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freebsd-skq/sys/vm/vm_object.c
alc 132707858e Hold the page queues lock while performing pmap_page_protect(). 
Approved by:	re (blanket)
2002-11-27 08:03:24 +00:00

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/*
* Copyright (c) 1991, 1993
* The Regents of the University of California. All rights reserved.
*
* This code is derived from software contributed to Berkeley by
* The Mach Operating System project at Carnegie-Mellon University.
*
* 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 the University of
* California, Berkeley and its contributors.
* 4. Neither the name of the University nor the names of its contributors
* may be used to endorse or promote products derived from this software
* without specific prior written permission.
*
* THIS SOFTWARE IS PROVIDED BY THE REGENTS 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 REGENTS 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.
*
* from: @(#)vm_object.c 8.5 (Berkeley) 3/22/94
*
*
* Copyright (c) 1987, 1990 Carnegie-Mellon University.
* All rights reserved.
*
* Authors: Avadis Tevanian, Jr., Michael Wayne Young
*
* Permission to use, copy, modify and distribute this software and
* its documentation is hereby granted, provided that both the copyright
* notice and this permission notice appear in all copies of the
* software, derivative works or modified versions, and any portions
* thereof, and that both notices appear in supporting documentation.
*
* CARNEGIE MELLON ALLOWS FREE USE OF THIS SOFTWARE IN ITS "AS IS"
* CONDITION. CARNEGIE MELLON DISCLAIMS ANY LIABILITY OF ANY KIND
* FOR ANY DAMAGES WHATSOEVER RESULTING FROM THE USE OF THIS SOFTWARE.
*
* Carnegie Mellon requests users of this software to return to
*
* Software Distribution Coordinator or Software.Distribution@CS.CMU.EDU
* School of Computer Science
* Carnegie Mellon University
* Pittsburgh PA 15213-3890
*
* any improvements or extensions that they make and grant Carnegie the
* rights to redistribute these changes.
*
* $FreeBSD$
*/
/*
* Virtual memory object module.
*/
#include <sys/param.h>
#include <sys/systm.h>
#include <sys/lock.h>
#include <sys/mman.h>
#include <sys/mount.h>
#include <sys/kernel.h>
#include <sys/sysctl.h>
#include <sys/mutex.h>
#include <sys/proc.h> /* for curproc, pageproc */
#include <sys/socket.h>
#include <sys/stdint.h>
#include <sys/vnode.h>
#include <sys/vmmeter.h>
#include <sys/sx.h>
#include <vm/vm.h>
#include <vm/vm_param.h>
#include <vm/pmap.h>
#include <vm/vm_map.h>
#include <vm/vm_object.h>
#include <vm/vm_page.h>
#include <vm/vm_pageout.h>
#include <vm/vm_pager.h>
#include <vm/swap_pager.h>
#include <vm/vm_kern.h>
#include <vm/vm_extern.h>
#include <vm/uma.h>
#define EASY_SCAN_FACTOR 8
#define MSYNC_FLUSH_HARDSEQ 0x01
#define MSYNC_FLUSH_SOFTSEQ 0x02
/*
* msync / VM object flushing optimizations
*/
static int msync_flush_flags = MSYNC_FLUSH_HARDSEQ | MSYNC_FLUSH_SOFTSEQ;
SYSCTL_INT(_vm, OID_AUTO, msync_flush_flags,
CTLFLAG_RW, &msync_flush_flags, 0, "");
static void vm_object_qcollapse(vm_object_t object);
static int vm_object_page_collect_flush(vm_object_t object, vm_page_t p, int curgeneration, int pagerflags);
/*
* Virtual memory objects maintain the actual data
* associated with allocated virtual memory. A given
* page of memory exists within exactly one object.
*
* An object is only deallocated when all "references"
* are given up. Only one "reference" to a given
* region of an object should be writeable.
*
* Associated with each object is a list of all resident
* memory pages belonging to that object; this list is
* maintained by the "vm_page" module, and locked by the object's
* lock.
*
* Each object also records a "pager" routine which is
* used to retrieve (and store) pages to the proper backing
* storage. In addition, objects may be backed by other
* objects from which they were virtual-copied.
