rcu: Add more tracing of expedited grace periods
This commit adds more tracing of expedited grace periods to enable
improved debugging of slowdowns.
Signed-off-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
diff --git a/kernel/rcu/rcu.h b/kernel/rcu/rcu.h
index 5d13f65..507a080 100644
--- a/kernel/rcu/rcu.h
+++ b/kernel/rcu/rcu.h
@@ -77,12 +77,18 @@ static inline void rcu_seq_start(unsigned long *sp)
WARN_ON_ONCE(rcu_seq_state(*sp) != 1);
}
+/* Compute the end-of-grace-period value for the specified sequence number. */
+static inline unsigned long rcu_seq_endval(unsigned long *sp)
+{
+ return (*sp | RCU_SEQ_STATE_MASK) + 1;
+}
+
/* Adjust sequence number for end of update-side operation. */
static inline void rcu_seq_end(unsigned long *sp)
{
smp_mb(); /* Ensure update-side operation before counter increment. */
WARN_ON_ONCE(!rcu_seq_state(*sp));
- WRITE_ONCE(*sp, (*sp | RCU_SEQ_STATE_MASK) + 1);
+ WRITE_ONCE(*sp, rcu_seq_endval(sp));
}
/* Take a snapshot of the update side's sequence number. */