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/sched.c | 16 ++++++---------- 1 file changed, 6 insertions(+), 10 deletions(-) (limited to 'kernel/sched.c') diff --git a/kernel/sched.c b/kernel/sched.c index 524285e46fa..ba4c88088f6 100644 --- a/kernel/sched.c +++ b/kernel/sched.c @@ -4945,19 +4945,15 @@ EXPORT_SYMBOL(_cond_resched); */ int cond_resched_lock(spinlock_t *lock) { + int resched = need_resched() && system_state == SYSTEM_RUNNING; int ret = 0; - if (need_lockbreak(lock)) { + if (spin_needbreak(lock) || resched) { spin_unlock(lock); - cpu_relax(); - ret = 1; - spin_lock(lock); - } - if (need_resched() && system_state == SYSTEM_RUNNING) { - spin_release(&lock->dep_map, 1, _THIS_IP_); - _raw_spin_unlock(lock); - preempt_enable_no_resched(); - __cond_resched(); + if (resched && need_resched()) + __cond_resched(); + else + cpu_relax(); ret = 1; spin_lock(lock); } -- cgit v1.2.3