/*
* Check the RCU kernel configuration parameters and print informative
- * messages about anything out of the ordinary. If you like #ifdef, you
- * will love this function.
+ * messages about anything out of the ordinary.
*/
static void __init rcu_bootup_announce_oddness(void)
{
* the corresponding expedited grace period will also be the end of the
* normal grace period.
*/
-static void rcu_preempt_ctxt_queue(struct rcu_node *rnp, struct rcu_data *rdp,
- unsigned long flags) __releases(rnp->lock)
+static void rcu_preempt_ctxt_queue(struct rcu_node *rnp, struct rcu_data *rdp)
+ __releases(rnp->lock) /* But leaves rrupts disabled. */
{
int blkd_state = (rnp->gp_tasks ? RCU_GP_TASKS : 0) +
(rnp->exp_tasks ? RCU_EXP_TASKS : 0) +
rnp->gp_tasks = &t->rcu_node_entry;
if (!rnp->exp_tasks && (blkd_state & RCU_EXP_BLKD))
rnp->exp_tasks = &t->rcu_node_entry;
- raw_spin_unlock(&rnp->lock);
+ raw_spin_unlock(&rnp->lock); /* rrupts remain disabled. */
/*
* Report the quiescent state for the expedited GP. This expedited
} else {
WARN_ON_ONCE(t->rcu_read_unlock_special.b.exp_need_qs);
}
- local_irq_restore(flags);
}
/*
* predating the current grace period drain, in other words, until
* rnp->gp_tasks becomes NULL.
*
- * Caller must disable preemption.
+ * Caller must disable interrupts.
*/
static void rcu_preempt_note_context_switch(void)
{
struct task_struct *t = current;
- unsigned long flags;
struct rcu_data *rdp;
struct rcu_node *rnp;
/* Possibly blocking in an RCU read-side critical section. */
rdp = this_cpu_ptr(rcu_state_p->rda);
rnp = rdp->mynode;
- raw_spin_lock_irqsave(&rnp->lock, flags);
- smp_mb__after_unlock_lock();
+ raw_spin_lock_rcu_node(rnp);
t->rcu_read_unlock_special.b.blocked = true;
t->rcu_blocked_node = rnp;
(rnp->qsmask & rdp->grpmask)
? rnp->gpnum
: rnp->gpnum + 1);
- rcu_preempt_ctxt_queue(rnp, rdp, flags);
+ rcu_preempt_ctxt_queue(rnp, rdp);
} else if (t->rcu_read_lock_nesting < 0 &&
t->rcu_read_unlock_special.s) {
/*
* Remove this task from the list it blocked on. The task
- * now remains queued on the rcu_node corresponding to
- * the CPU it first blocked on, so the first attempt to
- * acquire the task's rcu_node's ->lock will succeed.
- * Keep the loop and add a WARN_ON() out of sheer paranoia.
+ * now remains queued on the rcu_node corresponding to the
+ * CPU it first blocked on, so there is no longer any need
+ * to loop. Retain a WARN_ON_ONCE() out of sheer paranoia.
*/
- for (;;) {
- rnp = t->rcu_blocked_node;
- raw_spin_lock(&rnp->lock); /* irqs already disabled. */
- smp_mb__after_unlock_lock();
- if (rnp == t->rcu_blocked_node)
- break;
- WARN_ON_ONCE(1);
- raw_spin_unlock(&rnp->lock); /* irqs remain disabled. */
- }
+ rnp = t->rcu_blocked_node;
+ raw_spin_lock_rcu_node(rnp); /* irqs already disabled. */
+ WARN_ON_ONCE(rnp != t->rcu_blocked_node);
empty_norm = !rcu_preempt_blocked_readers_cgp(rnp);
empty_exp = sync_rcu_preempt_exp_done(rnp);
smp_mb(); /* ensure expedited fastpath sees end of RCU c-s. */
unsigned long flags;
struct task_struct *t;
- raw_spin_lock_irqsave(&rnp->lock, flags);
+ raw_spin_lock_irqsave_rcu_node(rnp, flags);
if (!rcu_preempt_blocked_readers_cgp(rnp)) {
raw_spin_unlock_irqrestore(&rnp->lock, flags);
return;
struct rcu_state *rsp = rcu_state_p;
unsigned long s;
+ /* If expedited grace periods are prohibited, fall back to normal. */
+ if (rcu_gp_is_normal()) {
+ wait_rcu_gp(call_rcu);
+ return;
+ }
+
s = rcu_exp_gp_seq_snap(rsp);
rnp_unlock = exp_funnel_lock(rsp, s);
*/
static void __init __rcu_init_preempt(void)
{
- rcu_init_one(rcu_state_p, rcu_data_p);
+ rcu_init_one(rcu_state_p);
}
/*
READ_ONCE(rnp->boost_tasks) == NULL)
return 0; /* Nothing left to boost. */
- raw_spin_lock_irqsave(&rnp->lock, flags);
- smp_mb__after_unlock_lock();
+ raw_spin_lock_irqsave_rcu_node(rnp, flags);
/*
* Recheck under the lock: all tasks in need of boosting
"rcub/%d", rnp_index);
if (IS_ERR(t))
return PTR_ERR(t);
- raw_spin_lock_irqsave(&rnp->lock, flags);
- smp_mb__after_unlock_lock();
+ raw_spin_lock_irqsave_rcu_node(rnp, flags);
rnp->boost_kthread_task = t;
raw_spin_unlock_irqrestore(&rnp->lock, flags);
sp.sched_priority = kthread_prio;
struct rcu_state *rsp;
int tne;
- if (IS_ENABLED(CONFIG_RCU_NOCB_CPU_ALL))
+ if (IS_ENABLED(CONFIG_RCU_NOCB_CPU_ALL) ||
+ rcu_is_nocb_cpu(smp_processor_id()))
return;
/* Handle nohz enablement switches conservatively. */
if (!tne)
return;
- /* If this is a no-CBs CPU, no callbacks, just return. */
- if (rcu_is_nocb_cpu(smp_processor_id()))
- return;
-
/*
* If a non-lazy callback arrived at a CPU having only lazy
* callbacks, invoke RCU core for the side-effect of recalculating
if (!*rdp->nxttail[RCU_DONE_TAIL])
continue;
rnp = rdp->mynode;
- raw_spin_lock(&rnp->lock); /* irqs already disabled. */
- smp_mb__after_unlock_lock();
+ raw_spin_lock_rcu_node(rnp); /* irqs already disabled. */
needwake = rcu_accelerate_cbs(rsp, rnp, rdp);
raw_spin_unlock(&rnp->lock); /* irqs remain disabled. */
if (needwake)
bool needwake;
struct rcu_node *rnp = rdp->mynode;
- raw_spin_lock_irqsave(&rnp->lock, flags);
- smp_mb__after_unlock_lock();
+ raw_spin_lock_irqsave_rcu_node(rnp, flags);
needwake = rcu_start_future_gp(rnp, rdp, &c);
raw_spin_unlock_irqrestore(&rnp->lock, flags);
if (needwake)
projects / karo-tx-linux.git / blobdiff