*
* The only items within the object structure which are
* modified after time of creation are:
* reference count locked by object's lock
* pager routine locked by object's lock
*
*/
struct object_q vm_object_list;
struct mtx vm_object_list_mtx; /* lock for object list and count */
vm_object_t kernel_object;
vm_object_t kmem_object;
static struct vm_object kernel_object_store;
static struct vm_object kmem_object_store;
extern int vm_pageout_page_count;
static long object_collapses;
static long object_bypasses;
static int next_index;
static uma_zone_t obj_zone;
#define VM_OBJECTS_INIT 256
static void vm_object_zinit(void *mem, int size);
#ifdef INVARIANTS
static void vm_object_zdtor(void *mem, int size, void *arg);
static void
vm_object_zdtor(void *mem, int size, void *arg)
{
vm_object_t object;
object = (vm_object_t)mem;
KASSERT(object->paging_in_progress == 0,
("object %p paging_in_progress = %d",
object, object->paging_in_progress));
KASSERT(object->resident_page_count == 0,
("object %p resident_page_count = %d",
object, object->resident_page_count));
KASSERT(object->shadow_count == 0,
("object %p shadow_count = %d",
object, object->shadow_count));
}
#endif
static void
vm_object_zinit(void *mem, int size)
{
vm_object_t object;
object = (vm_object_t)mem;
/* These are true for any object that has been freed */
object->paging_in_progress = 0;
object->resident_page_count = 0;
object->shadow_count = 0;
}
void
_vm_object_allocate(objtype_t type, vm_pindex_t size, vm_object_t object)
{
static int object_hash_rand;
int exp, incr;
TAILQ_INIT(&object->memq);
TAILQ_INIT(&object->shadow_head);
object->root = NULL;
object->type = type;
object->size = size;
object->ref_count = 1;
object->flags = 0;
if ((object->type == OBJT_DEFAULT) || (object->type == OBJT_SWAP))
vm_object_set_flag(object, OBJ_ONEMAPPING);
if (size > (PQ_L2_SIZE / 3 + PQ_PRIME1))
incr = PQ_L2_SIZE / 3 + PQ_PRIME1;
else
incr = size;
do
object->pg_color = next_index;
while (!atomic_cmpset_int(&next_index, object->pg_color,
(object->pg_color + incr) & PQ_L2_MASK));
object->handle = NULL;
object->backing_object = NULL;
object->backing_object_offset = (vm_ooffset_t) 0;
/*
* Try to generate a number that will spread objects out in the
* hash table. We 'wipe' new objects across the hash in 128 page
* increments plus 1 more to offset it a little more by the time
* it wraps around.
*/
do {
exp = object_hash_rand;
object->hash_rand = exp - 129;
} while (!atomic_cmpset_int(&object_hash_rand, exp, object->hash_rand));
atomic_add_int(&object->generation, 1);
mtx_lock(&vm_object_list_mtx);
TAILQ_INSERT_TAIL(&vm_object_list, object, object_list);
mtx_unlock(&vm_object_list_mtx);
}
/*
* vm_object_init:
*
* Initialize the VM objects module.
*/
void
vm_object_init(void)
{
TAILQ_INIT(&vm_object_list);
mtx_init(&vm_object_list_mtx, "vm object_list", NULL, MTX_DEF);
kernel_object = &kernel_object_store;
_vm_object_allocate(OBJT_DEFAULT, OFF_TO_IDX(VM_MAX_KERNEL_ADDRESS - VM_MIN_KERNEL_ADDRESS),
kernel_object);
kmem_object = &kmem_object_store;
_vm_object_allocate(OBJT_DEFAULT, OFF_TO_IDX(VM_MAX_KERNEL_ADDRESS - VM_MIN_KERNEL_ADDRESS),
kmem_object);
obj_zone = uma_zcreate("VM OBJECT", sizeof (struct vm_object), NULL,
#ifdef INVARIANTS
vm_object_zdtor,
#else
NULL,
#endif
vm_object_zinit, NULL, UMA_ALIGN_PTR, UMA_ZONE_NOFREE);
uma_prealloc(obj_zone, VM_OBJECTS_INIT);
}
void
vm_object_init2(void)
{
}
void
vm_object_set_flag(vm_object_t object, u_short bits)
{
object->flags |= bits;
}
void
vm_object_clear_flag(vm_object_t object, u_short bits)
{
GIANT_REQUIRED;
object->flags &= ~bits;
}
void
vm_object_pip_add(vm_object_t object, short i)
{
GIANT_REQUIRED;
object->paging_in_progress += i;
}
void
vm_object_pip_subtract(vm_object_t object, short i)
{
GIANT_REQUIRED;
object->paging_in_progress -= i;
}
void
vm_object_pip_wakeup(vm_object_t object)
{
GIANT_REQUIRED;
object->paging_in_progress--;
if ((object->flags & OBJ_PIPWNT) && object->paging_in_progress == 0) {
vm_object_clear_flag(object, OBJ_PIPWNT);
wakeup(object);
}
}
void
vm_object_pip_wakeupn(vm_object_t object, short i)
{
GIANT_REQUIRED;
if (i)
object->paging_in_progress -= i;
if ((object->flags & OBJ_PIPWNT) && object->paging_in_progress == 0) {
vm_object_clear_flag(object, OBJ_PIPWNT);
wakeup(object);
}
}
void
vm_object_pip_sleep(vm_object_t object, char *waitid)
{
GIANT_REQUIRED;
if (object->paging_in_progress) {
int s = splvm();
if (object->paging_in_progress) {
vm_object_set_flag(object, OBJ_PIPWNT);
tsleep(object, PVM, waitid, 0);
}
splx(s);
}
}
void
vm_object_pip_wait(vm_object_t object, char *waitid)
{
GIANT_REQUIRED;
while (object->paging_in_progress)
vm_object_pip_sleep(object, waitid);
}
/*
* vm_object_allocate_wait
*
* Return a new object with the given size, and give the user the
* option of waiting for it to complete or failing if the needed
* memory isn't available.
