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Annotation of sys/uvm/uvm_page_i.h, Revision 1.1.1.1

1.1       nbrk        1: /*     $OpenBSD: uvm_page_i.h,v 1.17 2007/04/13 18:57:49 art Exp $     */
                      2: /*     $NetBSD: uvm_page_i.h,v 1.14 2000/11/27 07:47:42 chs Exp $      */
                      3:
                      4: /*
                      5:  * Copyright (c) 1997 Charles D. Cranor and Washington University.
                      6:  * Copyright (c) 1991, 1993, The Regents of the University of California.
                      7:  *
                      8:  * All rights reserved.
                      9:  *
                     10:  * This code is derived from software contributed to Berkeley by
                     11:  * The Mach Operating System project at Carnegie-Mellon University.
                     12:  *
                     13:  * Redistribution and use in source and binary forms, with or without
                     14:  * modification, are permitted provided that the following conditions
                     15:  * are met:
                     16:  * 1. Redistributions of source code must retain the above copyright
                     17:  *    notice, this list of conditions and the following disclaimer.
                     18:  * 2. Redistributions in binary form must reproduce the above copyright
                     19:  *    notice, this list of conditions and the following disclaimer in the
                     20:  *    documentation and/or other materials provided with the distribution.
                     21:  * 3. All advertising materials mentioning features or use of this software
                     22:  *    must display the following acknowledgement:
                     23:  *     This product includes software developed by Charles D. Cranor,
                     24:  *      Washington University, the University of California, Berkeley and
                     25:  *      its contributors.
                     26:  * 4. Neither the name of the University nor the names of its contributors
                     27:  *    may be used to endorse or promote products derived from this software
                     28:  *    without specific prior written permission.
                     29:  *
                     30:  * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
                     31:  * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
                     32:  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
                     33:  * ARE DISCLAIMED.  IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
                     34:  * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
                     35:  * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
                     36:  * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
                     37:  * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
                     38:  * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
                     39:  * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
                     40:  * SUCH DAMAGE.
                     41:  *
                     42:  *     @(#)vm_page.c   8.3 (Berkeley) 3/21/94
                     43:  * from: Id: uvm_page_i.h,v 1.1.2.7 1998/01/05 00:26:02 chuck Exp
                     44:  *
                     45:  *
                     46:  * Copyright (c) 1987, 1990 Carnegie-Mellon University.
                     47:  * All rights reserved.
                     48:  *
                     49:  * Permission to use, copy, modify and distribute this software and
                     50:  * its documentation is hereby granted, provided that both the copyright
                     51:  * notice and this permission notice appear in all copies of the
                     52:  * software, derivative works or modified versions, and any portions
                     53:  * thereof, and that both notices appear in supporting documentation.
                     54:  *
                     55:  * CARNEGIE MELLON ALLOWS FREE USE OF THIS SOFTWARE IN ITS "AS IS"
                     56:  * CONDITION.  CARNEGIE MELLON DISCLAIMS ANY LIABILITY OF ANY KIND
                     57:  * FOR ANY DAMAGES WHATSOEVER RESULTING FROM THE USE OF THIS SOFTWARE.
                     58:  *
                     59:  * Carnegie Mellon requests users of this software to return to
                     60:  *
                     61:  *  Software Distribution Coordinator  or  Software.Distribution@CS.CMU.EDU
                     62:  *  School of Computer Science
                     63:  *  Carnegie Mellon University
                     64:  *  Pittsburgh PA 15213-3890
                     65:  *
                     66:  * any improvements or extensions that they make and grant Carnegie the
                     67:  * rights to redistribute these changes.
                     68:  */
                     69:
                     70: #ifndef _UVM_UVM_PAGE_I_H_
                     71: #define _UVM_UVM_PAGE_I_H_
                     72:
                     73: /*
                     74:  * uvm_page_i.h
                     75:  */
                     76:
                     77: /*
                     78:  * inline functions [maybe]
                     79:  */
                     80:
                     81: #if defined(UVM_PAGE_INLINE) || defined(UVM_PAGE)
                     82:
                     83: /*
                     84:  * uvm_lock_fpageq: lock the free page queue
                     85:  *
                     86:  * => free page queue can be accessed in interrupt context, so this
                     87:  *     blocks all interrupts that can cause memory allocation, and
                     88:  *     returns the previous interrupt level.
