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 --- kernel/spinlock.c | 3 +-- 1 file changed, 1 insertion(+), 2 deletions(-) (limited to 'kernel/spinlock.c') diff --git a/kernel/spinlock.c b/kernel/spinlock.c index cd72424c266..ae28c824512 100644 --- a/kernel/spinlock.c +++ b/kernel/spinlock.c @@ -65,8 +65,7 @@ EXPORT_SYMBOL(_write_trylock); * even on CONFIG_PREEMPT, because lockdep assumes that interrupts are * not re-enabled during lock-acquire (which the preempt-spin-ops do): */ -#if !defined(CONFIG_PREEMPT) || !defined(CONFIG_SMP) || \ - defined(CONFIG_DEBUG_LOCK_ALLOC) +#if !defined(CONFIG_GENERIC_LOCKBREAK) || defined(CONFIG_DEBUG_LOCK_ALLOC) void __lockfunc _read_lock(rwlock_t *lock) { -- cgit v1.2.3