void *aux; /* Auxiliary data for function. */
};
+/* Statistics. */
+static long long idle_ticks; /* # of timer ticks spent idle. */
+static long long kernel_ticks; /* # of timer ticks in kernel threads. */
+static long long user_ticks; /* # of timer ticks in user programs. */
+
static void kernel_thread (thread_func *, void *aux);
static void idle (void *aux UNUSED);
static void init_thread (struct thread *, const char *name, int priority);
static bool is_thread (struct thread *);
static void *alloc_frame (struct thread *, size_t size);
-static void destroy_thread (struct thread *);
static void schedule (void);
void schedule_tail (struct thread *prev);
static tid_t allocate_tid (void);
/* Initializes the threading system by transforming the code
- that's currently running into a thread. Note that this is
- possible only because the loader was careful to put the bottom
- of the stack at a page boundary; it won't work in general.
- Also initializes the run queue.
+ that's currently running into a thread. This can't work in
+ general and it is possible in this case only because loader.S
+ was careful to put the bottom of the stack at a page boundary.
+
+ Also initializes the run queue and the tid lock.
After calling this function, be sure to initialize the page
allocator before trying to create any threads with
ASSERT (intr_get_level () == INTR_OFF);
lock_init (&tid_lock, "tid");
+ list_init (&ready_list);
/* Set up a thread structure for the running thread. */
initial_thread = running_thread ();
init_thread (initial_thread, "main", PRI_DEFAULT);
initial_thread->status = THREAD_RUNNING;
initial_thread->tid = allocate_tid ();
-
- /* Initialize run queue. */
- list_init (&ready_list);
}
/* Starts preemptive thread scheduling by enabling interrupts.
intr_enable ();
}
+/* Called by the timer interrupt handler at each timer tick to
+ update statistics. */
+void
+thread_tick (void)
+{
+ struct thread *t = thread_current ();
+ if (t == idle_thread)
+ idle_ticks++;
+#ifdef USERPROG
+ else if (t->pagedir != NULL)
+ user_ticks++;
+#endif
+ else
+ kernel_ticks++;
+}
+
+/* Prints thread statistics. */
+void
+thread_print_stats (void)
+{
+ printf ("Thread: %lld idle ticks, %lld kernel ticks, %lld user ticks\n",
+ idle_ticks, kernel_ticks, user_ticks);
+}
+
/* Creates a new kernel thread named NAME with the given initial
PRIORITY, which executes FUNCTION passing AUX as the argument,
and adds it to the ready queue. If thread_start() has been
ASSERT (function != NULL);
/* Allocate thread. */
- t = palloc_get (PAL_ZERO);
+ t = palloc_get_page (PAL_ZERO);
if (t == NULL)
return TID_ERROR;
return tid;
}
-/* Transitions a blocked thread T from its current state to the
- ready-to-run state. This is an error if T is not blocked.
- (Use thread_yield() to make the running thread ready.) */
+/* Puts the current thread to sleep. It will not be scheduled
+ again until awoken by thread_unblock().
+
+ This function must be called with interrupts turned off. It
+ is usually a better idea to use one of the synchronization
+ primitives in synch.h. */
+void
+thread_block (void)
+{
+ ASSERT (!intr_context ());
+ ASSERT (intr_get_level () == INTR_OFF);
+
+ thread_current ()->status = THREAD_BLOCKED;
+ schedule ();
+}
+
+/* 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.) */
void
thread_unblock (struct thread *t)
{
{
ASSERT (!intr_context ());
+#ifdef USERPROG
+ process_exit ();
+#endif
+
/* Just set our status to dying and schedule another process.
We will be destroyed during the call to schedule_tail(). */
intr_disable ();
schedule ();
intr_set_level (old_level);
}
-
-/* Puts the current thread to sleep. It will not be scheduled
- again until awoken by thread_unblock().
-
- This function must be called with interrupts turned off. It
- is usually a better idea to use one of the synchronization
- primitives in synch.h. */
-void
-thread_block (void)
-{
- ASSERT (!intr_context ());
- ASSERT (intr_get_level () == INTR_OFF);
-
- thread_current ()->status = THREAD_BLOCKED;
- schedule ();
-}
\f
/* Idle thread. Executes when no other thread is ready to run. */
static void
thread_block ();
intr_enable ();
- /* Use CPU `hlt' instruction to wait for interrupt. */
+ /* Use CPU `hlt' instruction to wait for interrupt.
+ See [IA32-v2a] "HLT" and [IA32-v3] 7.7. */
asm ("hlt");
}
}
down to the start of a page. Because `struct thread' is
always at the beginning of a page and the stack pointer is
somewhere in the middle, this locates the curent thread. */
- asm ("movl %%esp, %0\n" : "=g" (esp));
+ asm ("mov %0, %%esp" : "=g" (esp));
return pg_round_down (esp);
}
return list_entry (list_pop_front (&ready_list), struct thread, elem);
}
-/* Destroys T, which must not be the running thread. */
-static void
-destroy_thread (struct thread *t)
-{
- ASSERT (is_thread (t));
- ASSERT (t != thread_current ());
-
-#ifdef USERPROG
- process_destroy (t);
-#endif
- if (t != initial_thread)
- palloc_free (t);
-}
-
/* Completes a thread switch by activating the new thread's page
tables, and, if the previous thread is dying, destroying it.
the first time a thread is scheduled it is called by
switch_entry() (see switch.S).
+ It's not safe to call printf() until the thread switch is
+ complete. In practice that means that printf()s should be
+ added at the end of the function.
+
After this function and its caller returns, the thread switch
is complete. */
void
process_activate ();
#endif
- /* If the thread we switched from is dying, destroy it.
- This must happen late because it's not a good idea to
- e.g. destroy the page table you're currently using. */
+ /* If the thread we switched from is dying, destroy its struct
+ thread. This must happen late so that thread_exit() doesn't
+ pull out the rug under itself. */
if (prev != NULL && prev->status == THREAD_DYING)
- destroy_thread (prev);
+ {
+ ASSERT (prev != cur);
+ if (prev != initial_thread)
+ palloc_free_page (prev);
+ }
}
/* Schedules a new process. At entry, interrupts must be off and
the running process's state must have been changed from
running to some other state. This function finds another
- thread to run and switches to it. */
+ thread to run and switches to it.
+
+ It's not safe to call printf() until schedule_tail() has
+ completed. */
static void
schedule (void)
{
projects / pintos-anon / blobdiff