*/
vm_object_t
vm_object_allocate_wait(objtype_t type, vm_pindex_t size, int flags)
{
vm_object_t result;
result = (vm_object_t) uma_zalloc(obj_zone, flags);
if (result != NULL)
_vm_object_allocate(type, size, result);
return (result);
}
/*
* vm_object_allocate:
*
* Returns a new object with the given size.
*/
vm_object_t
vm_object_allocate(objtype_t type, vm_pindex_t size)
{
return(vm_object_allocate_wait(type, size, M_WAITOK));
}
/*
* vm_object_reference:
*
* Gets another reference to the given object.
*/
void
vm_object_reference(vm_object_t object)
{
if (object == NULL)
return;
vm_object_lock(object);
#if 0
/* object can be re-referenced during final cleaning */
KASSERT(!(object->flags & OBJ_DEAD),
("vm_object_reference: attempting to reference dead obj"));
#endif
object->ref_count++;
if (object->type == OBJT_VNODE) {
while (vget((struct vnode *) object->handle, LK_RETRY, curthread)) {
printf("vm_object_reference: delay in getting object\n");
}
}
vm_object_unlock(object);
}
/*
* handle deallocating a object of type OBJT_VNODE
*/
void
vm_object_vndeallocate(vm_object_t object)
{
struct vnode *vp = (struct vnode *) object->handle;
GIANT_REQUIRED;
KASSERT(object->type == OBJT_VNODE,
("vm_object_vndeallocate: not a vnode object"));
KASSERT(vp != NULL, ("vm_object_vndeallocate: missing vp"));
#ifdef INVARIANTS
if (object->ref_count == 0) {
vprint("vm_object_vndeallocate", vp);
panic("vm_object_vndeallocate: bad object reference count");
}
#endif
object->ref_count--;
if (object->ref_count == 0) {
mp_fixme("Unlocked vflag access.");
vp->v_vflag &= ~VV_TEXT;
#ifdef ENABLE_VFS_IOOPT
vm_object_clear_flag(object, OBJ_OPT);
#endif
}
/*
* vrele may need a vop lock
*/
vrele(vp);
}
/*
* vm_object_deallocate:
*
* Release a reference to the specified object,
* gained either through a vm_object_allocate
* or a vm_object_reference call. When all references
* are gone, storage associated with this object
* may be relinquished.
*
* No object may be locked.
*/
void
vm_object_deallocate(vm_object_t object)
{
vm_object_t temp;
mtx_lock(&Giant);
while (object != NULL) {
if (object->type == OBJT_VNODE) {
vm_object_vndeallocate(object);
mtx_unlock(&Giant);
return;
}
KASSERT(object->ref_count != 0,
("vm_object_deallocate: object deallocated too many times: %d", object->type));
/*
* If the reference count goes to 0 we start calling
* vm_object_terminate() on the object chain.
* A ref count of 1 may be a special case depending on the
* shadow count being 0 or 1.
*/
object->ref_count--;
if (object->ref_count > 1) {
mtx_unlock(&Giant);
return;
} else if (object->ref_count == 1) {
if (object->shadow_count == 0) {
vm_object_set_flag(object, OBJ_ONEMAPPING);
} else if ((object->shadow_count == 1) &&
(object->handle == NULL) &&
(object->type == OBJT_DEFAULT ||
object->type == OBJT_SWAP)) {
vm_object_t robject;
robject = TAILQ_FIRST(&object->shadow_head);
KASSERT(robject != NULL,
("vm_object_deallocate: ref_count: %d, shadow_count: %d",
object->ref_count,
object->shadow_count));
if ((robject->handle == NULL) &&
(robject->type == OBJT_DEFAULT ||
robject->type == OBJT_SWAP)) {
robject->ref_count++;
while (
robject->paging_in_progress ||
object->paging_in_progress
) {
vm_object_pip_sleep(robject, "objde1");
vm_object_pip_sleep(object, "objde2");
}
if (robject->ref_count == 1) {
robject->ref_count--;
object = robject;
goto doterm;
}
object = robject;
vm_object_collapse(object);
continue;
}
}
mtx_unlock(&Giant);
return;
}
doterm:
temp = object->backing_object;
if (temp) {
TAILQ_REMOVE(&temp->shadow_head, object, shadow_list);
temp->shadow_count--;
#ifdef ENABLE_VFS_IOOPT
if (temp->ref_count == 0)
vm_object_clear_flag(temp, OBJ_OPT);
#endif
temp->generation++;
object->backing_object = NULL;
}
/*
* Don't double-terminate, we could be in a termination
* recursion due to the terminate having to sync data
* to disk.
*/
if ((object->flags & OBJ_DEAD) == 0)
vm_object_terminate(object);
object = temp;
}
mtx_unlock(&Giant);
}
/*
* vm_object_terminate actually destroys the specified object, freeing
* up all previously used resources.
*
* The object must be locked.
* This routine may block.
*/
void
vm_object_terminate(vm_object_t object)
{
vm_page_t p;
int s;
GIANT_REQUIRED;
/*
* Make sure no one uses us.
*/
vm_object_set_flag(object, OBJ_DEAD);
/*
* wait for the pageout daemon to be done with the object
*/
vm_object_pip_wait(object, "objtrm");
KASSERT(!object->paging_in_progress,
("vm_object_terminate: pageout in progress"));
/*
* Clean and free the pages, as appropriate. All references to the
* object are gone, so we don't need to lock it.
