path: root/erts/include/internal/ethr_mutex.h

/*
 * %CopyrightBegin%
 *
 * Copyright Ericsson AB 2010. All Rights Reserved.
 *
 * The contents of this file are subject to the Erlang Public License,
 * Version 1.1, (the "License"); you may not use this file except in
 * compliance with the License. You should have received a copy of the
 * Erlang Public License along with this software. If not, it can be
 * retrieved online at http://www.erlang.org/.
 *
 * Software distributed under the License is distributed on an "AS IS"
 * basis, WITHOUT WARRANTY OF ANY KIND, either express or implied. See
 * the License for the specific language governing rights and limitations
 * under the License.
 *
 * %CopyrightEnd%
 */

/*
 * Description: Mutex, rwmutex and condition variable implementation
 * Author: Rickard Green
 */

#ifndef ETHR_MUTEX_H__
#define ETHR_MUTEX_H__

#define ETHR_RWMUTEX_INITIALIZED 	0x99999999
#define ETHR_MUTEX_INITIALIZED		0x77777777
#define ETHR_COND_INITIALIZED		0x55555555

#if 0
#  define ETHR_MTX_HARD_DEBUG
#endif

#ifdef ETHR_MTX_HARD_DEBUG
#  ifdef __GNUC__
#    warning ETHR_MTX_HARD_DEBUG
#  endif
/*#  define ETHR_MTX_HARD_DEBUG_LFS*/
/*#  define ETHR_MTX_HARD_DEBUG_FENCE*/
/*#  define ETHR_MTX_HARD_DEBUG_Q*/
#  define ETHR_MTX_HARD_DEBUG_WSQ

#  if !defined(ETHR_MTX_HARD_DEBUG_WSQ) && defined(ETHR_MTX_HARD_DEBUG_Q)
#    define ETHR_MTX_HARD_DEBUG_WSQ
#  endif
#endif

#if defined(ETHR_USE_OWN_RWMTX_IMPL__) || defined(ETHR_USE_OWN_MTX_IMPL__)

#if 0
#  define ETHR_MTX_Q_LOCK_SPINLOCK__
#  define ETHR_MTX_QLOCK_TYPE__ ethr_spinlock_t
#elif defined(ETHR_PTHREADS)
#  define ETHR_MTX_Q_LOCK_PTHREAD_MUTEX__
#  define ETHR_MTX_QLOCK_TYPE__ pthread_mutex_t
#elif defined(ETHR_WIN32_THREADS)
#  define ETHR_MTX_Q_LOCK_CRITICAL_SECTION__
#  define ETHR_MTX_QLOCK_TYPE__ CRITICAL_SECTION
#else
#  error Need a qlock implementation
#endif

#define ETHR_RWMTX_W_FLG__		(((long) 1) << 31)
#define ETHR_RWMTX_W_WAIT_FLG__		(((long) 1) << 30)
#define ETHR_RWMTX_R_WAIT_FLG__		(((long) 1) << 29)

/* frequent read kind */
#define ETHR_RWMTX_R_FLG__		(((long) 1) << 28)
#define ETHR_RWMTX_R_PEND_UNLCK_MASK__	(ETHR_RWMTX_R_FLG__ - 1)
#define ETHR_RWMTX_R_MASK__		(ETHR_RWMTX_R_WAIT_FLG__ - 1)

/* normal kind */
#define ETHR_RWMTX_RS_MASK__		(ETHR_RWMTX_R_WAIT_FLG__ - 1)

#define ETHR_RWMTX_WAIT_FLGS__ \
  (ETHR_RWMTX_W_WAIT_FLG__|ETHR_RWMTX_R_WAIT_FLG__)

#define ETHR_CND_WAIT_FLG__		ETHR_RWMTX_R_WAIT_FLG__

struct ethr_mutex_base_ {
#ifdef ETHR_MTX_HARD_DEBUG_FENCE
    long pre_fence;
#endif
    ethr_atomic_t flgs;
    ETHR_MTX_QLOCK_TYPE__ qlck;
    ethr_ts_event *q;
    short aux_scnt;
    short main_scnt;
#ifdef ETHR_MTX_HARD_DEBUG_WSQ
    int ws;
#endif
#ifdef ETHR_MTX_HARD_DEBUG_LFS
    ethr_atomic_t hdbg_lfs;
#endif
};

#endif

typedef struct {
    int main_spincount;
    int aux_spincount;
} ethr_mutex_opt;

typedef struct {
    int main_spincount;
    int aux_spincount;
} ethr_cond_opt;