                     89:  */
                     90:
                     91: PAGE_INLINE int
                     92: uvm_lock_fpageq(void)
                     93: {
                     94:        int s;
                     95:
                     96:        s = splvm();
                     97:        simple_lock(&uvm.fpageqlock);
                     98:        return (s);
                     99: }
                    100:
                    101: /*
                    102:  * uvm_unlock_fpageq: unlock the free page queue
                    103:  *
                    104:  * => caller must supply interrupt level returned by uvm_lock_fpageq()
                    105:  *     so that it may be restored.
                    106:  */
                    107:
                    108: PAGE_INLINE void
                    109: uvm_unlock_fpageq(int s)
                    110: {
                    111:
                    112:        simple_unlock(&uvm.fpageqlock);
                    113:        splx(s);
                    114: }
                    115:
                    116: /*
                    117:  * uvm_pagelookup: look up a page
                    118:  *
                    119:  * => caller should lock object to keep someone from pulling the page
                    120:  *     out from under it
                    121:  */
                    122:
                    123: struct vm_page *
                    124: uvm_pagelookup(struct uvm_object *obj, voff_t off)
                    125: {
                    126:        struct vm_page *pg;
                    127:        struct pglist *buck;
                    128:        int s;
                    129:
                    130:        buck = &uvm.page_hash[uvm_pagehash(obj,off)];
                    131:
                    132:        s = splvm();
                    133:        simple_lock(&uvm.hashlock);
                    134:        TAILQ_FOREACH(pg, buck, hashq) {
                    135:                if (pg->uobject == obj && pg->offset == off) {
                    136:                        break;
                    137:                }
                    138:        }
                    139:        simple_unlock(&uvm.hashlock);
                    140:        splx(s);
                    141:        return(pg);
                    142: }
                    143:
                    144: /*
                    145:  * uvm_pagewire: wire the page, thus removing it from the daemon's grasp
                    146:  *
                    147:  * => caller must lock page queues
                    148:  */
                    149:
                    150: PAGE_INLINE void
                    151: uvm_pagewire(struct vm_page *pg)
                    152: {
                    153:        if (pg->wire_count == 0) {
                    154:                if (pg->pg_flags & PQ_ACTIVE) {
                    155:                        TAILQ_REMOVE(&uvm.page_active, pg, pageq);
                    156:                        atomic_clearbits_int(&pg->pg_flags, PQ_ACTIVE);
                    157:                        uvmexp.active--;
                    158:                }
                    159:                if (pg->pg_flags & PQ_INACTIVE) {
                    160:                        if (pg->pg_flags & PQ_SWAPBACKED)
                    161:                                TAILQ_REMOVE(&uvm.page_inactive_swp, pg, pageq);
                    162:                        else
                    163:                                TAILQ_REMOVE(&uvm.page_inactive_obj, pg, pageq);
                    164:                        atomic_clearbits_int(&pg->pg_flags, PQ_INACTIVE);
                    165:                        uvmexp.inactive--;
                    166:                }
                    167:                uvmexp.wired++;
                    168:        }
                    169:        pg->wire_count++;
                    170: }
                    171:
                    172: /*
                    173:  * uvm_pageunwire: unwire the page.
                    174:  *
                    175:  * => activate if wire count goes to zero.
                    176:  * => caller must lock page queues
                    177:  */
                    178:
                    179: PAGE_INLINE void
                    180: uvm_pageunwire(struct vm_page *pg)
                    181: {
                    182:        pg->wire_count--;
                    183:        if (pg->wire_count == 0) {
                    184:                TAILQ_INSERT_TAIL(&uvm.page_active, pg, pageq);
                    185:                uvmexp.active++;
                    186:                atomic_setbits_int(&pg->pg_flags, PQ_ACTIVE);
                    187:                uvmexp.wired--;
                    188:        }
                    189: }
                    190:
                    191: /*
                    192:  * uvm_pagedeactivate: deactivate page -- no pmaps have access to page
                    193:  *
                    194:  * => caller must lock page queues
                    195:  * => caller must check to make sure page is not wired
                    196:  * => object that page belongs to must be locked (so we can adjust pg->flags)
                    197:  */
                    198:
                    199: PAGE_INLINE void
                    200: uvm_pagedeactivate(struct vm_page *pg)
                    201: {
                    202:        if (pg->pg_flags & PQ_ACTIVE) {
                    203:                TAILQ_REMOVE(&uvm.page_active, pg, pageq);
                    204:                atomic_clearbits_int(&pg->pg_flags, PQ_ACTIVE);
                    205:                uvmexp.active--;
                    206:        }
                    207:        if ((pg->pg_flags & PQ_INACTIVE) == 0) {
                    208:                KASSERT(pg->wire_count == 0);
                    209:                if (pg->pg_flags & PQ_SWAPBACKED)
                    210:                        TAILQ_INSERT_TAIL(&uvm.page_inactive_swp, pg, pageq);
                    211:                else
                    212:                        TAILQ_INSERT_TAIL(&uvm.page_inactive_obj, pg, pageq);
                    213:                atomic_setbits_int(&pg->pg_flags, PQ_INACTIVE);
                    214:                uvmexp.inactive++;
                    215:                pmap_clear_reference(pg);
                    216:                /*
                    217:                 * update the "clean" bit.  this isn't 100%
                    218:                 * accurate, and doesn't have to be.  we'll
                    219:                 * re-sync it after we zap all mappings when
                    220:                 * scanning the inactive list.