*/
if (object->type == OBJT_VNODE) {
struct vnode *vp;
#ifdef ENABLE_VFS_IOOPT
/*
* Freeze optimized copies.
*/
vm_freeze_copyopts(object, 0, object->size);
#endif
/*
* Clean pages and flush buffers.
*/
vm_object_page_clean(object, 0, 0, OBJPC_SYNC);
vp = (struct vnode *) object->handle;
vinvalbuf(vp, V_SAVE, NOCRED, NULL, 0, 0);
}
KASSERT(object->ref_count == 0,
("vm_object_terminate: object with references, ref_count=%d",
object->ref_count));
/*
* Now free any remaining pages. For internal objects, this also
* removes them from paging queues. Don't free wired pages, just
* remove them from the object.
*/
s = splvm();
vm_page_lock_queues();
while ((p = TAILQ_FIRST(&object->memq)) != NULL) {
KASSERT(!p->busy && (p->flags & PG_BUSY) == 0,
("vm_object_terminate: freeing busy page %p "
"p->busy = %d, p->flags %x\n", p, p->busy, p->flags));
if (p->wire_count == 0) {
vm_page_busy(p);
vm_page_free(p);
cnt.v_pfree++;
} else {
vm_page_busy(p);
vm_page_remove(p);
}
}
vm_page_unlock_queues();
splx(s);
/*
* Let the pager know object is dead.
*/
vm_pager_deallocate(object);
/*
* Remove the object from the global object list.
*/
mtx_lock(&vm_object_list_mtx);
TAILQ_REMOVE(&vm_object_list, object, object_list);
mtx_unlock(&vm_object_list_mtx);
wakeup(object);
/*
* Free the space for the object.
*/
uma_zfree(obj_zone, object);
}
/*
* vm_object_page_clean
*
* Clean all dirty pages in the specified range of object. Leaves page
* on whatever queue it is currently on. If NOSYNC is set then do not
* write out pages with PG_NOSYNC set (originally comes from MAP_NOSYNC),
* leaving the object dirty.
*
* Odd semantics: if start == end, we clean everything.
*
* The object must be locked.
*/
void
vm_object_page_clean(vm_object_t object, vm_pindex_t start, vm_pindex_t end, int flags)
{
vm_page_t p, np;
vm_pindex_t tstart, tend;
vm_pindex_t pi;
struct vnode *vp;
int clearobjflags;
int pagerflags;
int curgeneration;
GIANT_REQUIRED;
if (object->type != OBJT_VNODE ||
(object->flags & OBJ_MIGHTBEDIRTY) == 0)
return;
pagerflags = (flags & (OBJPC_SYNC | OBJPC_INVAL)) ? VM_PAGER_PUT_SYNC : 0;
pagerflags |= (flags & OBJPC_INVAL) ? VM_PAGER_PUT_INVAL : 0;
vp = object->handle;
vm_object_set_flag(object, OBJ_CLEANING);
tstart = start;
if (end == 0) {
tend = object->size;
} else {
tend = end;
}
/*
* If the caller is smart and only msync()s a range he knows is
* dirty, we may be able to avoid an object scan. This results in
* a phenominal improvement in performance. We cannot do this
* as a matter of course because the object may be huge - e.g.
* the size might be in the gigabytes or terrabytes.
*/
if (msync_flush_flags & MSYNC_FLUSH_HARDSEQ) {
vm_pindex_t tscan;
int scanlimit;
int scanreset;
scanreset = object->resident_page_count / EASY_SCAN_FACTOR;
if (scanreset < 16)
scanreset = 16;
scanlimit = scanreset;
tscan = tstart;
while (tscan < tend) {
curgeneration = object->generation;
p = vm_page_lookup(object, tscan);
if (p == NULL || p->valid == 0 ||
(p->queue - p->pc) == PQ_CACHE) {
if (--scanlimit == 0)
break;
++tscan;
continue;
}
vm_page_test_dirty(p);
if ((p->dirty & p->valid) == 0) {
if (--scanlimit == 0)
break;
++tscan;
continue;
}
/*
* If we have been asked to skip nosync pages and
* this is a nosync page, we can't continue.
*/
if ((flags & OBJPC_NOSYNC) && (p->flags & PG_NOSYNC)) {
if (--scanlimit == 0)
break;
++tscan;
continue;
}
scanlimit = scanreset;
/*
* This returns 0 if it was unable to busy the first
* page (i.e. had to sleep).
*/
tscan += vm_object_page_collect_flush(object, p, curgeneration, pagerflags);
}
/*
* If everything was dirty and we flushed it successfully,
* and the requested range is not the entire object, we
* don't have to mess with CLEANCHK or MIGHTBEDIRTY and can
* return immediately.
*/
if (tscan >= tend && (tstart || tend < object->size)) {
vm_object_clear_flag(object, OBJ_CLEANING);
return;
}
}
/*
* Generally set CLEANCHK interlock and make the page read-only so
* we can then clear the object flags.
*
* However, if this is a nosync mmap then the object is likely to
* stay dirty so do not mess with the page and do not clear the
* object flags.
