sys/uvm/uvm_object.c

   1 /*      $NetBSD: uvm_object.c,v 1.6 2008/04/28 20:24:12 martin Exp $    */
   2
   3 /*
   4  * Copyright (c) 2006 The NetBSD Foundation, Inc.
   5  * All rights reserved.
   6  *
   7  * This code is derived from software contributed to The NetBSD Foundation
   8  * by Mindaugas Rasiukevicius.
   9  *
  10  * Redistribution and use in source and binary forms, with or without
  11  * modification, are permitted provided that the following conditions
  12  * are met:
  13  * 1. Redistributions of source code must retain the above copyright
  14  *    notice, this list of conditions and the following disclaimer.
  15  * 2. Redistributions in binary form must reproduce the above copyright
  16  *    notice, this list of conditions and the following disclaimer in the
  17  *    documentation and/or other materials provided with the distribution.
  18  *
  19  * THIS SOFTWARE IS PROVIDED BY THE NETBSD FOUNDATION, INC. AND CONTRIBUTORS
  20  * ``AS IS'' AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED
  21  * TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR
  22  * PURPOSE ARE DISCLAIMED.  IN NO EVENT SHALL THE FOUNDATION OR CONTRIBUTORS
  23  * BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
  24  * CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
  25  * SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
  26  * INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
  27  * CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
  28  * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
  29  * POSSIBILITY OF SUCH DAMAGE.
  30  */
  31
  32 /*
  33  * uvm_object.c: operate with memory objects
  34  *
  35  * TODO:
  36  *  1. Support PG_RELEASED-using objects
  37  *
  38  */
  39
  40 #include <sys/cdefs.h>
  41 __KERNEL_RCSID(0, "$NetBSD: uvm_object.c,v 1.6 2008/04/28 20:24:12 martin Exp $");
  42
  43 #include "opt_ddb.h"
  44 #include "opt_uvmhist.h"
  45
  46 #include <sys/param.h>
  47
  48 #include <uvm/uvm.h>
  49 #include <uvm/uvm_ddb.h>
  50
  51 /* We will fetch this page count per step */
  52 #define FETCH_PAGECOUNT 16
  53
  54 /*
  55  * uobj_wirepages: wire the pages of entire uobj
  56  *
  57  * => NOTE: this function should only be used for types of objects
  58  *  where PG_RELEASED flag is never set (aobj objects)
  59  * => caller must pass page-aligned start and end values
  60  */
  61
  62 int
  63 uobj_wirepages(struct uvm_object *uobj, off_t start, off_t end)
  64 {
  65         int i, npages, error;
  66         struct vm_page *pgs[FETCH_PAGECOUNT], *pg = NULL;
  67         off_t offset = start, left;
  68
  69         left = (end - start) >> PAGE_SHIFT;
  70
  71         mutex_enter(&uobj->vmobjlock);
  72         while (left) {
  73
  74                 npages = MIN(FETCH_PAGECOUNT, left);
  75
  76                 /* Get the pages */
  77                 memset(pgs, 0, sizeof(pgs));
  78                 error = (*uobj->pgops->pgo_get)(uobj, offset, pgs, &npages, 0,
  79                         VM_PROT_READ | VM_PROT_WRITE, UVM_ADV_SEQUENTIAL,
  80                         PGO_ALLPAGES | PGO_SYNCIO);
  81
  82                 if (error)
  83                         goto error;
  84
  85                 mutex_enter(&uobj->vmobjlock);
  86                 for (i = 0; i < npages; i++) {
  87
  88                         KASSERT(pgs[i] != NULL);
  89                         KASSERT(!(pgs[i]->flags & PG_RELEASED));
  90
  91                         /*
  92                          * Loan break
  93                          */
  94                         if (pgs[i]->loan_count) {
  95                                 while (pgs[i]->loan_count) {
  96                                         pg = uvm_loanbreak(pgs[i]);
  97                                         if (!pg) {
  98                                                 mutex_exit(&uobj->vmobjlock);
  99                                                 uvm_wait("uobjwirepg");
 100                                                 mutex_enter(&uobj->vmobjlock);
 101                                                 continue;
 102                                         }
 103                                 }
 104                                 pgs[i] = pg;
 105                         }
 106
 107                         if (pgs[i]->pqflags & PQ_AOBJ) {
 108                                 pgs[i]->flags &= ~(PG_CLEAN);
 109                                 uao_dropswap(uobj, i);
 110                         }
 111                 }
 112
 113                 /* Wire the pages */
 114                 mutex_enter(&uvm_pageqlock);
 115                 for (i = 0; i < npages; i++) {
 116                         uvm_pagewire(pgs[i]);
 117                 }
 118                 mutex_exit(&uvm_pageqlock);
 119
 120                 /* Unbusy the pages */
 121                 uvm_page_unbusy(pgs, npages);
 122
 123                 left -= npages;
 124                 offset += npages << PAGE_SHIFT;
 125         }
 126         mutex_exit(&uobj->vmobjlock);
 127
 128         return 0;
 129
 130 error:
 131         /* Unwire the pages which has been wired */
 132         uobj_unwirepages(uobj, start, offset);
 133
 134         return error;
 135 }
 136
 137 /*
 138  * uobj_unwirepages: unwire the pages of entire uobj
 139  *
 140  * => NOTE: this function should only be used for types of objects
 141  *  where PG_RELEASED flag is never set
 142  * => caller must pass page-aligned start and end values
 143  */
 144
 145 void
 146 uobj_unwirepages(struct uvm_object *uobj, off_t start, off_t end)
 147 {
 148         struct vm_page *pg;
 149         off_t offset;
 150
 151         mutex_enter(&uobj->vmobjlock);
 152         mutex_enter(&uvm_pageqlock);
 153         for (offset = start; offset < end; offset += PAGE_SIZE) {
 154                 pg = uvm_pagelookup(uobj, offset);
 155
 156                 KASSERT(pg != NULL);
 157                 KASSERT(!(pg->flags & PG_RELEASED));
 158
 159                 uvm_pageunwire(pg);
 160         }
 161         mutex_exit(&uvm_pageqlock);
 162         mutex_exit(&uobj->vmobjlock);
 163 }
 164
 165 #if defined(DDB) || defined(DEBUGPRINT)
 166
 167 /*
 168  * uvm_object_printit: actually prints the object
 169  */
 170
 171 void
 172 uvm_object_printit(struct uvm_object *uobj, bool full,
 173     void (*pr)(const char *, ...))
 174 {
 175         struct vm_page *pg;
 176         int cnt = 0;
 177
 178         (*pr)("OBJECT %p: locked=%d, pgops=%p, npages=%d, ",
 179             uobj, mutex_owned(&uobj->vmobjlock), uobj->pgops, uobj->uo_npages);
 180         if (UVM_OBJ_IS_KERN_OBJECT(uobj))
 181                 (*pr)("refs=<SYSTEM>\n");
 182         else
 183                 (*pr)("refs=%d\n", uobj->uo_refs);
 184
 185         if (!full) {
 186                 return;
 187         }
 188         (*pr)("  PAGES <pg,offset>:\n  ");
 189         TAILQ_FOREACH(pg, &uobj->memq, listq.queue) {
 190                 cnt++;
 191                 (*pr)("<%p,0x%llx> ", pg, (long long)pg->offset);
 192                 if ((cnt % 3) == 0) {
 193                         (*pr)("\n  ");
 194                 }
 195         }
 196         if ((cnt % 3) != 0) {
 197                 (*pr)("\n");
 198         }
 199 }
 200
 201 #endif /* DDB || DEBUGPRINT */