Current Path : /sys/vm/ |
FreeBSD hs32.drive.ne.jp 9.1-RELEASE FreeBSD 9.1-RELEASE #1: Wed Jan 14 12:18:08 JST 2015 root@hs32.drive.ne.jp:/sys/amd64/compile/hs32 amd64 |
Current File : //sys/vm/default_pager.c |
/*- * Copyright (c) 1995, David Greenman * All rights reserved. * * Redistribution and use in source and binary forms, with or without * modification, are permitted provided that the following conditions * are met: * 1. Redistributions of source code must retain the above copyright * notice, this list of conditions and the following disclaimer. * 2. Redistributions in binary form must reproduce the above copyright * notice, this list of conditions and the following disclaimer in the * documentation and/or other materials provided with the distribution. * 3. All advertising materials mentioning features or use of this software * must display the following acknowledgement: * This product includes software developed by David Greenman. * 4. The name of the author may not be used to endorse or promote products * derived from this software without specific prior written permission. * * THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE * ARE DISCLAIMED. IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF * SUCH DAMAGE. * * The default pager is responsible for supplying backing store to unbacked * storage. The backing store is usually swap so we just fall through to * the swap routines. However, since swap metadata has not been assigned, * the swap routines assign and manage the swap backing store through the * vm_page->swapblk field. The object is only converted when the page is * physically freed after having been cleaned and even then vm_page->swapblk * is maintained whenever a resident page also has swap backing store. */ #include <sys/cdefs.h> __FBSDID("$FreeBSD: release/9.1.0/sys/vm/default_pager.c 216128 2010-12-02 17:37:16Z trasz $"); #include <sys/param.h> #include <sys/systm.h> #include <sys/lock.h> #include <sys/proc.h> #include <sys/resourcevar.h> #include <sys/mutex.h> #include <vm/vm.h> #include <vm/vm_object.h> #include <vm/vm_page.h> #include <vm/vm_pager.h> #include <vm/swap_pager.h> static vm_object_t default_pager_alloc(void *, vm_ooffset_t, vm_prot_t, vm_ooffset_t, struct ucred *); static void default_pager_dealloc(vm_object_t); static int default_pager_getpages(vm_object_t, vm_page_t *, int, int); static void default_pager_putpages(vm_object_t, vm_page_t *, int, boolean_t, int *); static boolean_t default_pager_haspage(vm_object_t, vm_pindex_t, int *, int *); /* * pagerops for OBJT_DEFAULT - "default pager". */ struct pagerops defaultpagerops = { .pgo_alloc = default_pager_alloc, .pgo_dealloc = default_pager_dealloc, .pgo_getpages = default_pager_getpages, .pgo_putpages = default_pager_putpages, .pgo_haspage = default_pager_haspage, }; /* * no_pager_alloc just returns an initialized object. */ static vm_object_t default_pager_alloc(void *handle, vm_ooffset_t size, vm_prot_t prot, vm_ooffset_t offset, struct ucred *cred) { vm_object_t object; if (handle != NULL) panic("default_pager_alloc: handle specified"); if (cred != NULL) { if (!swap_reserve_by_cred(size, cred)) return (NULL); crhold(cred); } object = vm_object_allocate(OBJT_DEFAULT, OFF_TO_IDX(round_page(offset + size))); if (cred != NULL) { VM_OBJECT_LOCK(object); object->cred = cred; object->charge = size; VM_OBJECT_UNLOCK(object); } return (object); } /* * deallocate resources associated with default objects. The default objects * have no special resources allocated to them, but the vm_page's being used * in this object might. Still, we do not have to do anything - we will free * the swapblk in the underlying vm_page's when we free the vm_page or * garbage collect the vm_page cache list. */ static void default_pager_dealloc(object) vm_object_t object; { /* * OBJT_DEFAULT objects have no special resources allocated to them. */ } /* * Load pages from backing store. Since OBJT_DEFAULT is converted to * OBJT_SWAP at the time a swap-backed vm_page_t is freed, we will never * see a vm_page with assigned swap here. */ static int default_pager_getpages(object, m, count, reqpage) vm_object_t object; vm_page_t *m; int count; int reqpage; { return VM_PAGER_FAIL; } /* * Store pages to backing store. We should assign swap and initiate * I/O. We do not actually convert the object to OBJT_SWAP here. The * object will be converted when the written-out vm_page_t is moved from the * cache to the free list. */ static void default_pager_putpages(object, m, c, sync, rtvals) vm_object_t object; vm_page_t *m; int c; boolean_t sync; int *rtvals; { swappagerops.pgo_putpages(object, m, c, sync, rtvals); } /* * Tell us whether the backing store for the requested (object,index) is * synchronized. i.e. tell us whether we can throw the page away and * reload it later. So, for example, if we are in the process of writing * the page to its backing store, or if no backing store has been assigned, * it is not yet synchronized. * * It is possible to have fully-synchronized swap assigned without the * object having been converted. We just call swap_pager_haspage() to * deal with it since it must already deal with it plus deal with swap * meta-data structures. */ static boolean_t default_pager_haspage(object, pindex, before, after) vm_object_t object; vm_pindex_t pindex; int *before; int *after; { return FALSE; }