From: Andreea-Cristina Bernat <bernat.ada@gmail.com>
Date: Mon, 17 Mar 2014 16:33:28 +0000 (+0200)
Subject: rcu: Add event tracing to dyntick_save_progress_counter().
X-Git-Tag: next-20140430~27^2~1^2~9
X-Git-Url: https://git.karo-electronics.de/?a=commitdiff_plain;h=7941dbdebe2a1fda31aefa033794510f95720a5a;p=karo-tx-linux.git

rcu: Add event tracing to dyntick_save_progress_counter().

This patch adds event tracing to dyntick_save_progress_counter() in the case
where it returns 1. I used the tracepoint string "dti" because this function
returns 1 in case the CPU is in dynticks idle mode.

Signed-off-by: Andreea-Cristina Bernat <bernat.ada@gmail.com>
Signed-off-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
Reviewed-by: Josh Triplett <josh@joshtriplett.org>
---

diff --git a/kernel/rcu/tree.c b/kernel/rcu/tree.c
index fca911b6b29c..c6fd0f15425c 100644
--- a/kernel/rcu/tree.c
+++ b/kernel/rcu/tree.c
@@ -772,7 +772,12 @@ static int dyntick_save_progress_counter(struct rcu_data *rdp,
 {
 	rdp->dynticks_snap = atomic_add_return(0, &rdp->dynticks->dynticks);
 	rcu_sysidle_check_cpu(rdp, isidle, maxj);
-	return (rdp->dynticks_snap & 0x1) == 0;
+	if ((rdp->dynticks_snap & 0x1) == 0) {
+		trace_rcu_fqs(rdp->rsp->name, rdp->gpnum, rdp->cpu, TPS("dti"));
+		return 1;
+	} else {
+		return 0;
+	}
 }
 
 /*