Merge branch 'core-urgent-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip

torvalds · torvalds · commit 02f0f5721e2c · 2015-05-06T10:26:37.000-07:00
Pull RCU fix from Ingo Molnar:
 "An RCU Kconfig fix that eliminates an annoying interactive kconfig
  question for CONFIG_RCU_TORTURE_TEST_SLOW_INIT"

* 'core-urgent-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip:
  rcu: Control grace-period delays directly from value
diff --git a/kernel/rcu/tree.c b/kernel/rcu/tree.c
@@ -162,11 +162,14 @@ static void invoke_rcu_callbacks(struct rcu_state *rsp, struct rcu_data *rdp);
 static int kthread_prio = CONFIG_RCU_KTHREAD_PRIO;
 module_param(kthread_prio, int, 0644);
 
-/* Delay in jiffies for grace-period initialization delays. */
-static int gp_init_delay = IS_ENABLED(CONFIG_RCU_TORTURE_TEST_SLOW_INIT)
-				? CONFIG_RCU_TORTURE_TEST_SLOW_INIT_DELAY
-				: 0;
+/* Delay in jiffies for grace-period initialization delays, debug only. */
+#ifdef CONFIG_RCU_TORTURE_TEST_SLOW_INIT
+static int gp_init_delay = CONFIG_RCU_TORTURE_TEST_SLOW_INIT_DELAY;
 module_param(gp_init_delay, int, 0644);
+#else /* #ifdef CONFIG_RCU_TORTURE_TEST_SLOW_INIT */
+static const int gp_init_delay;
+#endif /* #else #ifdef CONFIG_RCU_TORTURE_TEST_SLOW_INIT */
+#define PER_RCU_NODE_PERIOD 10	/* Number of grace periods between delays. */
 
 /*
  * Track the rcutorture test sequence number and the update version
@@ -1843,9 +1846,8 @@ static int rcu_gp_init(struct rcu_state *rsp)
 		raw_spin_unlock_irq(&rnp->lock);
 		cond_resched_rcu_qs();
 		ACCESS_ONCE(rsp->gp_activity) = jiffies;
-		if (IS_ENABLED(CONFIG_RCU_TORTURE_TEST_SLOW_INIT) &&
-		    gp_init_delay > 0 &&
-		    !(rsp->gpnum % (rcu_num_nodes * 10)))
+		if (gp_init_delay > 0 &&
+		    !(rsp->gpnum % (rcu_num_nodes * PER_RCU_NODE_PERIOD)))
 			schedule_timeout_uninterruptible(gp_init_delay);
 	}
 
diff --git a/lib/Kconfig.debug b/lib/Kconfig.debug
@@ -1281,6 +1281,7 @@ config RCU_TORTURE_TEST_SLOW_INIT_DELAY
 	int "How much to slow down RCU grace-period initialization"
 	range 0 5
 	default 3
+	depends on RCU_TORTURE_TEST_SLOW_INIT
 	help
 	  This option specifies the number of jiffies to wait between
 	  each rcu_node structure initialization.
