cregit-Linux how code gets into the kernel

Release 4.14 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", "IRQ_POLL",
	"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); }

Contributors

PersonTokensPropCommitsCommitProp
Linus Torvalds2985.29%125.00%
Rusty Russell38.82%125.00%
Thomas Gleixner12.94%125.00%
Christoph Lameter12.94%125.00%
Total34100.00%4100.00%

/* * If ksoftirqd is scheduled, we do not want to process pending softirqs * right now. Let ksoftirqd handle this at its own rate, to get fairness. */
static bool ksoftirqd_running(void) { struct task_struct *tsk = __this_cpu_read(ksoftirqd); return tsk && (tsk->state == TASK_RUNNING); }

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PersonTokensPropCommitsCommitProp
Eric Dumazet29100.00%1100.00%
Total29100.00%1100.00%

/* * 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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PersonTokensPropCommitsCommitProp
Ingo Molnar4148.24%111.11%
Heiko Carstens1214.12%111.11%
Steven Rostedt1214.12%111.11%
Peter Zijlstra910.59%444.44%
Venkatesh Pallipadi78.24%111.11%
Sebastian Andrzej Siewior44.71%111.11%
Total85100.00%9100.00%

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); }

Contributors

PersonTokensPropCommitsCommitProp
Ingo Molnar2257.89%120.00%
Venkatesh Pallipadi1026.32%120.00%
Peter Zijlstra513.16%240.00%
Davidlohr Bueso A12.63%120.00%
Total38100.00%5100.00%

/* * 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); }

Contributors

PersonTokensPropCommitsCommitProp
Venkatesh Pallipadi950.00%133.33%
Frédéric Weisbecker633.33%133.33%
Ingo Molnar316.67%133.33%
Total18100.00%3100.00%

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(); }

Contributors

PersonTokensPropCommitsCommitProp
Ingo Molnar5161.45%112.50%
Tim Chen1012.05%112.50%
Johannes Berg910.84%112.50%
Peter Zijlstra89.64%225.00%
Frédéric Weisbecker33.61%112.50%
Joe Perches11.20%112.50%
Venkatesh Pallipadi11.20%112.50%
Total83100.00%8100.00%

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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PersonTokensPropCommitsCommitProp
Peter Zijlstra1952.78%150.00%
Frédéric Weisbecker1747.22%150.00%
Total36100.00%2100.00%


static inline void lockdep_softirq_end(bool in_hardirq) { lockdep_softirq_exit(); if (in_hardirq) trace_hardirq_enter(); }

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PersonTokensPropCommitsCommitProp
Peter Zijlstra1785.00%150.00%
Frédéric Weisbecker315.00%150.00%
Total20100.00%2100.00%

#else
static inline bool lockdep_softirq_start(void) { return false; }

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PersonTokensPropCommitsCommitProp
Peter Zijlstra650.00%150.00%
Frédéric Weisbecker650.00%150.00%
Total12100.00%2100.00%


static inline void lockdep_softirq_end(bool in_hardirq) { }

Contributors

PersonTokensPropCommitsCommitProp
Peter Zijlstra777.78%150.00%
Frédéric Weisbecker222.22%150.00%
Total9100.00%2100.00%

#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()); current_restore_flags(old_flags, PF_MEMALLOC); }

Contributors

PersonTokensPropCommitsCommitProp
Thomas Gleixner4115.71%25.13%
Linus Torvalds (pre-git)3413.03%512.82%
Joe Perches2810.73%25.13%
Eric Dumazet238.81%25.13%
Mel Gorman228.43%12.56%
Frédéric Weisbecker166.13%37.69%
Linus Torvalds166.13%37.69%
Peter Zijlstra155.75%37.69%
Jason Baron124.60%25.13%
Andrew Morton103.83%37.69%
Ben Greear83.07%12.56%
Paul Mackerras83.07%12.56%
Venkatesh Pallipadi62.30%12.56%
David S. Miller51.92%12.56%
Ingo Molnar51.92%25.13%
Keika Kobayashi41.53%12.56%
Andi Kleen41.53%25.13%
Dipankar Sarma10.38%12.56%
Alexander Potapenko10.38%12.56%
Neil Brown10.38%12.56%
Davidlohr Bueso A10.38%12.56%
Total261100.00%39100.00%


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 && !ksoftirqd_running()) do_softirq_own_stack(); local_irq_restore(flags); }

Contributors

PersonTokensPropCommitsCommitProp
Andrew Morton3675.00%120.00%
Linus Torvalds612.50%120.00%
Eric Dumazet48.33%120.00%
Andi Kleen12.08%120.00%
Frédéric Weisbecker12.08%120.00%
Total48100.00%5100.00%

