spinlock.h

Linux下的一个关系数据库源代码

#ifndef __SPINLOCK_H__
#define __SPINLOCK_H__

#if HAVE_CONFIG_H
#include <config.h>
#endif

#include "tdb.h"

#ifdef USE_SPINLOCKS

#define RWLOCK_BIAS 0x1000UL

/* OS SPECIFIC */
#define MAX_BUSY_LOOPS 1000
#undef USE_SCHED_YIELD

/* ARCH SPECIFIC */
/* We should make sure these are padded to a cache line */
#if defined(SPARC_SPINLOCKS)
typedef volatile char spinlock_t;
#elif defined(POWERPC_SPINLOCKS)
typedef volatile unsigned long spinlock_t;
#elif defined(INTEL_SPINLOCKS)
typedef volatile int spinlock_t;
#elif defined(MIPS_SPINLOCKS)
typedef volatile unsigned long spinlock_t;
#else
#error Need to implement spinlock code in spinlock.h
#endif

typedef struct {
	spinlock_t lock;
	volatile int count;
} tdb_rwlock_t;

int tdb_spinlock(TDB_CONTEXT *tdb, int list, int rw_type);
int tdb_spinunlock(TDB_CONTEXT *tdb, int list, int rw_type);
int tdb_create_rwlocks(int fd, unsigned int hash_size);
int tdb_clear_spinlocks(TDB_CONTEXT *tdb);

#else /* !USE_SPINLOCKS */
#if 0
#define tdb_create_rwlocks(fd, hash_size) 0
#define tdb_spinlock(tdb, list, rw_type) (-1)
#define tdb_spinunlock(tdb, list, rw_type) (-1)
#else
int tdb_spinlock(TDB_CONTEXT *tdb, int list, int rw_type);
int tdb_spinunlock(TDB_CONTEXT *tdb, int list, int rw_type);
int tdb_create_rwlocks(int fd, unsigned int hash_size);
#endif
int tdb_clear_spinlocks(TDB_CONTEXT *tdb);
#endif

#endif