From: Zqiang <[email protected]> When someone CPU offlined, the 'kthread_worker' which bind this CPU, will run anywhere, if this CPU online, recovery of 'kthread_worker' affinity by cpuhp notifiers.
Signed-off-by: Zqiang <[email protected]> --- include/linux/kthread.h | 2 ++ kernel/kthread.c | 35 ++++++++++++++++++++++++++++++++++- 2 files changed, 36 insertions(+), 1 deletion(-) diff --git a/include/linux/kthread.h b/include/linux/kthread.h index 65b81e0c494d..5acbf2e731cb 100644 --- a/include/linux/kthread.h +++ b/include/linux/kthread.h @@ -93,6 +93,8 @@ struct kthread_worker { struct list_head delayed_work_list; struct task_struct *task; struct kthread_work *current_work; + struct hlist_node cpuhp_node; + int bind_cpu; }; struct kthread_work { diff --git a/kernel/kthread.c b/kernel/kthread.c index e29773c82b70..68968832777f 100644 --- a/kernel/kthread.c +++ b/kernel/kthread.c @@ -28,8 +28,10 @@ #include <linux/uaccess.h> #include <linux/numa.h> #include <linux/sched/isolation.h> +#include <linux/cpu.h> #include <trace/events/sched.h> +static enum cpuhp_state kworker_online; static DEFINE_SPINLOCK(kthread_create_lock); static LIST_HEAD(kthread_create_list); @@ -649,6 +651,8 @@ void __kthread_init_worker(struct kthread_worker *worker, lockdep_set_class_and_name(&worker->lock, key, name); INIT_LIST_HEAD(&worker->work_list); INIT_LIST_HEAD(&worker->delayed_work_list); + worker->bind_cpu = -1; + INIT_HLIST_NODE(&worker->cpuhp_node); } EXPORT_SYMBOL_GPL(__kthread_init_worker); @@ -737,8 +741,11 @@ __kthread_create_worker(int cpu, unsigned int flags, if (IS_ERR(task)) goto fail_task; - if (cpu >= 0) + if (cpu >= 0) { kthread_bind(task, cpu); + worker->bind_cpu = cpu; + cpuhp_state_add_instance_nocalls(kworker_online, &worker->cpuhp_node); + } worker->flags = flags; worker->task = task; @@ -1220,6 +1227,9 @@ void kthread_destroy_worker(struct kthread_worker *worker) if (WARN_ON(!task)) return; + if (worker->bind_cpu >= 0) + cpuhp_state_remove_instance_nocalls(kworker_online, &worker->cpuhp_node); + kthread_flush_worker(worker); kthread_stop(task); WARN_ON(!list_empty(&worker->work_list)); @@ -1227,6 +1237,29 @@ void kthread_destroy_worker(struct kthread_worker *worker) } EXPORT_SYMBOL(kthread_destroy_worker); +static int kworker_cpu_online(unsigned int cpu, struct hlist_node *node) +{ + struct kthread_worker *worker = hlist_entry(node, struct kthread_worker, cpuhp_node); + struct task_struct *task = worker->task; + + if (cpu == worker->bind_cpu) + WARN_ON_ONCE(set_cpus_allowed_ptr(task, cpumask_of(cpu)) < 0); + return 0; +} + +static __init int kthread_worker_hotplug_init(void) +{ + int ret; + + ret = cpuhp_setup_state_multi(CPUHP_AP_ONLINE_DYN, "kthread-worker/online", + kworker_cpu_online, NULL); + if (ret < 0) + return ret; + kworker_online = ret; + return 0; +} +subsys_initcall(kthread_worker_hotplug_init); + /** * kthread_use_mm - make the calling kthread operate on an address space * @mm: address space to operate on -- 2.17.1