*/
clearobjflags = 1;
vm_page_lock_queues();
TAILQ_FOREACH(p, &object->memq, listq) {
vm_page_flag_set(p, PG_CLEANCHK);
if ((flags & OBJPC_NOSYNC) && (p->flags & PG_NOSYNC))
clearobjflags = 0;
else
pmap_page_protect(p, VM_PROT_READ);
}
vm_page_unlock_queues();
if (clearobjflags && (tstart == 0) && (tend == object->size)) {
struct vnode *vp;
vm_object_clear_flag(object, OBJ_WRITEABLE|OBJ_MIGHTBEDIRTY);
if (object->type == OBJT_VNODE &&
(vp = (struct vnode *)object->handle) != NULL) {
VI_LOCK(vp);
if (vp->v_iflag & VI_OBJDIRTY)
vp->v_iflag &= ~VI_OBJDIRTY;
VI_UNLOCK(vp);
}
}
rescan:
curgeneration = object->generation;
for (p = TAILQ_FIRST(&object->memq); p; p = np) {
int n;
np = TAILQ_NEXT(p, listq);
again:
pi = p->pindex;
if (((p->flags & PG_CLEANCHK) == 0) ||
(pi < tstart) || (pi >= tend) ||
(p->valid == 0) ||
((p->queue - p->pc) == PQ_CACHE)) {
vm_page_flag_clear(p, PG_CLEANCHK);
continue;
}
vm_page_test_dirty(p);
if ((p->dirty & p->valid) == 0) {
vm_page_flag_clear(p, PG_CLEANCHK);
continue;
}
/*
* If we have been asked to skip nosync pages and this is a
* nosync page, skip it. Note that the object flags were
* not cleared in this case so we do not have to set them.
*/
if ((flags & OBJPC_NOSYNC) && (p->flags & PG_NOSYNC)) {
vm_page_flag_clear(p, PG_CLEANCHK);
continue;
}
n = vm_object_page_collect_flush(object, p,
curgeneration, pagerflags);
if (n == 0)
goto rescan;
if (object->generation != curgeneration)
goto rescan;
/*
* Try to optimize the next page. If we can't we pick up
* our (random) scan where we left off.
*/
if (msync_flush_flags & MSYNC_FLUSH_SOFTSEQ) {
if ((p = vm_page_lookup(object, pi + n)) != NULL)
goto again;
}
}
#if 0
VOP_FSYNC(vp, NULL, (pagerflags & VM_PAGER_PUT_SYNC)?MNT_WAIT:0, curproc);
#endif
vm_object_clear_flag(object, OBJ_CLEANING);
return;
}
static int
vm_object_page_collect_flush(vm_object_t object, vm_page_t p, int curgeneration, int pagerflags)
{
int runlen;
int s;
int maxf;
int chkb;
int maxb;
int i;
vm_pindex_t pi;
vm_page_t maf[vm_pageout_page_count];
vm_page_t mab[vm_pageout_page_count];
vm_page_t ma[vm_pageout_page_count];
s = splvm();
pi = p->pindex;
while (vm_page_sleep_busy(p, TRUE, "vpcwai")) {
if (object->generation != curgeneration) {
splx(s);
return(0);
}
}
vm_page_lock_queues();
maxf = 0;
for(i = 1; i < vm_pageout_page_count; i++) {
vm_page_t tp;
if ((tp = vm_page_lookup(object, pi + i)) != NULL) {
if ((tp->flags & PG_BUSY) ||
(tp->flags & PG_CLEANCHK) == 0 ||
(tp->busy != 0))
break;
if((tp->queue - tp->pc) == PQ_CACHE) {
vm_page_flag_clear(tp, PG_CLEANCHK);
break;
}
vm_page_test_dirty(tp);
if ((tp->dirty & tp->valid) == 0) {
vm_page_flag_clear(tp, PG_CLEANCHK);
break;
}
maf[ i - 1 ] = tp;
maxf++;
continue;
}
break;
}
maxb = 0;
chkb = vm_pageout_page_count - maxf;
if (chkb) {
for(i = 1; i < chkb;i++) {
vm_page_t tp;
if ((tp = vm_page_lookup(object, pi - i)) != NULL) {
if ((tp->flags & PG_BUSY) ||
(tp->flags & PG_CLEANCHK) == 0 ||
(tp->busy != 0))
break;
if ((tp->queue - tp->pc) == PQ_CACHE) {
vm_page_flag_clear(tp, PG_CLEANCHK);
break;
}
vm_page_test_dirty(tp);
if ((tp->dirty & tp->valid) == 0) {
vm_page_flag_clear(tp, PG_CLEANCHK);
break;
}
mab[ i - 1 ] = tp;
maxb++;
continue;
}
break;
}
}
for(i = 0; i < maxb; i++) {
int index = (maxb - i) - 1;
ma[index] = mab[i];
vm_page_flag_clear(ma[index], PG_CLEANCHK);
}
vm_page_flag_clear(p, PG_CLEANCHK);
ma[maxb] = p;
for(i = 0; i < maxf; i++) {
int index = (maxb + i) + 1;
ma[index] = maf[i];
vm_page_flag_clear(ma[index], PG_CLEANCHK);
}
runlen = maxb + maxf + 1;
splx(s);
vm_pageout_flush(ma, runlen, pagerflags);
for (i = 0; i < runlen; i++) {
if (ma[i]->valid & ma[i]->dirty) {
pmap_page_protect(ma[i], VM_PROT_READ);
vm_page_flag_set(ma[i], PG_CLEANCHK);
/*
* maxf will end up being the actual number of pages
* we wrote out contiguously, non-inclusive of the
* first page. We do not count look-behind pages.
