that are ready to run but not actually running. */
static struct list ready_list;
+/* List of all processes. Processes are added to this list
+ when they are first scheduled and removed when they exit. */
+static struct list all_list;
+
/* Idle thread. */
static struct thread *idle_thread;
/* If false (default), use round-robin scheduler.
If true, use multi-level feedback queue scheduler.
- Controlled by kernel command-line options "-o mlfqs".
- Note that the command line is not parsed until well after
- thread_init() is called. */
+ Controlled by kernel command-line option "-o mlfqs". */
bool thread_mlfqs;
static void kernel_thread (thread_func *, void *aux);
static bool is_thread (struct thread *) UNUSED;
static void *alloc_frame (struct thread *, size_t size);
static void schedule (void);
-void schedule_tail (struct thread *prev);
+void thread_schedule_tail (struct thread *prev);
static tid_t allocate_tid (void);
/* Initializes the threading system by transforming the code
allocator before trying to create any threads with
thread_create().
- The kernel command line is not parsed until *after* this
- function returns, so that when this function runs,
- thread_mlfqs is always false.
-
It is not safe to call thread_current() until this function
finishes. */
void
lock_init (&tid_lock);
list_init (&ready_list);
+ list_init (&all_list);
/* Set up a thread structure for the running thread. */
initial_thread = running_thread ();
}
/* Starts preemptive thread scheduling by enabling interrupts.
- Also creates the idle thread.
-
- By the time this function runs, thread_mlfqs has been properly
- initialized to its final value. */
+ Also creates the idle thread. */
void
thread_start (void)
{
struct switch_entry_frame *ef;
struct switch_threads_frame *sf;
tid_t tid;
+ enum intr_level old_level;
ASSERT (function != NULL);
init_thread (t, name, priority);
tid = t->tid = allocate_tid ();
+ /* Prepare thread for first run by initializing its stack.
+ Do this atomically so intermediate values for the 'stack'
+ member cannot be observed. */
+ old_level = intr_disable ();
+
/* Stack frame for kernel_thread(). */
kf = alloc_frame (t, sizeof *kf);
kf->eip = NULL;
/* Stack frame for switch_threads(). */
sf = alloc_frame (t, sizeof *sf);
sf->eip = switch_entry;
+ sf->ebp = 0;
+
+ intr_set_level (old_level);
/* Add to run queue. */
thread_unblock (t);
/* Transitions a blocked thread T to the ready-to-run state.
This is an error if T is not blocked. (Use thread_yield() to
- make the running thread ready.) */
+ make the running thread ready.)
+
+ This function does not preempt the running thread. This can
+ be important: if the caller had disabled interrupts itself,
+ it may expect that it can atomically unblock a thread and
+ update other data. */
void
thread_unblock (struct thread *t)
{
process_exit ();
#endif
- /* Just set our status to dying and schedule another process.
- We will be destroyed during the call to schedule_tail(). */
+ /* Remove thread from all threads list, set our status to dying,
+ and schedule another process. That process will destroy us
+ when it calls thread_schedule_tail(). */
intr_disable ();
+ list_remove (&thread_current()->allelem);
thread_current ()->status = THREAD_DYING;
schedule ();
NOT_REACHED ();
intr_set_level (old_level);
}
+/* Invoke function 'func' on all threads, passing along 'aux'.
+ This function must be called with interrupts off. */
+void
+thread_foreach (thread_action_func *func, void *aux)
+{
+ struct list_elem *e;
+
+ ASSERT (intr_get_level () == INTR_OFF);
+
+ for (e = list_begin (&all_list); e != list_end (&all_list);
+ e = list_next (e))
+ {
+ struct thread *t = list_entry (e, struct thread, allelem);
+ func (t, aux);
+ }
+}
+
/* Sets the current thread's priority to NEW_PRIORITY. */
void
thread_set_priority (int new_priority)
See [IA32-v2a] "HLT", [IA32-v2b] "STI", and [IA32-v3a]
7.11.1 "HLT Instruction". */
- asm ("sti; hlt");
+ asm volatile ("sti; hlt" : : : "memory");
}
}
static void
init_thread (struct thread *t, const char *name, int priority)
{
+ enum intr_level old_level;
+
ASSERT (t != NULL);
ASSERT (PRI_MIN <= priority && priority <= PRI_MAX);
ASSERT (name != NULL);
t->stack = (uint8_t *) t + PGSIZE;
t->priority = priority;
t->magic = THREAD_MAGIC;
+
+ old_level = intr_disable ();
+ list_push_back (&all_list, &t->allelem);
+ intr_set_level (old_level);
}
/* Allocates a SIZE-byte frame at the top of thread T's stack and
After this function and its caller returns, the thread switch
is complete. */
void
-schedule_tail (struct thread *prev)
+thread_schedule_tail (struct thread *prev)
{
struct thread *cur = running_thread ();
running to some other state. This function finds another
thread to run and switches to it.
- It's not safe to call printf() until schedule_tail() has
- completed. */
+ It's not safe to call printf() until thread_schedule_tail()
+ has completed. */
static void
schedule (void)
{
if (cur != next)
prev = switch_threads (cur, next);
- schedule_tail (prev);
+ thread_schedule_tail (prev);
}
/* Returns a tid to use for a new thread. */