cosmopolitan/libc/intrin/spinlock.h
Justine Tunney 7838edae88 Fix many thread and file descriptor issues on Windows
The greenbean web server now works nearly perfectly on Windows with over
1000 threads. But some synchronization issues still remain which prevent
us from going over nine thousand.
2022-05-20 20:57:19 -07:00

83 lines
3.7 KiB
C

#ifndef COSMOPOLITAN_LIBC_INTRIN_SPINLOCK_H_
#define COSMOPOLITAN_LIBC_INTRIN_SPINLOCK_H_
#include "libc/assert.h"
#include "libc/calls/calls.h"
#include "libc/intrin/lockcmpxchg.h"
#include "libc/intrin/lockcmpxchgp.h"
/*───────────────────────────────────────────────────────────────────────────│─╗
│ cosmopolitan § spinlocks ─╬─│┼
╚────────────────────────────────────────────────────────────────────────────│─╝
privileged unsophisticated locking subroutines */
#if IsModeDbg() && !defined(_SPINLOCK_DEBUG)
#define _SPINLOCK_DEBUG
#endif
#if defined(_SPINLOCK_DEBUG)
#define _spinlock(lock) _spinlock_ndebug(lock)
#define _spinlock_ndebug(lock) _spinlock_cooperative(lock)
#define _trylock(lock) _trylock_debug(lock)
#define _seizelock(lock) _seizelock_impl(lock, gettid())
#elif defined(TINY)
#define _spinlock(lock) _spinlock_tiny(lock)
#define _spinlock_ndebug(lock) _spinlock_tiny(lock)
#define _trylock(lock) _trylock_inline(lock)
#define _seizelock(lock) _seizelock_impl(lock, 1)
#else
#define _spinlock(lock) _spinlock_cooperative(lock)
#define _spinlock_ndebug(lock) _spinlock_cooperative(lock)
#define _trylock(lock) _trylock_inline(lock)
#define _seizelock(lock) _seizelock_impl(lock, 1)
#endif
#define _trylock_inline(lock) __atomic_test_and_set(lock, __ATOMIC_SEQ_CST)
#define _trylock_debug(lock) \
_trylock_debug_4(lock, #lock, __FILE__, __LINE__, __FUNCTION__)
#define _spinlock_debug(lock) \
_spinlock_debug_4(lock, #lock, __FILE__, __LINE__, __FUNCTION__)
#define _spunlock(lock) \
do { \
autotype(lock) __lock = (lock); \
typeof(*__lock) __x = 0; \
__atomic_store(__lock, &__x, __ATOMIC_RELAXED); \
} while (0)
#define _seizelock_impl(lock, value) \
do { \
autotype(lock) __lock = (lock); \
typeof(*__lock) __x = (value); \
__atomic_store(__lock, &__x, __ATOMIC_RELEASE); \
} while (0)
#define _spinlock_tiny(lock) \
do { \
autotype(lock) __lock = (lock); \
while (_trylock_inline(__lock)) { \
__builtin_ia32_pause(); \
} \
} while (0)
#define _spinlock_cooperative(lock) \
do { \
autotype(lock) __lock = (lock); \
typeof(*__lock) __x; \
int __tries = 0; \
for (;;) { \
__atomic_load(__lock, &__x, __ATOMIC_RELAXED); \
if (!__x && !_trylock_inline(__lock)) { \
break; \
} else if (++__tries & 7) { \
__builtin_ia32_pause(); \
} else { \
sched_yield(); \
} \
} \
} while (0)
int _trylock_debug_4(int *, const char *, const char *, int, const char *);
void _spinlock_debug_4(int *, const char *, const char *, int, const char *);
#endif /* COSMOPOLITAN_LIBC_INTRIN_SPINLOCK_H_ */