diff options
Diffstat (limited to 'libpthread/nptl/pthread_mutex_lock.c')
| -rw-r--r-- | libpthread/nptl/pthread_mutex_lock.c | 118 | 
1 files changed, 118 insertions, 0 deletions
| diff --git a/libpthread/nptl/pthread_mutex_lock.c b/libpthread/nptl/pthread_mutex_lock.c new file mode 100644 index 000000000..faa5391dd --- /dev/null +++ b/libpthread/nptl/pthread_mutex_lock.c @@ -0,0 +1,118 @@ +/* Copyright (C) 2002, 2003, 2004 Free Software Foundation, Inc. +   This file is part of the GNU C Library. +   Contributed by Ulrich Drepper <drepper@redhat.com>, 2002. + +   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.  */ + +#include <assert.h> +#include <errno.h> +#include "pthreadP.h" +#include <lowlevellock.h> + + +#ifndef LLL_MUTEX_LOCK +# define LLL_MUTEX_LOCK(mutex) lll_mutex_lock (mutex) +# define LLL_MUTEX_TRYLOCK(mutex) lll_mutex_trylock (mutex) +#endif + + +int +__pthread_mutex_lock (pthread_mutex_t *mutex) +{ +  assert (sizeof (mutex->__size) >= sizeof (mutex->__data)); + +  pid_t id = THREAD_GETMEM (THREAD_SELF, tid); + +  switch (__builtin_expect (mutex->__data.__kind, PTHREAD_MUTEX_TIMED_NP)) +    { +      /* Recursive mutex.  */ +    case PTHREAD_MUTEX_RECURSIVE_NP: +      /* Check whether we already hold the mutex.  */ +      if (mutex->__data.__owner == id) +	{ +	  /* Just bump the counter.  */ +	  if (__builtin_expect (mutex->__data.__count + 1 == 0, 0)) +	    /* Overflow of the counter.  */ +	    return EAGAIN; + +	  ++mutex->__data.__count; + +	  return 0; +	} + +      /* We have to get the mutex.  */ +      LLL_MUTEX_LOCK (mutex->__data.__lock); + +      mutex->__data.__count = 1; +      break; + +      /* Error checking mutex.  */ +    case PTHREAD_MUTEX_ERRORCHECK_NP: +      /* Check whether we already hold the mutex.  */ +      if (mutex->__data.__owner == id) +	return EDEADLK; + +      /* FALLTHROUGH */ + +    default: +      /* Correct code cannot set any other type.  */ +    case PTHREAD_MUTEX_TIMED_NP: +    simple: +      /* Normal mutex.  */ +      LLL_MUTEX_LOCK (mutex->__data.__lock); +      break; + +    case PTHREAD_MUTEX_ADAPTIVE_NP: +      if (! __is_smp) +	goto simple; + +      if (LLL_MUTEX_TRYLOCK (mutex->__data.__lock) != 0) +	{ +	  int cnt = 0; +	  int max_cnt = MIN (MAX_ADAPTIVE_COUNT, +			     mutex->__data.__spins * 2 + 10); +	  do +	    { +	      if (cnt++ >= max_cnt) +		{ +		  LLL_MUTEX_LOCK (mutex->__data.__lock); +		  break; +		} + +#ifdef BUSY_WAIT_NOP +	      BUSY_WAIT_NOP; +#endif +	    } +	  while (LLL_MUTEX_TRYLOCK (mutex->__data.__lock) != 0); + +	  mutex->__data.__spins += (cnt - mutex->__data.__spins) / 8; +	} +      break; +    } + +  /* Record the ownership.  */ +  assert (mutex->__data.__owner == 0); +  mutex->__data.__owner = id; +#ifndef NO_INCR +  ++mutex->__data.__nusers; +#endif + +  return 0; +} +#ifndef __pthread_mutex_lock +strong_alias (__pthread_mutex_lock, pthread_mutex_lock) +strong_alias (__pthread_mutex_lock, __pthread_mutex_lock_internal) +#endif | 
