glibc/malloc/thread-m.h

299 lines
8.6 KiB
C++

/* Basic platform-independent macro definitions for mutexes and
thread-specific data.
Copyright (C) 1996,1997,1998,2000,2001,2002 Free Software Foundation, Inc.
This file is part of the GNU C Library.
Contributed by Wolfram Gloger <wg@malloc.de>, 2001.
The GNU C Library is free software; you can redistribute it and/or
modify it under the terms of the GNU Lesser General Public
License as published by the Free Software Foundation; either
version 2.1 of the License, or (at your option) any later version.
The GNU C Library is distributed in the hope that it will be useful,
but WITHOUT ANY WARRANTY; without even the implied warranty of
MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
Lesser General Public License for more details.
You should have received a copy of the GNU Lesser General Public
License along with the GNU C Library; if not, write to the Free
Software Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA
02111-1307 USA. */
/* $Id$
One out of _LIBC, USE_PTHREADS, USE_THR or USE_SPROC should be
defined, otherwise the token NO_THREADS and dummy implementations
of the macros will be defined. */
#ifndef _THREAD_M_H
#define _THREAD_M_H
#undef thread_atfork_static
#if defined(_LIBC) /* The GNU C library, a special case of Posix threads */
#include <bits/libc-lock.h>
#ifdef PTHREAD_MUTEX_INITIALIZER
typedef pthread_t thread_id;
/* mutex */
typedef pthread_mutex_t mutex_t;
#define MUTEX_INITIALIZER PTHREAD_MUTEX_INITIALIZER
/* Even if not linking with libpthread, ensure usability of mutex as
an `in use' flag, see also the NO_THREADS case below. Assume
pthread_mutex_t is at least one int wide. */
#define mutex_init(m) \
(__pthread_mutex_init != NULL \
? __pthread_mutex_init (m, NULL) : (*(int *)(m) = 0))
#define mutex_lock(m) \
(__pthread_mutex_lock != NULL \
? __pthread_mutex_lock (m) : ((*(int *)(m) = 1), 0))
#define mutex_trylock(m) \
(__pthread_mutex_trylock != NULL \
? __pthread_mutex_trylock (m) : (*(int *)(m) ? 1 : ((*(int *)(m) = 1), 0)))
#define mutex_unlock(m) \
(__pthread_mutex_unlock != NULL \
? __pthread_mutex_unlock (m) : (*(int*)(m) = 0))
#define thread_atfork(prepare, parent, child) \
(__pthread_atfork != NULL ? __pthread_atfork(prepare, parent, child) : 0)
#elif defined(MUTEX_INITIALIZER)
/* Assume hurd, with cthreads */
/* Cthreads `mutex_t' is a pointer to a mutex, and malloc wants just the
mutex itself. */
#undef mutex_t
#define mutex_t struct mutex
#undef mutex_init
#define mutex_init(m) (__mutex_init(m), 0)
#undef mutex_lock
#define mutex_lock(m) (__mutex_lock(m), 0)
#undef mutex_unlock
#define mutex_unlock(m) (__mutex_unlock(m), 0)
#define mutex_trylock(m) (!__mutex_trylock(m))
#define thread_atfork(prepare, parent, child) do {} while(0)
#define thread_atfork_static(prepare, parent, child) \
text_set_element(_hurd_fork_prepare_hook, prepare); \
text_set_element(_hurd_fork_parent_hook, parent); \
text_set_element(_hurd_fork_child_hook, child);
/* No we're *not* using pthreads. */
#define __pthread_initialize ((void (*)(void))0)
#else
#define NO_THREADS
#endif /* MUTEX_INITIALIZER && PTHREAD_MUTEX_INITIALIZER */
#ifndef NO_THREADS
/* thread specific data for glibc */
#include <bits/libc-tsd.h>
typedef int tsd_key_t[1]; /* no key data structure, libc magic does it */
__libc_tsd_define (static, MALLOC) /* declaration/common definition */
#define tsd_key_create(key, destr) ((void) (key))
#define tsd_setspecific(key, data) __libc_tsd_set (MALLOC, (data))
#define tsd_getspecific(key, vptr) ((vptr) = __libc_tsd_get (MALLOC))
#endif
#elif defined(USE_PTHREADS) /* Posix threads */
#include <pthread.h>
typedef pthread_t thread_id;
/* mutex */
#if (defined __i386__ || defined __x86_64__) && defined __GNUC__ && \
!defined USE_NO_SPINLOCKS
#include <time.h>
/* Use fast inline spinlocks. */
typedef struct {
volatile unsigned int lock;
int pad0_;
} mutex_t;
#define MUTEX_INITIALIZER { 0 }
#define mutex_init(m) ((m)->lock = 0)
static inline int mutex_lock(mutex_t *m) {
int cnt = 0, r;
struct timespec tm;
for(;;) {
__asm__ __volatile__
("xchgl %0, %1"
: "=r"(r), "=m"(m->lock)
: "0"(1), "m"(m->lock)
: "memory");
if(!r)
return 0;
if(cnt < 50) {
sched_yield();
cnt++;
} else {
tm.tv_sec = 0;
tm.tv_nsec = 2000001;
nanosleep(&tm, NULL);
cnt = 0;
}
}
}
static inline int mutex_trylock(mutex_t *m) {
int r;
__asm__ __volatile__
("xchgl %0, %1"
: "=r"(r), "=m"(m->lock)
: "0"(1), "m"(m->lock)
: "memory");
return r;
}
static inline int mutex_unlock(mutex_t *m) {
m->lock = 0;
__asm __volatile ("" : "=m" (m->lock) : "0" (m->lock));
return 0;
}
#else
/* Normal pthread mutex. */
typedef pthread_mutex_t mutex_t;
#define MUTEX_INITIALIZER PTHREAD_MUTEX_INITIALIZER
#define mutex_init(m) pthread_mutex_init(m, NULL)
#define mutex_lock(m) pthread_mutex_lock(m)
#define mutex_trylock(m) pthread_mutex_trylock(m)
#define mutex_unlock(m) pthread_mutex_unlock(m)
#endif /* (__i386__ || __x86_64__) && __GNUC__ && !USE_NO_SPINLOCKS */
/* thread specific data */
#if defined(__sgi) || defined(USE_TSD_DATA_HACK)
/* Hack for thread-specific data, e.g. on Irix 6.x. We can't use
pthread_setspecific because that function calls malloc() itself.
