From 95c354fe9f7d6decc08a92aa26eb233ecc2155bf Mon Sep 17 00:00:00 2001 From: Nick Piggin Date: Wed, 30 Jan 2008 13:31:20 +0100 Subject: 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 Signed-off-by: Ingo Molnar Signed-off-by: Thomas Gleixner --- include/linux/spinlock.h | 6 ++++++ 1 file changed, 6 insertions(+) (limited to 'include/linux/spinlock.h') diff --git a/include/linux/spinlock.h b/include/linux/spinlock.h index c376f3b36c89..124449733c55 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. -- cgit