wake_up_process(kthreadd_task); /* * Wait for completion in killable state, for I might be chosen by * the OOM killer while kthreadd is trying to allocate memory for * new kernel thread. */ if (unlikely(wait_for_completion_killable(&done))) { /* * If I was killed by a fatal signal before kthreadd (or new * kernel thread) calls complete(), leave the cleanup of this * structure to that thread. */ if (xchg(&create->done, NULL)) return ERR_PTR(-EINTR); /* * kthreadd (or new kernel thread) will call complete() * shortly. */ wait_for_completion(&done); } task = create->result;free_create: kfree(create); return task;} /** * kthread_create_on_node - create a kthread. * @threadfn: the function to run until signal_pending(current). * @data: data ptr for @threadfn. * @node: task and thread structures for the thread are allocated on this node * @namefmt: printf-style name for the thread. * * Description: This helper function creates and names a kernel * thread. The thread will be stopped: use wake_up_process() to start * it. See also kthread_run(). The new thread has SCHED_NORMAL policy and * is affine to all CPUs. * * If thread is going to be bound on a particular cpu, give its node * in @node, to get NUMA affinity for kthread stack, or else give NUMA_NO_NODE. * When woken, the thread will run @threadfn() with @data as its * argument. @threadfn() can either return directly if it is a * standalone thread for which no one will call kthread_stop(), or * return when 'kthread_should_stop()' is true (which means * kthread_stop() has been called). The return value should be zero * or a negative error number; it will be passed to kthread_stop(). * * Returns a task_struct or ERR_PTR(-ENOMEM) or ERR_PTR(-EINTR). */struct task_struct *kthread_create_on_node(int (*threadfn)(void *data), void *data, int node, const char namefmt[], ...){ struct task_struct *task; va_list args; va_start(args, namefmt); task = __kthread_create_on_node(threadfn, data, node, namefmt, args); va_end(args); return task;}EXPORT_SYMBOL(kthread_create_on_node); static void __kthread_bind_mask(struct task_struct *p, const struct cpumask *mask, unsigned int state){ if (!wait_task_inactive(p, state)) { WARN_ON(1); return; } scoped_guard (raw_spinlock_irqsave, &p->pi_lock) set_cpus_allowed_force(p, mask); /* It's safe because the task is inactive. */ p->flags |= PF_NO_SETAFFINITY;} static void __kthread_bind(struct task_struct *p, unsigned int cpu, unsigned int state){ __kthread_bind_mask(p, cpumask_of(cpu), state);} void kthread_bind_mask(struct task_struct *p, const struct cpumask *mask){ struct kthread *kthread = to_kthread(p); __kthread_bind_mask(p, mask, TASK_UNINTERRUPTIBLE); WARN_ON_ONCE(kthread->started);} /** * kthread_bind - bind a just-created kthread to a cpu. * @p: thread created by kthread_create(). * @cpu: cpu (might not be online, must be possible) for @k to run on. * * Description: This function is equivalent to set_cpus_allowed(), * except that @cpu doesn't need to be online, and the thread must be * stopped (i.e., just returned from kthread_create()). */void kthread_bind(struct task_struct *p, unsigned int cpu){ struct kthread *kthread = to_kthread(p); __kthread_bind(p, cpu, TASK_UNINTERRUPTIBLE); WARN_ON_ONCE(kthread->started);}EXPORT_SYMBOL(kthread_bind); /** * kthread_create_on_cpu - Create a cpu bound kthread * @threadfn: the function to run until signal_pending(current). * @data: data ptr for @threadfn. * @cpu: The cpu on which the thread should be bound, * @namefmt: printf-style name for the thread. Format is restricted * to "name.*%u". Code fills in cpu number. * * Description: This helper function creates and names a kernel thread */struct task_struct *kthread_create_on_cpu(int (*threadfn)(void *data), void *data, unsigned int cpu, const char *namefmt){ struct task_struct *p; p = kthread_create_on_node(threadfn, data, cpu_to_node(cpu), namefmt, cpu); if (IS_ERR(p)) return p; kthread_bind(p, cpu); /* CPU hotplug need to bind once again when unparking the thread. */ to_kthread(p)->cpu = cpu; return p;}EXPORT_SYMBOL(kthread_create_on_cpu); void kthread_set_per_cpu(struct task_struct *k, int cpu){ struct kthread *kthread = to_kthread(k); if (!kthread) return; WARN_ON_ONCE(!