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

 #include <print.h>
 #include <lib/elf.h>
 #include <errno.h>
 #include <func.h>
 #include <syscall/copy.h>
-#include <console/klog.h>
 #ifndef LOADED_PROG_STACK_PAGES_NO
 #define LOADED_PROG_STACK_PAGES_NO 1
 #endif
  */
 btree_t tasks_btree;
 static task_id_t task_counter = 0;
-static void ktaskclnp(void *arg);
-static void ktaskgc(void *arg);
 /** Initialize tasks
+ *
  * Initialize kernel tasks support.
+ *
  */
     spinlock_initialize(&ta->lock, "task_ta_lock");
     list_initialize(&ta->th_head);
     ta->as = as;
     ta->name = name;
-    ta->main_thread = NULL;
+    atomic_set(&ta->refcount, 0);
-    ta->refcount = 0;
+    atomic_set(&ta->lifecount, 0);
     ta->context = CONTEXT;
     ta->capabilities = 0;
-    ta->accept_new_threads = true;
     ta->cycles = 0;
     ipc_answerbox_init(&ta->answerbox);
     for (i = 0; i < IPC_MAX_PHONES; i++)
         ipc_phone_init(&ta->phones[i]);
      * Increment address space reference count.
      */
     atomic_inc(&as->refcount);
     spinlock_lock(&tasks_lock);
     ta->taskid = ++task_counter;
     btree_insert(&tasks_btree, (btree_key_t) ta->taskid, (void *) ta, NULL);
     spinlock_unlock(&tasks_lock);
     interrupts_restore(ipl);
     return ta;
+}
+ *
  * @param t Task to be destroyed.
  */
 void task_destroy(task_t *t)
+{
+    /*
+     * Remove the task from the task B+tree.
+     */
+    spinlock_lock(&tasks_lock);
+    btree_remove(&tasks_btree, t->taskid, NULL);
+    spinlock_unlock(&tasks_lock);
+    /*
+     * Perform architecture specific task destruction.
+     */
     task_destroy_arch(t);
+    /*
+     * Free up dynamically allocated state.
+     */
     btree_destroy(&t->futexes);
+    /*
+     * Drop our reference to the address space.
+     */
     if (atomic_predec(&t->as->refcount) == 0)
         as_destroy(t->as);
     free(t);
     TASK = NULL;
 task_t *task_run_program(void *program_addr, char *name)
+{
     as_t *as;
     as_area_t *a;
     int rc;
-    thread_t *t1, *t2;
+    thread_t *t;
     task_t *task;
     uspace_arg_t *kernel_uarg;
     as = as_create(0);
     ASSERT(as);
         AS_AREA_ATTR_NONE, &anon_backend, NULL);
     /*
      * Create the main thread.
      */
-    t1 = thread_create(uinit, kernel_uarg, task, THREAD_FLAG_USPACE,
+    t = thread_create(uinit, kernel_uarg, task, THREAD_FLAG_USPACE,
         "uinit", false);
-    ASSERT(t1);
+    ASSERT(t);
-    /*
-     * Create killer thread for the new task.
-     */
-    t2 = thread_create(ktaskgc, t1, task, 0, "ktaskgc", true);
-    ASSERT(t2);
-    thread_ready(t2);
+    thread_ready(t);
-    thread_ready(t1);
     return task;
+}
 /** Syscall for reading task ID from userspace.
     return ret;
+}
 /** Kill task.
+ *
+ * This function is idempotent.
+ * It signals all the task's threads to bail it out.
+ *
  * @param id ID of the task to be killed.
+ *
  * @return 0 on success or an error code from errno.h
  */
 int task_kill(task_id_t id)
+{
     ipl_t ipl;
     task_t *ta;
-    thread_t *t;
     link_t *cur;
     if (id == 1)
         return EPERM;
     ipl = interrupts_disable();
     spinlock_lock(&tasks_lock);
     if (!(ta = task_find_by_id(id))) {
         spinlock_unlock(&tasks_lock);
         interrupts_restore(ipl);
         return ENOENT;
+    }
-    spinlock_lock(&ta->lock);
-    ta->refcount++;
-    spinlock_unlock(&ta->lock);
-    btree_remove(&tasks_btree, ta->taskid, NULL);
     spinlock_unlock(&tasks_lock);
-    t = thread_create(ktaskclnp, NULL, ta, 0, "ktaskclnp", true);
-    spinlock_lock(&ta->lock);
-    ta->accept_new_threads = false;
-    ta->refcount--;
     /*
      * Interrupt all threads except ktaskclnp.
      */
+    spinlock_lock(&ta->lock);
     for (cur = ta->th_head.next; cur != &ta->th_head; cur = cur->next) {
         thread_t *thr;
-        bool  sleeping = false;
+        bool sleeping = false;
         thr = list_get_instance(cur, thread_t, th_link);
-        if (thr == t)
-            continue;
         spinlock_lock(&thr->lock);
         thr->interrupted = true;
         if (thr->state == Sleeping)
             sleeping = true;
         spinlock_unlock(&thr->lock);
         if (sleeping)
             waitq_interrupt_sleep(thr);
+    }
     spinlock_unlock(&ta->lock);
     interrupts_restore(ipl);
