159 lines
5.3 KiB
C
159 lines
5.3 KiB
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("$FreeBSD$");
|
|
|
|
#include <sys/param.h>
|
|
#include <sys/systm.h>
|
|
#include <sys/lock.h>
|
|
#include <sys/proc.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);
|
|
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 = {
|
|
NULL,
|
|
default_pager_alloc,
|
|
default_pager_dealloc,
|
|
default_pager_getpages,
|
|
default_pager_putpages,
|
|
default_pager_haspage,
|
|
NULL
|
|
};
|
|
|
|
/*
|
|
* 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)
|
|
{
|
|
if (handle != NULL)
|
|
panic("default_pager_alloc: handle specified");
|
|
|
|
return vm_object_allocate(OBJT_DEFAULT, OFF_TO_IDX(round_page(offset + size)));
|
|
}
|
|
|
|
/*
|
|
* 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;
|
|
{
|
|
swap_pager_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;
|
|
}
|
|
|