bueso davidlohr bueso 2 0.08% 1 0.75%
h hartley sweeten h hartley sweeten 2 0.08% 1 0.75%
li shaohua li shaohua 2 0.08% 1 0.75%
alexander potapenko alexander potapenko 1 0.04% 1 0.75%
alexey dobriyan alexey dobriyan 1 0.04% 1 0.75%
lucas de marchi lucas de marchi 1 0.04% 1 0.75%
paul gortmaker paul gortmaker 1 0.04% 1 0.75%
calvin owens calvin owens 1 0.04% 1 0.75%
zwane mwaikambo zwane mwaikambo 1 0.04% 1 0.75%
dave jones dave jones 1 0.04% 1 0.75%
robert love robert love 1 0.04% 1 0.75%
Total 2579 100.00% 134 100.00%
  Directory: kernel

Information contained on this website is for historical information purposes only and does not indicate or represent copyright ownership.
	Person	Tokens	Prop	Commits	CommitProp
linus torvalds	linus torvalds	29	85.29%	1	25.00%
rusty russell	rusty russell	3	8.82%	1	25.00%
thomas gleixner	thomas gleixner	1	2.94%	1	25.00%
christoph lameter	christoph lameter	1	2.94%	1	25.00%
	Total	34	100.00%	4	100.00%
cregit-Linux how code gets into the kernel

Release 4.7 kernel/softirq.c

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