#ifdef ETHR_USE_OWN_MTX_IMPL__

typedef struct ethr_mutex_ ethr_mutex;
struct ethr_mutex_ {
    struct ethr_mutex_base_ mtxb;
#ifdef ETHR_MTX_HARD_DEBUG_FENCE
    long post_fence;
#endif
#if ETHR_XCHK
    int initialized;
#endif
};

typedef struct ethr_cond_ ethr_cond;
struct ethr_cond_ {
#ifdef ETHR_MTX_HARD_DEBUG_FENCE
    struct {
	long pre_fence;
    } mtxb; /* mtxb allows us to use same macro as for mutex and rwmutex... */
#endif
    ETHR_MTX_QLOCK_TYPE__ qlck;
    ethr_ts_event *q;
    short aux_scnt;
    short main_scnt;
#ifdef ETHR_MTX_HARD_DEBUG_FENCE
    long post_fence;
#endif
#if ETHR_XCHK
    int initialized;
#endif
};

#else /* pthread */

typedef struct ethr_mutex_ ethr_mutex;
struct ethr_mutex_ {
    pthread_mutex_t pt_mtx;
#if ETHR_XCHK
    int initialized;
#endif
};

typedef struct ethr_cond_ ethr_cond;
struct ethr_cond_ {
    pthread_cond_t pt_cnd;
#if ETHR_XCHK
    int initialized;
#endif
};

#endif /* pthread */

int ethr_mutex_init_opt(ethr_mutex *, ethr_mutex_opt *);
int ethr_mutex_init(ethr_mutex *);
int ethr_mutex_destroy(ethr_mutex *);
#if !defined(ETHR_TRY_INLINE_FUNCS) || defined(ETHR_MUTEX_IMPL__)
int ethr_mutex_trylock(ethr_mutex *);
void ethr_mutex_lock(ethr_mutex *);
void ethr_mutex_unlock(ethr_mutex *);
#endif
int ethr_cond_init_opt(ethr_cond *, ethr_cond_opt *);
int ethr_cond_init(ethr_cond *);
int ethr_cond_destroy(ethr_cond *);
void ethr_cond_signal(ethr_cond *);
void ethr_cond_broadcast(ethr_cond *);
int ethr_cond_wait(ethr_cond *, ethr_mutex *);

typedef enum {
    ETHR_RWMUTEX_TYPE_NORMAL,
    ETHR_RWMUTEX_TYPE_FREQUENT_READ,
    ETHR_RWMUTEX_TYPE_EXTREMELY_FREQUENT_READ
} ethr_rwmutex_type;

typedef enum {
    ETHR_RWMUTEX_LONG_LIVED,
    ETHR_RWMUTEX_SHORT_LIVED,
    ETHR_RWMUTEX_UNKNOWN_LIVED
} ethr_rwmutex_lived;

typedef struct {
    ethr_rwmutex_type type;
    ethr_rwmutex_lived lived;
    int main_spincount;
    int aux_spincount;
} ethr_rwmutex_opt;

#define ETHR_RWMUTEX_OPT_DEFAULT_INITER \
  {ETHR_RWMUTEX_TYPE_NORMAL, ETHR_RWMUTEX_UNKNOWN_LIVED, -1, -1}

#ifdef ETHR_USE_OWN_RWMTX_IMPL__

typedef union {
    struct {
	ethr_atomic_t readers;
	int waiting_readers;
	int byte_offset;
	ethr_rwmutex_lived lived;
    } data;
    char align__[ETHR_CACHE_LINE_SIZE];
} ethr_rwmtx_readers_array__;

typedef struct ethr_rwmutex_ ethr_rwmutex;
struct ethr_rwmutex_ {
    struct ethr_mutex_base_ mtxb;
    ethr_rwmutex_type type;
    ethr_ts_event *rq_end;
    union {
	ethr_rwmtx_readers_array__ *ra;
	int rs;
    } tdata;
#ifdef ETHR_MTX_HARD_DEBUG_FENCE
    long post_fence;
#endif
#if ETHR_XCHK
    int initialized;
#endif
};

#else /* pthread_rwlock */

typedef struct ethr_rwmutex_ ethr_rwmutex;
struct ethr_rwmutex_ {
    pthread_rwlock_t pt_rwlock;
#if ETHR_XCHK
    int initialized;
#endif
};

