diff options
| author | Paul E. McKenney <paulmck@linux.ibm.com> | 2019-05-23 10:43:58 -0700 |
|---|---|---|
| committer | Paul E. McKenney <paulmck@linux.ibm.com> | 2019-08-13 14:35:49 -0700 |
| commit | aeeacd9d844b2219d47e9010298b635c68a2a4c9 (patch) | |
| tree | 25d875d28d600c3aebd746fbe0174c207f824238 /kernel/rcu | |
| parent | 0bd55c693617cd2488378d011b66b92e1dd66ecf (diff) | |
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>
Diffstat (limited to 'kernel/rcu')
| -rw-r--r-- | kernel/rcu/tree_plugin.h | 4 |
1 files changed, 2 insertions, 2 deletions
diff --git a/kernel/rcu/tree_plugin.h b/kernel/rcu/tree_plugin.h index ae927710d670..7077ef7bea96 100644 --- a/kernel/rcu/tree_plugin.h +++ b/kernel/rcu/tree_plugin.h @@ -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); |