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[pintos-anon]
/
src
/
threads
/
thread.c
diff --git
a/src/threads/thread.c
b/src/threads/thread.c
index 2694a10959ba9ccd9965f498197ec5add8905a5f..52f0f8d4fc73d8f65818163aaca9c7229cf8e97e 100644
(file)
--- a/
src/threads/thread.c
+++ b/
src/threads/thread.c
@@
-12,6
+12,9
@@
#include "gdt.h"
#endif
#include "gdt.h"
#endif
+/* Value for struct thread's `magic' member.
+ Used to detect stack overflow. See the big comment at the top
+ of thread.h for details. */
#define THREAD_MAGIC 0x1234abcdu
/* List of processes in THREAD_READY state, that is, processes
#define THREAD_MAGIC 0x1234abcdu
/* List of processes in THREAD_READY state, that is, processes
@@
-194,7
+197,8
@@
thread_name (struct thread *t)
}
/* Returns the running thread.
}
/* Returns the running thread.
- This is running_thread() plus a couple of sanity checks. */
+ This is running_thread() plus a couple of sanity checks.
+ See the big comment at the top of thread.h for details. */
struct thread *
thread_current (void)
{
struct thread *
thread_current (void)
{
@@
-218,6
+222,8
@@
thread_exit (void)
{
ASSERT (!intr_context ());
{
ASSERT (!intr_context ());
+ /* Just set our status to dying and schedule another process.
+ We will be destroyed during the call to schedule_tail(). */
intr_disable ();
thread_current ()->status = THREAD_DYING;
schedule ();
intr_disable ();
thread_current ()->status = THREAD_DYING;
schedule ();
@@
-242,7
+248,11
@@
thread_yield (void)
}
/* Puts the current thread to sleep. It will not be scheduled
}
/* Puts the current thread to sleep. It will not be scheduled
- again until awoken by thread_unblock(). */
+ 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)
{
void
thread_block (void)
{
@@
-319,7
+329,7
@@
new_thread (const char *name)
return t;
}
return t;
}
-/* Initializes T as a new thread named NAME. */
+/* Initializes T as a new
, blocked
thread named NAME. */
static void
init_thread (struct thread *t, const char *name)
{
static void
init_thread (struct thread *t, const char *name)
{
@@
-391,12
+401,17
@@
schedule_tail (struct thread *prev)
ASSERT (intr_get_level () == INTR_OFF);
ASSERT (intr_get_level () == INTR_OFF);
+ /* Mark us as running. */
cur->status = THREAD_RUNNING;
#ifdef USERPROG
cur->status = THREAD_RUNNING;
#ifdef USERPROG
+ /* Activate the new address space. */
addrspace_activate (cur);
#endif
addrspace_activate (cur);
#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 (prev != NULL && prev->status == THREAD_DYING)
destroy_thread (prev);
}
if (prev != NULL && prev->status == THREAD_DYING)
destroy_thread (prev);
}