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- #ifndef THREADS_THREAD_H
- #define THREADS_THREAD_H
- #include <debug.h>
- #include <list.h>
- #include <stdint.h>
- /* 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. */
- #ifdef USERPROG
- #include "userprog/process.h"
- #endif
- /* 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 |
- | : |
- | : |
- | 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). */
- uint8_t *stack; /* Saved stack pointer. */
- int priority; /* Priority. */
- struct list_elem allelem; /* List element for all threads list. */
- /* Shared between thread.c and synch.c. */
- struct list_elem elem; /* List element. */
- #ifdef USERPROG
- /* Owned by userprog/process.c. */
- uint32_t *pagedir; /* Page directory. */
- struct process* process; /* This thread's associated process */
- #endif
- /* Owned by thread.c. */
- 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);
- /* Performs some operation on thread t, given auxiliary data AUX. */
- typedef void thread_action_func (struct thread *t, void *aux);
- void thread_foreach (thread_action_func *, 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);
- #endif /* threads/thread.h */
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