According to commit '3063b33a347c ("Avoid raw-spinlocked wakeups
from call_rcu_tasks_generic()")', the grace-period kthread is delayed
to wakeup using irq_work_queue() is because if the caller of
call_rcu_tasks_generic() holds a raw spinlock, when the kernel is
built with CONFIG_PROVE_RAW_LOCK_NESTING=y, due to a spinlock will
be hold in wake_up(), so the lockdep splats will happen. but now
using rcuwait_wake_up() to wakeup grace-period kthread instead of
wake_up(), in rcuwait_wake_up() no spinlock will be acquired, so
this commit remove using irq_work_queue(), invoke rcuwait_wake_up()
directly in call_rcu_tasks_generic().
Signed-off-by: Zqiang <qiang1.zhang@xxxxxxxxx>
---
kernel/rcu/tasks.h | 16 +---------------
1 file changed, 1 insertion(+), 15 deletions(-)
diff --git a/kernel/rcu/tasks.h b/kernel/rcu/tasks.h
index baf7ec178155..757b8c6da1ad 100644
--- a/kernel/rcu/tasks.h
+++ b/kernel/rcu/tasks.h
@@ -39,7 +39,6 @@ struct rcu_tasks_percpu {
unsigned long rtp_jiffies;
unsigned long rtp_n_lock_retries;
struct work_struct rtp_work;
- struct irq_work rtp_irq_work;
struct rcu_head barrier_q_head;
struct list_head rtp_blkd_tasks;
int cpu;
@@ -112,12 +111,9 @@ struct rcu_tasks {
char *kname;
};
-static void call_rcu_tasks_iw_wakeup(struct irq_work *iwp);
-
#define DEFINE_RCU_TASKS(rt_name, gp, call, n) \
static DEFINE_PER_CPU(struct rcu_tasks_percpu, rt_name ## __percpu) = { \
.lock = __RAW_SPIN_LOCK_UNLOCKED(rt_name ## __percpu.cbs_pcpu_lock), \
- .rtp_irq_work = IRQ_WORK_INIT_HARD(call_rcu_tasks_iw_wakeup), \
}; \
static struct rcu_tasks rt_name = \
{ \
@@ -273,16 +269,6 @@ static void cblist_init_generic(struct rcu_tasks *rtp)
pr_info("%s: Setting shift to %d and lim to %d.\n", __func__, data_race(rtp->percpu_enqueue_shift), data_race(rtp->percpu_enqueue_lim));
}
-// IRQ-work handler that does deferred wakeup for call_rcu_tasks_generic().
-static void call_rcu_tasks_iw_wakeup(struct irq_work *iwp)
-{
- struct rcu_tasks *rtp;
- struct rcu_tasks_percpu *rtpcp = container_of(iwp, struct rcu_tasks_percpu, rtp_irq_work);
-
- rtp = rtpcp->rtpp;
- rcuwait_wake_up(&rtp->cbs_wait);
-}
-
// Enqueue a callback for the specified flavor of Tasks RCU.
static void call_rcu_tasks_generic(struct rcu_head *rhp, rcu_callback_t func,
struct rcu_tasks *rtp)
@@ -334,7 +320,7 @@ static void call_rcu_tasks_generic(struct rcu_head *rhp, rcu_callback_t func,
rcu_read_unlock();
/* We can't create the thread unless interrupts are enabled. */
if (needwake && READ_ONCE(rtp->kthread_ptr))
- irq_work_queue(&rtpcp->rtp_irq_work);
+ rcuwait_wake_up(&rtp->cbs_wait);
}
// RCU callback function for rcu_barrier_tasks_generic().
--
2.25.1
