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authorNick Piggin <npiggin@suse.de>2008-01-30 13:31:20 +0100
committerIngo Molnar <mingo@elte.hu>2008-01-30 13:31:20 +0100
commit95c354fe9f7d6decc08a92aa26eb233ecc2155bf (patch)
treeec9267032ea875e84216cfb20acb2cfc7c62149f /include/linux/spinlock.h
parenta95d67f87e1a5f1b4429be3ba3bf7b4051657908 (diff)
downloadop-kernel-dev-95c354fe9f7d6decc08a92aa26eb233ecc2155bf.zip
op-kernel-dev-95c354fe9f7d6decc08a92aa26eb233ecc2155bf.tar.gz
spinlock: lockbreak cleanup
The break_lock data structure and code for spinlocks is quite nasty. Not only does it double the size of a spinlock but it changes locking to a potentially less optimal trylock. Put all of that under CONFIG_GENERIC_LOCKBREAK, and introduce a __raw_spin_is_contended that uses the lock data itself to determine whether there are waiters on the lock, to be used if CONFIG_GENERIC_LOCKBREAK is not set. Rename need_lockbreak to spin_needbreak, make it use spin_is_contended to decouple it from the spinlock implementation, and make it typesafe (rwlocks do not have any need_lockbreak sites -- why do they even get bloated up with that break_lock then?). Signed-off-by: Nick Piggin <npiggin@suse.de> Signed-off-by: Ingo Molnar <mingo@elte.hu> Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Diffstat (limited to 'include/linux/spinlock.h')
-rw-r--r--include/linux/spinlock.h6
1 files changed, 6 insertions, 0 deletions
diff --git a/include/linux/spinlock.h b/include/linux/spinlock.h
index c376f3b..1244497 100644
--- a/include/linux/spinlock.h
+++ b/include/linux/spinlock.h
@@ -120,6 +120,12 @@ do { \
#define spin_is_locked(lock) __raw_spin_is_locked(&(lock)->raw_lock)
+#ifdef CONFIG_GENERIC_LOCKBREAK
+#define spin_is_contended(lock) ((lock)->break_lock)
+#else
+#define spin_is_contended(lock) __raw_spin_is_contended(&(lock)->raw_lock)
+#endif
+
/**
* spin_unlock_wait - wait until the spinlock gets unlocked
* @lock: the spinlock in question.
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