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From:   Lukasz Luba <l.luba@partner.samsung.com>
To:     linux-kernel@vger.kernel.org
Cc:     l.luba@partner.samsung.com, b.zolnierkie@samsung.com,
        longman@redhat.com, mingo@redhat.com
Subject: [PATCH] lib/Kconfig.debug: add a comment to PROVE_LOCKING impact
Date:   Tue,  9 Oct 2018 17:39:50 +0200
Message-Id: <20181009153959eucas1p1ab3c10ba4868a4e97a1bff24d8f34c41~b_u5xrZ3z3130331303eucas1p1U@eucas1p1.samsung.com>
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CMS-TYPE: 201P
References: <CGME20181009153959eucas1p1ab3c10ba4868a4e97a1bff24d8f34c41@eucas1p1.samsung.com>
Sender: linux-kernel-owner@vger.kernel.org
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This patch add some comment related to performance impact,
which can be really big (x3 times slower context switch).

Signed-off-by: Lukasz Luba <l.luba@partner.samsung.com>
---
 lib/Kconfig.debug | 11 +++++++++++
 1 file changed, 11 insertions(+)

diff --git a/lib/Kconfig.debug b/lib/Kconfig.debug
index 4966c4f..9e67a2a3 100644
--- a/lib/Kconfig.debug
+++ b/lib/Kconfig.debug
@@ -1088,6 +1088,9 @@ config PROVE_LOCKING
 	 the proof of observed correctness is also maintained for an
 	 arbitrary combination of these separate locking variants.
 
+	 This feature enables LOCKDEP which can harm system performance
+	 even x3 times.
+
 	 For more details, see Documentation/locking/lockdep-design.txt.
 
 config LOCK_STAT
@@ -1112,6 +1115,10 @@ config LOCK_STAT
 	 CONFIG_LOCK_STAT defines "contended" and "acquired" lock events.
 	 (CONFIG_LOCKDEP defines "acquire" and "release" events.)
 
+	 This feature enables LOCKDEP which can harm system performance
+	 even x3 times.
+	 For more details, see Documentation/locking/lockdep-design.txt.
+
 config DEBUG_RT_MUTEXES
 	bool "RT Mutex debugging, deadlock detection"
 	depends on DEBUG_KERNEL && RT_MUTEXES
@@ -1175,6 +1182,10 @@ config DEBUG_LOCK_ALLOC
 	 spin_lock_init()/mutex_init()/etc., or whether there is any lock
 	 held during task exit.
 
+	 This feature enables LOCKDEP which can harm system performance
+	 even x3 times.
+	 For more details, see Documentation/locking/lockdep-design.txt.
+
 config LOCKDEP
 	bool
 	depends on DEBUG_KERNEL && LOCK_DEBUGGING_SUPPORT
-- 
2.7.4