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freebsd/sys/vm/phys_pager.c
Konstantin Belousov 3364c323e6 Implement global and per-uid accounting of the anonymous memory. Add
rlimit RLIMIT_SWAP that limits the amount of swap that may be reserved
for the uid.

The accounting information (charge) is associated with either map entry,
or vm object backing the entry, assuming the object is the first one
in the shadow chain and entry does not require COW. Charge is moved
from entry to object on allocation of the object, e.g. during the mmap,
assuming the object is allocated, or on the first page fault on the
entry. It moves back to the entry on forks due to COW setup.

The per-entry granularity of accounting makes the charge process fair
for processes that change uid during lifetime, and decrements charge
for proper uid when region is unmapped.

The interface of vm_pager_allocate(9) is extended by adding struct ucred *,
that is used to charge appropriate uid when allocation if performed by
kernel, e.g. md(4).

Several syscalls, among them is fork(2), may now return ENOMEM when
global or per-uid limits are enforced.

In collaboration with:	pho
Reviewed by:	alc
Approved by:	re (kensmith)
2009-06-23 20:45:22 +00:00

204 lines
5.3 KiB
C

/*-
* 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.
*/
#include <sys/cdefs.h>
__FBSDID("$FreeBSD$");
#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>
/* list of phys 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);
}
/*
* MPSAFE
*/
static vm_object_t
phys_pager_alloc(void *handle, vm_ooffset_t size, vm_prot_t prot,
vm_ooffset_t foff, struct ucred *cred)
{
vm_object_t object, object1;
vm_pindex_t pindex;
/*
* Offset should be page aligned.
*/
if (foff & PAGE_MASK)
return (NULL);
pindex = OFF_TO_IDX(foff + PAGE_MASK + size);
if (handle != NULL) {
mtx_lock(&phys_pager_mtx);
/*
* Look up pager, creating as necessary.
*/
object1 = NULL;
object = vm_pager_object_lookup(&phys_pager_object_list, handle);
if (object == NULL) {
/*
* Allocate object and associate it with the pager.
*/
mtx_unlock(&phys_pager_mtx);
object1 = vm_object_allocate(OBJT_PHYS, pindex);
mtx_lock(&phys_pager_mtx);
object = vm_pager_object_lookup(&phys_pager_object_list,
handle);
if (object != NULL) {
/*
* We raced with other thread while
* allocating object.
*/
if (pindex > object->size)
object->size = pindex;
} else {
object = object1;
object1 = NULL;
object->handle = handle;
TAILQ_INSERT_TAIL(&phys_pager_object_list, object,
pager_object_list);
}
} else {
if (pindex > object->size)
object->size = pindex;
}
mtx_unlock(&phys_pager_mtx);
vm_object_deallocate(object1);
} else {
object = vm_object_allocate(OBJT_PHYS, pindex);
}
return (object);
}
/*
* MPSAFE
*/
static void
phys_pager_dealloc(vm_object_t object)
{
if (object->handle != NULL) {
VM_OBJECT_UNLOCK(object);
mtx_lock(&phys_pager_mtx);
TAILQ_REMOVE(&phys_pager_object_list, object, pager_object_list);
mtx_unlock(&phys_pager_mtx);
VM_OBJECT_LOCK(object);
}
}
/*
* Fill as many pages as vm_fault has allocated for us.
*/
static int
phys_pager_getpages(vm_object_t object, vm_page_t *m, int count, int reqpage)
{
int i;
VM_OBJECT_LOCK_ASSERT(object, MA_OWNED);
for (i = 0; i < count; i++) {
if (m[i]->valid == 0) {
if ((m[i]->flags & PG_ZERO) == 0)
pmap_zero_page(m[i]);
m[i]->valid = VM_PAGE_BITS_ALL;
}
KASSERT(m[i]->valid == VM_PAGE_BITS_ALL,
("phys_pager_getpages: partially valid page %p", m[i]));
KASSERT(m[i]->dirty == 0,
("phys_pager_getpages: dirty page %p", m[i]));
/* The requested page must remain busy, the others not. */
if (reqpage != i) {
m[i]->oflags &= ~VPO_BUSY;
m[i]->busy = 0;
}
}
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 = {
.pgo_init = phys_pager_init,
.pgo_alloc = phys_pager_alloc,
.pgo_dealloc = phys_pager_dealloc,
.pgo_getpages = phys_pager_getpages,
.pgo_putpages = phys_pager_putpages,
.pgo_haspage = phys_pager_haspage,
};