diff options
Diffstat (limited to 'kernel/rcu/update.c')
| -rw-r--r-- | kernel/rcu/update.c | 28 |
1 files changed, 8 insertions, 20 deletions
diff --git a/kernel/rcu/update.c b/kernel/rcu/update.c index 5033b66d2753..fbd56d6e575b 100644 --- a/kernel/rcu/update.c +++ b/kernel/rcu/update.c @@ -51,6 +51,7 @@ #include <linux/kthread.h> #include <linux/tick.h> #include <linux/rcupdate_wait.h> +#include <linux/sched/isolation.h> #define CREATE_TRACE_POINTS @@ -494,6 +495,7 @@ EXPORT_SYMBOL_GPL(do_trace_rcu_torture_read); #endif int rcu_cpu_stall_suppress __read_mostly; /* 1 = suppress stall warnings. */ +EXPORT_SYMBOL_GPL(rcu_cpu_stall_suppress); static int rcu_cpu_stall_timeout __read_mostly = CONFIG_RCU_CPU_STALL_TIMEOUT; module_param(rcu_cpu_stall_suppress, int, 0644); @@ -575,7 +577,6 @@ DEFINE_STATIC_SRCU(tasks_rcu_exit_srcu); static int rcu_task_stall_timeout __read_mostly = RCU_TASK_STALL_TIMEOUT; module_param(rcu_task_stall_timeout, int, 0644); -static void rcu_spawn_tasks_kthread(void); static struct task_struct *rcu_tasks_kthread_ptr; /** @@ -600,7 +601,6 @@ void call_rcu_tasks(struct rcu_head *rhp, rcu_callback_t func) { unsigned long flags; bool needwake; - bool havetask = READ_ONCE(rcu_tasks_kthread_ptr); rhp->next = NULL; rhp->func = func; @@ -610,11 +610,8 @@ void call_rcu_tasks(struct rcu_head *rhp, rcu_callback_t func) rcu_tasks_cbs_tail = &rhp->next; raw_spin_unlock_irqrestore(&rcu_tasks_cbs_lock, flags); /* We can't create the thread unless interrupts are enabled. */ - if ((needwake && havetask) || - (!havetask && !irqs_disabled_flags(flags))) { - rcu_spawn_tasks_kthread(); + if (needwake && READ_ONCE(rcu_tasks_kthread_ptr)) wake_up(&rcu_tasks_cbs_wq); - } } EXPORT_SYMBOL_GPL(call_rcu_tasks); @@ -718,7 +715,7 @@ static int __noreturn rcu_tasks_kthread(void *arg) LIST_HEAD(rcu_tasks_holdouts); /* Run on housekeeping CPUs by default. Sysadm can move if desired. */ - housekeeping_affine(current); + housekeeping_affine(current, HK_FLAG_RCU); /* * Each pass through the following loop makes one check for @@ -853,27 +850,18 @@ static int __noreturn rcu_tasks_kthread(void *arg) } } -/* Spawn rcu_tasks_kthread() at first call to call_rcu_tasks(). */ -static void rcu_spawn_tasks_kthread(void) +/* Spawn rcu_tasks_kthread() at core_initcall() time. */ +static int __init rcu_spawn_tasks_kthread(void) { - static DEFINE_MUTEX(rcu_tasks_kthread_mutex); struct task_struct *t; - if (READ_ONCE(rcu_tasks_kthread_ptr)) { - smp_mb(); /* Ensure caller sees full kthread. */ - return; - } - mutex_lock(&rcu_tasks_kthread_mutex); - if (rcu_tasks_kthread_ptr) { - mutex_unlock(&rcu_tasks_kthread_mutex); - return; - } t = kthread_run(rcu_tasks_kthread, NULL, "rcu_tasks_kthread"); BUG_ON(IS_ERR(t)); smp_mb(); /* Ensure others see full kthread. */ WRITE_ONCE(rcu_tasks_kthread_ptr, t); - mutex_unlock(&rcu_tasks_kthread_mutex); + return 0; } +core_initcall(rcu_spawn_tasks_kthread); /* Do the srcu_read_lock() for the above synchronize_srcu(). */ void exit_tasks_rcu_start(void) |