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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 | |||
| 1264 | jermar | 29 | /** |
| 30 | * @file clock.c |
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| 31 | * @brief High-level clock interrupt handler. |
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| 32 | * |
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| 33 | * This file contains the clock() function which is the source |
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| 34 | * of preemption. It is also responsible for executing expired |
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| 35 | * timeouts. |
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| 36 | */ |
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| 37 | |||
| 1 | jermar | 38 | #include <time/clock.h> |
| 39 | #include <time/timeout.h> |
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| 40 | #include <arch/types.h> |
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| 41 | #include <config.h> |
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| 42 | #include <synch/spinlock.h> |
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| 43 | #include <synch/waitq.h> |
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| 44 | #include <func.h> |
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| 45 | #include <proc/scheduler.h> |
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| 46 | #include <cpu.h> |
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| 47 | #include <arch.h> |
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| 788 | jermar | 48 | #include <adt/list.h> |
| 1104 | jermar | 49 | #include <atomic.h> |
| 391 | jermar | 50 | #include <proc/thread.h> |
| 1 | jermar | 51 | |
| 107 | decky | 52 | /** Clock routine |
| 53 | * |
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| 54 | * Clock routine executed from clock interrupt handler |
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| 413 | jermar | 55 | * (assuming interrupts_disable()'d). Runs expired timeouts |
| 107 | decky | 56 | * and preemptive scheduling. |
| 57 | * |
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| 1 | jermar | 58 | */ |
| 59 | void clock(void) |
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| 60 | { |
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| 61 | link_t *l; |
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| 62 | timeout_t *h; |
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| 411 | jermar | 63 | timeout_handler_t f; |
| 1 | jermar | 64 | void *arg; |
| 1431 | jermar | 65 | int i; |
| 1 | jermar | 66 | |
| 67 | /* |
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| 68 | * To avoid lock ordering problems, |
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| 69 | * run all expired timeouts as you visit them. |
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| 70 | */ |
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| 1433 | jermar | 71 | for (i = 0; i <= CPU->missed_clock_ticks; i++) { |
| 1431 | jermar | 72 | spinlock_lock(&CPU->timeoutlock); |
| 73 | while ((l = CPU->timeout_active_head.next) != &CPU->timeout_active_head) { |
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| 74 | h = list_get_instance(l, timeout_t, link); |
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| 75 | spinlock_lock(&h->lock); |
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| 76 | if (h->ticks-- != 0) { |
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| 77 | spinlock_unlock(&h->lock); |
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| 78 | break; |
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| 79 | } |
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| 80 | list_remove(l); |
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| 81 | f = h->handler; |
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| 82 | arg = h->arg; |
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| 83 | timeout_reinitialize(h); |
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| 84 | spinlock_unlock(&h->lock); |
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| 85 | spinlock_unlock(&CPU->timeoutlock); |
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| 86 | |||
| 87 | f(arg); |
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| 88 | |||
| 89 | spinlock_lock(&CPU->timeoutlock); |
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| 1 | jermar | 90 | } |
| 15 | jermar | 91 | spinlock_unlock(&CPU->timeoutlock); |
| 1 | jermar | 92 | } |
| 1431 | jermar | 93 | CPU->missed_clock_ticks = 0; |
| 1 | jermar | 94 | |
| 95 | /* |
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| 15 | jermar | 96 | * Do CPU usage accounting and find out whether to preempt THREAD. |
| 1 | jermar | 97 | */ |
| 98 | |||
| 15 | jermar | 99 | if (THREAD) { |
| 221 | jermar | 100 | __u64 ticks; |
| 101 | |||
| 15 | jermar | 102 | spinlock_lock(&CPU->lock); |
| 103 | CPU->needs_relink++; |
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| 104 | spinlock_unlock(&CPU->lock); |
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| 1 | jermar | 105 | |
| 15 | jermar | 106 | spinlock_lock(&THREAD->lock); |
| 615 | palkovsky | 107 | if ((ticks = THREAD->ticks)) |
| 221 | jermar | 108 | THREAD->ticks--; |
| 109 | spinlock_unlock(&THREAD->lock); |
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| 110 | |||
| 111 | if (!ticks && !PREEMPTION_DISABLED) { |
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| 1 | jermar | 112 | scheduler(); |
| 113 | } |
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| 114 | } |
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| 115 | |||
| 116 | } |