                    221:                 */
                    222:                if ((pg->pg_flags & PG_CLEAN) != 0 &&
                    223:                    pmap_is_modified(pg))
                    224:                        atomic_clearbits_int(&pg->pg_flags, PG_CLEAN);
                    225:        }
                    226: }
                    227:
                    228: /*
                    229:  * uvm_pageactivate: activate page
                    230:  *
                    231:  * => caller must lock page queues
                    232:  */
                    233:
                    234: PAGE_INLINE void
                    235: uvm_pageactivate(struct vm_page *pg)
                    236: {
                    237:        if (pg->pg_flags & PQ_INACTIVE) {
                    238:                if (pg->pg_flags & PQ_SWAPBACKED)
                    239:                        TAILQ_REMOVE(&uvm.page_inactive_swp, pg, pageq);
                    240:                else
                    241:                        TAILQ_REMOVE(&uvm.page_inactive_obj, pg, pageq);
                    242:                atomic_clearbits_int(&pg->pg_flags, PQ_INACTIVE);
                    243:                uvmexp.inactive--;
                    244:        }
                    245:        if (pg->wire_count == 0) {
                    246:
                    247:                /*
                    248:                 * if page is already active, remove it from list so we
                    249:                 * can put it at tail.  if it wasn't active, then mark
                    250:                 * it active and bump active count
                    251:                 */
                    252:                if (pg->pg_flags & PQ_ACTIVE)
                    253:                        TAILQ_REMOVE(&uvm.page_active, pg, pageq);
                    254:                else {
                    255:                        atomic_setbits_int(&pg->pg_flags, PQ_ACTIVE);
                    256:                        uvmexp.active++;
                    257:                }
                    258:
                    259:                TAILQ_INSERT_TAIL(&uvm.page_active, pg, pageq);
                    260:        }
                    261: }
                    262:
                    263: /*
                    264:  * uvm_pagezero: zero fill a page
                    265:  *
                    266:  * => if page is part of an object then the object should be locked
                    267:  *     to protect pg->flags.
                    268:  */
                    269:
                    270: PAGE_INLINE void
                    271: uvm_pagezero(struct vm_page *pg)
                    272: {
                    273:        atomic_clearbits_int(&pg->pg_flags, PG_CLEAN);
                    274:        pmap_zero_page(pg);
                    275: }
                    276:
                    277: /*
                    278:  * uvm_pagecopy: copy a page
                    279:  *
                    280:  * => if page is part of an object then the object should be locked
                    281:  *     to protect pg->flags.
                    282:  */
                    283:
                    284: PAGE_INLINE void
                    285: uvm_pagecopy(struct vm_page *src, struct vm_page *dst)
                    286: {
                    287:        atomic_clearbits_int(&dst->pg_flags, PG_CLEAN);
                    288:        pmap_copy_page(src, dst);
                    289: }
                    290:
                    291: /*
                    292:  * uvm_page_lookup_freelist: look up the free list for the specified page
                    293:  */
                    294:
                    295: PAGE_INLINE int
                    296: uvm_page_lookup_freelist(struct vm_page *pg)
                    297: {
                    298:        int lcv;
                    299:
                    300:        lcv = vm_physseg_find(atop(VM_PAGE_TO_PHYS(pg)), NULL);
                    301:        KASSERT(lcv != -1);
                    302:        return (vm_physmem[lcv].free_list);
                    303: }
                    304:
                    305: #endif /* defined(UVM_PAGE_INLINE) || defined(UVM_PAGE) */
                    306:
                    307: #endif /* _UVM_UVM_PAGE_I_H_ */

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