diff options
author | Martin Schwidefsky <schwidefsky@de.ibm.com> | 2006-10-01 06:27:45 (GMT) |
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committer | Linus Torvalds <torvalds@g5.osdl.org> | 2006-10-01 07:39:22 (GMT) |
commit | 3c1fcfe229e99752c74efb945a4a3f560be04204 (patch) | |
tree | 44085d9b599e06a92426141811a6f712beac17aa /arch/s390/lib | |
parent | cdc39363d33506b0e067d41fc91f89d186bdf7f7 (diff) | |
download | linux-3c1fcfe229e99752c74efb945a4a3f560be04204.tar.xz |
[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 <schwidefsky@de.ibm.com>
Cc: Ingo Molnar <mingo@elte.hu>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
Diffstat (limited to 'arch/s390/lib')
-rw-r--r-- | arch/s390/lib/spinlock.c | 62 |
1 files changed, 39 insertions, 23 deletions
diff --git a/arch/s390/lib/spinlock.c b/arch/s390/lib/spinlock.c index b9b7958..8d76403 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; |