(k->flags & PF_NO_SETAFFINITY)); if (cpu < 0) { clear_bit(KTHREAD_IS_PER_CPU, &kthread->flags); return; } kthread->cpu = cpu; set_bit(KTHREAD_IS_PER_CPU, &kthread->flags);} bool kthread_is_per_cpu(struct task_struct *p){ struct kthread *kthread = tsk_is_kthread(p); if (!kthread) return false; return test_bit(KTHREAD_IS_PER_CPU, &kthread->flags);} /** * kthread_unpark - unpark a thread created by kthread_create(). * @k: thread created by kthread_create(). * * Sets kthread_should_park() for @k to return false, wakes it, and * waits for it to return. If the thread is marked percpu then its * bound to the cpu again. */void kthread_unpark(struct task_struct *k){ struct kthread *kthread = to_kthread(k); if (!test_bit(KTHREAD_SHOULD_PARK, &kthread->flags)) return; /* * Newly created kthread was parked when the CPU was offline. * The binding was lost and we need to set it again. */ if (test_bit(KTHREAD_IS_PER_CPU, &kthread->flags)) __kthread_bind(k, kthread->cpu, TASK_PARKED); clear_bit(KTHREAD_SHOULD_PARK, &kthread->flags); /* * __kthread_parkme() will either see !SHOULD_PARK or get the wakeup. */ wake_up_state(k, TASK_PARKED);}EXPORT_SYMBOL_GPL(kthread_unpark); /** * kthread_park - park a thread created by kthread_create(). * @k: thread created by kthread_create(). * * Sets kthread_should_park() for @k to return true, wakes it, and * waits for it to return. This can also be called after kthread_create() * instead of calling wake_up_process(): the thread will park without * calling threadfn(). * * Returns 0 if the thread is parked, -ENOSYS if the thread exited. * If called by the kthread itself just the park bit is set. */int kthread_park(struct task_struct *k){ struct kthread *kthread = to_kthread(k); if (WARN_ON(k->flags & PF_EXITING)) return -ENOSYS; if (WARN_ON_ONCE(test_bit(KTHREAD_SHOULD_PARK, &kthread->flags))) return -EBUSY; set_bit(KTHREAD_SHOULD_PARK, &kthread->flags); if (k != current) { wake_up_process(k); /* * Wait for __kthread_parkme() to complete(), this means we * _will_ have TASK_PARKED and are about to call schedule(). */ wait_for_completion(&kthread->parked); /* * Now wait for that schedule() to complete and the task to * get scheduled out. */ WARN_ON_ONCE(!wait_task_inactive(k, TASK_PARKED)); } return 0;}EXPORT_SYMBOL_GPL(kthread_park); /** * kthread_stop - stop a thread created by kthread_create(). * @k: thread created by kthread_create(). * * Sets kthread_should_stop() for @k to return true, wakes it, and * waits for it to exit. This can also be called after kthread_create() * instead of calling wake_up_process(): the thread will exit without * calling threadfn(). * * If threadfn() may call kthread_exit() itself, the caller must ensure * task_struct can't go away. * * Returns the result of threadfn(), or %-EINTR if wake_up_process() * was never called. */int kthread_stop(struct task_struct *k){ struct kthread *kthread; int ret; trace_sched_kthread_stop(k); get_task_struct(k); kthread = to_kthread(k); set_bit(KTHREAD_SHOULD_STOP, &kthread->flags); kthread_unpark(k); set_tsk_thread_flag(k, TIF_NOTIFY_SIGNAL); wake_up_process(k); wait_for_completion(&kthread->exited); ret = kthread->result; put_task_struct(k); trace_sched_kthread_stop_ret(ret); return ret;}EXPORT_SYMBOL(kthread_stop); /** * kthread_stop_put - stop a thread and put its task struct * @k: thread created by kthread_create(). * * Stops a thread created by kthread_create() and put its task_struct. * Only use when holding an extra task struct reference obtained by * calling get_task_struct(). */int kthread_stop_put(struct task_struct *k){ int ret; ret = kthread_stop(k); put_task_struct(k); return ret;}EXPORT_SYMBOL(kthread_stop_put); int kthreadd(void *unused){ static const char comm[TASK_COMM_LEN] = "kthreadd"; struct task_struct *tsk = current; /* Setup a clean context for our children to inherit. */ set_task_comm(tsk, comm); ignore_signals(tsk); set_mems_allowed(node_states[N_MEMORY]); current->flags |= PF_NOFREEZE; cgroup_init_kthreadd(); kthread_affine_node(); for (;;) { set_current_state(TASK_INTERRUPTIBLE); if (list_empty(&kthread_create_list)) schedule(); __set_current_state(TASK_RUNNING); spin_lock(&kthread_create_lock); while (!list_empty(&kthread_create_list)) { struct kthread_create_info *create; create = list_entry(kthread_create_list.next, struct kthread_create_info, list); list_del_init(&create->list); spin_unlock(&kthread_create_lock); create_kthread(create); spin_lock(&kthread_create_lock); } spin_unlock(&kthread_create_lock); } return 0;} /** * kthread_affine_preferred - Define a kthread's preferred affinity * @p: thread created by kthread_create(). * @mask: preferred mask of CPUs (might not be online, must be possible) for @p * to run on. * * Similar to kthread_bind_mask() except that the affinity is not a requirement * but rather a preference that can be constrained by CPU isolation or CPU hotplug. * Must be called before the first wakeup of the kthread. * * Returns 0 if the affinity has been applied. */int kthread_affine_preferred(struct task_struct *p, const struct cpumask *mask){ struct kthread *kthread = to_kthread(p); cpumask_var_t affinity; int ret = 0; if (!wait_task_inactive(p, TASK_UNINTERRUPTIBLE) || kthread->started) { WARN_ON(1); return -EINVAL; } WARN_ON_ONCE(kthread->preferred_affinity); if (!zalloc_cpumask_var(&affinity, GFP_KERNEL)) return -ENOMEM; kthread->preferred_affinity = kzalloc(sizeof(struct cpumask), GFP_KERNEL); if (!kthread->preferred_affinity) { ret = -ENOMEM; goto out; } mutex_lock(&kthread_affinity_lock); cpumask_copy(kthread->preferred_affinity, mask); WARN_ON_ONCE(!list_empty(&kthread->affinity_node)); list_add_tail(&kthread->affinity_node, &kthread_affinity_list); kthread_fetch_affinity(kthread, affinity); scoped_guard (raw_spinlock_irqsave, &p->pi_lock) set_cpus_allowed_force(p, affinity); mutex_unlock(&kthread_affinity_lock);out: free_cpumask_var(affinity); return ret;}EXPORT_SYMBOL_GPL(kthread_affine_preferred); static int kthreads_update_affinity(bool force){ cpumask_var_t affinity; struct kthread *k; int ret; guard(mutex)(&kthread_affinity_lock); if (list_empty(&kthread_affinity_list)) return 0; if (!zalloc_cpumask_var(&affinity, GFP_KERNEL)) return -ENOMEM; ret = 0; list_for_each_entry(k, &kthread_affinity_list, affinity_node) { if (WARN_ON_ONCE((k->task->flags & PF_NO_SETAFFINITY) || kthread_is_per_cpu(k->task))) { ret = -EINVAL; continue; } /* * Unbound kthreads without preferred affinity are already affine * to housekeeping, whether those CPUs are online or not. So no need * to handle newly online CPUs for them. However housekeeping changes * have to be applied. * * But kthreads with a preferred affinity or node are different: * if none of their preferred CPUs are online and part of * housekeeping at the same time, they must be affine to housekeeping. * But as soon as one of their preferred CPU becomes online, they must * be affine to them. */ if (force || k->preferred_affinity || k->node != NUMA_NO_NODE) { kthread_fetch_affinity(k, affinity); set_cpus_allowed_ptr(k->task, affinity); } } free_cpumask_var(affinity); return ret;} /** * kthreads_update_housekeeping - Update kthreads affinity on cpuset change * * When cpuset changes a partition type to/from "isolated" or updates related * cpumasks, propagate the housekeeping cpumask change to preferred kthreads * affinity. * * Returns 0 if successful, -ENOMEM if temporary mask couldn't * be allocated or -EINVAL in case of internal error. */int kthreads_update_housekeeping(void){ return