*/
if (i >= maxb + 1 && (maxf > i - maxb - 1))
maxf = i - maxb - 1;
}
}
vm_page_unlock_queues();
return(maxf + 1);
}
#ifdef ENABLE_VFS_IOOPT
/*
* Same as vm_object_pmap_copy, except range checking really
* works, and is meant for small sections of an object.
*
* This code protects resident pages by making them read-only
* and is typically called on a fork or split when a page
* is converted to copy-on-write.
*
* NOTE: If the page is already at VM_PROT_NONE, calling
* pmap_page_protect will have no effect.
*/
void
vm_object_pmap_copy_1(vm_object_t object, vm_pindex_t start, vm_pindex_t end)
{
vm_pindex_t idx;
vm_page_t p;
GIANT_REQUIRED;
if (object == NULL || (object->flags & OBJ_WRITEABLE) == 0)
return;
vm_page_lock_queues();
for (idx = start; idx < end; idx++) {
p = vm_page_lookup(object, idx);
if (p == NULL)
continue;
pmap_page_protect(p, VM_PROT_READ);
}
vm_page_unlock_queues();
}
#endif
/*
* vm_object_madvise:
*
* Implements the madvise function at the object/page level.
*
* MADV_WILLNEED (any object)
*
* Activate the specified pages if they are resident.
*
* MADV_DONTNEED (any object)
*
* Deactivate the specified pages if they are resident.
*
* MADV_FREE (OBJT_DEFAULT/OBJT_SWAP objects,
* OBJ_ONEMAPPING only)
*
* Deactivate and clean the specified pages if they are
* resident. This permits the process to reuse the pages
* without faulting or the kernel to reclaim the pages
* without I/O.
*/
void
vm_object_madvise(vm_object_t object, vm_pindex_t pindex, int count, int advise)
{
vm_pindex_t end, tpindex;
vm_object_t tobject;
vm_page_t m;
if (object == NULL)
return;
vm_object_lock(object);
end = pindex + count;
/*
* Locate and adjust resident pages
*/
for (; pindex < end; pindex += 1) {
relookup:
tobject = object;
tpindex = pindex;
shadowlookup:
/*
* MADV_FREE only operates on OBJT_DEFAULT or OBJT_SWAP pages
* and those pages must be OBJ_ONEMAPPING.
*/
if (advise == MADV_FREE) {
if ((tobject->type != OBJT_DEFAULT &&
tobject->type != OBJT_SWAP) ||
(tobject->flags & OBJ_ONEMAPPING) == 0) {
continue;
}
}
m = vm_page_lookup(tobject, tpindex);
if (m == NULL) {
/*
* There may be swap even if there is no backing page
*/
if (advise == MADV_FREE && tobject->type == OBJT_SWAP)
swap_pager_freespace(tobject, tpindex, 1);
/*
* next object
*/
tobject = tobject->backing_object;
if (tobject == NULL)
continue;
tpindex += OFF_TO_IDX(tobject->backing_object_offset);
goto shadowlookup;
}
/*
* If the page is busy or not in a normal active state,
* we skip it. If the page is not managed there are no
* page queues to mess with. Things can break if we mess
* with pages in any of the below states.
*/
vm_page_lock_queues();
if (m->hold_count ||
m->wire_count ||
(m->flags & PG_UNMANAGED) ||
m->valid != VM_PAGE_BITS_ALL) {
vm_page_unlock_queues();
continue;
}
if (vm_page_sleep_if_busy(m, TRUE, "madvpo"))
goto relookup;
if (advise == MADV_WILLNEED) {
vm_page_activate(m);
} else if (advise == MADV_DONTNEED) {
vm_page_dontneed(m);
} else if (advise == MADV_FREE) {
/*
* Mark the page clean. This will allow the page
* to be freed up by the system. However, such pages
* are often reused quickly by malloc()/free()
* so we do not do anything that would cause
* a page fault if we can help it.
*
* Specifically, we do not try to actually free
* the page now nor do we try to put it in the
* cache (which would cause a page fault on reuse).
*
* But we do make the page is freeable as we
* can without actually taking the step of unmapping
* it.
*/
pmap_clear_modify(m);
m->dirty = 0;
m->act_count = 0;
vm_page_dontneed(m);
}
vm_page_unlock_queues();
if (advise == MADV_FREE && tobject->type == OBJT_SWAP)
swap_pager_freespace(tobject, tpindex, 1);
}
vm_object_unlock(object);
}
/*
* vm_object_shadow:
*
* Create a new object which is backed by the
* specified existing object range. The source
* object reference is deallocated.
*
* The new object and offset into that object
* are returned in the source parameters.