/* * 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(); }

Contributors

PersonTokensPropCommitsCommitProp
Venkatesh Pallipadi1541.67%222.22%
Ingo Molnar822.22%111.11%
Thomas Gleixner616.67%222.22%
Frédéric Weisbecker411.11%333.33%
Paul E. McKenney38.33%111.11%
Total36100.00%9100.00%


static inline void invoke_softirq(void) { if (ksoftirqd_running()) return; 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(); } }

Contributors

PersonTokensPropCommitsCommitProp
Thomas Gleixner1944.19%116.67%
Frédéric Weisbecker1739.53%350.00%
Eric Dumazet613.95%116.67%
Christoph Hellwig12.33%116.67%
Total43100.00%6100.00%


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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PersonTokensPropCommitsCommitProp
Frédéric Weisbecker50100.00%1100.00%
Total50100.00%1100.00%

/* * 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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PersonTokensPropCommitsCommitProp
Christoph Hellwig2035.71%17.69%
Thomas Gleixner1628.57%215.38%
Frédéric Weisbecker916.07%646.15%
Peter Zijlstra58.93%215.38%
Martin Schwidefsky47.14%17.69%
Ingo Molnar23.57%17.69%
Total56100.00%13100.00%

/* * 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(); }

Contributors

PersonTokensPropCommitsCommitProp
Linus Torvalds1976.00%120.00%
Ingo Molnar312.00%240.00%
Rusty Russell312.00%240.00%
Total25100.00%5100.00%


void raise_softirq(unsigned int nr) { unsigned long flags; local_irq_save(flags); raise_softirq_irqoff(nr); local_irq_restore(flags); }

Contributors

PersonTokensPropCommitsCommitProp
Linus Torvalds2589.29%350.00%
Rusty Russell13.57%116.67%
Robert Love13.57%116.67%
Linus Torvalds (pre-git)13.57%116.67%
Total28100.00%6100.00%


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

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Steven Rostedt21100.00%1100.00%
Total21100.00%1100.00%


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

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Linus Torvalds (pre-git)28100.00%3100.00%
Total28100.00%3100.00%

/* * 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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PersonTokensPropCommitsCommitProp
Linus Torvalds3966.10%233.33%
Olof Johansson1220.34%116.67%
Christoph Lameter58.47%116.67%
Rusty Russell35.08%233.33%
Total59100.00%6100.00%

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); }

Contributors

PersonTokensPropCommitsCommitProp
Linus Torvalds3966.10%233.33%
Olof Johansson1220.34%116.67%
Christoph Lameter58.47%116.67%
Rusty Russell35.08%233.33%
Total59100.00%6100.00%

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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PersonTokensPropCommitsCommitProp
Vegard Nossum3788.10%150.00%
Christoph Lameter511.90%150.00%
Total42100.00%2100.00%

EXPORT_SYMBOL(__tasklet_hi_schedule_first);
static __latent_entropy 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(); } }

Contributors

PersonTokensPropCommitsCommitProp
Linus Torvalds (pre-git)8951.15%741.18%
Linus Torvalds4022.99%423.53%
Olof Johansson2313.22%15.88%
Christoph Lameter169.20%211.76%
Rusty Russell52.87%211.76%
Emese Revfy10.57%15.88%
Total174100.00%17100.00%


static __latent_entropy 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(); } }

Contributors

PersonTokensPropCommitsCommitProp
Linus Torvalds (pre-git)8951.15%19.09%
Linus Torvalds4022.99%436.36%
Olof Johansson2313.22%19.09%
Christoph Lameter169.20%218.18%
Rusty Russell52.87%218.18%
Emese Revfy10.57%19.09%
Total174100.00%11100.00%


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; }

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Linus Torvalds (pre-git)4475.86%150.00%
Linus Torvalds1424.14%150.00%
Total58100.00%2100.00%

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); }

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PersonTokensPropCommitsCommitProp
Linus Torvalds (pre-git)6494.12%350.00%
H Hartley Sweeten22.94%116.67%
Linus Torvalds11.47%116.67%
Joe Perches11.47%116.67%
Total68100.00%6100.00%

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; }

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PersonTokensPropCommitsCommitProp
Peter Zijlstra38100.00%1100.00%
Total38100.00%1100.00%

/* * 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); }

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PersonTokensPropCommitsCommitProp
Peter Zijlstra51100.00%1100.00%
Total51100.00%1100.00%

/** * 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

PersonTokensPropCommitsCommitProp
Olof Johansson4768.12%125.00%
Linus Torvalds (pre-git)1927.54%250.00%
Linus Torvalds34.35%125.00%
Total69100.00%4100.00%


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

Contributors

PersonTokensPropCommitsCommitProp
Thomas Gleixner642.86%125.00%
Linus Torvalds535.71%125.00%
David S. Miller214.29%125.00%
Zwane Mwaikambo17.14%125.00%
Total14100.00%4100.00%