kthreads_update_affinity(true);} /* * Re-affine kthreads according to their preferences * and the newly online CPU. The CPU down part is handled * by select_fallback_rq() which default re-affines to * housekeepers from other nodes in case the preferred * affinity doesn't apply anymore. */static int kthreads_online_cpu(unsigned int cpu){ return kthreads_update_affinity(false);} static int kthreads_init(void){ return cpuhp_setup_state(CPUHP_AP_KTHREADS_ONLINE, "kthreads:online", kthreads_online_cpu, NULL);}early_initcall(kthreads_init); void __kthread_init_worker(struct kthread_worker *worker, const char *name, struct lock_class_key *key){ memset(worker, 0, sizeof(struct kthread_worker)); raw_spin_lock_init(&worker->lock); lockdep_set_class_and_name(&worker->lock, key, name); INIT_LIST_HEAD(&worker->work_list); INIT_LIST_HEAD(&worker->delayed_work_list);}EXPORT_SYMBOL_GPL(__kthread_init_worker); /** * kthread_worker_fn - kthread function to process kthread_worker * @worker_ptr: pointer to initialized kthread_worker * * This function implements the main cycle of kthread worker. It processes * work_list until it is stopped with kthread_stop(). It sleeps when the queue * is empty. * * The works are not allowed to keep any locks, disable preemption or interrupts * when they finish. There is defined a safe point for freezing when one work * finishes and before a new one is started. * * Also the works must not be handled by more than one worker at the same time, * see also kthread_queue_work(). */int kthread_worker_fn(void *worker_ptr){ struct kthread_worker *worker = worker_ptr; struct kthread_work *work; /* * FIXME: Update the check and remove the assignment when all kthread * worker users are created using kthread_create_worker*() functions. */ WARN_ON(worker->task && worker->task != current); worker->task = current; if (worker->flags & KTW_FREEZABLE) set_freezable(); repeat:Lines 501–1000 of 1738. Previous lines Load more
wake_up_process(kthreadd_task); /* * Wait for completion in killable state, for I might be chosen by * the OOM killer while kthreadd is trying to allocate memory for * new kernel thread. */ if (unlikely(wait_for_completion_killable(&done))) { /* * If I was killed by a fatal signal before kthreadd (or new * kernel thread) calls complete(), leave the cleanup of this * structure to that thread. */ if (xchg(&create->done, NULL)) return ERR_PTR(-EINTR); /* * kthreadd (or new kernel thread) will call complete() * shortly. */ wait_for_completion(&done); } task = create->result; free_create: kfree(create); return task; } /** * kthread_create_on_node - create a kthread. * @threadfn: the function to run until signal_pending(current). * @data: data ptr for @threadfn. * @node: task and thread structures for the thread are allocated on this node * @namefmt: printf-style name for the thread. * * Description: This helper function creates and names a kernel * thread. The thread will be stopped: use wake_up_process() to start * it. See also kthread_run(). The new thread has SCHED_NORMAL policy and * is affine to all CPUs. * * If thread is going to be bound on a particular cpu, give its node * in @node, to get NUMA affinity for kthread stack, or else give NUMA_NO_NODE. * When woken, the thread will run @threadfn() with @data as its * argument. @threadfn() can either return directly if it is a * standalone thread for which no one will call kthread_stop(), or * return when 'kthread_should_stop()' is true (which means * kthread_stop() has been called). The return value should be zero * or a negative error number; it will be passed to kthread_stop(). * * Returns a task_struct or ERR_PTR(-ENOMEM) or ERR_PTR(-EINTR). */ struct task_struct *kthread_create_on_node(int (*threadfn)(void *data), void *data, int node, const char namefmt[], ...) { struct task_struct *task; va_list args; va_start(args, namefmt); task = __kthread_create_on_node(threadfn, data, node, namefmt, args); va_end(args); return