Rev 1705 | Rev 1757 | Go to most recent revision | Details | Compare with Previous | Last modification | View Log | RSS feed
| Rev | Author | Line No. | Line |
|---|---|---|---|
| 1 | jermar | 1 | /* |
| 2 | * Copyright (C) 2001-2004 Jakub Jermar |
||
| 3 | * All rights reserved. |
||
| 4 | * |
||
| 5 | * Redistribution and use in source and binary forms, with or without |
||
| 6 | * modification, are permitted provided that the following conditions |
||
| 7 | * are met: |
||
| 8 | * |
||
| 9 | * - Redistributions of source code must retain the above copyright |
||
| 10 | * notice, this list of conditions and the following disclaimer. |
||
| 11 | * - Redistributions in binary form must reproduce the above copyright |
||
| 12 | * notice, this list of conditions and the following disclaimer in the |
||
| 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 |
||
| 15 | * derived from this software without specific prior written permission. |
||
| 16 | * |
||
| 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 |
||
| 19 | * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED. |
||
| 20 | * IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT, |
||
| 21 | * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT |
||
| 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 |
||
| 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 |
||
| 26 | * THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE. |
||
| 27 | */ |
||
| 28 | |||
| 1731 | jermar | 29 | /** @addtogroup time |
| 1702 | cejka | 30 | * @{ |
| 31 | */ |
||
| 32 | |||
| 1264 | jermar | 33 | /** |
| 1702 | cejka | 34 | * @file |
| 1264 | jermar | 35 | * @brief High-level clock interrupt handler. |
| 36 | * |
||
| 37 | * This file contains the clock() function which is the source |
||
| 38 | * of preemption. It is also responsible for executing expired |
||
| 39 | * timeouts. |
||
| 40 | */ |
||
| 41 | |||
| 1 | jermar | 42 | #include <time/clock.h> |
| 43 | #include <time/timeout.h> |
||
| 44 | #include <arch/types.h> |
||
| 45 | #include <config.h> |
||
| 46 | #include <synch/spinlock.h> |
||
| 47 | #include <synch/waitq.h> |
||
| 48 | #include <func.h> |
||
| 49 | #include <proc/scheduler.h> |
||
| 50 | #include <cpu.h> |
||
| 51 | #include <arch.h> |
||
| 788 | jermar | 52 | #include <adt/list.h> |
| 1104 | jermar | 53 | #include <atomic.h> |
| 391 | jermar | 54 | #include <proc/thread.h> |
| 1434 | palkovsky | 55 | #include <sysinfo/sysinfo.h> |
| 56 | #include <arch/barrier.h> |
||
| 1 | jermar | 57 | |
| 1434 | palkovsky | 58 | /* Pointers to public variables with time */ |
| 59 | struct ptime { |
||
| 1438 | palkovsky | 60 | __native seconds1; |
| 1434 | palkovsky | 61 | __native useconds; |
| 1438 | palkovsky | 62 | __native seconds2; |
| 1434 | palkovsky | 63 | }; |
| 64 | struct ptime *public_time; |
||
| 65 | /* Variable holding fragment of second, so that we would update |
||
| 66 | * seconds correctly |
||
| 67 | */ |
||
| 68 | static __native secfrag = 0; |
||
| 69 | |||
| 70 | /** Initialize realtime clock counter |
||
| 71 | * |
||
| 72 | * The applications (and sometimes kernel) need to access accurate |
||
| 73 | * information about realtime data. We allocate 1 page with these |
||
| 74 | * data and update it periodically. |
||
| 75 | * |
||
| 76 | * |
||
| 77 | */ |
||
| 78 | void clock_counter_init(void) |
||
| 79 | { |
||
| 80 | void *faddr; |
||
| 81 | |||
| 82 | faddr = (void *)PFN2ADDR(frame_alloc(0, FRAME_ATOMIC)); |
||
| 83 | if (!faddr) |
||
| 84 | panic("Cannot allocate page for clock"); |
||
| 85 | |||
| 86 | public_time = (struct ptime *)PA2KA(faddr); |
||
| 87 | |||
| 88 | /* TODO: We would need some arch dependent settings here */ |
||
| 1438 | palkovsky | 89 | public_time->seconds1 = 0; |
| 90 | public_time->seconds2 = 0; |
||
| 1434 | palkovsky | 91 | public_time->useconds = 0; |
| 92 | |||
| 93 | sysinfo_set_item_val("clock.faddr", NULL, (__native)faddr); |
||
| 94 | } |
||
| 95 | |||
| 96 | |||
| 97 | /** Update public counters |
||
| 98 | * |
||
| 99 | * Update it only on first processor |
||
| 100 | * TODO: Do we really need so many write barriers? |
||
| 101 | */ |
||
| 102 | static void clock_update_counters(void) |
||
| 103 | { |
||
| 104 | if (CPU->id == 0) { |
||
| 105 | secfrag += 1000000/HZ; |
||
| 106 | if (secfrag >= 1000000) { |
||
| 1438 | palkovsky | 107 | secfrag -= 1000000; |
| 108 | public_time->seconds1++; |
||
| 1434 | palkovsky | 109 | write_barrier(); |
| 1438 | palkovsky | 110 | public_time->useconds = secfrag; |
| 111 | write_barrier(); |
||
| 112 | public_time->seconds2 = public_time->seconds1; |
||
| 1434 | palkovsky | 113 | } else |
| 114 | public_time->useconds += 1000000/HZ; |
||
| 115 | } |
||
| 116 | } |
||
| 117 | |||
| 107 | decky | 118 | /** Clock routine |
| 119 | * |
||
| 120 | * Clock routine executed from clock interrupt handler |
||
| 413 | jermar | 121 | * (assuming interrupts_disable()'d). Runs expired timeouts |
| 107 | decky | 122 | * and preemptive scheduling. |
| 123 | * |
||
| 1 | jermar | 124 | */ |
| 125 | void clock(void) |
||
| 126 | { |
||
| 127 | link_t *l; |
||
| 128 | timeout_t *h; |
||
| 411 | jermar | 129 | timeout_handler_t f; |
| 1 | jermar | 130 | void *arg; |
| 1457 | jermar | 131 | count_t missed_clock_ticks = CPU->missed_clock_ticks; |
| 1431 | jermar | 132 | int i; |
| 1 | jermar | 133 | |
| 134 | /* |
||
| 135 | * To avoid lock ordering problems, |
||
| 136 | * run all expired timeouts as you visit them. |
||
| 137 | */ |
||
| 1457 | jermar | 138 | for (i = 0; i <= missed_clock_ticks; i++) { |
| 1434 | palkovsky | 139 | clock_update_counters(); |
| 1431 | jermar | 140 | spinlock_lock(&CPU->timeoutlock); |
| 141 | while ((l = CPU->timeout_active_head.next) != &CPU->timeout_active_head) { |
||
| 142 | h = list_get_instance(l, timeout_t, link); |
||
| 143 | spinlock_lock(&h->lock); |
||
| 144 | if (h->ticks-- != 0) { |
||
| 145 | spinlock_unlock(&h->lock); |
||
| 146 | break; |
||
| 147 | } |
||
| 148 | list_remove(l); |
||
| 149 | f = h->handler; |
||
| 150 | arg = h->arg; |
||
| 151 | timeout_reinitialize(h); |
||
| 152 | spinlock_unlock(&h->lock); |
||
| 153 | spinlock_unlock(&CPU->timeoutlock); |
||
| 154 | |||
| 155 | f(arg); |
||
| 156 | |||
| 157 | spinlock_lock(&CPU->timeoutlock); |
||
| 1 | jermar | 158 | } |
| 15 | jermar | 159 | spinlock_unlock(&CPU->timeoutlock); |
| 1 | jermar | 160 | } |
| 1431 | jermar | 161 | CPU->missed_clock_ticks = 0; |
| 1 | jermar | 162 | |
| 163 | /* |
||
| 15 | jermar | 164 | * Do CPU usage accounting and find out whether to preempt THREAD. |
| 1 | jermar | 165 | */ |
| 166 | |||
| 15 | jermar | 167 | if (THREAD) { |
| 221 | jermar | 168 | __u64 ticks; |
| 169 | |||
| 15 | jermar | 170 | spinlock_lock(&CPU->lock); |
| 1457 | jermar | 171 | CPU->needs_relink += 1 + missed_clock_ticks; |
| 15 | jermar | 172 | spinlock_unlock(&CPU->lock); |
| 1 | jermar | 173 | |
| 15 | jermar | 174 | spinlock_lock(&THREAD->lock); |
| 1457 | jermar | 175 | if ((ticks = THREAD->ticks)) { |
| 176 | if (ticks >= 1 + missed_clock_ticks) |
||
| 177 | THREAD->ticks -= 1 + missed_clock_ticks; |
||
| 178 | else |
||
| 179 | THREAD->ticks = 0; |
||
| 180 | } |
||
| 221 | jermar | 181 | spinlock_unlock(&THREAD->lock); |
| 182 | |||
| 183 | if (!ticks && !PREEMPTION_DISABLED) { |
||
| 1 | jermar | 184 | scheduler(); |
| 185 | } |
||
| 186 | } |
||
| 187 | |||
| 188 | } |
||
| 1702 | cejka | 189 | |
| 1731 | jermar | 190 | /** @} |
| 1702 | cejka | 191 | */ |
| 192 |