#include <debug.h>
#include <stddef.h>
#include <random.h>
+#include <stdio.h>
#include <string.h>
+#include "threads/flags.h"
#include "threads/interrupt.h"
#include "threads/intr-stubs.h"
#include "threads/mmu.h"
#include "threads/switch.h"
#include "threads/synch.h"
#ifdef USERPROG
-#include "userprog/gdt.h"
+#include "userprog/process.h"
#endif
/* Random value for struct thread's `magic' member.
static void idle (void *aux UNUSED);
static struct thread *running_thread (void);
static struct thread *next_thread_to_run (void);
-static struct thread *new_thread (const char *name);
-static void init_thread (struct thread *, const char *name);
+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 *);
/* Set up a thread structure for the running thread. */
initial_thread = running_thread ();
- init_thread (initial_thread, "main");
+ init_thread (initial_thread, "main", PRI_DEFAULT);
initial_thread->status = THREAD_RUNNING;
initial_thread->tid = allocate_tid ();
void
thread_start (void)
{
- thread_create ("idle", idle, NULL);
+ thread_create ("idle", PRI_DEFAULT, idle, NULL);
intr_enable ();
}
-/* Creates a new kernel thread named NAME, which executes
- FUNCTION passing AUX as the argument, and adds it to the ready
- queue. If thread_start() has been called, then the new thread
- may be scheduled before thread_create() returns. It could
- even exit before thread_create() returns. Use a semaphore or
- some other form of synchronization if you need to ensure
- ordering. Returns the thread identifier for the new thread,
- or TID_ERROR if creation fails. */
+/* 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
+ called, then the new thread may be scheduled before
+ thread_create() returns. It could even exit before
+ thread_create() returns. Use a semaphore or some other form
+ of synchronization if you need to ensure ordering. Returns
+ the thread identifier for the new thread, or TID_ERROR if
+ creation fails.
+
+ The code provided sets the new thread's `priority' member to
+ PRIORITY, but no actual priority scheduling is implemented.
+ Priority scheduling is the goal of Problem 1-3. */
tid_t
-thread_create (const char *name, thread_func *function, void *aux)
+thread_create (const char *name, int priority,
+ thread_func *function, void *aux)
{
struct thread *t;
struct kernel_thread_frame *kf;
ASSERT (function != NULL);
- t = new_thread (name);
+ /* Allocate thread. */
+ t = palloc_get (PAL_ZERO);
if (t == NULL)
return TID_ERROR;
+
+ /* Initialize thread. */
+ init_thread (t, name, priority);
tid = t->tid = allocate_tid ();
/* Stack frame for kernel_thread(). */
return tid;
}
-#ifdef USERPROG
-/* Starts a new thread running a user program loaded from
- FILENAME, and adds it to the ready queue. If thread_start()
- has been called, then new thread may be scheduled before
- thread_execute() returns.*/
-tid_t
-thread_execute (const char *filename)
-{
- struct thread *t;
- struct intr_frame *if_;
- struct switch_entry_frame *ef;
- struct switch_threads_frame *sf;
- void (*start) (void);
- tid_t tid;
-
- ASSERT (filename != NULL);
-
- t = new_thread (filename);
- if (t == NULL)
- return TID_ERROR;
- tid = t->tid = allocate_tid ();
-
- if (!addrspace_load (t, filename, &start))
- PANIC ("%s: program load failed", filename);
-
- /* Interrupt frame. */
- if_ = alloc_frame (t, sizeof *if_);
- if_->es = SEL_UDSEG;
- if_->ds = SEL_UDSEG;
- if_->eip = start;
- if_->cs = SEL_UCSEG;
- if_->eflags = FLAG_IF | FLAG_MBS;
- if_->esp = PHYS_BASE;
- if_->ss = SEL_UDSEG;
-
- /* Stack frame for switch_entry(). */
- ef = alloc_frame (t, sizeof *ef);
- ef->eip = intr_exit;
-
- /* Stack frame for switch_threads(). */
- sf = alloc_frame (t, sizeof *sf);
- sf->eip = switch_entry;
-
- /* Add to run queue. */
- thread_unblock (t);
-
- return tid;
-}
-#endif
-
/* Transitions a blocked thread T from its current state to the
- ready-to-run state. If T is not blocked, there is no effect.
+ 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 (is_thread (t));
old_level = intr_disable ();
- if (t->status == THREAD_BLOCKED)
- {
- list_push_back (&ready_list, &t->elem);
- t->status = THREAD_READY;
- }
+ ASSERT (t->status == THREAD_BLOCKED);
+ list_push_back (&ready_list, &t->elem);
+ t->status = THREAD_READY;
intr_set_level (old_level);
}
return t != NULL && t->magic == THREAD_MAGIC;
}
-/* Creates a new thread named NAME and initializes its fields.
- Returns the new thread if successful or a null pointer on
- failure. */
-static struct thread *
-new_thread (const char *name)
+/* Does basic initialization of T as a blocked thread named
+ NAME. */
+static void
+init_thread (struct thread *t, const char *name, int priority)
{
- struct thread *t;
-
+ ASSERT (t != NULL);
+ ASSERT (PRI_MIN <= priority && priority <= PRI_MAX);
ASSERT (name != NULL);
-
- t = palloc_get (PAL_ZERO);
- if (t != NULL)
- init_thread (t, name);
- return t;
-}
-
-/* Initializes T as a new, blocked thread named NAME. */
-static void
-init_thread (struct thread *t, const char *name)
-{
memset (t, 0, sizeof *t);
t->status = THREAD_BLOCKED;
strlcpy (t->name, name, sizeof t->name);
t->stack = (uint8_t *) t + PGSIZE;
+ t->priority = priority;
t->magic = THREAD_MAGIC;
}
return list_entry (list_pop_front (&ready_list), struct thread, elem);
}
-/* Destroys T, which must be in the dying state and must not be
- the running thread. */
+/* Destroys T, which must not be the running thread. */
static void
destroy_thread (struct thread *t)
{
ASSERT (is_thread (t));
- ASSERT (t->status == THREAD_DYING);
ASSERT (t != thread_current ());
#ifdef USERPROG
- addrspace_destroy (t);
+ process_destroy (t);
#endif
if (t != initial_thread)
palloc_free (t);
#ifdef USERPROG
/* Activate the new address space. */
- addrspace_activate (cur);
+ process_activate ();
#endif
/* If the thread we switched from is dying, destroy it.