WebSVN – HelenOS – Diff – /trunk/kernel/generic/src/proc/thread.c

 #include <mm/slab.h>
 #include <debug.h>
 #include <main/uinit.h>
 #include <syscall/copy.h>
 #include <errno.h>
+#include <console/klog.h>
 /** Thread states */
 char *thread_states[] = {
     "Invalid",
     "Running",
     "Sleeping",
     "Ready",
     "Entering",
     "Exiting",
-    "Undead"
+    "JoinMe"
 };
 /** Lock protecting the threads_btree B+tree.
+ *
  * For locking rules, see declaration thereof.
     t->in_copy_from_uspace = false;
     t->in_copy_to_uspace = false;
     t->interrupted = false;
-    t->join_type = None;
     t->detached = false;
     waitq_initialize(&t->join_wq);
     t->rwlock_holder_type = RWLOCK_NONE;
     t->fpu_context_engaged = 0;
     /* might depend on previous initialization */
     thread_create_arch(t);
-    ipl = interrupts_disable();
-    spinlock_lock(&task->lock);
-    if (!task->accept_new_threads) {
-        spinlock_unlock(&task->lock);
-        slab_free(thread_slab, t);
-        interrupts_restore(ipl);
-        return NULL;
-    } else {
-        /*
-         * Bump the reference count so that this task cannot be
-         * destroyed while the new thread is being attached to it.
-         */
-        task->refcount++;
-    }
-    spinlock_unlock(&task->lock);
-    interrupts_restore(ipl);
     if (!(flags & THREAD_FLAG_NOATTACH))
         thread_attach(t, task);
     return t;
+}
+ *
  * Assume thread->lock is held!!
  */
 void thread_destroy(thread_t *t)
+{
-    bool destroy_task = false;
-    ASSERT(t->state == Exiting || t->state == Undead);
+    ASSERT(t->state == Exiting || t->state == JoinMe);
     ASSERT(t->task);
     ASSERT(t->cpu);
     spinlock_lock(&t->cpu->lock);
     if (t->cpu->fpu_owner == t)
     /*
      * Detach from the containing task.
      */
     spinlock_lock(&t->task->lock);
     list_remove(&t->th_link);
-    if (--t->task->refcount == 0) {
-        t->task->accept_new_threads = false;
-        destroy_task = true;
-    }
     spinlock_unlock(&t->task->lock);
+    /*
+     * t is guaranteed to be the very last thread of its task.
-    if (destroy_task)
+     * It is safe to destroy the task.
+     */
+    if (atomic_predec(&t->task->refcount) == 0)
         task_destroy(t->task);
     /*
      * If the thread had a userspace context, free up its kernel_uarg
      * structure.
     ipl_t ipl;
     /*
      * Attach to the current task.
      */
     ipl = interrupts_disable();
     spinlock_lock(&task->lock);
-    ASSERT(task->refcount);
+    atomic_inc(&task->refcount);
+    atomic_inc(&task->lifecount);
     list_append(&t->th_link, &task->th_head);
-    if (task->refcount == 1)
-        task->main_thread = t;
     spinlock_unlock(&task->lock);
     /*
      * Register this thread in the system-wide list.
      */
  */
 void thread_exit(void)
+{
     ipl_t ipl;
+    if (atomic_predec(&TASK->lifecount) == 0) {
+        /*
+         * We are the last thread in the task that still has not exited.
+         * With the exception of the moment the task was created, new
+         * threads can only be created by threads of the same task.
+         * We are safe to perform cleanup.
+         */
+        if (THREAD->flags & THREAD_FLAG_USPACE) {
+            ipc_cleanup();
+                futex_cleanup();
+            klog_printf("Cleanup of task %llu completed.",
+                TASK->taskid);
+        }
+    }
 restart:
     ipl = interrupts_disable();
     spinlock_lock(&THREAD->lock);
     if (THREAD->timeout_pending) {
         /* busy waiting for timeouts in progress */
         spinlock_unlock(&THREAD->lock);
         interrupts_restore(ipl);
         goto restart;
+    }
     THREAD->state = Exiting;
     spinlock_unlock(&THREAD->lock);
     scheduler();
     /* Not reached */
     return rc;
+}
 /** Detach thread.
+ *
- * Mark the thread as detached, if the thread is already in the Undead state,
+ * Mark the thread as detached, if the thread is already in the JoinMe state,
  * deallocate its resources.
+ *
  * @param t Thread to be detached.
  */
 void thread_detach(thread_t *t)
      * pointer to it must be still valid.
      */
     ipl = interrupts_disable();
     spinlock_lock(&t->lock);
     ASSERT(!t->detached);
-    if (t->state == Undead) {
+    if (t->state == JoinMe) {
         thread_destroy(t);  /* unlocks &t->lock */
         interrupts_restore(ipl);
         return;
     } else {
         t->detached = true;
             int rc;
             rc = copy_to_uspace(uspace_thread_id, &t->tid,
                 sizeof(t->tid));
             if (rc != 0) {
-                ipl_t ipl;
                 /*
                  * We have encountered a failure, but the thread
                  * has already been created. We need to undo its
                  * creation now.
                  */
                 /*
-                 * The new thread structure is initialized,
+                 * The new thread structure is initialized, but
-                 * but is still not visible to the system.
+                 * is still not visible to the system.
                  * We can safely deallocate it.
                  */
                 slab_free(thread_slab, t);
                 free(kernel_uarg);
-                /*
-                 * Now we need to decrement the task reference
-                 * counter. Because we are running within the
-                 * same task, thread t is not the last thread
-                 * in the task, so it is safe to merely
-                 * decrement the counter.
-                 */
-                ipl = interrupts_disable();
-                spinlock_lock(&TASK->lock);
-                TASK->refcount--;
-                spinlock_unlock(&TASK->lock);
-                interrupts_restore(ipl);
                 return (unative_t) rc;
+             }
+        }
         thread_attach(t, TASK);
         thread_ready(t);

Subversion Repositories HelenOS

(root)/trunk/kernel/generic/src/proc/thread.c – Rev 2440 → 2446