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