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thread.h
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thread.h
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#ifndef THREADS_THREAD_H
#define THREADS_THREAD_H
#include <debug.h>
#include <list.h>
#include <stdint.h>
#include "threads/interrupt.h"
#ifdef VM
#include "vm/vm.h"
#endif
/* States in a thread's life cycle. */
enum thread_status {
THREAD_RUNNING, /* Running thread. */
THREAD_READY, /* Not running but ready to run. */
THREAD_BLOCKED, /* Waiting for an event to trigger. */
THREAD_DYING /* About to be destroyed. */
};
/* Thread identifier type.
You can redefine this to whatever type you like. */
typedef int tid_t;
#define TID_ERROR ((tid_t) -1) /* Error value for tid_t. */
/* Thread priorities. */
#define PRI_MIN 0 /* Lowest priority. */
#define PRI_DEFAULT 31 /* Default priority. */
#define PRI_MAX 63 /* Highest priority. */
/* A kernel thread or user process.
*
* Each thread structure is stored in its own 4 kB page. The
* thread structure itself sits at the very bottom of the page
* (at offset 0). The rest of the page is reserved for the
* thread's kernel stack, which grows downward from the top of
* the page (at offset 4 kB). Here's an illustration:
*
* 4 kB +---------------------------------+
* | kernel stack |
* | | |
* | | |
* | V |
* | grows downward |
* | |
* | |
* | |
* | |
* | |
* | |
* | |
* | |
* +---------------------------------+
* | magic |
* | intr_frame |
* | : |
* | : |
* | name |
* | status |
* 0 kB +---------------------------------+
*
* The upshot of this is twofold:
*
* 1. First, `struct thread' must not be allowed to grow too
* big. If it does, then there will not be enough room for
* the kernel stack. Our base `struct thread' is only a
* few bytes in size. It probably should stay well under 1
* kB.
*
* 2. Second, kernel stacks must not be allowed to grow too
* large. If a stack overflows, it will corrupt the thread
* state. Thus, kernel functions should not allocate large
* structures or arrays as non-static local variables. Use
* dynamic allocation with malloc() or palloc_get_page()
* instead.
*
* The first symptom of either of these problems will probably be
* an assertion failure in thread_current(), which checks that
* the `magic' member of the running thread's `struct thread' is
* set to THREAD_MAGIC. Stack overflow will normally change this
* value, triggering the assertion. */
/* The `elem' member has a dual purpose. It can be an element in
* the run queue (thread.c), or it can be an element in a
* semaphore wait list (synch.c). It can be used these two ways
* only because they are mutually exclusive: only a thread in the
* ready state is on the run queue, whereas only a thread in the
* blocked state is on a semaphore wait list. */
struct thread {
/* Owned by thread.c. */
tid_t tid; /* Thread identifier. */
enum thread_status status; /* Thread state. */
char name[16]; /* Name (for debugging purposes). */
int priority; /* Priority. */
/* Shared between thread.c and synch.c. */
struct list_elem elem; /* List element. */
#ifdef USERPROG
/* Owned by userprog/process.c. */
uint64_t *pml4; /* Page map level 4 */
#endif
#ifdef VM
/* Table for whole virtual memory owned by thread. */
struct supplemental_page_table spt;
#endif
/* Owned by thread.c. */
struct intr_frame tf; /* Information for switching */
unsigned magic; /* Detects stack overflow. */
};
/* If false (default), use round-robin scheduler.
If true, use multi-level feedback queue scheduler.
Controlled by kernel command-line option "-o mlfqs". */
extern bool thread_mlfqs;
void thread_init (void);
void thread_start (void);
void thread_tick (void);
void thread_print_stats (void);
typedef void thread_func (void *aux);
tid_t thread_create (const char *name, int priority, thread_func *, void *);
void thread_block (void);
void thread_unblock (struct thread *);
struct thread *thread_current (void);
tid_t thread_tid (void);
const char *thread_name (void);
void thread_exit (void) NO_RETURN;
void thread_yield (void);
int thread_get_priority (void);
void thread_set_priority (int);
int thread_get_nice (void);
void thread_set_nice (int);
int thread_get_recent_cpu (void);
int thread_get_load_avg (void);
void do_iret (struct intr_frame *tf);
#endif /* threads/thread.h */