linux-kernel - [PATCH tip/core/rcu 14/16] rcu: Consolidate expedited GP tracing into rcu_exp_gp_seq

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Message-Id: <1460474975-24560-14-git-send-email-paulmck@linux.vnet.ibm.com>
Date:	Tue, 12 Apr 2016 08:29:33 -0700
From:	"Paul E. McKenney" <paulmck@...ux.vnet.ibm.com>
To:	linux-kernel@...r.kernel.org
Cc:	mingo@...nel.org, jiangshanlai@...il.com, dipankar@...ibm.com,
	akpm@...ux-foundation.org, mathieu.desnoyers@...icios.com,
	josh@...htriplett.org, tglx@...utronix.de, peterz@...radead.org,
	rostedt@...dmis.org, dhowells@...hat.com, edumazet@...gle.com,
	dvhart@...ux.intel.com, fweisbec@...il.com, oleg@...hat.com,
	bobby.prani@...il.com,
	"Paul E. McKenney" <paulmck@...ux.vnet.ibm.com>
Subject: [PATCH tip/core/rcu 14/16] rcu: Consolidate expedited GP tracing into rcu_exp_gp_seq_snap()

This commit moves some duplicate code from synchronize_rcu_expedited()
and synchronize_sched_expedited() into rcu_exp_gp_seq_snap().  This
doesn't save lines of code, but does eliminate a "tell me twice" issue.

Signed-off-by: Paul E. McKenney <paulmck@...ux.vnet.ibm.com>
---
 kernel/rcu/tree.c        | 8 +++++---
 kernel/rcu/tree_plugin.h | 2 --
 2 files changed, 5 insertions(+), 5 deletions(-)

diff --git a/kernel/rcu/tree.c b/kernel/rcu/tree.c
index fd86eca9478e..5b1c8fd89af0 100644
--- a/kernel/rcu/tree.c
+++ b/kernel/rcu/tree.c
@@ -3392,8 +3392,12 @@ static void rcu_exp_gp_seq_end(struct rcu_state *rsp)
 }
 static unsigned long rcu_exp_gp_seq_snap(struct rcu_state *rsp)
 {
+	unsigned long s;
+
 	smp_mb(); /* Caller's modifications seen first by other CPUs. */
-	return rcu_seq_snap(&rsp->expedited_sequence);
+	s = rcu_seq_snap(&rsp->expedited_sequence);
+	trace_rcu_exp_grace_period(rsp->name, s, TPS("snap"));
+	return s;
 }
 static bool rcu_exp_gp_seq_done(struct rcu_state *rsp, unsigned long s)
 {
@@ -3898,8 +3902,6 @@ void synchronize_sched_expedited(void)
 
 	/* Take a snapshot of the sequence number.  */
 	s = rcu_exp_gp_seq_snap(rsp);
-	trace_rcu_exp_grace_period(rsp->name, s, TPS("snap"));
-
 	if (exp_funnel_lock(rsp, s))
 		return;  /* Someone else did our work for us. */
 
diff --git a/kernel/rcu/tree_plugin.h b/kernel/rcu/tree_plugin.h
index b6d5dde6eab9..529a44085a63 100644
--- a/kernel/rcu/tree_plugin.h
+++ b/kernel/rcu/tree_plugin.h
@@ -748,8 +748,6 @@ void synchronize_rcu_expedited(void)
 	}
 
 	s = rcu_exp_gp_seq_snap(rsp);
-	trace_rcu_exp_grace_period(rsp->name, s, TPS("snap"));
-
 	if (exp_funnel_lock(rsp, s))
 		return;  /* Someone else did our work for us. */
 
-- 
2.5.2