task; } EXPORT_SYMBOL(kthread_create_on_node); static void __kthread_bind_mask(struct task_struct *p, const struct cpumask *mask, unsigned int state) { if (!wait_task_inactive(p, state)) { WARN_ON(1); return; } scoped_guard (raw_spinlock_irqsave, &p->pi_lock) set_cpus_allowed_force(p, mask); /* It's safe because the task is inactive. */ p->flags |= PF_NO_SETAFFINITY; } static void __kthread_bind(struct task_struct *p, unsigned int cpu, unsigned int state) { __kthread_bind_mask(p, cpumask_of(cpu), state); } void kthread_bind_mask(struct task_struct *p, const struct cpumask *mask) { struct kthread *kthread = to_kthread(p); __kthread_bind_mask(p, mask, TASK_UNINTERRUPTIBLE); WARN_ON_ONCE(kthread->started); } /** * kthread_bind - bind a just-created kthread to a cpu. * @p: thread created by kthread_create(). * @cpu: cpu (might not be online, must be possible) for @k to run on. * * Description: This function is equivalent to set_cpus_allowed(), * except that @cpu doesn't need to be online, and the thread must be * stopped (i.e., just returned from kthread_create()). */ void kthread_bind(struct task_struct *p, unsigned int cpu) { struct kthread *kthread = to_kthread(p); __kthread_bind(p, cpu, TASK_UNINTERRUPTIBLE); WARN_ON_ONCE(kthread->started); } EXPORT_SYMBOL(kthread_bind); /** * kthread_create_on_cpu - Create a cpu bound kthread * @threadfn: the function to run until signal_pending(current). * @data: data ptr for @threadfn. * @cpu: The cpu on which the thread should be bound, * @namefmt: printf-style name for the thread. Format is restricted * to "name.*%u". Code fills in cpu number. * * Description: This helper function creates and names a kernel thread */ struct task_struct *kthread_create_on_cpu(int (*threadfn)(void *data), void *data, unsigned int cpu, const char *namefmt) { struct task_struct *p; p = kthread_create_on_node(threadfn, data, cpu_to_node(cpu), namefmt, cpu); if (IS_ERR(p)) return p; kthread_bind(p, cpu); /* CPU hotplug need to bind once again when unparking the thread. */ to_kthread(p)->cpu = cpu; return p; } EXPORT_SYMBOL(kthread_create_on_cpu); void kthread_set_per_cpu(struct task_struct *k, int cpu) { struct kthread *kthread = to_kthread(k); if (!kthread) return; WARN_ON_ONCE(!(k->flags & PF_NO_SETAFFINITY)); if (cpu < 0) { clear_bit(KTHREAD_IS_PER_CPU, &kthread->flags); return; } kthread->cpu = cpu; set_bit(KTHREAD_IS_PER_CPU, &kthread->flags); } bool kthread_is_per_cpu(struct task_struct *p) { struct kthread *kthread = tsk_is_kthread(p); if (!kthread) return false; return test_bit(KTHREAD_IS_PER_CPU, &kthread->flags); } /** * kthread_unpark - unpark a thread created by kthread_create(). * @k: thread created by kthread_create(). * * Sets kthread_should_park() for @k to return false, wakes it, and * waits for it to return. If the thread is marked percpu then its * bound to the cpu again. */ void kthread_unpark(struct task_struct *k) { struct kthread *kthread = to_kthread(k); if (!test_bit(KTHREAD_SHOULD_PARK, &kthread->flags)) return; /* * Newly created kthread was parked when the CPU was offline. * The binding was lost and we need to set it again. */ if (test_bit(KTHREAD_IS_PER_CPU, &kthread->flags)) __kthread_bind(k, kthread->cpu, TASK_PARKED); clear_bit(KTHREAD_SHOULD_PARK, &kthread->flags); /* * __kthread_parkme() will either see !SHOULD_PARK or get the wakeup. */ wake_up_state(k, TASK_PARKED); } EXPORT_SYMBOL_GPL(kthread_unpark); /** * kthread_park - park a thread created by kthread_create(). * @k: thread created by kthread_create(). * * Sets kthread_should_park() for @k to return true, wakes it, and * waits for it to return. This can also be called after kthread_create() * instead of calling wake_up_process(): the thread will park without * calling threadfn(). * * Returns 0 if the thread is parked, -ENOSYS if the thread exited. * If called by the kthread itself just the