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1 | /* |
1 | /* |
2 | * Copyright (C) 2001-2004 Jakub Jermar |
2 | * Copyright (C) 2001-2004 Jakub Jermar |
3 | * All rights reserved. |
3 | * All rights reserved. |
4 | * |
4 | * |
5 | * Redistribution and use in source and binary forms, with or without |
5 | * Redistribution and use in source and binary forms, with or without |
6 | * modification, are permitted provided that the following conditions |
6 | * modification, are permitted provided that the following conditions |
7 | * are met: |
7 | * are met: |
8 | * |
8 | * |
9 | * - Redistributions of source code must retain the above copyright |
9 | * - Redistributions of source code must retain the above copyright |
10 | * notice, this list of conditions and the following disclaimer. |
10 | * notice, this list of conditions and the following disclaimer. |
11 | * - Redistributions in binary form must reproduce the above copyright |
11 | * - Redistributions in binary form must reproduce the above copyright |
12 | * notice, this list of conditions and the following disclaimer in the |
12 | * notice, this list of conditions and the following disclaimer in the |
13 | * documentation and/or other materials provided with the distribution. |
13 | * documentation and/or other materials provided with the distribution. |
14 | * - The name of the author may not be used to endorse or promote products |
14 | * - The name of the author may not be used to endorse or promote products |
15 | * derived from this software without specific prior written permission. |
15 | * derived from this software without specific prior written permission. |
16 | * |
16 | * |
17 | * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR |
17 | * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR |
18 | * IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES |
18 | * IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES |
19 | * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED. |
19 | * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED. |
20 | * IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT, |
20 | * IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT, |
21 | * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT |
21 | * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT |
22 | * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, |
22 | * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, |
23 | * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY |
23 | * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY |
24 | * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT |
24 | * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT |
25 | * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF |
25 | * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF |
26 | * THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE. |
26 | * THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE. |
27 | */ |
27 | */ |
28 | 28 | ||
29 | /** |
29 | /** |
30 | * @file clock.c |
30 | * @file clock.c |
31 | * @brief High-level clock interrupt handler. |
31 | * @brief High-level clock interrupt handler. |
32 | * |
32 | * |
33 | * This file contains the clock() function which is the source |
33 | * This file contains the clock() function which is the source |
34 | * of preemption. It is also responsible for executing expired |
34 | * of preemption. It is also responsible for executing expired |
35 | * timeouts. |
35 | * timeouts. |
36 | */ |
36 | */ |
37 | 37 | ||
38 | #include <time/clock.h> |
38 | #include <time/clock.h> |
39 | #include <time/timeout.h> |
39 | #include <time/timeout.h> |
40 | #include <arch/types.h> |
40 | #include <arch/types.h> |
41 | #include <config.h> |
41 | #include <config.h> |