The hack only works when pthread_t can be converted to an integral
type. */
typedef void *tsd_key_t[256];
#define tsd_key_create(key, destr) do { \
int i; \
for(i=0; i<256; i++) (*key)[i] = 0; \
} while(0)
#define tsd_setspecific(key, data) \
(key[(unsigned)pthread_self() % 256] = (data))
#define tsd_getspecific(key, vptr) \
(vptr = key[(unsigned)pthread_self() % 256])
#else
typedef pthread_key_t tsd_key_t;
#define tsd_key_create(key, destr) pthread_key_create(key, destr)
#define tsd_setspecific(key, data) pthread_setspecific(key, data)
#define tsd_getspecific(key, vptr) (vptr = pthread_getspecific(key))
#endif
/* at fork */
#define thread_atfork(prepare, parent, child) \
pthread_atfork(prepare, parent, child)
#elif USE_THR /* Solaris threads */
#include <thread.h>
typedef thread_t thread_id;
#define MUTEX_INITIALIZER { 0 }
#define mutex_init(m) mutex_init(m, USYNC_THREAD, NULL)
/*
* Hack for thread-specific data on Solaris. We can't use thr_setspecific
* because that function calls malloc() itself.
*/
typedef void *tsd_key_t[256];
#define tsd_key_create(key, destr) do { \
int i; \
for(i=0; i<256; i++) (*key)[i] = 0; \
} while(0)
#define tsd_setspecific(key, data) (key[(unsigned)thr_self() % 256] = (data))
#define tsd_getspecific(key, vptr) (vptr = key[(unsigned)thr_self() % 256])
#define thread_atfork(prepare, parent, child) do {} while(0)
#elif USE_SPROC /* SGI sproc() threads */
#include <sys/wait.h>
#include <sys/types.h>
#include <sys/prctl.h>
#include <abi_mutex.h>
typedef int thread_id;
typedef abilock_t mutex_t;
#define MUTEX_INITIALIZER { 0 }
#define mutex_init(m) init_lock(m)
#define mutex_lock(m) (spin_lock(m), 0)
#define mutex_trylock(m) acquire_lock(m)
#define mutex_unlock(m) release_lock(m)
typedef int tsd_key_t;
int tsd_key_next;
#define tsd_key_create(key, destr) ((*key) = tsd_key_next++)
#define tsd_setspecific(key, data) (((void **)(&PRDA->usr_prda))[key] = data)
#define tsd_getspecific(key, vptr) (vptr = ((void **)(&PRDA->usr_prda))[key])
#define thread_atfork(prepare, parent, child) do {} while(0)
#else /* no _LIBC or USE_... are defined */
#define NO_THREADS
#endif /* defined(_LIBC) */
#ifdef NO_THREADS /* No threads, provide dummy macros */
typedef int thread_id;
/* The mutex functions used to do absolutely nothing, i.e. lock,
trylock and unlock would always just return 0. However, even
without any concurrently active threads, a mutex can be used
legitimately as an `in use' flag. To make the code that is
protected by a mutex async-signal safe, these macros would have to
be based on atomic test-and-set operations, for example. */
typedef int mutex_t;
#define MUTEX_INITIALIZER 0
#define mutex_init(m) (*(m) = 0)
#define mutex_lock(m) ((*(m) = 1), 0)
#define mutex_trylock(m) (*(m) ? 1 : ((*(m) = 1), 0))
#define mutex_unlock(m) (*(m) = 0)
typedef void *tsd_key_t;
#define tsd_key_create(key, destr) do {} while(0)
#define tsd_setspecific(key, data) ((key) = (data))
#define tsd_getspecific(key, vptr) (vptr = (key))
#define thread_atfork(prepare, parent, child) do {} while(0)
#endif /* defined(NO_THREADS) */
#endif /* !defined(_THREAD_M_H) */