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authormanuel <manuel@mausz.at>2012-03-26 12:54:45 +0200
committermanuel <manuel@mausz.at>2012-03-26 12:54:45 +0200
commitb5f0874cd96ee2a62aabc645b9626c2749cb6a01 (patch)
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initial pintos checkin
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-rw-r--r--pintos-progos/threads/thread.h144
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diff --git a/pintos-progos/threads/thread.h b/pintos-progos/threads/thread.h
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1#ifndef THREADS_THREAD_H
2#define THREADS_THREAD_H
3
4#include <debug.h>
5#include <list.h>
6#include <stdint.h>
7#include "threads/synch.h"
8
9/* States in a thread's life cycle. */
10enum thread_status
11 {
12 THREAD_RUNNING, /* Running thread. */
13 THREAD_READY, /* Not running but ready to run. */
14 THREAD_BLOCKED, /* Waiting for an event to trigger. */
15 THREAD_DYING /* About to be destroyed. */
16 };
17
18/* Thread identifier type.
19 You can redefine this to whatever type you like. */
20typedef int tid_t;
21#define TID_ERROR ((tid_t) -1) /* Error value for tid_t. */
22
23/* Thread priorities. */
24#define PRI_MIN 0 /* Lowest priority. */
25#define PRI_DEFAULT 31 /* Default priority. */
26#define PRI_MAX 63 /* Highest priority. */
27
28/* A kernel thread or user process.
29
30 Each thread structure is stored in its own 4 kB page. The
31 thread structure itself sits at the very bottom of the page
32 (at offset 0). The rest of the page is reserved for the
33 thread's kernel stack, which grows downward from the top of
34 the page (at offset 4 kB). Here's an illustration:
35
36 4 kB +---------------------------------+
37 | kernel stack |
38 | | |
39 | | |
40 | V |
41 | grows downward |
42 | |
43 | |
44 | |
45 | |
46 | |
47 | |
48 | |
49 | |
50 +---------------------------------+
51 | magic |
52 | : |
53 | : |
54 | name |
55 | status |
56 0 kB +---------------------------------+
57
58 The upshot of this is twofold:
59
60 1. First, `struct thread' must not be allowed to grow too
61 big. If it does, then there will not be enough room for
62 the kernel stack. Our base `struct thread' is only a
63 few bytes in size. It probably should stay well under 1
64 kB.
65
66 2. Second, kernel stacks must not be allowed to grow too
67 large. If a stack overflows, it will corrupt the thread
68 state. Thus, kernel functions should not allocate large
69 structures or arrays as non-static local variables. Use
70 dynamic allocation with malloc() or palloc_get_page()
71 instead.
72
73 The first symptom of either of these problems will probably be
74 an assertion failure in thread_current(), which checks that
75 the `magic' member of the running thread's `struct thread' is
76 set to THREAD_MAGIC. Stack overflow will normally change this
77 value, triggering the assertion. */
78/* The `elem' member has a dual purpose. It can be an element in
79 the run queue (thread.c), or it can be an element in a
80 semaphore wait list (synch.c). It can be used these two ways
81 only because they are mutually exclusive: only a thread in the
82 ready state is on the run queue, whereas only a thread in the
83 blocked state is on a semaphore wait list. */
84struct thread
85 {
86 /* Owned by thread.c. */
87 tid_t tid; /* Thread identifier. */
88 enum thread_status status; /* Thread state. */
89 char name[16]; /* Name (for debugging purposes). */
90 uint8_t *stack; /* Saved stack pointer. */
91 int priority; /* Priority. */
92 struct list_elem allelem; /* List element for all threads list. */
93
94 /* Shared between thread.c and synch.c. */
95 struct list_elem elem; /* List element. */
96
97#ifdef USERPROG
98 /* Owned by userprog/process.c */
99 struct process* process; /* Process Structure */
100 struct list children; /* Threads can hold processes, but not vice versa */
101 uint32_t *pagedir; /* Page directory. */
102#endif
103
104 /* Owned by thread.c. */
105 unsigned magic; /* Detects stack overflow. */
106 };
107
108/* If false (default), use round-robin scheduler.
109 If true, use multi-level feedback queue scheduler.
110 Controlled by kernel command-line option "-o mlfqs". */
111extern bool thread_mlfqs;
112
113void thread_init (void);
114void thread_start (void);
115
116void thread_tick (void);
117void thread_print_stats (void);
118
119typedef void thread_func (void *aux);
120tid_t thread_create (const char *name, int priority, thread_func *, void *);
121
122void thread_block (void);
123void thread_unblock (struct thread *);
124
125struct thread *thread_current (void);
126tid_t thread_tid (void);
127const char *thread_name (void);
128
129void thread_exit (void) NO_RETURN;
130void thread_yield (void);
131
132/* Performs some operation on thread t, given auxiliary data AUX. */
133typedef void thread_action_func (struct thread *t, void *aux);
134void thread_foreach (thread_action_func *, void *);
135
136int thread_get_priority (void);
137void thread_set_priority (int);
138
139int thread_get_nice (void);
140void thread_set_nice (int);
141int thread_get_recent_cpu (void);
142int thread_get_load_avg (void);
143
144#endif /* threads/thread.h */