Changes between Version 90 and Version 91 of processus_thread

Timestamp:

Mar 2, 2018, 10:06:37 AM (6 years ago)

Author:

alain

Comment:

--

processus_thread

@@ -120 +120 @@
 == __5) Thread destruction__ ==
 
-The destruction of an user thread T can be caused by another thread K, executing  the ''pthread_cancel()'' sys call requesting the target thread T to stop execution. It can be caused by the thread T itself, executing the ''pthread_exit()'' sys call to suicide. Finally, it can be caused by the ''exit()'' or ''kill()'' syscalls requesting the destruction of all threads of a given process.    
+The destruction of a target thread T can be caused by another thread K, executing  the ''pthread_cancel()'' sys call requesting the target thread T to stop execution. It can be caused by the thread T itself, executing the ''pthread_exit()'' sys call to suicide. Finally, it can be caused by the ''exit()'' or ''kill()'' syscalls requesting the destruction of all threads of a given process.    
 
 The unique method to destroy a thread is to call the '''thread_kill()''' function, that set the THREAD_FLAG_REQ_DELETE bit in the ''flags'' field of the target thread descriptor. The thread will be asynchronously deleted by the scheduler at the next scheduling point,
-that calls the ''thread_destroy()'' function. This function detach the thread from the scheduler, detach the thread from the local process descriptor, and releases the memory allocated to the thread descriptor. The '''thread_kill(''') function can be called by the ''target'' thread itself (for an exit), or it can be done by another ''killer'' thread (for a kill).
+that calls the ''thread_destroy()'' function. This function detach the thread from the scheduler, detach the thread from the local process descriptor, and releases the memory allocated to the thread descriptor. The '''thread_kill()''' function can be called by the target thread itself (for an exit), or by another thread (for a kill). 
 
-The main thread (i.e. the thread 0 in the process owner cluster) is a special case, because the main thread of a given process can only be deleted (i.e. marked for delete) by the parent process main thread executing the ''sys_wait()'' syscall (see section [6] below).   
+If the target thread is running in attached mode, the '''thread_kill()''' function synchronize with the joining thread, waiting the actual execution of the pthread_join() syscall before marking the target thread for delete. 
+
+If the target thread is main thread (i.e. the thread 0 in the process owner cluster) the  '''thread_kill()''' does not mark the target thread for delete, because this must be done by the parent process main thread executing the ''sys_wait()'' syscall (see section [6] below).   
 
 === 5.1) thread running in DETACHED mode ===
@@ -150 +152 @@
    * If the FLAG_KILL_DONE is set, the K thread arrived first and is blocked on the BLOCKED_JOIN condition: the J thread unblocks the killer thread, reset the FLAF_KILL_DONE in the T thread, releases the "join_lock" in T thread, and returns. 
    * If the FLAG_KILL_DONE is not set, the J thread arrived first: the J thread register its extended pointer in the T thread "join_xp" field, set the FLAG_JOIN_DONE in the T thread, sets the BLOCKED_EXIT bit in the J thread, releases the "join_lock" in the T thread, and deschedules. It simply returns when it is unblocked by the K thread.
+
+=== 5.3) main thread destruction ===
 
 == __6) Process destruction__ ==