rcu/nocb: Enable re-awakening under high callback load
The __call_rcu_nocb_wake() function and its predecessors set ->qlen_last_fqs_check to zero for the first callback and to LONG_MAX / 2 for forced reawakenings. The former can result in a too-quick reawakening when there are many callbacks ready to invoke and the latter prevents a second reawakening. This commit therefore sets ->qlen_last_fqs_check to the current number of callbacks in both cases. While in the area, this commit also moves both assignments under ->nocb_lock. Signed-off-by: Paul E. McKenney <paulmck@linux.ibm.com>
This commit is contained in:
parent
0bd55c6936
commit
aeeacd9d84
|
@ -1628,6 +1628,7 @@ static void __call_rcu_nocb_wake(struct rcu_data *rdp, bool was_alldone,
|
|||
// Need to actually to a wakeup.
|
||||
len = rcu_segcblist_n_cbs(&rdp->cblist);
|
||||
if (was_alldone) {
|
||||
rdp->qlen_last_fqs_check = len;
|
||||
if (!irqs_disabled_flags(flags)) {
|
||||
/* ... if queue was empty ... */
|
||||
wake_nocb_gp(rdp, false, flags);
|
||||
|
@ -1638,9 +1639,9 @@ static void __call_rcu_nocb_wake(struct rcu_data *rdp, bool was_alldone,
|
|||
TPS("WakeEmptyIsDeferred"));
|
||||
rcu_nocb_unlock_irqrestore(rdp, flags);
|
||||
}
|
||||
rdp->qlen_last_fqs_check = 0;
|
||||
} else if (len > rdp->qlen_last_fqs_check + qhimark) {
|
||||
/* ... or if many callbacks queued. */
|
||||
rdp->qlen_last_fqs_check = len;
|
||||
if (!irqs_disabled_flags(flags)) {
|
||||
wake_nocb_gp(rdp, true, flags);
|
||||
trace_rcu_nocb_wake(rcu_state.name, rdp->cpu,
|
||||
|
@ -1650,7 +1651,6 @@ static void __call_rcu_nocb_wake(struct rcu_data *rdp, bool was_alldone,
|
|||
TPS("WakeOvfIsDeferred"));
|
||||
rcu_nocb_unlock_irqrestore(rdp, flags);
|
||||
}
|
||||
rdp->qlen_last_fqs_check = LONG_MAX / 2;
|
||||
} else {
|
||||
trace_rcu_nocb_wake(rcu_state.name, rdp->cpu, TPS("WakeNot"));
|
||||
rcu_nocb_unlock_irqrestore(rdp, flags);
|
||||
|
|
Loading…
Reference in New Issue