park bit is set. */ int kthread_park(struct task_struct *k) { struct kthread *kthread = to_kthread(k); if (WARN_ON(k->flags & PF_EXITING)) return -ENOSYS; if (WARN_ON_ONCE(test_bit(KTHREAD_SHOULD_PARK, &kthread->flags))) return -EBUSY; set_bit(KTHREAD_SHOULD_PARK, &kthread->flags); if (k != current) { wake_up_process(k); /* * Wait for __kthread_parkme() to complete(), this means we * _will_ have TASK_PARKED and are about to call schedule(). */ wait_for_completion(&kthread->parked); /* * Now wait for that schedule() to complete and the task to * get scheduled out. */ WARN_ON_ONCE(!wait_task_inactive(k, TASK_PARKED)); } return 0; } EXPORT_SYMBOL_GPL(kthread_park); /** * kthread_stop - stop a thread created by kthread_create(). * @k: thread created by kthread_create(). * * Sets kthread_should_stop() for @k to return true, wakes it, and * waits for it to exit. This can also be called after kthread_create() * instead of calling wake_up_process(): the thread will exit without * calling threadfn(). * * If threadfn() may call kthread_exit() itself, the caller must ensure * task_struct can't go away. * * Returns the result of threadfn(), or %-EINTR if wake_up_process() * was never called. */ int kthread_stop(struct task_struct *k) { struct kthread *kthread; int ret; trace_sched_kthread_stop(k); get_task_struct(k); kthread = to_kthread(k); set_bit(KTHREAD_SHOULD_STOP, &kthread->flags); kthread_unpark(k); set_tsk_thread_flag(k, TIF_NOTIFY_SIGNAL); wake_up_process(k); wait_for_completion(&kthread->exited); ret = kthread->result; put_task_struct(k); trace_sched_kthread_stop_ret(ret); return ret; } EXPORT_SYMBOL(kthread_stop); /** * kthread_stop_put - stop a thread and put its task struct * @k: thread created by kthread_create(). * * Stops a thread created by kthread_create() and put its task_struct. * Only use when holding an extra task struct reference obtained by * calling get_task_struct(). */ int kthread_stop_put(struct task_struct *k) { int ret; ret = kthread_stop(k); put_task_struct(k); return ret; } EXPORT_SYMBOL(kthread_stop_put); int kthreadd(void *unused) { static const char comm[TASK_COMM_LEN] = "kthreadd"; struct task_struct *tsk = current; /* Setup a clean context for our children to inherit. */ set_task_comm(tsk, comm); ignore_signals(tsk); set_mems_allowed(node_states[N_MEMORY]); current->flags |= PF_NOFREEZE; cgroup_init_kthreadd(); kthread_affine_node(); for (;;) { set_current_state(TASK_INTERRUPTIBLE); if (list_empty(&kthread_create_list)) schedule(); __set_current_state(TASK_RUNNING); spin_lock(&kthread_create_lock); while (!list_empty(&kthread_create_list)) { struct kthread_create_info *create; create = list_entry(kthread_create_list.next, struct kthread_create_info, list); list_del_init(&create->list); spin_unlock(&kthread_create_lock); create_kthread(create); spin_lock(&kthread_create_lock); } spin_unlock(&kthread_create_lock); } return 0; } /** * kthread_affine_preferred - Define a kthread's preferred affinity * @p: thread created by kthread_create(). * @mask: preferred mask of CPUs (might not be online, must be possible) for @p * to run on. * * Similar to kthread_bind_mask() except that the affinity is not a requirement * but rather a preference that can be constrained by CPU isolation or CPU hotplug. * Must be called before the first wakeup of the kthread. * * Returns 0 if the affinity has been applied. */ int kthread_affine_preferred(struct task_struct *p, const struct cpumask *mask) { struct kthread *kthread = to_kthread(p); cpumask_var_t affinity; int ret = 0; if (!wait_task_inactive(p, TASK_UNINTERRUPTIBLE) || kthread->started) { WARN_ON(1); return -EINVAL; } WARN_ON_ONCE(kthread->preferred_affinity); if (!zalloc_cpumask_var(&affinity, GFP_KERNEL)) return -ENOMEM; kthread->preferred_affinity = kzalloc(sizeof(struct cpumask), GFP_KERNEL); if (!kthread->preferred_affinity) { ret = -ENOMEM; goto