2 * Copyright (c) 1990 University of Utah.
3 * Copyright (c) 1991, 1993
4 * The Regents of the University of California. All rights reserved.
6 * This code is derived from software contributed to Berkeley by
7 * the Systems Programming Group of the University of Utah Computer
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11 * modification, are permitted provided that the following conditions
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
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17 * documentation and/or other materials provided with the distribution.
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19 * may be used to endorse or promote products derived from this software
20 * without specific prior written permission.
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31 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
34 * @(#)vm_pager.h 8.4 (Berkeley) 1/12/94
39 * Pager routine interface definition.
45 #include <sys/queue.h>
47 TAILQ_HEAD(pagerlst, vm_object);
49 typedef void pgo_init_t(void);
50 typedef vm_object_t pgo_alloc_t(void *, vm_ooffset_t, vm_prot_t, vm_ooffset_t,
52 typedef void pgo_dealloc_t(vm_object_t);
53 typedef int pgo_getpages_t(vm_object_t, vm_page_t *, int, int);
54 typedef void pgo_putpages_t(vm_object_t, vm_page_t *, int, int, int *);
55 typedef boolean_t pgo_haspage_t(vm_object_t, vm_pindex_t, int *, int *);
56 typedef void pgo_pageunswapped_t(vm_page_t);
59 pgo_init_t *pgo_init; /* Initialize pager. */
60 pgo_alloc_t *pgo_alloc; /* Allocate pager. */
61 pgo_dealloc_t *pgo_dealloc; /* Disassociate. */
62 pgo_getpages_t *pgo_getpages; /* Get (read) page. */
63 pgo_putpages_t *pgo_putpages; /* Put (write) page. */
64 pgo_haspage_t *pgo_haspage; /* Does pager have page? */
65 pgo_pageunswapped_t *pgo_pageunswapped;
68 extern struct pagerops defaultpagerops;
69 extern struct pagerops swappagerops;
70 extern struct pagerops vnodepagerops;
71 extern struct pagerops devicepagerops;
72 extern struct pagerops physpagerops;
73 extern struct pagerops sgpagerops;
76 * get/put return values
77 * OK operation was successful
78 * BAD specified data was out of the accepted range
79 * FAIL specified data was in range, but doesn't exist
80 * PEND operations was initiated but not completed
81 * ERROR error while accessing data that is in range and exists
82 * AGAIN temporary resource shortage prevented operation from happening
85 #define VM_PAGER_BAD 1
86 #define VM_PAGER_FAIL 2
87 #define VM_PAGER_PEND 3
88 #define VM_PAGER_ERROR 4
89 #define VM_PAGER_AGAIN 5
91 #define VM_PAGER_PUT_SYNC 0x0001
92 #define VM_PAGER_PUT_INVAL 0x0002
93 #define VM_PAGER_CLUSTER_OK 0x0008
97 MALLOC_DECLARE(M_VMPGDATA);
100 extern vm_map_t pager_map;
101 extern struct pagerops *pagertab[];
102 extern struct mtx pbuf_mtx;
104 vm_object_t vm_pager_allocate(objtype_t, void *, vm_ooffset_t, vm_prot_t,
105 vm_ooffset_t, struct ucred *);
106 void vm_pager_bufferinit(void);
107 void vm_pager_deallocate(vm_object_t);
108 static __inline int vm_pager_get_pages(vm_object_t, vm_page_t *, int, int);
109 static __inline boolean_t vm_pager_has_page(vm_object_t, vm_pindex_t, int *, int *);
110 void vm_pager_init(void);
111 vm_object_t vm_pager_object_lookup(struct pagerlst *, void *);
116 * Retrieve pages from the VM system in order to map them into an object
117 * ( or into VM space somewhere ). If the pagein was successful, we
118 * must fully validate it.
129 VM_OBJECT_LOCK_ASSERT(object, MA_OWNED);
130 r = (*pagertab[object->type]->pgo_getpages)(object, m, count, reqpage);
131 if (r == VM_PAGER_OK && m[reqpage]->valid != VM_PAGE_BITS_ALL) {
132 vm_page_zero_invalid(m[reqpage], TRUE);
146 VM_OBJECT_LOCK_ASSERT(object, MA_OWNED);
147 (*pagertab[object->type]->pgo_putpages)
148 (object, m, count, flags, rtvals);
154 * Check to see if an object's pager has the requested page. The
155 * object's pager will also set before and after to give the caller
156 * some idea of the number of pages before and after the requested
157 * page can be I/O'd efficiently.
159 * The object must be locked.
161 static __inline boolean_t
170 VM_OBJECT_LOCK_ASSERT(object, MA_OWNED);
171 ret = (*pagertab[object->type]->pgo_haspage)
172 (object, offset, before, after);
177 * vm_pager_page_unswapped
179 * Destroy swap associated with the page.
181 * The object containing the page must be locked.
182 * This function may not block.
184 * XXX: A much better name would be "vm_pager_page_dirtied()"
185 * XXX: It is not obvious if this could be profitably used by any
186 * XXX: pagers besides the swap_pager or if it should even be a
187 * XXX: generic pager_op in the first place.
190 vm_pager_page_unswapped(vm_page_t m)
193 VM_OBJECT_LOCK_ASSERT(m->object, MA_OWNED);
194 if (pagertab[m->object->type]->pgo_pageunswapped)
195 (*pagertab[m->object->type]->pgo_pageunswapped)(m);
199 #endif /* _VM_PAGER_ */