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

PersonTokensPropCommitsCommitProp
Thomas Gleixner2470.59%228.57%
Rusty Russell411.76%114.29%
Linus Torvalds25.88%114.29%
Calvin Owens25.88%114.29%
Frédéric Weisbecker12.94%114.29%
Paul E. McKenney12.94%114.29%
Total34100.00%7100.00%

#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

PersonTokensPropCommitsCommitProp
Rusty Russell10483.87%150.00%
Olof Johansson2016.13%150.00%
Total124100.00%2100.00%


static int 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(); return 0; }

Contributors

PersonTokensPropCommitsCommitProp
Olof Johansson7235.47%120.00%
Rusty Russell7134.98%120.00%
Christian Bornträger4622.66%120.00%
Christoph Lameter104.93%120.00%
Sebastian Andrzej Siewior41.97%120.00%
Total203100.00%5100.00%

#else #define takeover_tasklets NULL #endif /* CONFIG_HOTPLUG_CPU */ 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) { cpuhp_setup_state_nocalls(CPUHP_SOFTIRQ_DEAD, "softirq:dead", NULL, takeover_tasklets); BUG_ON(smpboot_register_percpu_thread(&softirq_threads)); return 0; }

Contributors

PersonTokensPropCommitsCommitProp
Rusty Russell1031.25%114.29%
Sebastian Andrzej Siewior825.00%114.29%
Linus Torvalds412.50%114.29%
Andrew Morton412.50%114.29%
Thomas Gleixner39.38%114.29%
Akinobu Mita26.25%114.29%
Eduard - Gabriel Munteanu13.12%114.29%
Total32100.00%7100.00%

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

PersonTokensPropCommitsCommitProp
Yinghai Lu12100.00%1100.00%
Total12100.00%1100.00%


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

Contributors

PersonTokensPropCommitsCommitProp
Yinghai Lu1191.67%150.00%
Thomas Gleixner18.33%150.00%
Total12100.00%2100.00%


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

Contributors

PersonTokensPropCommitsCommitProp
Yinghai Lu12100.00%1100.00%
Total12100.00%1100.00%


unsigned int __weak arch_dynirq_lower_bound(unsigned int from) { return from; }

Contributors

PersonTokensPropCommitsCommitProp
Thomas Gleixner14100.00%1100.00%
Total14100.00%1100.00%


Overall Contributors

PersonTokensPropCommitsCommitProp
Linus Torvalds (pre-git)39115.21%139.35%
Linus Torvalds28611.12%85.76%
Peter Zijlstra27010.50%75.04%
Rusty Russell25910.07%85.76%
Olof Johansson2168.40%10.72%
Thomas Gleixner1686.53%128.63%
Ingo Molnar1505.83%64.32%
Frédéric Weisbecker1365.29%1611.51%
Andrew Morton732.84%85.76%
Eric Dumazet652.53%32.16%
Christoph Lameter582.26%21.44%
Venkatesh Pallipadi501.94%32.16%
Christian Bornträger461.79%10.72%
Steven Rostedt451.75%42.88%
Vegard Nossum421.63%10.72%
Joe Perches391.52%32.16%
Yinghai Lu361.40%21.44%
Jason Baron291.13%21.44%
Christoph Hellwig230.89%21.44%
Mel Gorman220.86%10.72%
Sebastian Andrzej Siewior220.86%21.44%
Arnaldo Carvalho de Melo200.78%10.72%
Tim Chen190.74%10.72%
Heiko Carstens150.58%21.44%
Ben Greear130.51%10.72%
Johannes Berg90.35%10.72%
David S. Miller90.35%21.44%
Paul Mackerras80.31%10.72%
Eduard - Gabriel Munteanu60.23%10.72%
Andi Kleen50.19%21.44%
Martin Schwidefsky40.16%10.72%
Keika Kobayashi40.16%10.72%
Dipankar Sarma40.16%10.72%
Paul E. McKenney40.16%21.44%
Rafael J. Wysocki30.12%10.72%
Akinobu Mita20.08%10.72%
David Shaohua Li20.08%10.72%
Davidlohr Bueso A20.08%10.72%
H Hartley Sweeten20.08%10.72%
Calvin Owens20.08%10.72%
Emese Revfy20.08%10.72%
Lucas De Marchi10.04%10.72%
Zwane Mwaikambo10.04%10.72%
Alexey Dobriyan10.04%10.72%
Robert Love10.04%10.72%
Paul Gortmaker10.04%10.72%
Dave Jones10.04%10.72%
Li Zefan10.04%10.72%
Sagi Grimberg10.04%10.72%
Alexander Potapenko10.04%10.72%
Neil Brown10.04%10.72%
Total2571100.00%139100.00%
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