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  *
  54  *      File:   kern/thread_swap.c
  55  *      Author: Avadis Tevanian, Jr.
  56  *      Date:   1987
  57  *
  58  *      Mach thread swapper:
  59  *              Swap in threads that need to be run.  This is done here
  60  *              by the swapper thread since it cannot be done (in general)
  61  *              when the kernel tries to place a thread on a run queue.
  62  *
  63  *      Note: The act of swapping a thread in Mach does not mean that
  64  *      its memory gets forcibly swapped to secondary storage.  The memory
  65  *      for the task corresponding to a swapped thread is paged out
  66  *      through the normal paging mechanism.
  67  *
  68  */
  69
  70 #include <kern/thread.h>
  71 #include <kern/lock.h>
  72 #include <vm/vm_map.h>
  73 #include <vm/vm_kern.h>
  74 #include <mach/vm_param.h>
  75 #include <kern/sched_prim.h>
  76 #include <kern/sf.h>
  77 #include <kern/processor.h>
  78 #include <kern/thread_swap.h>
  79 #include <kern/spl.h>           /* for splsched */
  80 #include <kern/misc_protos.h>
  81 #include <kern/counters.h>
  82 #include <mach/policy.h>
  83
  84 queue_head_t            swapin_queue;
  85 decl_simple_lock_data(, swapper_lock_data)
  86
  87 #define swapper_lock()          simple_lock(&swapper_lock_data)
  88 #define swapper_unlock()        simple_unlock(&swapper_lock_data)
  89
  90 mach_counter_t c_swapin_thread_block;
  91
  92 /*
  93  *      swapper_init: [exported]
  94  *
  95  *      Initialize the swapper module.
  96  */
  97 void swapper_init()
  98 {
  99          queue_init(&swapin_queue);
 100          simple_lock_init(&swapper_lock_data, ETAP_THREAD_SWAPPER);
 101 }
 102
 103 /*
 104  *      thread_swapin: [exported]
 105  *
 106  *      Place the specified thread in the list of threads to swapin.  It
 107  *      is assumed that the thread is locked, therefore we are at splsched.
 108  *
 109  *      We don't bother with stack_alloc_try to optimize swapin;
 110  *      our callers have already tried that route.
 111  */
 112
 113 void thread_swapin(thread)
 114         thread_t        thread;
 115 {
 116         switch (thread->state & TH_STACK_STATE) {
 117         case TH_STACK_HANDOFF:
 118                 /*
 119                  *      Swapped out - queue for swapin thread.
 120                  */
 121                 thread->state = (thread->state & ~TH_STACK_STATE)
 122                                 | TH_STACK_COMING_IN;
 123                 swapper_lock();
 124                 enqueue_tail(&swapin_queue, (queue_entry_t) thread);
 125                 swapper_unlock();
 126                 thread_wakeup((event_t) &swapin_queue);
 127                 break;
 128
 129             case TH_STACK_COMING_IN:
 130                 /*
 131                  *      Already queued for swapin thread, or being
 132                  *      swapped in.
 133                  */
 134                 break;
 135
 136             default:
 137                 /*
 138                  *      Already swapped in.
 139                  */
 140                 panic("thread_swapin");
 141         }
 142 }
 143
 144 /*
 145  *      thread_doswapin:
 146  *
 147  *      Swapin the specified thread, if it should be runnable, then put
 148  *      it on a run queue.  No locks should be held on entry, as it is
 149  *      likely that this routine will sleep (waiting for stack allocation).
 150  */
 151 void thread_doswapin(thread)
 152         register thread_t thread;
 153 {
 154         spl_t   s;
 155         vm_offset_t stack;
 156
 157         /*
 158          * do machdep allocation
 159          */
 160
 161         /*
 162          *      Allocate the kernel stack.
 163          */
 164         stack = stack_alloc(thread, thread_continue);
 165         assert(stack);
 166
 167         /*
 168          *      Place on run queue.
 169          */
 170
 171         s = splsched();
 172         thread_lock(thread);
 173         thread->state &= ~(TH_STACK_HANDOFF | TH_STACK_COMING_IN);
 174         if (thread->state & TH_RUN)
 175                 thread_setrun(thread, TRUE, FALSE);
 176         thread_unlock(thread);
 177         (void) splx(s);
 178 }
 179
 180 /*
 181  *      swapin_thread: [exported]
 182  *
 183  *      This procedure executes as a kernel thread.  Threads that need to
 184  *      be swapped in are swapped in by this thread.
 185  */
 186 void swapin_thread_continue()
 187 {
 188         for (;;) {
 189                 register thread_t thread;
 190                 spl_t s;
 191
 192                 s = splsched();
 193                 swapper_lock();
 194
 195                 while ((thread = (thread_t) dequeue_head(&swapin_queue))
 196                                                         != THREAD_NULL) {
 197                         swapper_unlock();
 198                         (void) splx(s);
 199
 200                         thread_doswapin(thread);                /* may block */
 201
 202                         s = splsched();
 203                         swapper_lock();
 204                 }
 205
 206                 assert_wait((event_t) &swapin_queue, THREAD_UNINT);
 207                 swapper_unlock();
 208                 (void) splx(s);
 209                 counter(c_swapin_thread_block++);
 210 #if defined (__i386__)
 211                 thread_block((void (*)(void)) 0);
 212 #else
 213                 thread_block(swapin_thread_continue);
 214 #endif
 215         }
 216 }
 217
 218 void swapin_thread()
 219 {
 220         stack_privilege(current_thread());
 221         current_thread()->vm_privilege = TRUE;
 222
 223         swapin_thread_continue();
 224         /*NOTREACHED*/
 225 }