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| author | Nick Piggin <npiggin@suse.de> | 2008-01-30 13:31:20 +0100 |
|---|---|---|
| committer | Ingo Molnar <mingo@elte.hu> | 2008-01-30 13:31:20 +0100 |
| commit | 95c354fe9f7d6decc08a92aa26eb233ecc2155bf (patch) | |
| tree | ec9267032ea875e84216cfb20acb2cfc7c62149f /kernel | |
| parent | a95d67f87e1a5f1b4429be3ba3bf7b4051657908 (diff) | |
| download | linux-95c354fe9f7d6decc08a92aa26eb233ecc2155bf.tar.gz linux-95c354fe9f7d6decc08a92aa26eb233ecc2155bf.tar.bz2 linux-95c354fe9f7d6decc08a92aa26eb233ecc2155bf.zip | |
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 'kernel')
| -rw-r--r-- | kernel/sched.c | 16 | ||||
| -rw-r--r-- | kernel/spinlock.c | 3 |
2 files changed, 7 insertions, 12 deletions
diff --git a/kernel/sched.c b/kernel/sched.c index 524285e46fa7..ba4c88088f62 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); } diff --git a/kernel/spinlock.c b/kernel/spinlock.c index cd72424c2662..ae28c8245123 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) { |