osfmk/kern/thread_swap.c

   1 /*
   2  * Copyright (c) 2000 Apple Computer, Inc. All rights reserved.
   3  *
   4  * @APPLE_LICENSE_HEADER_START@
   5  *
   6  * The contents of this file constitute Original Code as defined in and
   7  * are subject to the Apple Public Source License Version 1.1 (the
   8  * "License").  You may not use this file except in compliance with the
   9  * License.  Please obtain a copy of the License at
  10  * http://www.apple.com/publicsource and read it before using this file.
  11  *
  12  * This Original Code and all software distributed under the License are
  13  * distributed on an "AS IS" basis, WITHOUT WARRANTY OF ANY KIND, EITHER
  14  * EXPRESS OR IMPLIED, AND APPLE HEREBY DISCLAIMS ALL SUCH WARRANTIES,
  15  * INCLUDING WITHOUT LIMITATION, ANY WARRANTIES OF MERCHANTABILITY,
  16  * FITNESS FOR A PARTICULAR PURPOSE OR NON-INFRINGEMENT.  Please see the
  17  * License for the specific language governing rights and limitations
  18  * under the License.
  19  *
  20  * @APPLE_LICENSE_HEADER_END@
  21  */
  22 /*
  23  * @OSF_COPYRIGHT@
  24  */
  25 /*
  26  * Mach Operating System
  27  * Copyright (c) 1991,1990,1989,1988,1987 Carnegie Mellon University
  28  * All Rights Reserved.
  29  *
  30  * Permission to use, copy, modify and distribute this software and its
  31  * documentation is hereby granted, provided that both the copyright
  32  * notice and this permission notice appear in all copies of the
  33  * software, derivative works or modified versions, and any portions
  34  * thereof, and that both notices appear in supporting documentation.
  35  *
  36  * CARNEGIE MELLON ALLOWS FREE USE OF THIS SOFTWARE IN ITS "AS IS"
  37  * CONDITION.  CARNEGIE MELLON DISCLAIMS ANY LIABILITY OF ANY KIND FOR
  38  * ANY DAMAGES WHATSOEVER RESULTING FROM THE USE OF THIS SOFTWARE.
  39  *
  40  * Carnegie Mellon requests users of this software to return to
  41  *
  42  *  Software Distribution Coordinator  or  Software.Distribution@CS.CMU.EDU
  43  *  School of Computer Science
  44  *  Carnegie Mellon University
  45  *  Pittsburgh PA 15213-3890
  46  *
  47  * any improvements or extensions that they make and grant Carnegie Mellon
  48  * the rights to redistribute these changes.
  49  */
  50 /*
  51  */
  52
  53 #include <kern/thread.h>
  54 #include <kern/lock.h>
  55 #include <vm/vm_map.h>
  56 #include <vm/vm_kern.h>
  57 #include <mach/vm_param.h>
  58 #include <kern/sched_prim.h>
  59 #include <kern/processor.h>
  60 #include <kern/thread_swap.h>
  61 #include <kern/spl.h>           /* for splsched */
  62 #include <kern/misc_protos.h>
  63 #include <kern/counters.h>
  64 #include <mach/policy.h>
  65
  66 queue_head_t            swapin_queue;
  67 decl_simple_lock_data(,swapin_lock)
  68
  69 mach_counter_t c_swapin_thread_block;
  70
  71 void    swapin_thread(void);
  72
  73 /*
  74  *      swapin_init: [exported]
  75  *
  76  *      Initialize the swapper module.
  77  */
  78 void
  79 swapin_init(void)
  80 {
  81          queue_init(&swapin_queue);
  82          simple_lock_init(&swapin_lock, ETAP_THREAD_SWAPPER);
  83          kernel_thread_with_priority(
  84                                                 kernel_task, BASEPRI_PREEMPT - 2,
  85                                                                                 swapin_thread, TRUE, TRUE);
  86 }
  87
  88 /*
  89  *      thread_swapin: [exported]
  90  *
  91  *      Place the specified thread in the list of threads to swapin.
  92  *      Called with thread locked, returned unlocked.
  93  */
  94
  95 void
  96 thread_swapin(
  97         register thread_t       thread)
  98 {
  99         switch (thread->state & TH_STACK_STATE) {
 100
 101         case TH_STACK_HANDOFF:
 102                 /*
 103                  *      Swapped out.
 104                  */
 105                 thread->state = (thread->state & ~TH_STACK_STATE) | TH_STACK_ALLOC;
 106                 thread_unlock(thread);
 107                 simple_lock(&swapin_lock);
 108                 enqueue_tail(&swapin_queue, (queue_entry_t) thread);
 109                 simple_unlock(&swapin_lock);
 110                 thread_wakeup((event_t)&swapin_queue);
 111                 break;
 112
 113         case TH_STACK_ALLOC:
 114                 /*
 115                  *      Already queued.
 116                  */
 117                 thread_unlock(thread);
 118                 break;
 119
 120         default:
 121                 /*
 122                  *      Already swapped in.
 123                  */
 124                 panic("thread_swapin");
 125         }
 126 }
 127
 128 /*
 129  *      thread_doswapin:
 130  *
 131  *      Swapin the specified thread, if it should be runnable, then put
 132  *      it on a run queue.
 133  */
 134 void
 135 thread_doswapin(
 136         register thread_t       thread)
 137 {
 138         vm_offset_t             stack;
 139         spl_t                   s;
 140
 141         /*
 142          *      Allocate the kernel stack.
 143          */
 144         stack = stack_alloc(thread, thread_continue);
 145         assert(stack);
 146
 147         /*
 148          *      Place on run queue.
 149          */
 150         s = splsched();
 151         thread_lock(thread);
 152         thread->state &= ~(TH_STACK_HANDOFF | TH_STACK_ALLOC);
 153         if (thread->state & TH_RUN)
 154                 thread_setrun(thread, HEAD_Q);
 155         thread_unlock(thread);
 156         (void) splx(s);
 157 }
 158
 159 /*
 160  *      swapin_thread: [exported]
 161  *
 162  *      This procedure executes as a kernel thread.  Threads that need to
 163  *      be swapped in are swapped in by this thread.
 164  */
 165 void
 166 swapin_thread_continue(void)
 167 {
 168         register thread_t       thread;
 169
 170         (void)splsched();
 171         simple_lock(&swapin_lock);
 172
 173         while ((thread = (thread_t)dequeue_head(&swapin_queue)) != THREAD_NULL) {
 174                 simple_unlock(&swapin_lock);
 175                 (void)spllo();
 176
 177                 thread_doswapin(thread);
 178
 179                 (void)splsched();
 180                 simple_lock(&swapin_lock);
 181         }
 182
 183         assert_wait((event_t)&swapin_queue, THREAD_UNINT);
 184         simple_unlock(&swapin_lock);
 185         (void)spllo();
 186
 187         counter(c_swapin_thread_block++);
 188         thread_block(swapin_thread_continue);
 189         /*NOTREACHED*/
 190 }
 191
 192 void
 193 swapin_thread(void)
 194 {
 195         thread_t        self = current_thread();
 196
 197         stack_privilege(self);
 198
 199         swapin_thread_continue();
 200         /*NOTREACHED*/
 201 }