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/*
* Copyright (c) 2000 Peter Wemm
*
* 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.
*
* THIS SOFTWARE IS PROVIDED BY THE AUTHORS 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 AUTHORS 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.
*
* $FreeBSD$
*/
#include <sys/param.h>
#include <sys/systm.h>
#include <sys/linker_set.h>
#include <sys/conf.h>
#include <sys/kernel.h>
#include <sys/lock.h>
#include <sys/proc.h>
#include <sys/mutex.h>
#include <sys/mman.h>
#include <sys/sysctl.h>
#include <vm/vm.h>
#include <vm/vm_object.h>
#include <vm/vm_page.h>
#include <vm/vm_pager.h>
/* prevent concurrant creation races */
static int phys_pager_alloc_lock;
/* list of device pager objects */
static struct pagerlst phys_pager_object_list;
/* protect access to phys_pager_object_list */
static struct mtx phys_pager_mtx;
static void
phys_pager_init(void)
{
TAILQ_INIT(&phys_pager_object_list);
mtx_init(&phys_pager_mtx, "phys_pager list", NULL, MTX_DEF);
}
static vm_object_t
phys_pager_alloc(void *handle, vm_ooffset_t size, vm_prot_t prot,
vm_ooffset_t foff)
{
vm_object_t object;
GIANT_REQUIRED;
/*
* Offset should be page aligned.
*/
if (foff & PAGE_MASK)
return (NULL);
size = round_page(size);
if (handle != NULL) {
/*
* Lock to prevent object creation race condition.
*/
while (phys_pager_alloc_lock) {
phys_pager_alloc_lock = -1;
tsleep(&phys_pager_alloc_lock, PVM, "swpalc", 0);
}
phys_pager_alloc_lock = 1;
/*
* Look up pager, creating as necessary.
*/
object = vm_pager_object_lookup(&phys_pager_object_list, handle);
if (object == NULL) {
/*
* Allocate object and associate it with the pager.
*/
object = vm_object_allocate(OBJT_PHYS,
OFF_TO_IDX(foff + size));
object->handle = handle;
mtx_lock(&phys_pager_mtx);
TAILQ_INSERT_TAIL(&phys_pager_object_list, object,
pager_object_list);
mtx_unlock(&phys_pager_mtx);
} else {
/*
* Gain a reference to the object.
*/
vm_object_reference(object);
if (OFF_TO_IDX(foff + size) > object->size)
object->size = OFF_TO_IDX(foff + size);
}
if (phys_pager_alloc_lock == -1)
wakeup(&phys_pager_alloc_lock);
phys_pager_alloc_lock = 0;
} else {
object = vm_object_allocate(OBJT_PHYS,
OFF_TO_IDX(foff + size));
}
return (object);
}
static void
phys_pager_dealloc(vm_object_t object)
{
if (object->handle != NULL) {
mtx_lock(&phys_pager_mtx);
TAILQ_REMOVE(&phys_pager_object_list, object, pager_object_list);
mtx_unlock(&phys_pager_mtx);
}
}
static int
phys_pager_getpages(vm_object_t object, vm_page_t *m, int count, int reqpage)
{
int i, s;
s = splvm();
/*
* Fill as many pages as vm_fault has allocated for us.
*/
for (i = 0; i < count; i++) {
if ((m[i]->flags & PG_ZERO) == 0)
vm_page_zero_fill(m[i]);
vm_page_flag_set(m[i], PG_ZERO);
/* Switch off pv_entries */
vm_page_unmanage(m[i]);
m[i]->valid = VM_PAGE_BITS_ALL;
m[i]->dirty = 0;
/* The requested page must remain busy, the others not. */
if (reqpage != i) {
vm_page_flag_clear(m[i], PG_BUSY);
m[i]->busy = 0;
}
}
splx(s);
return (VM_PAGER_OK);
}
static void
phys_pager_putpages(vm_object_t object, vm_page_t *m, int count, boolean_t sync,
int *rtvals)
{
panic("phys_pager_putpage called");
}
/*
* Implement a pretty aggressive clustered getpages strategy. Hint that
* everything in an entire 4MB window should be prefaulted at once.
*
* XXX 4MB (1024 slots per page table page) is convenient for x86,
* but may not be for other arches.
*/
#ifndef PHYSCLUSTER
#define PHYSCLUSTER 1024
#endif
static boolean_t
phys_pager_haspage(vm_object_t object, vm_pindex_t pindex, int *before,
int *after)
{
vm_pindex_t base, end;
base = pindex & (~(PHYSCLUSTER - 1));
end = base + (PHYSCLUSTER - 1);
if (before != NULL)
*before = pindex - base;
if (after != NULL)
*after = end - pindex;
return (TRUE);
}
struct pagerops physpagerops = {
phys_pager_init,
phys_pager_alloc,
phys_pager_dealloc,
phys_pager_getpages,
phys_pager_putpages,
phys_pager_haspage,
NULL
};
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