From: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
Date: Fri, 28 Apr 2017 18:24:22 +0000 (-0700)
Subject: srcu: Print non-default exp_holdoff values at boot time
X-Git-Tag: v4.13-rc1~209^2^2~50
X-Git-Url: https://git.karo-electronics.de/?a=commitdiff_plain;h=0c8e0e3c37955d17cced37222a10c00ab47efd4b;p=karo-tx-linux.git

srcu: Print non-default exp_holdoff values at boot time

This commit makes srcu_bootup_announce() check for non-default values
of the auto-expedite holdoff time exp_holdoff and print a message if so.

Signed-off-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
---

diff --git a/kernel/rcu/srcutree.c b/kernel/rcu/srcutree.c
index 08d43736f72a..0b6ea105d9f8 100644
--- a/kernel/rcu/srcutree.c
+++ b/kernel/rcu/srcutree.c
@@ -40,7 +40,9 @@
 #include "rcu.h"
 #include "rcu_segcblist.h"
 
-static ulong exp_holdoff = 25 * 1000; /* Holdoff (ns) for auto-expediting. */
+/* Holdoff in nanoseconds for auto-expediting. */
+#define DEFAULT_SRCU_EXP_HOLDOFF (25 * 1000)
+static ulong exp_holdoff = DEFAULT_SRCU_EXP_HOLDOFF;
 module_param(exp_holdoff, ulong, 0444);
 
 static void srcu_invoke_callbacks(struct work_struct *work);
@@ -1171,6 +1173,8 @@ EXPORT_SYMBOL_GPL(srcutorture_get_gp_data);
 static int __init srcu_bootup_announce(void)
 {
 	pr_info("Hierarchical SRCU implementation.\n");
+	if (exp_holdoff != DEFAULT_SRCU_EXP_HOLDOFF)
+		pr_info("\tNon-default auto-expedite holdoff of %lu ns.\n", exp_holdoff);
 	return 0;
 }
 early_initcall(srcu_bootup_announce);