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Annotation of Net2/vm/vm_pager.c, revision 1.1

1.1     ! root        1: /* 
        !             2:  * Copyright (c) 1991 Regents of the University of California.
        !             3:  * All rights reserved.
        !             4:  *
        !             5:  * This code is derived from software contributed to Berkeley by
        !             6:  * The Mach Operating System project at Carnegie-Mellon University.
        !             7:  *
        !             8:  * Redistribution and use in source and binary forms, with or without
        !             9:  * modification, are permitted provided that the following conditions
        !            10:  * are met:
        !            11:  * 1. Redistributions of source code must retain the above copyright
        !            12:  *    notice, this list of conditions and the following disclaimer.
        !            13:  * 2. Redistributions in binary form must reproduce the above copyright
        !            14:  *    notice, this list of conditions and the following disclaimer in the
        !            15:  *    documentation and/or other materials provided with the distribution.
        !            16:  * 3. All advertising materials mentioning features or use of this software
        !            17:  *    must display the following acknowledgement:
        !            18:  *     This product includes software developed by the University of
        !            19:  *     California, Berkeley and its contributors.
        !            20:  * 4. Neither the name of the University nor the names of its contributors
        !            21:  *    may be used to endorse or promote products derived from this software
        !            22:  *    without specific prior written permission.
        !            23:  *
        !            24:  * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
        !            25:  * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
        !            26:  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
        !            27:  * ARE DISCLAIMED.  IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
        !            28:  * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
        !            29:  * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
        !            30:  * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
        !            31:  * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
        !            32:  * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
        !            33:  * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
        !            34:  * SUCH DAMAGE.
        !            35:  *
        !            36:  *     @(#)vm_pager.c  7.4 (Berkeley) 5/7/91
        !            37:  *
        !            38:  *
        !            39:  * Copyright (c) 1987, 1990 Carnegie-Mellon University.
        !            40:  * All rights reserved.
        !            41:  *
        !            42:  * Authors: Avadis Tevanian, Jr., Michael Wayne Young
        !            43:  * 
        !            44:  * Permission to use, copy, modify and distribute this software and
        !            45:  * its documentation is hereby granted, provided that both the copyright
        !            46:  * notice and this permission notice appear in all copies of the
        !            47:  * software, derivative works or modified versions, and any portions
        !            48:  * thereof, and that both notices appear in supporting documentation.
        !            49:  * 
        !            50:  * CARNEGIE MELLON ALLOWS FREE USE OF THIS SOFTWARE IN ITS "AS IS" 
        !            51:  * CONDITION.  CARNEGIE MELLON DISCLAIMS ANY LIABILITY OF ANY KIND 
        !            52:  * FOR ANY DAMAGES WHATSOEVER RESULTING FROM THE USE OF THIS SOFTWARE.
        !            53:  * 
        !            54:  * Carnegie Mellon requests users of this software to return to
        !            55:  *
        !            56:  *  Software Distribution Coordinator  or  [email protected]
        !            57:  *  School of Computer Science
        !            58:  *  Carnegie Mellon University
        !            59:  *  Pittsburgh PA 15213-3890
        !            60:  *
        !            61:  * any improvements or extensions that they make and grant Carnegie the
        !            62:  * rights to redistribute these changes.
        !            63:  */
        !            64: 
        !            65: /*
        !            66:  *     Paging space routine stubs.  Emulates a matchmaker-like interface
        !            67:  *     for builtin pagers.
