From 3c1fcfe229e99752c74efb945a4a3f560be04204 Mon Sep 17 00:00:00 2001 From: Martin Schwidefsky Date: Sat, 30 Sep 2006 23:27:45 -0700 Subject: [PATCH] Directed yield: direct yield of spinlocks for s390. Use the new diagnose 0x9c in the spinlock implementation for s390. It yields the remaining timeslice of the virtual cpu that tries to acquire a lock to the virtual cpu that is the current holder of the lock. Signed-off-by: Martin Schwidefsky Cc: Ingo Molnar Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds --- arch/s390/lib/spinlock.c | 62 ++++++++++++++++++++++++++++++------------------ 1 file changed, 39 insertions(+), 23 deletions(-) (limited to 'arch/s390/lib/spinlock.c') diff --git a/arch/s390/lib/spinlock.c b/arch/s390/lib/spinlock.c index b9b7958a226a7..8d76403fcf89b 100644 --- a/arch/s390/lib/spinlock.c +++ b/arch/s390/lib/spinlock.c @@ -24,57 +24,76 @@ static int __init spin_retry_setup(char *str) } __setup("spin_retry=", spin_retry_setup); -static inline void -_diag44(void) +static inline void _raw_yield(void) { -#ifdef CONFIG_64BIT if (MACHINE_HAS_DIAG44) -#endif asm volatile("diag 0,0,0x44"); } -void -_raw_spin_lock_wait(raw_spinlock_t *lp, unsigned int pc) +static inline void _raw_yield_cpu(int cpu) +{ + if (MACHINE_HAS_DIAG9C) + asm volatile("diag %0,0,0x9c" + : : "d" (__cpu_logical_map[cpu])); + else + _raw_yield(); +} + +void _raw_spin_lock_wait(raw_spinlock_t *lp, unsigned int pc) { int count = spin_retry; + unsigned int cpu = ~smp_processor_id(); while (1) { if (count-- <= 0) { - _diag44(); + unsigned int owner = lp->owner_cpu; + if (owner != 0) + _raw_yield_cpu(~owner); count = spin_retry; } if (__raw_spin_is_locked(lp)) continue; - if (_raw_compare_and_swap(&lp->lock, 0, pc) == 0) + if (_raw_compare_and_swap(&lp->owner_cpu, 0, cpu) == 0) { + lp->owner_pc = pc; return; + } } } EXPORT_SYMBOL(_raw_spin_lock_wait); -int -_raw_spin_trylock_retry(raw_spinlock_t *lp, unsigned int pc) +int _raw_spin_trylock_retry(raw_spinlock_t *lp, unsigned int pc) { - int count = spin_retry; + unsigned int cpu = ~smp_processor_id(); + int count; - while (count-- > 0) { + for (count = spin_retry; count > 0; count--) { if (__raw_spin_is_locked(lp)) continue; - if (_raw_compare_and_swap(&lp->lock, 0, pc) == 0) + if (_raw_compare_and_swap(&lp->owner_cpu, 0, cpu) == 0) { + lp->owner_pc = pc; return 1; + } } return 0; } EXPORT_SYMBOL(_raw_spin_trylock_retry); -void -_raw_read_lock_wait(raw_rwlock_t *rw) +void _raw_spin_relax(raw_spinlock_t *lock) +{ + unsigned int cpu = lock->owner_cpu; + if (cpu != 0) + _raw_yield_cpu(~cpu); +} +EXPORT_SYMBOL(_raw_spin_relax); + +void _raw_read_lock_wait(raw_rwlock_t *rw) { unsigned int old; int count = spin_retry; while (1) { if (count-- <= 0) { - _diag44(); + _raw_yield(); count = spin_retry; } if (!__raw_read_can_lock(rw)) @@ -86,8 +105,7 @@ _raw_read_lock_wait(raw_rwlock_t *rw) } EXPORT_SYMBOL(_raw_read_lock_wait); -int -_raw_read_trylock_retry(raw_rwlock_t *rw) +int _raw_read_trylock_retry(raw_rwlock_t *rw) { unsigned int old; int count = spin_retry; @@ -103,14 +121,13 @@ _raw_read_trylock_retry(raw_rwlock_t *rw) } EXPORT_SYMBOL(_raw_read_trylock_retry); -void -_raw_write_lock_wait(raw_rwlock_t *rw) +void _raw_write_lock_wait(raw_rwlock_t *rw) { int count = spin_retry; while (1) { if (count-- <= 0) { - _diag44(); + _raw_yield(); count = spin_retry; } if (!__raw_write_can_lock(rw)) @@ -121,8 +138,7 @@ _raw_write_lock_wait(raw_rwlock_t *rw) } EXPORT_SYMBOL(_raw_write_lock_wait); -int -_raw_write_trylock_retry(raw_rwlock_t *rw) +int _raw_write_trylock_retry(raw_rwlock_t *rw) { int count = spin_retry; -- cgit 1.2.3-korg