From: "Paul E. McKenney" <paul...@linux.vnet.ibm.com>
One way to distinguish between NOCB and non-NOCB rcu_callback trace
events is that the former always print zero for the lazy and non-lazy
queue lengths. Unfortunately, this also means that we cannot see the NOCB
queue lengths. This commit therefore accesses the NOCB queue lengths,
but negates them. NOCB rcu_callback trace events should therefore have
negative queue lengths.
Signed-off-by: Paul E. McKenney <paul...@linux.vnet.ibm.com>
[ paulmck: Match operand size per kbuild test robot's advice. ]
---
kernel/rcutree_plugin.h | 6 ++++--
1 file changed, 4 insertions(+), 2 deletions(-)
diff --git a/kernel/rcutree_plugin.h b/kernel/rcutree_plugin.h
index f4ed24b..24b01b6 100644
--- a/kernel/rcutree_plugin.h
+++ b/kernel/rcutree_plugin.h
@@ -2147,10 +2147,12 @@ static bool __call_rcu_nocb(struct rcu_data *rdp,
struct rcu_head *rhp,
if (__is_kfree_rcu_offset((unsigned long)rhp->func))
trace_rcu_kfree_callback(rdp->rsp->name, rhp,
(unsigned long)rhp->func,
- rdp->qlen_lazy, rdp->qlen);
+
-atomic_long_read(&rdp->nocb_q_count_lazy),
+ -atomic_long_read(&rdp->nocb_q_count));
else
trace_rcu_callback(rdp->rsp->name, rhp,
- rdp->qlen_lazy, rdp->qlen);
+ -atomic_long_read(&rdp->nocb_q_count_lazy),
+ -atomic_long_read(&rdp->nocb_q_count));
return 1;
}
--
1.8.1.5
--
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