diff options
| -rw-r--r-- | src/mesa/glapi/glapi.c | 75 | ||||
| -rw-r--r-- | src/mesa/glapi/glapi.h | 5 | ||||
| -rw-r--r-- | src/mesa/glapi/glthread.h | 2 |
3 files changed, 41 insertions, 41 deletions
diff --git a/src/mesa/glapi/glapi.c b/src/mesa/glapi/glapi.c index e36fccb354..4bb10df1d8 100644 --- a/src/mesa/glapi/glapi.c +++ b/src/mesa/glapi/glapi.c @@ -160,26 +160,20 @@ static GLint NoOpUnused(void) * the variables \c _glapi_Dispatch and \c _glapi_Context are used for this * purpose. * - * In the "normal" threaded case, the variables \c _glapi_Dispatch and - * \c _glapi_Context will be \c NULL if an application is detected as being - * multithreaded. Single-threaded applications will use \c _glapi_Dispatch - * and \c _glapi_Context just like the case without any threading support. - * When \c _glapi_Dispatch and \c _glapi_Context are \c NULL, the thread state - * data \c _gl_DispatchTSD and \c ContextTSD are used. Drivers and the - * static dispatch functions access these variables via \c _glapi_get_dispatch - * and \c _glapi_get_context. + * In the "normal" threaded case, the variable \c _glapi_SingleThreaded will be + * \c GL_FALSE if an application is detected as being multithreaded. + * Single-threaded applications will use \c _glapi_Dispatch and \c + * _glapi_Context just like the case without any threading support. When \c + * _glapi_SingleThreaded is \c GL_FALSE, the thread state data \c + * _gl_DispatchTSD and \c ContextTSD are used. Drivers and the static dispatch + * functions access these variables via \c _glapi_get_dispatch and \c + * _glapi_get_context. * - * There is a race condition in setting \c _glapi_Dispatch to \c NULL. It is - * possible for the original thread to be setting it at the same instant a new - * thread, perhaps running on a different processor, is clearing it. Because - * of that, \c ThreadSafe, which can only ever be changed to \c GL_TRUE, is - * used to determine whether or not the application is multithreaded. - * * In the TLS case, the variables \c _glapi_Dispatch and \c _glapi_Context are * hardcoded to \c NULL. Instead the TLS variables \c _glapi_tls_Dispatch and - * \c _glapi_tls_Context are used. Having \c _glapi_Dispatch and - * \c _glapi_Context be hardcoded to \c NULL maintains binary compatability - * between TLS enabled loaders and non-TLS DRI drivers. + * \c _glapi_tls_Context are used. The variable \c _glapi_SingleThreaded, + * though not used, is defined and hardcoded to \c GL_FALSE to maintain binary + * compatability between TLS enabled loaders and non-TLS DRI drivers. */ /*@{*/ #if defined(GLX_USE_TLS) @@ -194,6 +188,9 @@ PUBLIC __thread void * _glapi_tls_Context PUBLIC const struct _glapi_table *_glapi_Dispatch = NULL; PUBLIC const void *_glapi_Context = NULL; +/* Unused, but maintain binary compatability with non-TLS DRI drivers */ +GLboolean _glapi_SingleThreaded = GL_FALSE; + #else #if defined(THREADS) @@ -208,9 +205,9 @@ _glthread_DECLARE_STATIC_MUTEX(ThreadCheckMutex); #define CHECK_MULTITHREAD_UNLOCK() _glthread_UNLOCK_MUTEX(ThreadCheckMutex) #endif -static GLboolean ThreadSafe = GL_FALSE; /**< In thread-safe mode? */ -_glthread_TSD _gl_DispatchTSD; /**< Per-thread dispatch pointer */ -static _glthread_TSD ContextTSD; /**< Per-thread context pointer */ +GLboolean _glapi_SingleThreaded = GL_TRUE; /**< In single-thread mode? */ +_glthread_TSD _gl_DispatchTSD; /**< Per-thread dispatch pointer */ +static _glthread_TSD ContextTSD; /**< Per-thread context pointer */ #if defined(WIN32_THREADS) void FreeTSD(_glthread_TSD *p); @@ -244,7 +241,7 @@ _glapi_check_multithread(void) static unsigned long knownID; static GLboolean firstCall = GL_TRUE; - if (ThreadSafe) + if (!