#endif /* pthread_rwlock */

int ethr_rwmutex_set_reader_group(int);
int ethr_rwmutex_init_opt(ethr_rwmutex *, ethr_rwmutex_opt *);
int ethr_rwmutex_init(ethr_rwmutex *);
int ethr_rwmutex_destroy(ethr_rwmutex *);
#if defined(ETHR_USE_OWN_RWMTX_IMPL__) \
    || !defined(ETHR_TRY_INLINE_FUNCS) \
    || defined(ETHR_MUTEX_IMPL__)
int ethr_rwmutex_tryrlock(ethr_rwmutex *);
void ethr_rwmutex_rlock(ethr_rwmutex *);
void ethr_rwmutex_runlock(ethr_rwmutex *);
int ethr_rwmutex_tryrwlock(ethr_rwmutex *);
void ethr_rwmutex_rwlock(ethr_rwmutex *);
void ethr_rwmutex_rwunlock(ethr_rwmutex *);
#endif

#ifdef ETHR_MTX_HARD_DEBUG
#define ETHR_MTX_HARD_ASSERT(A) \
  ((void) ((A) ? 1 : ethr_assert_failed(__FILE__, __LINE__, #A)))
#else
#define ETHR_MTX_HARD_ASSERT(A) ((void) 1)
#endif

#ifdef ETHR_MTX_HARD_DEBUG_LFS
#  define ETHR_MTX_HARD_DEBUG_LFS_INIT(MTXB)				\
do {									\
    ethr_atomic_init(&(MTXB)->hdbg_lfs, 0);				\
} while (0)
#  define ETHR_MTX_HARD_DEBUG_LFS_RLOCK(MTXB)				\
do {									\
    long val__;								\
    ETHR_COMPILER_BARRIER;						\
    val__ = ethr_atomic_inc_read(&(MTXB)->hdbg_lfs);			\
    ETHR_MTX_HARD_ASSERT(val__ > 0);					\
} while (0)
#  define ETHR_MTX_HARD_DEBUG_LFS_TRYRLOCK(MTXB, RES)			\
do {									\
    ETHR_COMPILER_BARRIER;						\
    if ((RES) == 0)							\
	ETHR_MTX_HARD_DEBUG_LFS_RLOCK((MTXB));				\
    else								\
	ETHR_MTX_HARD_ASSERT((RES) == EBUSY);				\
} while (0)
#  define ETHR_MTX_HARD_DEBUG_LFS_RUNLOCK(MTXB)				\
do {									\
    long val__ = ethr_atomic_dec_read(&(MTXB)->hdbg_lfs);		\
    ETHR_MTX_HARD_ASSERT(val__ >= 0);					\
    ETHR_COMPILER_BARRIER;						\
} while (0)
#  define ETHR_MTX_HARD_DEBUG_LFS_RWLOCK(MTXB)				\
do {									\
    long val__;								\
    ETHR_COMPILER_BARRIER;						\
    val__ = ethr_atomic_dec_read(&(MTXB)->hdbg_lfs);			\
    ETHR_MTX_HARD_ASSERT(val__ == -1);					\
} while (0)
#  define ETHR_MTX_HARD_DEBUG_LFS_TRYRWLOCK(MTXB, RES)			\
do {									\
    ETHR_COMPILER_BARRIER;						\
    if ((RES) == 0)							\
	ETHR_MTX_HARD_DEBUG_LFS_RWLOCK((MTXB));				\
    else								\
	ETHR_MTX_HARD_ASSERT((RES) == EBUSY);				\
} while (0)
#  define ETHR_MTX_HARD_DEBUG_LFS_RWUNLOCK(MTXB)			\
do {									\
    long val__ = ethr_atomic_inctest(&(MTXB)->hdbg_lfs);		\
    ETHR_MTX_HARD_ASSERT(val__ == 0);					\
    ETHR_COMPILER_BARRIER;						\
} while (0)
#else
#  define ETHR_MTX_HARD_DEBUG_LFS_INIT(MTXB)
#  define ETHR_MTX_HARD_DEBUG_LFS_RLOCK(MTXB)
#  define ETHR_MTX_HARD_DEBUG_LFS_TRYRLOCK(MTXB, RES)
#  define ETHR_MTX_HARD_DEBUG_LFS_RUNLOCK(MTXB)
#  define ETHR_MTX_HARD_DEBUG_LFS_RWLOCK(MTXB)
#  define ETHR_MTX_HARD_DEBUG_LFS_TRYRWLOCK(MTXB, RES)
#  define ETHR_MTX_HARD_DEBUG_LFS_RWUNLOCK(MTXB)
#endif

