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From: Byungchul Park <byungchul.park@lge.com>
To: peterz@infradead.org, mingo@kernel.org, axboe@kernel.dk
Cc: johan@kernel.org, tglx@linutronix.de,
	linux-kernel@vger.kernel.org, linux-mm@kvack.org, tj@kernel.org,
	johannes.berg@intel.com, oleg@redhat.com, amir73il@gmail.com,
	david@fromorbit.com, darrick.wong@oracle.com,
	linux-xfs@vger.kernel.org, linux-fsdevel@vger.kernel.org,
	linux-block@vger.kernel.org, hch@infradead.org,
	idryomov@gmail.com, kernel-team@lge.com
Subject: [PATCH v5 6/9] locking/lockdep: Introduce CONFIG_BOOTPARAM_LOCKDEP_CROSSRELEASE_FULLSTACK
Date: Wed, 25 Oct 2017 17:56:02 +0900	[thread overview]
Message-ID: <1508921765-15396-7-git-send-email-byungchul.park@lge.com> (raw)
In-Reply-To: <1508921765-15396-1-git-send-email-byungchul.park@lge.com>

The boot parameter, crossrelease_fullstack, was introduced to control
whether to enable unwind in cross-release or not. Add a Kconfig doing
the same thing.

Suggested-by: Ingo Molnar <mingo@kernel.org>
Signed-off-by: Byungchul Park <byungchul.park@lge.com>
---
 kernel/locking/lockdep.c |  4 ++++
 lib/Kconfig.debug        | 15 +++++++++++++++
 2 files changed, 19 insertions(+)

diff --git a/kernel/locking/lockdep.c b/kernel/locking/lockdep.c
index 160b5d6..db933d0 100644
--- a/kernel/locking/lockdep.c
+++ b/kernel/locking/lockdep.c
@@ -76,7 +76,11 @@
 #define lock_stat 0
 #endif
 
+#ifdef CONFIG_BOOTPARAM_LOCKDEP_CROSSRELEASE_FULLSTACK
+static int crossrelease_fullstack = 1;
+#else
 static int crossrelease_fullstack;
+#endif
 static int __init allow_crossrelease_fullstack(char *str)
 {
 	crossrelease_fullstack = 1;
diff --git a/lib/Kconfig.debug b/lib/Kconfig.debug
index 4bef610..e4b54a5 100644
--- a/lib/Kconfig.debug
+++ b/lib/Kconfig.debug
@@ -1225,6 +1225,21 @@ config LOCKDEP_COMPLETIONS
 	 A deadlock caused by wait_for_completion() and complete() can be
 	 detected by lockdep using crossrelease feature.
 
+config BOOTPARAM_LOCKDEP_CROSSRELEASE_FULLSTACK
+	bool "Enable the boot parameter, crossrelease_fullstack"
+	depends on LOCKDEP_CROSSRELEASE
+	default n
+	help
+	 The lockdep "cross-release" feature needs to record stack traces
+	 (of calling functions) for all acquisitions, for eventual later
+	 use during analysis. By default only a single caller is recorded,
+	 because the unwind operation can be very expensive with deeper
+	 stack chains.
+
+	 However a boot parameter, crossrelease_fullstack, was
+	 introduced since sometimes deeper traces are required for full
+	 analysis. This option turns on the boot parameter.
+
 config DEBUG_LOCKDEP
 	bool "Lock dependency engine debugging"
 	depends on DEBUG_KERNEL && LOCKDEP
-- 
1.9.1

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  parent reply	other threads:[~2017-10-25  8:56 UTC|newest]

Thread overview: 14+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2017-10-25  8:55 [PATCH v5 0/9] cross-release: Enhence performance and fix false positives Byungchul Park
2017-10-25  8:55 ` [PATCH v5 1/9] block: use DECLARE_COMPLETION_ONSTACK in submit_bio_wait Byungchul Park
2017-10-25  8:55 ` [PATCH v5 2/9] locking/lockdep: Provide empty lockdep_map structure for !CONFIG_LOCKDEP Byungchul Park
2017-10-25  8:55 ` [PATCH v5 3/9] completion: Change the prefix of lock name for completion variable Byungchul Park
2017-10-25  8:56 ` [PATCH v5 4/9] locking/lockdep: Add a boot parameter allowing unwind in cross-release and disable it by default Byungchul Park
2017-10-25  8:56 ` [PATCH v5 5/9] locking/lockdep: Remove the BROKEN flag from CONFIG_LOCKDEP_CROSSRELEASE and CONFIG_LOCKDEP_COMPLETIONS Byungchul Park
2017-10-25  8:56 ` Byungchul Park [this message]
2017-10-25  8:56 ` [PATCH v5 7/9] completion: Add support for initializing completion with lockdep_map Byungchul Park
2017-10-25  8:56 ` [PATCH v5 8/9] workqueue: Remove unnecessary acquisitions wrt workqueue flush Byungchul Park
2017-10-25  8:56 ` [PATCH v5 9/9] block: Assign a lock_class per gendisk used for wait_for_completion() Byungchul Park
2017-10-25 10:13   ` Ingo Molnar
2017-10-25 18:20     ` Jens Axboe
2017-10-26  5:50       ` Ingo Molnar
2017-10-26  5:58         ` Byungchul Park

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