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author | Martin Schwidefsky <schwidefsky@de.ibm.com> | 2014-09-19 12:29:31 (GMT) |
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committer | Martin Schwidefsky <schwidefsky@de.ibm.com> | 2014-09-25 08:52:05 (GMT) |
commit | d59b93da5e572703e1a7311c13dd3472a4e56e30 (patch) | |
tree | 4c75073780f54bc9785433256eee3d6d70eaf868 /arch/s390/include/asm/spinlock.h | |
parent | 46b05c7bd51edafb8c8da088b49bddf7f78d48f9 (diff) | |
download | linux-d59b93da5e572703e1a7311c13dd3472a4e56e30.tar.xz |
s390/rwlock: use directed yield for write-locked rwlocks
Add an owner field to the arch_rwlock_t to be able to pass the timeslice
of a virtual CPU with diagnose 0x9c to the lock owner in case the rwlock
is write-locked. The undirected yield in case the rwlock is acquired
writable but the lock is read-locked is removed.
Signed-off-by: Martin Schwidefsky <schwidefsky@de.ibm.com>
Diffstat (limited to 'arch/s390/include/asm/spinlock.h')
-rw-r--r-- | arch/s390/include/asm/spinlock.h | 28 |
1 files changed, 23 insertions, 5 deletions
diff --git a/arch/s390/include/asm/spinlock.h b/arch/s390/include/asm/spinlock.h index d26ad2a..e9865416 100644 --- a/arch/s390/include/asm/spinlock.h +++ b/arch/s390/include/asm/spinlock.h @@ -37,11 +37,17 @@ _raw_compare_and_swap(unsigned int *lock, unsigned int old, unsigned int new) * (the type definitions are in asm/spinlock_types.h) */ +void arch_lock_relax(unsigned int cpu); + void arch_spin_lock_wait(arch_spinlock_t *); int arch_spin_trylock_retry(arch_spinlock_t *); -void arch_spin_relax(arch_spinlock_t *); void arch_spin_lock_wait_flags(arch_spinlock_t *, unsigned long flags); +static inline void arch_spin_relax(arch_spinlock_t *lock) +{ + arch_lock_relax(lock->lock); +} + static inline u32 arch_spin_lockval(int cpu) { return ~cpu; @@ -170,17 +176,21 @@ static inline void arch_write_lock(arch_rwlock_t *rw) { if (!arch_write_trylock_once(rw)) _raw_write_lock_wait(rw); + rw->owner = SPINLOCK_LOCKVAL; } static inline void arch_write_lock_flags(arch_rwlock_t *rw, unsigned long flags) { if (!arch_write_trylock_once(rw)) _raw_write_lock_wait_flags(rw, flags); + rw->owner = SPINLOCK_LOCKVAL; } static inline void arch_write_unlock(arch_rwlock_t *rw) { typecheck(unsigned int, rw->lock); + + rw->owner = 0; asm volatile( __ASM_BARRIER "st %1,%0\n" @@ -198,12 +208,20 @@ static inline int arch_read_trylock(arch_rwlock_t *rw) static inline int arch_write_trylock(arch_rwlock_t *rw) { - if (!arch_write_trylock_once(rw)) - return _raw_write_trylock_retry(rw); + if (!arch_write_trylock_once(rw) && !_raw_write_trylock_retry(rw)) + return 0; + rw->owner = SPINLOCK_LOCKVAL; return 1; } -#define arch_read_relax(lock) cpu_relax() -#define arch_write_relax(lock) cpu_relax() +static inline void arch_read_relax(arch_rwlock_t *rw) +{ + arch_lock_relax(rw->owner); +} + +static inline void arch_write_relax(arch_rwlock_t *rw) +{ + arch_lock_relax(rw->owner); +} #endif /* __ASM_SPINLOCK_H */ |