diff options
Diffstat (limited to 'sysdeps/nptl/bits')
| -rw-r--r-- | sysdeps/nptl/bits/struct_mutex.h | 84 | ||||
| -rw-r--r-- | sysdeps/nptl/bits/thread-shared-types.h | 129 |
2 files changed, 104 insertions, 109 deletions
diff --git a/sysdeps/nptl/bits/struct_mutex.h b/sysdeps/nptl/bits/struct_mutex.h new file mode 100644 index 0000000000..138320b0f3 --- /dev/null +++ b/sysdeps/nptl/bits/struct_mutex.h @@ -0,0 +1,84 @@ +/* Default mutex implementation struct definitions. + Copyright (C) 2019 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_MUTEX_INTERNAL_H +#define _THREAD_MUTEX_INTERNAL_H 1 + +/* Generic struct for both POSIX and C11 mutexes. New ports are expected + to use the default layout, however architecture can redefine it to + add arch-specific extension (such as lock-elision). The struct have + a size of 32 bytes on LP32 and 40 bytes on LP64 architectures. */ + +struct __pthread_mutex_s +{ + int __lock __LOCK_ALIGNMENT; + unsigned int __count; + int __owner; +#if __WORDSIZE == 64 + 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; +#if __WORDSIZE != 64 + unsigned int __nusers; +#endif +#if __WORDSIZE == 64 + int __spins; + __pthread_list_t __list; +# define __PTHREAD_MUTEX_HAVE_PREV 1 +#else + __extension__ union + { + int __spins; + __pthread_slist_t __list; + }; +# define __PTHREAD_MUTEX_HAVE_PREV 0 +#endif +}; + +#if __PTHREAD_MUTEX_HAVE_PREV == 1 +# define __PTHREAD_MUTEX_INITIALIZER(__kind) \ + 0, 0, 0, 0, __kind, 0, { 0, 0 } +#else +# define __PTHREAD_MUTEX_INITIALIZER(__kind) \ + 0, 0, 0, 0, __kind, { 0 } +#endif + +#endif diff --git a/sysdeps/nptl/bits/thread-shared-types.h b/sysdeps/nptl/bits/thread-shared-types.h index f7eb8d4c5d..0727fdec96 100644 --- a/sysdeps/nptl/bits/thread-shared-types.h +++ b/sysdeps/nptl/bits/thread-shared-types.h @@ -32,36 +32,6 @@ __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: @@ -72,98 +42,39 @@ __ONCE_ALIGNMENT - for pthread_once_t/once_flag definition. And finally the internal pthread_rwlock_t (struct __pthread_rwlock_arch_t) - must be defined. - */ + 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 -}; + +/* Arch-specific mutex definitions. A generic implementation is provided + by sysdeps/nptl/bits/struct_mutex.h. If required, an architecture + can override it by defining: + + 1. struct __pthread_mutex_s (used on both pthread_mutex_t and mtx_t + definition). It should contains at least the internal members + defined in the generic version. + + 2. __LOCK_ALIGNMENT for any extra attribute for internal lock used with + atomic operations. + + 3. The macro __PTHREAD_MUTEX_INITIALIZER used for static initialization. + It should initialize the mutex internal flag. */ + +#include <bits/struct_mutex.h> /* Common definition of pthread_cond_t. */ |