#ifdef ETHR_MTX_HARD_DEBUG_FENCE

#if ETHR_SIZEOF_PTR == 8
#  define ETHR_MTX_HARD_DEBUG_PRE_FENCE		0xdeadbeefdeadbeefL
#  define ETHR_MTX_HARD_DEBUG_POST_FENCE	0xdeaddeaddeaddeadL
#else
#  define ETHR_MTX_HARD_DEBUG_PRE_FENCE		0xdeaddeadL
#  define ETHR_MTX_HARD_DEBUG_POST_FENCE	0xdeaddeadL
#endif

#define ETHR_MTX_HARD_DEBUG_FENCE_CHK(X) \
do { \
    ETHR_COMPILER_BARRIER; \
    ETHR_MTX_HARD_ASSERT((X)->mtxb.pre_fence == ETHR_MTX_HARD_DEBUG_PRE_FENCE);\
    ETHR_MTX_HARD_ASSERT((X)->post_fence == ETHR_MTX_HARD_DEBUG_POST_FENCE); \
    ETHR_COMPILER_BARRIER; \
} while (0)
#define ETHR_MTX_HARD_DEBUG_FENCE_INIT(X) \
do { \
    (X)->mtxb.pre_fence = ETHR_MTX_HARD_DEBUG_PRE_FENCE; \
    (X)->post_fence = ETHR_MTX_HARD_DEBUG_POST_FENCE; \
} while (0)
#else
#define ETHR_MTX_HARD_DEBUG_FENCE_CHK(X)
#define ETHR_MTX_HARD_DEBUG_FENCE_INIT(X)
#endif

#ifdef ETHR_USE_OWN_MTX_IMPL__

#define ETHR_MTX_DEFAULT_MAIN_SPINCOUNT_MAX 2000
#define ETHR_MTX_DEFAULT_MAIN_SPINCOUNT_BASE 800
#define ETHR_MTX_DEFAULT_MAIN_SPINCOUNT_INC 50
#define ETHR_MTX_DEFAULT_AUX_SPINCOUNT 50

#define ETHR_CND_DEFAULT_MAIN_SPINCOUNT 0
#define ETHR_CND_DEFAULT_AUX_SPINCOUNT 0

#if defined(ETHR_TRY_INLINE_FUNCS) || defined(ETHR_MUTEX_IMPL__)

void ethr_mutex_lock_wait__(ethr_mutex *, long);
void ethr_mutex_unlock_wake__(ethr_mutex *, long);

static ETHR_INLINE int
ETHR_INLINE_FUNC_NAME_(ethr_mutex_trylock)(ethr_mutex *mtx)
{
    long act;
    int res;
    ETHR_MTX_HARD_DEBUG_FENCE_CHK(mtx);

    act = ethr_atomic_cmpxchg_acqb(&mtx->mtxb.flgs, ETHR_RWMTX_W_FLG__, 0);
    res = (act == 0) ? 0 : EBUSY;

    ETHR_MTX_HARD_DEBUG_LFS_TRYRWLOCK(&mtx->mtxb, res);
    ETHR_MTX_HARD_DEBUG_FENCE_CHK(mtx);

    ETHR_COMPILER_BARRIER;
    return res;
}

static ETHR_INLINE void
ETHR_INLINE_FUNC_NAME_(ethr_mutex_lock)(ethr_mutex *mtx)
{
    long act;
    ETHR_MTX_HARD_DEBUG_FENCE_CHK(mtx);

    act = ethr_atomic_cmpxchg_acqb(&mtx->mtxb.flgs, ETHR_RWMTX_W_FLG__, 0);
    if (act != 0)
	ethr_mutex_lock_wait__(mtx, act);

    ETHR_MTX_HARD_DEBUG_LFS_RWLOCK(&mtx->mtxb);
    ETHR_MTX_HARD_DEBUG_FENCE_CHK(mtx);

    ETHR_COMPILER_BARRIER;
}

static ETHR_INLINE void
ETHR_INLINE_FUNC_NAME_(ethr_mutex_unlock)(ethr_mutex *mtx)
{
    long act;
    ETHR_COMPILER_BARRIER;
    ETHR_MTX_HARD_DEBUG_FENCE_CHK(mtx);
    ETHR_MTX_HARD_DEBUG_LFS_RWUNLOCK(&mtx->mtxb);

    act = ethr_atomic_cmpxchg_relb(&mtx->mtxb.flgs, 0, ETHR_RWMTX_W_FLG__);
    if (act != ETHR_RWMTX_W_FLG__)
	ethr_mutex_unlock_wake__(mtx, act);

