Re: Re-use of user-defined stacks for threads

[Wolfram Gloger <wmglo at dent dot med dot uni-muenchen dot de>]

Hello,

> Probably the joining thread should deallocate the stack somehow.
> Don't know yet what the solution should be.

OK, how about the appended patch instead?  I've only verified
it passes make check so far, but will investigate further.

Regards,
Wolfram.

2000-12-02  Wolfram Gloger  <wg@malloc.de>

	* manager.c (__pthread_handle_free): New function.

	* internals.h: Declare __pthread_handle_free.

	* join.c (pthread_join): Reclaim thread resources immediately in
	the context of the joining thread rather than via the manager.

--- internals.h	2000/12/03 10:42:39	1.1
+++ internals.h	2000/12/03 11:36:27
@@ -468,6 +468,9 @@
 
 void __pthread_wait_for_restart_signal(pthread_descr self);
 
+/* Assumes handle->h_lock is already locked.  */
+void __pthread_handle_free(pthread_handle handle);
+
 int __pthread_yield (void);
 
 /* Global pointers to old or new suspend functions */
--- join.c	2000/12/03 10:37:10	1.1
+++ join.c	2000/12/03 11:52:02
@@ -106,7 +106,6 @@
 int pthread_join(pthread_t thread_id, void ** thread_return)
 {
   volatile pthread_descr self = thread_self();
-  struct pthread_request request;
   pthread_handle handle = thread_handle(thread_id);
   pthread_descr th;
   pthread_extricate_if extr;
@@ -161,15 +160,9 @@
   }
   /* Get return value */
   if (thread_return != NULL) *thread_return = th->p_retval;
-  __pthread_unlock(&handle->h_lock);
-  /* Send notification to thread manager */
-  if (__pthread_manager_request >= 0) {
-    request.req_thread = self;
-    request.req_kind = REQ_FREE;
-    request.req_args.free.thread_id = thread_id;
-    __libc_write(__pthread_manager_request,
-		 (char *) &request, sizeof(request));
-  }
+  /* Reclaim resources immediately; if the user supplied a stack, it
+     must be reusable as soon as pthread_join() returns.  */
+  __pthread_handle_free(handle);
   return 0;
 }
 
--- manager.c	2000/12/03 10:36:33	1.1
+++ manager.c	2000/12/03 11:56:47
@@ -791,7 +791,6 @@
 static void pthread_handle_free(pthread_t th_id)
 {
   pthread_handle handle = thread_handle(th_id);
-  pthread_descr th;
 
   __pthread_lock(&handle->h_lock, NULL);
   if (nonexisting_handle(handle, th_id)) {
@@ -800,7 +799,15 @@
     __pthread_unlock(&handle->h_lock);
     return;
   }
-  th = handle->h_descr;
+  __pthread_handle_free(handle);
+}
+
+/* Assumes handle->h_lock is already locked.  */
+
+void __pthread_handle_free(pthread_handle handle)
+{
+  pthread_descr th = handle->h_descr;
+
   if (th->p_exited) {
     __pthread_unlock(&handle->h_lock);
     pthread_free(th);