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authorMaarten Lankhorst <maarten.lankhorst@canonical.com>2013-06-24 10:30:04 +0200
committerIngo Molnar <mingo@kernel.org>2013-06-26 12:10:56 +0200
commit040a0a37100563754bb1fee6ff6427420bcfa609 (patch)
tree153e76b27ef95f57ad2055d42b8bb07cb1f8d493 /lib/debug_locks.c
parenta41b56efa70e060f650aeb54740aaf52044a1ead (diff)
downloadlwn-040a0a37100563754bb1fee6ff6427420bcfa609.tar.gz
lwn-040a0a37100563754bb1fee6ff6427420bcfa609.zip
mutex: Add support for wound/wait style locks
Wound/wait mutexes are used when other multiple lock acquisitions of a similar type can be done in an arbitrary order. The deadlock handling used here is called wait/wound in the RDBMS literature: The older tasks waits until it can acquire the contended lock. The younger tasks needs to back off and drop all the locks it is currently holding, i.e. the younger task is wounded. For full documentation please read Documentation/ww-mutex-design.txt. References: https://lwn.net/Articles/548909/ Signed-off-by: Maarten Lankhorst <maarten.lankhorst@canonical.com> Acked-by: Daniel Vetter <daniel.vetter@ffwll.ch> Acked-by: Rob Clark <robdclark@gmail.com> Acked-by: Peter Zijlstra <a.p.zijlstra@chello.nl> Cc: dri-devel@lists.freedesktop.org Cc: linaro-mm-sig@lists.linaro.org Cc: rostedt@goodmis.org Cc: daniel@ffwll.ch Cc: Linus Torvalds <torvalds@linux-foundation.org> Cc: Andrew Morton <akpm@linux-foundation.org> Cc: Thomas Gleixner <tglx@linutronix.de> Link: http://lkml.kernel.org/r/51C8038C.9000106@canonical.com Signed-off-by: Ingo Molnar <mingo@kernel.org>
Diffstat (limited to 'lib/debug_locks.c')
-rw-r--r--lib/debug_locks.c2
1 files changed, 2 insertions, 0 deletions
diff --git a/lib/debug_locks.c b/lib/debug_locks.c
index f2fa60c59343..96c4c633d95e 100644
--- a/lib/debug_locks.c
+++ b/lib/debug_locks.c
@@ -30,6 +30,7 @@ EXPORT_SYMBOL_GPL(debug_locks);
* a locking bug is detected.
*/
int debug_locks_silent;
+EXPORT_SYMBOL_GPL(debug_locks_silent);
/*
* Generic 'turn off all lock debugging' function:
@@ -44,3 +45,4 @@ int debug_locks_off(void)
}
return 0;
}
+EXPORT_SYMBOL_GPL(debug_locks_off);