*/
void
vm_object_shadow(
vm_object_t *object, /* IN/OUT */
vm_ooffset_t *offset, /* IN/OUT */
vm_size_t length)
{
vm_object_t source;
vm_object_t result;
source = *object;
vm_object_lock(source);
/*
* Don't create the new object if the old object isn't shared.
*/
if (source != NULL &&
source->ref_count == 1 &&
source->handle == NULL &&
(source->type == OBJT_DEFAULT ||
source->type == OBJT_SWAP)) {
vm_object_unlock(source);
return;
}
/*
* Allocate a new object with the given length
*/
result = vm_object_allocate(OBJT_DEFAULT, length);
KASSERT(result != NULL, ("vm_object_shadow: no object for shadowing"));
/*
* The new object shadows the source object, adding a reference to it.
* Our caller changes his reference to point to the new object,
* removing a reference to the source object. Net result: no change
* of reference count.
*
* Try to optimize the result object's page color when shadowing
* in order to maintain page coloring consistency in the combined
* shadowed object.
*/
result->backing_object = source;
if (source) {
TAILQ_INSERT_TAIL(&source->shadow_head, result, shadow_list);
source->shadow_count++;
source->generation++;
if (length < source->size)
length = source->size;
if (length > PQ_L2_SIZE / 3 + PQ_PRIME1 ||
source->generation > 1)
length = PQ_L2_SIZE / 3 + PQ_PRIME1;
result->pg_color = (source->pg_color +
length * source->generation) & PQ_L2_MASK;
next_index = (result->pg_color + PQ_L2_SIZE / 3 + PQ_PRIME1) &
PQ_L2_MASK;
}
/*
* Store the offset into the source object, and fix up the offset into
* the new object.
*/
result->backing_object_offset = *offset;
/*
* Return the new things
*/
*offset = 0;
*object = result;
vm_object_unlock(source);
}
/*
* vm_object_split:
*
* Split the pages in a map entry into a new object. This affords
* easier removal of unused pages, and keeps object inheritance from
* being a negative impact on memory usage.
*/
void
vm_object_split(vm_map_entry_t entry)
{
vm_page_t m;
vm_object_t orig_object, new_object, source;
vm_offset_t s, e;
vm_pindex_t offidxstart, offidxend;
vm_size_t idx, size;
vm_ooffset_t offset;
GIANT_REQUIRED;
orig_object = entry->object.vm_object;
if (orig_object->type != OBJT_DEFAULT && orig_object->type != OBJT_SWAP)
return;
if (orig_object->ref_count <= 1)
return;
offset = entry->offset;
s = entry->start;
e = entry->end;
offidxstart = OFF_TO_IDX(offset);
offidxend = offidxstart + OFF_TO_IDX(e - s);
size = offidxend - offidxstart;
new_object = vm_pager_allocate(orig_object->type,
NULL, IDX_TO_OFF(size), VM_PROT_ALL, 0LL);
if (new_object == NULL)
return;
source = orig_object->backing_object;
if (source != NULL) {
vm_object_reference(source); /* Referenced by new_object */
TAILQ_INSERT_TAIL(&source->shadow_head,
new_object, shadow_list);
vm_object_clear_flag(source, OBJ_ONEMAPPING);
new_object->backing_object_offset =
orig_object->backing_object_offset + offset;
new_object->backing_object = source;
source->shadow_count++;
source->generation++;
}
for (idx = 0; idx < size; idx++) {
retry:
m = vm_page_lookup(orig_object, offidxstart + idx);
if (m == NULL)
continue;
/*
* We must wait for pending I/O to complete before we can
* rename the page.
*
* We do not have to VM_PROT_NONE the page as mappings should
* not be changed by this operation.
*/
vm_page_lock_queues();
if (vm_page_sleep_if_busy(m, TRUE, "spltwt"))
goto retry;
vm_page_busy(m);
vm_page_unlock_queues();
vm_page_rename(m, new_object, idx);
/* page automatically made dirty by rename and cache handled */
vm_page_busy(m);
}
if (orig_object->type == OBJT_SWAP) {
vm_object_pip_add(orig_object, 1);
/*
* copy orig_object pages into new_object
* and destroy unneeded pages in
* shadow object.
*/
swap_pager_copy(orig_object, new_object, offidxstart, 0);
vm_object_pip_wakeup(orig_object);
}
TAILQ_FOREACH(m, &new_object->memq, listq)
vm_page_wakeup(m);
entry->object.vm_object = new_object;
entry->offset = 0LL;
vm_object_deallocate(orig_object);
}
#define OBSC_TEST_ALL_SHADOWED 0x0001
#define OBSC_COLLAPSE_NOWAIT 0x0002
#define OBSC_COLLAPSE_WAIT 0x0004
static __inline int
vm_object_backing_scan(vm_object_t object, int op)
{
int s;
int r = 1;
vm_page_t p;
vm_object_t backing_object;
vm_pindex_t backing_offset_index;
s = splvm();
GIANT_REQUIRED;
backing_object = object->backing_object;
backing_offset_index = OFF_TO_IDX(object->backing_object_offset);
/*
* Initial conditions
*/
if (op & OBSC_TEST_ALL_SHADOWED) {
/*
* We do not want to have to test for the existence of
* swap pages in the backing object. XXX but with the
* new swapper this would be pretty easy to do.