_glapi_SingleThreaded) return; CHECK_MULTITHREAD_LOCK(); @@ -257,9 +254,12 @@ _glapi_check_multithread(void) firstCall = GL_FALSE; } else if (knownID != _glthread_GetID()) { - ThreadSafe = GL_TRUE; - _glapi_set_dispatch(NULL); - _glapi_set_context(NULL); + /* + * switch to thread-safe mode. _glapi_Context and _glapi_Dispatch are no + * longer accessed after this point, except for raced by the first + * thread. Because of the race, they cannot be reset to NULL. + */ + _glapi_SingleThreaded = GL_FALSE; } CHECK_MULTITHREAD_UNLOCK(); #endif @@ -279,8 +279,10 @@ _glapi_set_context(void *context) #if defined(GLX_USE_TLS) _glapi_tls_Context = context; #elif defined(THREADS) + if (_glapi_SingleThreaded) + _glapi_Context = context; + /* always update TSD because we might switch to it at any time */ _glthread_SetTSD(&ContextTSD, context); - _glapi_Context = (ThreadSafe) ? NULL : context; #else _glapi_Context = context; #endif @@ -299,12 +301,8 @@ _glapi_get_context(void) #if defined(GLX_USE_TLS) return _glapi_tls_Context; #elif defined(THREADS) - if (ThreadSafe) { - return _glthread_GetTSD(&ContextTSD); - } - else { - return _glapi_Context; - } + return (_glapi_SingleThreaded) + ? _glapi_Context : _glthread_GetTSD(&ContextTSD); #else return _glapi_Context; #endif @@ -519,8 +517,9 @@ _glapi_set_dispatch(struct _glapi_table *dispatch) #if defined(GLX_USE_TLS) _glapi_tls_Dispatch = dispatch; #elif defined(THREADS) + if (_glapi_SingleThreaded) + _glapi_Dispatch = dispatch; _glthread_SetTSD(&_gl_DispatchTSD, (void *) dispatch); - _glapi_Dispatch = (ThreadSafe) ? NULL : dispatch; #else /*THREADS*/ _glapi_Dispatch = dispatch; #endif /*THREADS*/ @@ -534,17 +533,15 @@ _glapi_set_dispatch(struct _glapi_table *dispatch) PUBLIC struct _glapi_table * _glapi_get_dispatch(void) { - struct _glapi_table * api; #if defined(GLX_USE_TLS) - api = _glapi_tls_Dispatch; + return _glapi_tls_Dispatch; #elif defined(THREADS) - api = (ThreadSafe) - ? (struct _glapi_table *) _glthread_GetTSD(&_gl_DispatchTSD) - : _glapi_Dispatch; + return (_glapi_SingleThreaded) + ? _glapi_Dispatch + : (struct _glapi_table *) _glthread_GetTSD(&_gl_DispatchTSD); #else - api = _glapi_Dispatch; + return _glapi_Dispatch; #endif - return api; } diff --git a/src/mesa/glapi/glapi.h b/src/mesa/glapi/glapi.h index 8f2cf66218..b2a1fe6ee9 100644 --- a/src/mesa/glapi/glapi.h +++ b/src/mesa/glapi/glapi.h @@ -94,7 +94,10 @@ extern void *_glapi_Context; extern struct _glapi_table *_glapi_Dispatch; # ifdef THREADS -# define GET_CURRENT_CONTEXT(C) GLcontext *C = (GLcontext *) (_glapi_Context ? _glapi_Context : _glapi_get_context()) +/* this variable is here only for quick access to current context/dispatch */ +extern GLboolean _glapi_SingleThreaded; +# define GET_CURRENT_CONTEXT(C) GLcontext *C = (GLcontext *) \ + ((_glapi_SingleThreaded) ? _glapi_Context : _glapi_get_context()) # else # define GET_CURRENT_CONTEXT(C) GLcontext *C = (GLcontext *) _glapi_Context # endif diff --git a/src/mesa/glapi/glthread.h b/src/mesa/glapi/glthread.h index 8ec933a851..a36bea7176 100644 --- a/src/mesa/glapi/glthread.h +++ b/src/mesa/glapi/glthread.h @@ -322,7 +322,7 @@ extern __thread struct _glapi_table * _glapi_tls_Dispatch #elif !defined(GL_CALL) # if defined(THREADS) # define GET_DISPATCH() \ - ((__builtin_expect( _glapi_Dispatch != NULL, 1 )) \ + ((__builtin_expect(_glapi_SingleThreaded, 1)) \ ? _glapi_Dispatch : _glapi_get_dispatch()) # else # define GET_DISPATCH() _glapi_Dispatch |