-    if (t)
-        thread_ready(t);
     return 0;
+}
 /** Print task list */
 void task_print_list(void)
     ipl = interrupts_disable();
     spinlock_lock(&tasks_lock);
     printf("taskid name       ctx address    as         cycles     threads "
         "calls  callee\n");
-    printf("------ ---------- --- ---------- ---------- ---------- ------- "        "------ ------>\n");
+    printf("------ ---------- --- ---------- ---------- ---------- ------- "
+        "------ ------>\n");
     for (cur = tasks_btree.leaf_head.next; cur != &tasks_btree.leaf_head;
         cur = cur->next) {
         btree_node_t *node;
         unsigned int i;
     spinlock_unlock(&tasks_lock);
     interrupts_restore(ipl);
+}
-/** Kernel thread used to cleanup the task after it is killed. */
-void ktaskclnp(void *arg)
-{
-    ipl_t ipl;
-    thread_t *t = NULL, *main_thread;
-    link_t *cur;
-    bool again;
-    thread_detach(THREAD);
-loop:
-    ipl = interrupts_disable();
-    spinlock_lock(&TASK->lock);
-    main_thread = TASK->main_thread;
-    /*
-     * Find a thread to join.
-     */
-    again = false;
-    for (cur = TASK->th_head.next; cur != &TASK->th_head; cur = cur->next) {
-        t = list_get_instance(cur, thread_t, th_link);
-        spinlock_lock(&t->lock);
-        if (t == THREAD) {
-            spinlock_unlock(&t->lock);
-            continue;
-        } else if (t == main_thread) {
-            spinlock_unlock(&t->lock);
-            continue;
-        } else if (t->join_type != None) {
-            spinlock_unlock(&t->lock);
-            again = true;
-            continue;
-        } else {
-            t->join_type = TaskClnp;
-            spinlock_unlock(&t->lock);
-            again = false;
-            break;
-        }
-    }
-    spinlock_unlock(&TASK->lock);
-    interrupts_restore(ipl);
-    if (again) {
-        /*
-         * Other cleanup (e.g. ktaskgc) is in progress.
-         */
-        scheduler();
-        goto loop;
-    }
-    if (t != THREAD) {
-        ASSERT(t != main_thread);   /* uninit is joined and detached
-                         * in ktaskgc */
-        thread_join(t);
-        thread_detach(t);
-        goto loop;          /* go for another thread */
-    }
-    /*
-     * Now there are no other threads in this task
-     * and no new threads can be created.
-     */
-    ipc_cleanup();
-    futex_cleanup();
-    klog_printf("Cleanup of task %llu completed.", TASK->taskid);
-}
-/** Kernel thread used to kill the userspace task when its main thread exits.
- *
- * This thread waits until the main userspace thread (i.e. uninit) exits.
- * When this happens, the task is killed. In the meantime, exited threads
- * are garbage collected.
- *
- * @param arg Pointer to the thread structure of the task's main thread.
- */
-void ktaskgc(void *arg)
-{
-    thread_t *t = (thread_t *) arg;
-loop:
-    /*
-     * Userspace threads cannot detach themselves,
-     * therefore the thread pointer is guaranteed to be valid.
-     */
-    if (thread_join_timeout(t, 1000000, SYNCH_FLAGS_NONE) ==
-        ESYNCH_TIMEOUT) {   /* sleep uninterruptibly here! */
-        ipl_t ipl;
-        link_t *cur;
-        thread_t *thr = NULL;
-        /*
-         * The join timed out. Try to do some garbage collection of
-         * Undead threads.
-         */
-more_gc:
-        ipl = interrupts_disable();
-        spinlock_lock(&TASK->lock);
-        for (cur = TASK->th_head.next; cur != &TASK->th_head;
-            cur = cur->next) {
-            thr = list_get_instance(cur, thread_t, th_link);
-            spinlock_lock(&thr->lock);
-            if (thr != t && thr->state == Undead &&
-                thr->join_type == None) {
-                thr->join_type = TaskGC;
-                spinlock_unlock(&thr->lock);
-                break;
-            }
-            spinlock_unlock(&thr->lock);
-            thr = NULL;
-        }
-        spinlock_unlock(&TASK->lock);
-        interrupts_restore(ipl);
-        if (thr) {
-            thread_join(thr);
-            thread_detach(thr);
-            scheduler();
-            goto more_gc;
-        }
-        goto loop;
-    }
-    thread_detach(t);
-    task_kill(TASK->taskid);
-}
 /** @}
  */

Subversion Repositories HelenOS

(root)/trunk/kernel/generic/src/proc/task.c – Rev 2436 → 2446