        !            68:  */
        !            69: 
        !            70: #include "param.h"
        !            71: #include "malloc.h"
        !            72: 
        !            73: #include "vm.h"
        !            74: #include "vm_page.h"
        !            75: #include "vm_kern.h"
        !            76: 
        !            77: #include "swappager.h"
        !            78: 
        !            79: #if NSWAPPAGER > 0
        !            80: extern struct pagerops swappagerops;
        !            81: #else
        !            82: #define        swappagerops    NULL
        !            83: #endif
        !            84: #include "vnodepager.h"
        !            85: #if NVNODEPAGER > 0
        !            86: extern struct pagerops vnodepagerops;
        !            87: #else
        !            88: #define        vnodepagerops   NULL
        !            89: #endif
        !            90: #include "devpager.h"
        !            91: #if NDEVPAGER > 0
        !            92: extern struct pagerops devicepagerops;
        !            93: #else
        !            94: #define        devicepagerops  NULL
        !            95: #endif
        !            96: 
        !            97: struct pagerops *pagertab[] = {
        !            98:        &swappagerops,          /* PG_SWAP */
        !            99:        &vnodepagerops,         /* PG_VNODE */
        !           100:        &devicepagerops,        /* PG_DEV */
        !           101: };
        !           102: int npagers = sizeof (pagertab) / sizeof (pagertab[0]);
        !           103: 
        !           104: struct pagerops *dfltpagerops = NULL;  /* default pager */
        !           105: 
        !           106: /*
        !           107:  * Kernel address space for mapping pages.
        !           108:  * Used by pagers where KVAs are needed for IO.
        !           109:  */
        !           110: #define PAGER_MAP_SIZE (256 * PAGE_SIZE)
        !           111: vm_map_t pager_map;
        !           112: vm_offset_t pager_sva, pager_eva;
        !           113: 
        !           114: void
        !           115: vm_pager_init()
        !           116: {
        !           117:        struct pagerops **pgops;
        !           118: 
        !           119:        /*
        !           120:         * Allocate a kernel submap for tracking get/put page mappings
        !           121:         */
        !           122:        pager_map = kmem_suballoc(kernel_map, &pager_sva, &pager_eva,
        !           123:                                  PAGER_MAP_SIZE, FALSE);
        !           124:        /*
        !           125:         * Initialize known pagers
        !           126:         */
        !           127:        for (pgops = pagertab; pgops < &pagertab[npagers]; pgops++)
        !           128:                (*(*pgops)->pgo_init)();
        !           129:        if (dfltpagerops == NULL)
        !           130:                panic("no default pager");
        !           131: }
        !           132: 
        !           133: /*
        !           134:  * Allocate an instance of a pager of the given type.
        !           135:  */
        !           136: vm_pager_t
        !           137: vm_pager_allocate(type, handle, size, prot)
        !           138:        int type;
        !           139:        caddr_t handle;
        !           140:        vm_size_t size;
        !           141:        vm_prot_t prot;
        !           142: {
        !           143:        vm_pager_t pager;
        !           144:        struct pagerops *ops;
        !           145: 
        !           146:        ops = (type == PG_DFLT) ? dfltpagerops : pagertab[type];
        !           147:        return((*ops->pgo_alloc)(handle, size, prot));
        !           148: }
        !           149: 
        !           150: void
        !           151: vm_pager_deallocate(pager)
        !           152:        vm_pager_t      pager;
        !           153: {
        !           154:        if (pager == NULL)
        !           155:                panic("vm_pager_deallocate: null pager");
        !           156: 
        !           157:        VM_PAGER_DEALLOC(pager);
        !           158: }
        !           159: 
        !           160: vm_pager_get(pager, m, sync)
        !           161:        vm_pager_t      pager;
        !           162:        vm_page_t       m;
        !           163:        boolean_t       sync;
        !           164: {
        !           165:        extern boolean_t vm_page_zero_fill();
        !           166: 
        !           167:        if (pager == NULL)
        !           168:                return(vm_page_zero_fill(m) ? VM_PAGER_OK : VM_PAGER_FAIL);
        !           169:        return(VM_PAGER_GET(pager, m, sync));
        !           170: }
        !           171: 
        !           172: vm_pager_put(pager, m, sync)
        !           173:        vm_pager_t      pager;
        !           174:        vm_page_t       m;
        !           175:        boolean_t       sync;
        !           176: {
        !           177:        if (pager == NULL)
        !           178:                panic("vm_pager_put: null pager");
        !           179:        return(VM_PAGER_PUT(pager, m, sync));
        !           180: }
        !           181: 
        !           182: boolean_t
        !           183: vm_pager_has_page(pager, offset)
        !           184:        vm_pager_t      pager;
        !           185:        vm_offset_t     offset;
        !           186: {
        !           187:        if (pager == NULL)
        !           188:                panic("vm_pager_has_page");
        !           189:        return(VM_PAGER_HASPAGE(pager, offset));
        !           190: }
        !           191: 
        !           192: /*
        !           193:  * Called by pageout daemon before going back to sleep.
