diff options
Diffstat (limited to 'pthread/pt-internal.h')
| -rw-r--r-- | pthread/pt-internal.h | 36 |
1 files changed, 22 insertions, 14 deletions
diff --git a/pthread/pt-internal.h b/pthread/pt-internal.h index aeac009..9e0bbe9 100644 --- a/pthread/pt-internal.h +++ b/pthread/pt-internal.h @@ -72,6 +72,12 @@ struct __pthread /* Thread ID. */ pthread_t thread; + __atomic_t nr_refs; /* Detached threads have a self reference only, + while joinable threads have two references. + These are used to keep the structure valid at + thread destruction. Detaching/joining a thread + drops a reference. */ + /* Cancellation. */ pthread_mutex_t cancel_lock; /* Protect cancel_xxx members. */ void (*cancel_hook)(void *); /* Called to unblock a thread blocking @@ -208,12 +214,13 @@ extern int __pthread_create_internal (struct __pthread **__restrict pthread, void *__restrict arg); /* Allocate a new thread structure and a pthread thread ID (but not a - kernel thread or a stack). */ + kernel thread or a stack). THREAD has one reference. */ extern int __pthread_alloc (struct __pthread **thread); /* Deallocate the thread structure. This is the dual of - __pthread_alloc (N.B. it does not call __pthread_stack_alloc nor - __pthread_thread_halt). */ + __pthread_alloc (N.B. it does not call __pthread_stack_dealloc nor + __pthread_thread_terminate). THREAD loses one reference and is + released if the reference counter drops to 0. */ extern void __pthread_dealloc (struct __pthread *thread); @@ -238,22 +245,23 @@ extern int __pthread_setup (struct __pthread *__restrict thread, resources) for THREAD; it must not be placed on the run queue. */ extern int __pthread_thread_alloc (struct __pthread *thread); -/* Deallocate any kernel resources associated with THREAD. The thread - must not be running (that is, if __pthread_thread_start was called, - __pthread_thread_halt must first be called). This function will - never be called by a thread on itself. In the case that a thread - exits, its thread structure will be cached and cleaned up - later. */ +/* Deallocate any kernel resources associated with THREAD. */ extern void __pthread_thread_dealloc (struct __pthread *thread); /* Start THREAD making it eligible to run. */ extern int __pthread_thread_start (struct __pthread *thread); -/* Stop the kernel thread associated with THREAD. This function may - be called by two threads in parallel. In particular, by the thread - itself and another thread trying to join it. This function must be - implemented such that this is safe. */ -extern void __pthread_thread_halt (struct __pthread *thread); +/* Terminate the kernel thread associated with THREAD, and deallocate its + stack. In addition, THREAD loses one reference. + + This function can be called by any thread, including the target thread. + Since some resources that are destroyed along the kernel thread are + stored in thread-local variables, the conditions required for this + function to behave correctly are a bit unusual : as long as the target + thread hasn't been started, any thread can terminate it, but once it + has started, no other thread can terminate it, so that thread-local + variables created by that thread are correctly released. */ +extern void __pthread_thread_terminate (struct __pthread *thread); /* Called by a thread just before it calls the provided start |