42 | #include <synch/spinlock.h> |
42 | #include <synch/spinlock.h> |
43 | #include <synch/waitq.h> |
43 | #include <synch/waitq.h> |
44 | #include <func.h> |
44 | #include <func.h> |
45 | #include <proc/scheduler.h> |
45 | #include <proc/scheduler.h> |
46 | #include <cpu.h> |
46 | #include <cpu.h> |
47 | #include <arch.h> |
47 | #include <arch.h> |
48 | #include <adt/list.h> |
48 | #include <adt/list.h> |
49 | #include <atomic.h> |
49 | #include <atomic.h> |
50 | #include <proc/thread.h> |
50 | #include <proc/thread.h> |
51 | 51 | ||
52 | /** Clock routine |
52 | /** Clock routine |
53 | * |
53 | * |
54 | * Clock routine executed from clock interrupt handler |
54 | * Clock routine executed from clock interrupt handler |
55 | * (assuming interrupts_disable()'d). Runs expired timeouts |
55 | * (assuming interrupts_disable()'d). Runs expired timeouts |
56 | * and preemptive scheduling. |
56 | * and preemptive scheduling. |
57 | * |
57 | * |
58 | */ |
58 | */ |
59 | void clock(void) |
59 | void clock(void) |
60 | { |
60 | { |
61 | link_t *l; |
61 | link_t *l; |
62 | timeout_t *h; |
62 | timeout_t *h; |
63 | timeout_handler_t f; |
63 | timeout_handler_t f; |
64 | void *arg; |
64 | void *arg; |
- | 65 | int i; |
|
65 | 66 | ||
66 | /* |
67 | /* |
67 | * To avoid lock ordering problems, |
68 | * To avoid lock ordering problems, |
68 | * run all expired timeouts as you visit them. |
69 | * run all expired timeouts as you visit them. |
69 | */ |
70 | */ |
- | 71 | for (i = 0; i < CPU->missed_clock_ticks; i++) { |
|
70 | spinlock_lock(&CPU->timeoutlock); |
72 | spinlock_lock(&CPU->timeoutlock); |
71 | while ((l = CPU->timeout_active_head.next) != &CPU->timeout_active_head) { |
73 | while ((l = CPU->timeout_active_head.next) != &CPU->timeout_active_head) { |
72 | h = list_get_instance(l, timeout_t, link); |
74 | h = list_get_instance(l, timeout_t, link); |
73 | spinlock_lock(&h->lock); |
75 | spinlock_lock(&h->lock); |
74 | if (h->ticks-- != 0) { |
76 | if (h->ticks-- != 0) { |
75 | spinlock_unlock(&h->lock); |
77 | spinlock_unlock(&h->lock); |
76 | break; |
78 | break; |
77 | } |
79 | } |
78 | list_remove(l); |
80 | list_remove(l); |
79 | f = h->handler; |
81 | f = h->handler; |
80 | arg = h->arg; |
82 | arg = h->arg; |
81 | timeout_reinitialize(h); |
83 | timeout_reinitialize(h); |
82 | spinlock_unlock(&h->lock); |
84 | spinlock_unlock(&h->lock); |
83 | spinlock_unlock(&CPU->timeoutlock); |
85 | spinlock_unlock(&CPU->timeoutlock); |
84 | 86 | ||
85 | f(arg); |
87 | f(arg); |
86 | 88 | ||
87 | spinlock_lock(&CPU->timeoutlock); |
89 | spinlock_lock(&CPU->timeoutlock); |
- | 90 | } |
|
- | 91 | spinlock_unlock(&CPU->timeoutlock); |
|
88 | } |
92 | } |
89 | spinlock_unlock(&CPU->timeoutlock); |
93 | CPU->missed_clock_ticks = 0; |
90 | 94 | ||
91 | /* |
95 | /* |
92 | * Do CPU usage accounting and find out whether to preempt THREAD. |
96 | * Do CPU usage accounting and find out whether to preempt THREAD. |
93 | */ |
97 | */ |
94 | 98 | ||
95 | if (THREAD) { |
99 | if (THREAD) { |
96 | __u64 ticks; |
100 | __u64 ticks; |
97 | 101 | ||
98 | spinlock_lock(&CPU->lock); |
102 | spinlock_lock(&CPU->lock); |
99 | CPU->needs_relink++; |
103 | CPU->needs_relink++; |
100 | spinlock_unlock(&CPU->lock); |
104 | spinlock_unlock(&CPU->lock); |
101 | 105 | ||
102 | spinlock_lock(&THREAD->lock); |
106 | spinlock_lock(&THREAD->lock); |
103 | if ((ticks = THREAD->ticks)) |
107 | if ((ticks = THREAD->ticks)) |
104 | THREAD->ticks--; |
108 | THREAD->ticks--; |
105 | spinlock_unlock(&THREAD->lock); |
109 | spinlock_unlock(&THREAD->lock); |
106 | 110 | ||
107 | if (!ticks && !PREEMPTION_DISABLED) { |
111 | if (!ticks && !PREEMPTION_DISABLED) { |
108 | scheduler(); |
112 | scheduler(); |
109 | } |
113 | } |
110 | } |
114 | } |
111 | 115 | ||
112 | } |
116 | } |
113 | 117 |