        !           194:  * Gives pagers a chance to clean up any completed async pageing operations.
        !           195:  */
        !           196: void
        !           197: vm_pager_sync()
        !           198: {
        !           199:        struct pagerops **pgops;
        !           200: 
        !           201:        for (pgops = pagertab; pgops < &pagertab[npagers]; pgops++)
        !           202:                (*(*pgops)->pgo_putpage)(NULL, NULL, FALSE);
        !           203: }
        !           204: 
        !           205: vm_offset_t
        !           206: vm_pager_map_page(m)
        !           207:        vm_page_t       m;
        !           208: {
        !           209:        vm_offset_t kva;
        !           210: 
        !           211: #ifdef DEBUG
        !           212:        if (!m->busy || m->active)
        !           213:                panic("vm_pager_map_page: page active or not busy");
        !           214:        if (m->pagerowned)
        !           215:                printf("vm_pager_map_page: page %x already in pager\n", m);
        !           216: #endif
        !           217:        kva = kmem_alloc_wait(pager_map, PAGE_SIZE);
        !           218: #ifdef DEBUG
        !           219:        m->pagerowned = 1;
        !           220: #endif
        !           221:        pmap_enter(vm_map_pmap(pager_map), kva, VM_PAGE_TO_PHYS(m),
        !           222:                   VM_PROT_DEFAULT, TRUE);
        !           223:        return(kva);
        !           224: }
        !           225: 
        !           226: void
        !           227: vm_pager_unmap_page(kva)
        !           228:        vm_offset_t     kva;
        !           229: {
        !           230: #ifdef DEBUG
        !           231:        vm_page_t m;
        !           232: 
        !           233:        m = PHYS_TO_VM_PAGE(pmap_extract(vm_map_pmap(pager_map), kva));
        !           234: #endif
        !           235:        pmap_remove(vm_map_pmap(pager_map), kva, kva + PAGE_SIZE);
        !           236:        kmem_free_wakeup(pager_map, kva, PAGE_SIZE);
        !           237: #ifdef DEBUG
        !           238:        if (m->pagerowned)
        !           239:                m->pagerowned = 0;
        !           240:        else
        !           241:                printf("vm_pager_unmap_page: page %x(%x/%x) not owned\n",
        !           242:                       m, kva, VM_PAGE_TO_PHYS(m));
        !           243: #endif
        !           244: }
        !           245: 
        !           246: vm_pager_t
        !           247: vm_pager_lookup(list, handle)
        !           248:        register queue_head_t *list;
        !           249:        caddr_t handle;
        !           250: {
        !           251:        register vm_pager_t pager;
        !           252: 
        !           253:        pager = (vm_pager_t) queue_first(list);
        !           254:        while (!queue_end(list, (queue_entry_t)pager)) {
        !           255:                if (pager->pg_handle == handle)
        !           256:                        return(pager);
        !           257:                pager = (vm_pager_t) queue_next(&pager->pg_list);
        !           258:        }
        !           259:        return(NULL);
        !           260: }
        !           261: 
        !           262: /*
        !           263:  * This routine gains a reference to the object.
        !           264:  * Explicit deallocation is necessary.
        !           265:  */
        !           266: pager_cache(object, should_cache)
        !           267:        vm_object_t     object;
        !           268:        boolean_t       should_cache;
        !           269: {
        !           270:        if (object == NULL)
        !           271:                return(KERN_INVALID_ARGUMENT);
        !           272: 
        !           273:        vm_object_cache_lock();
        !           274:        vm_object_lock(object);
        !           275:        object->can_persist = should_cache;
        !           276:        vm_object_unlock(object);
        !           277:        vm_object_cache_unlock();
        !           278: 
        !           279:        vm_object_deallocate(object);
        !           280: 
        !           281:        return(KERN_SUCCESS);
        !           282: }

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