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(swapin_thread, MINPRI_KERNEL);
  87 }
  88
  89 /*
  90  *      thread_swapin: [exported]
  91  *
  92  *      Place the specified thread in the list of threads to swapin.
  93  *      Called with thread locked, returned unlocked.
  94  */
  95
  96 void
  97 thread_swapin(
  98         register thread_t       thread)
  99 {
 100         switch (thread->state & TH_STACK_STATE) {
 101
 102         case TH_STACK_HANDOFF:
 103                 /*
 104                  *      Swapped out.
 105                  */
 106                 thread->state = (thread->state & ~TH_STACK_STATE) | TH_STACK_ALLOC;
 107                 thread_unlock(thread);
 108                 simple_lock(&swapin_lock);
 109                 enqueue_tail(&swapin_queue, (queue_entry_t) thread);
 110                 simple_unlock(&swapin_lock);
 111                 thread_wakeup((event_t)&swapin_queue);
 112                 break;
 113
 114         case TH_STACK_ALLOC:
 115                 /*
 116                  *      Already queued.
 117                  */
 118                 thread_unlock(thread);
 119                 break;
 120
 121         default:
 122                 /*
 123                  *      Already swapped in.
 124                  */
 125                 panic("thread_swapin");
 126         }
 127 }
 128
 129 /*
 130  *      thread_doswapin:
 131  *
 132  *      Swapin the specified thread, if it should be runnable, then put
 133  *      it on a run queue.
 134  */
 135 void
 136 thread_doswapin(
 137         register thread_t       thread)
 138 {
 139         vm_offset_t             stack;
 140         spl_t                   s;
 141
 142         /*
 143          *      Allocate the kernel stack.
 144          */
 145         stack = stack_alloc(thread, thread_continue);
 146         assert(stack);
 147
 148         /*
 149          *      Place on run queue.
 150          */
 151         s = splsched();
 152         thread_lock(thread);
 153         thread->state &= ~(TH_STACK_HANDOFF | TH_STACK_ALLOC);
 154         if (thread->state & TH_RUN)
 155                 thread_setrun(thread, SCHED_PREEMPT | SCHED_TAILQ);
 156         thread_unlock(thread);
 157         (void) splx(s);
 158 }
 159
 160 /*
 161  *      swapin_thread: [exported]
 162  *
 163  *      This procedure executes as a kernel thread.  Threads that need to
 164  *      be swapped in are swapped in by this thread.
 165  */
 166 void
 167 swapin_thread_continue(void)
 168 {
 169         register thread_t       thread;
 170
 171         (void)splsched();
 172         simple_lock(&swapin_lock);
 173
 174         while ((thread = (thread_t)dequeue_head(&swapin_queue)) != THREAD_NULL) {
 175                 simple_unlock(&swapin_lock);
 176                 (void)spllo();
 177
 178                 thread_doswapin(thread);
 179
 180                 (void)splsched();
 181                 simple_lock(&swapin_lock);
 182         }
 183
 184         assert_wait((event_t)&swapin_queue, THREAD_UNINT);
 185         simple_unlock(&swapin_lock);
 186         (void)spllo();
 187
 188         counter(c_swapin_thread_block++);
 189         thread_block(swapin_thread_continue);
 190         /*NOTREACHED*/
 191 }
 192
 193 void
 194 swapin_thread(void)
 195 {
 196         swapin_thread_continue();
 197         /*NOTREACHED*/
 198 }