linux-kernel - [PATCH tip/core/rcu 79/88] rcu: Remove the now-obsolete PROVE_RCU

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Date:   Thu, 25 May 2017 14:59:52 -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,
        fweisbec@...il.com, oleg@...hat.com, bobby.prani@...il.com,
        "Paul E. McKenney" <paulmck@...ux.vnet.ibm.com>
Subject: [PATCH tip/core/rcu 79/88] rcu: Remove the now-obsolete PROVE_RCU_REPEATEDLY Kconfig option

The PROVE_RCU_REPEATEDLY Kconfig option was initially added due to
the volume of messages from PROVE_RCU: Doing just one per boot would
have required excessive numbers of boots to locate them all.  However,
PROVE_RCU messages are now relatively rare, so there is no longer any
reason to need more than one such message per boot.  This commit therefore
removes the PROVE_RCU_REPEATEDLY Kconfig option.

Signed-off-by: Paul E. McKenney <paulmck@...ux.vnet.ibm.com>
Cc: Ingo Molnar <mingo@...nel.org>
---
 kernel/locking/lockdep.c                                   |  4 ----
 kernel/rcu/tree_plugin.h                                   |  4 +---
 lib/Kconfig.debug                                          | 14 --------------
 tools/testing/selftests/rcutorture/configs/rcu/TINY02      |  1 -
 .../testing/selftests/rcutorture/doc/TREE_RCU-kconfig.txt  |  1 -
 5 files changed, 1 insertion(+), 23 deletions(-)

diff --git a/kernel/locking/lockdep.c b/kernel/locking/lockdep.c
index cceb9534338a..7d2499bec5fe 100644
--- a/kernel/locking/lockdep.c
+++ b/kernel/locking/lockdep.c
@@ -4490,10 +4490,6 @@ void lockdep_rcu_suspicious(const char *file, const int line, const char *s)
 {
 	struct task_struct *curr = current;
 
-#ifndef CONFIG_PROVE_RCU_REPEATEDLY
-	if (!debug_locks_off())
-		return;
-#endif /* #ifdef CONFIG_PROVE_RCU_REPEATEDLY */
 	/* Note: the following can be executed concurrently, so be careful. */
 	pr_warn("\n");
 	pr_warn("=============================\n");
diff --git a/kernel/rcu/tree_plugin.h b/kernel/rcu/tree_plugin.h
index f524d967f7b6..7f5919ab24c4 100644
--- a/kernel/rcu/tree_plugin.h
+++ b/kernel/rcu/tree_plugin.h
@@ -79,9 +79,7 @@ static void __init rcu_bootup_announce_oddness(void)
 		pr_info("\tHierarchical RCU autobalancing is disabled.\n");
 	if (IS_ENABLED(CONFIG_RCU_FAST_NO_HZ))
 		pr_info("\tRCU dyntick-idle grace-period acceleration is enabled.\n");
-	if (IS_ENABLED(CONFIG_PROVE_RCU_REPEATEDLY))
-		pr_info("\tRCU lockdep checking is permanently enabled.\n");
-	else if (IS_ENABLED(CONFIG_PROVE_RCU))
+	if (IS_ENABLED(CONFIG_PROVE_RCU))
 		pr_info("\tRCU lockdep checking is enabled.\n");
 	if (RCU_NUM_LVLS >= 4)
 		pr_info("\tFour(or more)-level hierarchy is enabled.\n");
diff --git a/lib/Kconfig.debug b/lib/Kconfig.debug
index 960c5d2d3c03..762deab304fe 100644
--- a/lib/Kconfig.debug
+++ b/lib/Kconfig.debug
@@ -1306,20 +1306,6 @@ menu "RCU Debugging"
 config PROVE_RCU
 	def_bool PROVE_LOCKING
 
-config PROVE_RCU_REPEATEDLY
-	bool "RCU debugging: don't disable PROVE_RCU on first splat"
-	depends on PROVE_RCU
-	default n
-	help
-	 By itself, PROVE_RCU will disable checking upon issuing the
-	 first warning (or "splat").  This feature prevents such
-	 disabling, allowing multiple RCU-lockdep warnings to be printed
-	 on a single reboot.
-
-	 Say Y to allow multiple RCU-lockdep warnings per boot.
-
-	 Say N if you are unsure.
-
 config SPARSE_RCU_POINTER
 	bool "RCU debugging: sparse-based checks for pointer usage"
 	default n
diff --git a/tools/testing/selftests/rcutorture/configs/rcu/TINY02 b/tools/testing/selftests/rcutorture/configs/rcu/TINY02
index 9007cd979df7..1f6bebbf5da8 100644
--- a/tools/testing/selftests/rcutorture/configs/rcu/TINY02
+++ b/tools/testing/selftests/rcutorture/configs/rcu/TINY02
@@ -8,7 +8,6 @@ CONFIG_NO_HZ_IDLE=n
 CONFIG_NO_HZ_FULL=n
 CONFIG_RCU_TRACE=y
 CONFIG_PROVE_LOCKING=y
-CONFIG_PROVE_RCU_REPEATEDLY=y
 #CHECK#CONFIG_PROVE_RCU=y
 CONFIG_DEBUG_LOCK_ALLOC=y
 CONFIG_DEBUG_OBJECTS=y
diff --git a/tools/testing/selftests/rcutorture/doc/TREE_RCU-kconfig.txt b/tools/testing/selftests/rcutorture/doc/TREE_RCU-kconfig.txt
index 519e06d34d0b..b778a28f1386 100644
--- a/tools/testing/selftests/rcutorture/doc/TREE_RCU-kconfig.txt
+++ b/tools/testing/selftests/rcutorture/doc/TREE_RCU-kconfig.txt
@@ -13,7 +13,6 @@ CONFIG_NO_HZ_FULL -- Do two, one with partial CPU enablement.
 CONFIG_PREEMPT -- Do half.  (First three and #8.)
 CONFIG_PROVE_LOCKING -- Do several, covering CONFIG_DEBUG_LOCK_ALLOC=y and not.
 CONFIG_PROVE_RCU -- Hardwired to CONFIG_PROVE_LOCKING.
-CONFIG_PROVE_RCU_REPEATEDLY -- Do one.
 CONFIG_RCU_BOOST -- one of PREEMPT_RCU.
 CONFIG_RCU_FANOUT -- Cover hierarchy, but overlap with others.
 CONFIG_RCU_FANOUT_LEAF -- Do one non-default.
-- 
2.5.2