Edit File: thread-shared-types.h
/* Common threading primitives definitions for both POSIX and C11. Copyright (C) 2017-2018 Free Software Foundation, Inc. This file is part of the GNU C Library. 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, see <http://www.gnu.org/licenses/>. */ #ifndef _THREAD_SHARED_TYPES_H #define _THREAD_SHARED_TYPES_H 1 /* Arch-specific definitions. Each architecture must define the following macros to define the expected sizes of pthread data types: __SIZEOF_PTHREAD_ATTR_T - size of pthread_attr_t. __SIZEOF_PTHREAD_MUTEX_T - size of pthread_mutex_t. __SIZEOF_PTHREAD_MUTEXATTR_T - size of pthread_mutexattr_t. __SIZEOF_PTHREAD_COND_T - size of pthread_cond_t. __SIZEOF_PTHREAD_CONDATTR_T - size of pthread_condattr_t. __SIZEOF_PTHREAD_RWLOCK_T - size of pthread_rwlock_t. __SIZEOF_PTHREAD_RWLOCKATTR_T - size of pthread_rwlockattr_t. __SIZEOF_PTHREAD_BARRIER_T - size of pthread_barrier_t. __SIZEOF_PTHREAD_BARRIERATTR_T - size of pthread_barrierattr_t. Also, the following macros must be define for internal pthread_mutex_t struct definitions (struct __pthread_mutex_s): __PTHREAD_COMPAT_PADDING_MID - any additional members after 'kind' and before '__spin' (for 64 bits) or '__nusers' (for 32 bits). __PTHREAD_COMPAT_PADDING_END - any additional members at the end of the internal structure. __PTHREAD_MUTEX_LOCK_ELISION - 1 if the architecture supports lock elision or 0 otherwise. __PTHREAD_MUTEX_NUSERS_AFTER_KIND - control where to put __nusers. The preferred value for new architectures is 0. __PTHREAD_MUTEX_USE_UNION - control whether internal __spins and __list will be place inside a union for linuxthreads compatibility. The preferred value for new architectures is 0. For a new port the preferred values for the required defines are: #define __PTHREAD_COMPAT_PADDING_MID #define __PTHREAD_COMPAT_PADDING_END #define __PTHREAD_MUTEX_LOCK_ELISION 0 #define __PTHREAD_MUTEX_NUSERS_AFTER_KIND 0 #define __PTHREAD_MUTEX_USE_UNION 0 __PTHREAD_MUTEX_LOCK_ELISION can be set to 1 if the hardware plans to eventually support lock elision using transactional memory. The additional macro defines any constraint for the lock alignment inside the thread structures: __LOCK_ALIGNMENT - for internal lock/futex usage. Same idea but for the once locking primitive: __ONCE_ALIGNMENT - for pthread_once_t/once_flag definition. And finally the internal pthread_rwlock_t (struct __pthread_rwlock_arch_t) must be defined. */ #include <bits/pthreadtypes-arch.h> /* Common definition of pthread_mutex_t. */ #if !__PTHREAD_MUTEX_USE_UNION typedef struct __pthread_internal_list { struct __pthread_internal_list *__prev; struct __pthread_internal_list *__next; } __pthread_list_t; #else typedef struct __pthread_internal_slist { struct __pthread_internal_slist *__next; } __pthread_slist_t; #endif /* Lock elision support. */ #if __PTHREAD_MUTEX_LOCK_ELISION # if !__PTHREAD_MUTEX_USE_UNION # define __PTHREAD_SPINS_DATA \ short __spins; \ short __elision # define __PTHREAD_SPINS 0, 0 # else # define __PTHREAD_SPINS_DATA \ struct \ { \ short __espins; \ short __eelision; \ } __elision_data # define __PTHREAD_SPINS { 0, 0 } # define __spins __elision_data.__espins # define __elision __elision_data.__eelision # endif #else # define __PTHREAD_SPINS_DATA int __spins /* Mutex __spins initializer used by PTHREAD_MUTEX_INITIALIZER. */ # define __PTHREAD_SPINS 0 #endif struct __pthread_mutex_s { int __lock __LOCK_ALIGNMENT; unsigned int __count; int __owner; #if !__PTHREAD_MUTEX_NUSERS_AFTER_KIND unsigned int __nusers; #endif /* KIND must stay at this position in the structure to maintain binary compatibility with static initializers. Concurrency notes: The __kind of a mutex is initialized either by the static PTHREAD_MUTEX_INITIALIZER or by a call to pthread_mutex_init. After a mutex has been initialized, the __kind of a mutex is usually not changed. BUT it can be set to -1 in pthread_mutex_destroy or elision can be enabled. This is done concurrently in the pthread_mutex_*lock functions by using the macro FORCE_ELISION. This macro is only defined for architectures which supports lock elision. For elision, there are the flags PTHREAD_MUTEX_ELISION_NP and PTHREAD_MUTEX_NO_ELISION_NP which can be set in addition to the already set type of a mutex. Before a mutex is initialized, only PTHREAD_MUTEX_NO_ELISION_NP can be set with pthread_mutexattr_settype. After a mutex has been initialized, the functions pthread_mutex_*lock can enable elision - if the mutex-type and the machine supports it - by setting the flag PTHREAD_MUTEX_ELISION_NP. This is done concurrently. Afterwards the lock / unlock functions are using specific elision code-paths. */ int __kind; __PTHREAD_COMPAT_PADDING_MID #if __PTHREAD_MUTEX_NUSERS_AFTER_KIND unsigned int __nusers; #endif #if !__PTHREAD_MUTEX_USE_UNION __PTHREAD_SPINS_DATA; __pthread_list_t __list; # define __PTHREAD_MUTEX_HAVE_PREV 1 #else __extension__ union { __PTHREAD_SPINS_DATA; __pthread_slist_t __list; }; # define __PTHREAD_MUTEX_HAVE_PREV 0 #endif __PTHREAD_COMPAT_PADDING_END }; /* Common definition of pthread_cond_t. */ struct __pthread_cond_s { __extension__ union { __extension__ unsigned long long int __wseq; struct { unsigned int __low; unsigned int __high; } __wseq32; }; __extension__ union { __extension__ unsigned long long int __g1_start; struct { unsigned int __low; unsigned int __high; } __g1_start32; }; unsigned int __glibc_unused___g_refs[2] __LOCK_ALIGNMENT; unsigned int __g_size[2]; unsigned int __g1_orig_size; unsigned int __wrefs; unsigned int __g_signals[2]; }; #endif /* _THREAD_SHARED_TYPES_H */
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