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_up.h | 2 ++ 1 file changed, 2 insertions(+) (limited to 'include/linux/spinlock_up.h') diff --git a/include/linux/spinlock_up.h b/include/linux/spinlock_up.h index ea54c4c9a4ec..938234c4a996 100644 --- a/include/linux/spinlock_up.h +++ b/include/linux/spinlock_up.h @@ -64,6 +64,8 @@ static inline void __raw_spin_unlock(raw_spinlock_t *lock) # define __raw_spin_trylock(lock) ({ (void)(lock); 1; }) #endif /* DEBUG_SPINLOCK */ +#define __raw_spin_is_contended(lock) (((void)(lock), 0)) + #define __raw_read_can_lock(lock) (((void)(lock), 1)) #define __raw_write_can_lock(lock) (((void)(lock), 1)) -- cgit v1.2.3-59-g8ed1b