The Design and Implementation of the FreeBSD Operating System, Second Edition
Now available: The Design and Implementation of the FreeBSD Operating System (Second Edition)


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FreeBSD/Linux Kernel Cross Reference
sys/vm/vm_pager.h

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    1 /*-
    2  * Copyright (c) 1990 University of Utah.
    3  * Copyright (c) 1991, 1993
    4  *      The Regents of the University of California.  All rights reserved.
    5  *
    6  * This code is derived from software contributed to Berkeley by
    7  * the Systems Programming Group of the University of Utah Computer
    8  * Science Department.
    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  * 4. Neither the name of the University nor the names of its contributors
   19  *    may be used to endorse or promote products derived from this software
   20  *    without specific prior written permission.
   21  *
   22  * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
   23  * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
   24  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
   25  * ARE DISCLAIMED.  IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
   26  * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
   27  * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
   28  * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
   29  * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
   30  * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
   31  * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
   32  * SUCH DAMAGE.
   33  *
   34  *      @(#)vm_pager.h  8.4 (Berkeley) 1/12/94
   35  * $FreeBSD$
   36  */
   37 
   38 /*
   39  * Pager routine interface definition.
   40  */
   41 
   42 #ifndef _VM_PAGER_
   43 #define _VM_PAGER_
   44 
   45 #include <sys/queue.h>
   46 
   47 TAILQ_HEAD(pagerlst, vm_object);
   48 
   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,
   51     struct ucred *);
   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);
   57 
   58 struct pagerops {
   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;
   66 };
   67 
   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;
   74 extern struct pagerops mgtdevicepagerops;
   75 
   76 /*
   77  * get/put return values
   78  * OK    operation was successful
   79  * BAD   specified data was out of the accepted range
   80  * FAIL  specified data was in range, but doesn't exist
   81  * PEND  operations was initiated but not completed
   82  * ERROR error while accessing data that is in range and exists
   83  * AGAIN temporary resource shortage prevented operation from happening
   84  */
   85 #define VM_PAGER_OK     0
   86 #define VM_PAGER_BAD    1
   87 #define VM_PAGER_FAIL   2
   88 #define VM_PAGER_PEND   3
   89 #define VM_PAGER_ERROR  4
   90 #define VM_PAGER_AGAIN  5
   91 
   92 #define VM_PAGER_PUT_SYNC               0x0001
   93 #define VM_PAGER_PUT_INVAL              0x0002
   94 #define VM_PAGER_CLUSTER_OK             0x0008
   95 
   96 #ifdef _KERNEL
   97 
   98 extern struct pagerops *pagertab[];
   99 extern struct mtx_padalign pbuf_mtx;
  100 
  101 vm_object_t vm_pager_allocate(objtype_t, void *, vm_ooffset_t, vm_prot_t,
  102     vm_ooffset_t, struct ucred *);
  103 void vm_pager_bufferinit(void);
  104 void vm_pager_deallocate(vm_object_t);
  105 static __inline int vm_pager_get_pages(vm_object_t, vm_page_t *, int, int);
  106 void vm_pager_init(void);
  107 vm_object_t vm_pager_object_lookup(struct pagerlst *, void *);
  108 
  109 /*
  110  *      vm_page_get_pages:
  111  *
  112  *      Retrieve pages from the VM system in order to map them into an object
  113  *      ( or into VM space somewhere ).  If the pagein was successful, we
  114  *      must fully validate it.
  115  */
  116 static __inline int
  117 vm_pager_get_pages(
  118         vm_object_t object,
  119         vm_page_t *m,
  120         int count,
  121         int reqpage
  122 ) {
  123         int r;
  124 
  125         VM_OBJECT_ASSERT_WLOCKED(object);
  126         r = (*pagertab[object->type]->pgo_getpages)(object, m, count, reqpage);
  127         if (r == VM_PAGER_OK && m[reqpage]->valid != VM_PAGE_BITS_ALL) {
  128                 vm_page_zero_invalid(m[reqpage], TRUE);
  129         }
  130         return (r);
  131 }
  132 
  133 static __inline void
  134 vm_pager_put_pages(
  135         vm_object_t object,
  136         vm_page_t *m,
  137         int count,
  138         int flags,
  139         int *rtvals
  140 ) {
  141 
  142         VM_OBJECT_ASSERT_WLOCKED(object);
  143         (*pagertab[object->type]->pgo_putpages)
  144             (object, m, count, flags, rtvals);
  145 }
  146 
  147 /*
  148  *      vm_pager_haspage
  149  *
  150  *      Check to see if an object's pager has the requested page.  The
  151  *      object's pager will also set before and after to give the caller
  152  *      some idea of the number of pages before and after the requested
  153  *      page can be I/O'd efficiently.
  154  *
  155  *      The object must be locked.
  156  */
  157 static __inline boolean_t
  158 vm_pager_has_page(
  159         vm_object_t object,
  160         vm_pindex_t offset, 
  161         int *before,
  162         int *after
  163 ) {
  164         boolean_t ret;
  165 
  166         VM_OBJECT_ASSERT_WLOCKED(object);
  167         ret = (*pagertab[object->type]->pgo_haspage)
  168             (object, offset, before, after);
  169         return (ret);
  170 } 
  171 
  172 /* 
  173  *      vm_pager_page_unswapped
  174  * 
  175  *      Destroy swap associated with the page.
  176  * 
  177  *      The object containing the page must be locked.
  178  *      This function may not block.
  179  *
  180  *      XXX: A much better name would be "vm_pager_page_dirtied()"
  181  *      XXX: It is not obvious if this could be profitably used by any
  182  *      XXX: pagers besides the swap_pager or if it should even be a
  183  *      XXX: generic pager_op in the first place.
  184  */
  185 static __inline void
  186 vm_pager_page_unswapped(vm_page_t m)
  187 {
  188 
  189         VM_OBJECT_ASSERT_LOCKED(m->object);
  190         if (pagertab[m->object->type]->pgo_pageunswapped)
  191                 (*pagertab[m->object->type]->pgo_pageunswapped)(m);
  192 }
  193 
  194 struct cdev_pager_ops {
  195         int (*cdev_pg_fault)(vm_object_t vm_obj, vm_ooffset_t offset,
  196             int prot, vm_page_t *mres);
  197         int (*cdev_pg_ctor)(void *handle, vm_ooffset_t size, vm_prot_t prot,
  198             vm_ooffset_t foff, struct ucred *cred, u_short *color);
  199         void (*cdev_pg_dtor)(void *handle);
  200 };
  201 
  202 vm_object_t cdev_pager_allocate(void *handle, enum obj_type tp,
  203     struct cdev_pager_ops *ops, vm_ooffset_t size, vm_prot_t prot,
  204     vm_ooffset_t foff, struct ucred *cred);
  205 vm_object_t cdev_pager_lookup(void *handle);
  206 void cdev_pager_free_page(vm_object_t object, vm_page_t m);
  207 
  208 #endif                          /* _KERNEL */
  209 #endif                          /* _VM_PAGER_ */

Cache object: 8ac608132d9977ddb1ee5a0998e06a71


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