out; } mutex_lock(&kthread_affinity_lock); cpumask_copy(kthread->preferred_affinity, mask); WARN_ON_ONCE(!list_empty(&kthread->affinity_node)); list_add_tail(&kthread->affinity_node, &kthread_affinity_list); kthread_fetch_affinity(kthread, affinity); scoped_guard (raw_spinlock_irqsave, &p->pi_lock) set_cpus_allowed_force(p, affinity); mutex_unlock(&kthread_affinity_lock); out: free_cpumask_var(affinity); return ret; } EXPORT_SYMBOL_GPL(kthread_affine_preferred); static int kthreads_update_affinity(bool force) { cpumask_var_t affinity; struct kthread *k; int ret; guard(mutex)(&kthread_affinity_lock); if (list_empty(&kthread_affinity_list)) return 0; if (!zalloc_cpumask_var(&affinity, GFP_KERNEL)) return -ENOMEM; ret = 0; list_for_each_entry(k, &kthread_affinity_list, affinity_node) { if (WARN_ON_ONCE((k->task->flags & PF_NO_SETAFFINITY) || kthread_is_per_cpu(k->task))) { ret = -EINVAL; continue; } /* * Unbound kthreads without preferred affinity are already affine * to housekeeping, whether those CPUs are online or not. So no need * to handle newly online CPUs for them. However housekeeping changes * have to be applied. * * But kthreads with a preferred affinity or node are different: * if none of their preferred CPUs are online and part of * housekeeping at the same time, they must be affine to housekeeping. * But as soon as one of their preferred CPU becomes online, they must * be affine to them. */ if (force || k->preferred_affinity || k->node != NUMA_NO_NODE) { kthread_fetch_affinity(k, affinity); set_cpus_allowed_ptr(k->task, affinity); } } free_cpumask_var(affinity); return ret; } /** * kthreads_update_housekeeping - Update kthreads affinity on cpuset change * * When cpuset changes a partition type to/from "isolated" or updates related * cpumasks, propagate the housekeeping cpumask change to preferred kthreads * affinity. * * Returns 0 if successful, -ENOMEM if temporary mask couldn't * be allocated or -EINVAL in case of internal error. */ int kthreads_update_housekeeping(void) { return kthreads_update_affinity(true); } /* * Re-affine kthreads according to their preferences * and the newly online CPU. The CPU down part is handled * by select_fallback_rq() which default re-affines to * housekeepers from other nodes in case the preferred * affinity doesn't apply anymore. */ static int kthreads_online_cpu(unsigned int cpu) { return kthreads_update_affinity(false); } static int kthreads_init(void) { return cpuhp_setup_state(CPUHP_AP_KTHREADS_ONLINE, "kthreads:online", kthreads_online_cpu, NULL); } early_initcall(kthreads_init); void __kthread_init_worker(struct kthread_worker *worker, const char *name, struct lock_class_key *key) { memset(worker, 0, sizeof(struct kthread_worker)); raw_spin_lock_init(&worker->lock); lockdep_set_class_and_name(&worker->lock, key, name); INIT_LIST_HEAD(&worker->work_list); INIT_LIST_HEAD(&worker->delayed_work_list); } EXPORT_SYMBOL_GPL(__kthread_init_worker); /** * kthread_worker_fn - kthread function to process kthread_worker * @worker_ptr: pointer to initialized kthread_worker * * This function implements the main cycle of kthread worker. It processes * work_list until it is stopped with kthread_stop(). It sleeps when the queue * is empty. * * The works are not allowed to keep any locks, disable preemption or interrupts * when they finish. There is defined a safe point for freezing when one work * finishes and before a new one is started. * * Also the works must not be handled by more than one worker at the same time, * see also kthread_queue_work(). */ int kthread_worker_fn(void *worker_ptr) { struct kthread_worker *worker = worker_ptr; struct kthread_work *work; /* * FIXME: Update the check and remove the assignment when all kthread * worker users are created using kthread_create_worker*() functions. */ WARN_ON(worker->task && worker->task != current); worker->task = current; if (worker->flags & KTW_FREEZABLE) set_freezable(); repeat: