osfmk/kern/thread_swap.c

   1 /*
   2  * Copyright (c) 2000 Apple Computer, Inc. All rights reserved.
   3  *
   4  * @APPLE_LICENSE_HEADER_START@
   5  *
   6  * Copyright (c) 1999-2003 Apple Computer, Inc.  All Rights Reserved.
   7  *
   8  * This file contains Original Code and/or Modifications of Original Code
   9  * as defined in and that are subject to the Apple Public Source License
  10  * Version 2.0 (the 'License'). You may not use this file except in
  11  * compliance with the License. Please obtain a copy of the License at
  12  * http://www.opensource.apple.com/apsl/ and read it before using this
  13  * file.
  14  *
  15  * The Original Code and all software distributed under the License are
  16  * distributed on an 'AS IS' basis, WITHOUT WARRANTY OF ANY KIND, EITHER
  17  * EXPRESS OR IMPLIED, AND APPLE HEREBY DISCLAIMS ALL SUCH WARRANTIES,
  18  * INCLUDING WITHOUT LIMITATION, ANY WARRANTIES OF MERCHANTABILITY,
  19  * FITNESS FOR A PARTICULAR PURPOSE, QUIET ENJOYMENT OR NON-INFRINGEMENT.
  20  * Please see the License for the specific language governing rights and
  21  * limitations under the License.
  22  *
  23  * @APPLE_LICENSE_HEADER_END@
  24  */
  25 /*
  26  * @OSF_COPYRIGHT@
  27  */
  28 /*
  29  * Mach Operating System
  30  * Copyright (c) 1991,1990,1989,1988,1987 Carnegie Mellon University
  31  * All Rights Reserved.
  32  *
  33  * Permission to use, copy, modify and distribute this software and its
  34  * documentation is hereby granted, provided that both the copyright
  35  * notice and this permission notice appear in all copies of the
  36  * software, derivative works or modified versions, and any portions
  37  * thereof, and that both notices appear in supporting documentation.
  38  *
  39  * CARNEGIE MELLON ALLOWS FREE USE OF THIS SOFTWARE IN ITS "AS IS"
  40  * CONDITION.  CARNEGIE MELLON DISCLAIMS ANY LIABILITY OF ANY KIND FOR
  41  * ANY DAMAGES WHATSOEVER RESULTING FROM THE USE OF THIS SOFTWARE.
  42  *
  43  * Carnegie Mellon requests users of this software to return to
  44  *
  45  *  Software Distribution Coordinator  or  Software.Distribution@CS.CMU.EDU
  46  *  School of Computer Science
  47  *  Carnegie Mellon University
  48  *  Pittsburgh PA 15213-3890
  49  *
  50  * any improvements or extensions that they make and grant Carnegie Mellon
  51  * the rights to redistribute these changes.
  52  */
  53 /*
  54  */
  55
  56 #include <kern/thread.h>
  57 #include <kern/lock.h>
  58 #include <vm/vm_map.h>
  59 #include <vm/vm_kern.h>
  60 #include <mach/vm_param.h>
  61 #include <kern/sched_prim.h>
  62 #include <kern/processor.h>
  63 #include <kern/thread_swap.h>
  64 #include <kern/spl.h>           /* for splsched */
  65 #include <kern/misc_protos.h>
  66 #include <kern/counters.h>
  67 #include <mach/policy.h>
  68
  69 queue_head_t            swapin_queue;
  70 decl_simple_lock_data(,swapin_lock)
  71
  72 mach_counter_t c_swapin_thread_block;
  73
  74 void    swapin_thread(void);
  75
  76 /*
  77  *      swapin_init: [exported]
  78  *
  79  *      Initialize the swapper module.
  80  */
  81 void
  82 swapin_init(void)
  83 {
  84          queue_init(&swapin_queue);
  85          simple_lock_init(&swapin_lock, ETAP_THREAD_SWAPPER);
  86          kernel_thread_with_priority(
  87                                                 kernel_task, BASEPRI_PREEMPT - 2,
  88                                                                                 swapin_thread, TRUE, TRUE);
  89 }
  90
  91 /*
  92  *      thread_swapin: [exported]
  93  *
  94  *      Place the specified thread in the list of threads to swapin.
  95  *      Called with thread locked, returned unlocked.
  96  */
  97
  98 void
  99 thread_swapin(
 100         register thread_t       thread)
 101 {
 102         switch (thread->state & TH_STACK_STATE) {
 103
 104         case TH_STACK_HANDOFF:
 105                 /*
 106                  *      Swapped out.
 107                  */
 108                 thread->state = (thread->state & ~TH_STACK_STATE) | TH_STACK_ALLOC;
 109                 thread_unlock(thread);
 110                 simple_lock(&swapin_lock);
 111                 enqueue_tail(&swapin_queue, (queue_entry_t) thread);
 112                 simple_unlock(&swapin_lock);
 113                 thread_wakeup((event_t)&swapin_queue);
 114                 break;
 115
 116         case TH_STACK_ALLOC:
 117                 /*
 118                  *      Already queued.
 119                  */
 120                 thread_unlock(thread);
 121                 break;
 122
 123         default:
 124                 /*
 125                  *      Already swapped in.
 126                  */
 127                 panic("thread_swapin");
 128         }
 129 }
 130
 131 /*
 132  *      thread_doswapin:
 133  *
 134  *      Swapin the specified thread, if it should be runnable, then put
 135  *      it on a run queue.
 136  */
 137 void
 138 thread_doswapin(
 139         register thread_t       thread)
 140 {
 141         vm_offset_t             stack;
 142         spl_t                   s;
 143
 144         /*
 145          *      Allocate the kernel stack.
 146          */
 147         stack = stack_alloc(thread, thread_continue);
 148         assert(stack);
 149
 150         /*
 151          *      Place on run queue.
 152          */
 153         s = splsched();
 154         thread_lock(thread);
 155         thread->state &= ~(TH_STACK_HANDOFF | TH_STACK_ALLOC);
 156         if (thread->state & TH_RUN)
 157                 thread_setrun(thread, HEAD_Q);
 158         thread_unlock(thread);
 159         (void) splx(s);
 160 }
 161
 162 /*
 163  *      swapin_thread: [exported]
 164  *
 165  *      This procedure executes as a kernel thread.  Threads that need to
 166  *      be swapped in are swapped in by this thread.
 167  */
 168 void
 169 swapin_thread_continue(void)
 170 {
 171         register thread_t       thread;
 172
 173         (void)splsched();
 174         simple_lock(&swapin_lock);
 175
 176         while ((thread = (thread_t)dequeue_head(&swapin_queue)) != THREAD_NULL) {
 177                 simple_unlock(&swapin_lock);
 178                 (void)spllo();
 179
 180                 thread_doswapin(thread);
 181
 182                 (void)splsched();
 183                 simple_lock(&swapin_lock);
 184         }
 185
 186         assert_wait((event_t)&swapin_queue, THREAD_UNINT);
 187         simple_unlock(&swapin_lock);
 188         (void)spllo();
 189
 190         counter(c_swapin_thread_block++);
 191         thread_block(swapin_thread_continue);
 192         /*NOTREACHED*/
 193 }
 194
 195 void
 196 swapin_thread(void)
 197 {
 198         thread_t        self = current_thread();
 199
 200         stack_privilege(self);
 201
 202         swapin_thread_continue();
 203         /*NOTREACHED*/
 204 }