    ETHR_MTX_HARD_DEBUG_FENCE_CHK(mtx);
}

#endif /* ETHR_TRY_INLINE_FUNCS */

#else /* pthread_mutex */

#if defined(ETHR_TRY_INLINE_FUNCS) || defined(ETHR_MUTEX_IMPL__)

static ETHR_INLINE int
ETHR_INLINE_FUNC_NAME_(ethr_mutex_trylock)(ethr_mutex *mtx)
{
    int res;
    res = pthread_mutex_trylock(&mtx->pt_mtx);
    if (res != 0 && res != EBUSY)
	ETHR_FATAL_ERROR__(res);
    return res;
}

static ETHR_INLINE void
ETHR_INLINE_FUNC_NAME_(ethr_mutex_lock)(ethr_mutex *mtx)
{
    int res = pthread_mutex_lock(&mtx->pt_mtx);
    if (res != 0)
	ETHR_FATAL_ERROR__(res);
}

static ETHR_INLINE void
ETHR_INLINE_FUNC_NAME_(ethr_mutex_unlock)(ethr_mutex *mtx)
{
    int res = pthread_mutex_unlock(&mtx->pt_mtx);
    if (res != 0)
	ETHR_FATAL_ERROR__(res);
}

#endif /* ETHR_TRY_INLINE_FUNCS */

#endif /* pthread_mutex */

#ifdef ETHR_USE_OWN_RWMTX_IMPL__

#define ETHR_RWMTX_DEFAULT_MAIN_SPINCOUNT_MAX 2000
#define ETHR_RWMTX_DEFAULT_MAIN_SPINCOUNT_BASE 800
#define ETHR_RWMTX_DEFAULT_MAIN_SPINCOUNT_INC 50
#define ETHR_RWMTX_DEFAULT_AUX_SPINCOUNT 50

#else /* pthread_rwlock */

#if defined(ETHR_TRY_INLINE_FUNCS) || defined(ETHR_MUTEX_IMPL__)

static ETHR_INLINE int
ETHR_INLINE_FUNC_NAME_(ethr_rwmutex_tryrlock)(ethr_rwmutex *rwmtx)
{
    int res = pthread_rwlock_tryrdlock(&rwmtx->pt_rwlock);
    if (res != 0 && res != EBUSY)
	ETHR_FATAL_ERROR__(res);
    return res;
}

static ETHR_INLINE void
ETHR_INLINE_FUNC_NAME_(ethr_rwmutex_rlock)(ethr_rwmutex *rwmtx)
{
    int res = pthread_rwlock_rdlock(&rwmtx->pt_rwlock);
    if (res != 0)
	ETHR_FATAL_ERROR__(res);
}

static ETHR_INLINE void
ETHR_INLINE_FUNC_NAME_(ethr_rwmutex_runlock)(ethr_rwmutex *rwmtx)
{
    int res = pthread_rwlock_unlock(&rwmtx->pt_rwlock);
    if (res != 0)
	ETHR_FATAL_ERROR__(res);
}

static ETHR_INLINE int
ETHR_INLINE_FUNC_NAME_(ethr_rwmutex_tryrwlock)(ethr_rwmutex *rwmtx)
{
    int res = pthread_rwlock_trywrlock(&rwmtx->pt_rwlock);
    if (res != 0 && res != EBUSY)
	ETHR_FATAL_ERROR__(res);
    return res;
}

static ETHR_INLINE void
ETHR_INLINE_FUNC_NAME_(ethr_rwmutex_rwlock)(ethr_rwmutex *rwmtx)
{
    int res = pthread_rwlock_wrlock(&rwmtx->pt_rwlock);
    if (res != 0)
	ETHR_FATAL_ERROR__(res);
}

static ETHR_INLINE void
ETHR_INLINE_FUNC_NAME_(ethr_rwmutex_rwunlock)(ethr_rwmutex *rwmtx)
{
    int res = pthread_rwlock_unlock(&rwmtx->pt_rwlock);
    if (res != 0)
	ETHR_FATAL_ERROR__(res);
}

#endif /* ETHR_TRY_INLINE_FUNCS */

#endif /* pthread_rwlock */

int ethr_mutex_lib_init(int);
int ethr_mutex_lib_late_init(int, int);

#endif /* #ifndef ETHR_MUTEX_H__ */