*
* XXX what about anonymous MAP_SHARED memory that hasn't
* been ZFOD faulted yet? If we do not test for this, the
* shadow test may succeed! XXX
*/
if (backing_object->type != OBJT_DEFAULT) {
splx(s);
return (0);
}
}
if (op & OBSC_COLLAPSE_WAIT) {
vm_object_set_flag(backing_object, OBJ_DEAD);
}
/*
* Our scan
*/
p = TAILQ_FIRST(&backing_object->memq);
while (p) {
vm_page_t next = TAILQ_NEXT(p, listq);
vm_pindex_t new_pindex = p->pindex - backing_offset_index;
if (op & OBSC_TEST_ALL_SHADOWED) {
vm_page_t pp;
/*
* Ignore pages outside the parent object's range
* and outside the parent object's mapping of the
* backing object.
*
* note that we do not busy the backing object's
* page.
*/
if (
p->pindex < backing_offset_index ||
new_pindex >= object->size
) {
p = next;
continue;
}
/*
* See if the parent has the page or if the parent's
* object pager has the page. If the parent has the
* page but the page is not valid, the parent's
* object pager must have the page.
*
* If this fails, the parent does not completely shadow
* the object and we might as well give up now.
*/
pp = vm_page_lookup(object, new_pindex);
if (
(pp == NULL || pp->valid == 0) &&
!vm_pager_has_page(object, new_pindex, NULL, NULL)
) {
r = 0;
break;
}
}
/*
* Check for busy page
*/
if (op & (OBSC_COLLAPSE_WAIT | OBSC_COLLAPSE_NOWAIT)) {
vm_page_t pp;
vm_page_lock_queues();
if (op & OBSC_COLLAPSE_NOWAIT) {
if ((p->flags & PG_BUSY) ||
!p->valid ||
p->hold_count ||
p->wire_count ||
p->busy) {
vm_page_unlock_queues();
p = next;
continue;
}
} else if (op & OBSC_COLLAPSE_WAIT) {
if (vm_page_sleep_if_busy(p, TRUE, "vmocol")) {
/*
* If we slept, anything could have
* happened. Since the object is
* marked dead, the backing offset
* should not have changed so we
* just restart our scan.
*/
p = TAILQ_FIRST(&backing_object->memq);
continue;
}
}
/*
* Busy the page
*/
vm_page_busy(p);
vm_page_unlock_queues();
KASSERT(
p->object == backing_object,
("vm_object_qcollapse(): object mismatch")
);
/*
* Destroy any associated swap
*/
if (backing_object->type == OBJT_SWAP) {
swap_pager_freespace(
backing_object,
p->pindex,
1
);
}
if (
p->pindex < backing_offset_index ||
new_pindex >= object->size
) {
/*
* Page is out of the parent object's range, we
* can simply destroy it.
*/
vm_page_lock_queues();
pmap_remove_all(p);
vm_page_free(p);
vm_page_unlock_queues();
p = next;
continue;
}
pp = vm_page_lookup(object, new_pindex);
if (
pp != NULL ||
vm_pager_has_page(object, new_pindex, NULL, NULL)
) {
/*
* page already exists in parent OR swap exists
* for this location in the parent. Destroy
* the original page from the backing object.
*
* Leave the parent's page alone
*/
vm_page_lock_queues();
pmap_remove_all(p);
vm_page_free(p);
vm_page_unlock_queues();
p = next;
continue;
}
/*
* Page does not exist in parent, rename the
* page from the backing object to the main object.
*
* If the page was mapped to a process, it can remain
* mapped through the rename.
*/
vm_page_rename(p, object, new_pindex);
/* page automatically made dirty by rename */
}
p = next;
}
splx(s);
return (r);
}
/*
* this version of collapse allows the operation to occur earlier and
* when paging_in_progress is true for an object... This is not a complete
* operation, but should plug 99.9% of the rest of the leaks.
*/
static void
vm_object_qcollapse(vm_object_t object)
{
vm_object_t backing_object = object->backing_object;
GIANT_REQUIRED;
if (backing_object->ref_count != 1)
return;
backing_object->ref_count += 2;
vm_object_backing_scan(object, OBSC_COLLAPSE_NOWAIT);
backing_object->ref_count -= 2;
}
/*
* vm_object_collapse:
*
* Collapse an object with the object backing it.
* Pages in the backing object are moved into the
* parent, and the backing object is deallocated.
*/
void
vm_object_collapse(vm_object_t object)
{
GIANT_REQUIRED;
while (TRUE) {
vm_object_t backing_object;
/*
* Verify that the conditions are right for collapse:
*
* The object exists and the backing object exists.
*/
if (object == NULL)
break;
if ((backing_object = object->backing_object) == NULL)
break;
/*
* we check the backing object first, because it is most likely
* not collapsable.
*/
if (backing_object->handle != NULL ||
(backing_object->type != OBJT_DEFAULT &&
backing_object->type != OBJT_SWAP) ||
(backing_object->flags & OBJ_DEAD) ||
object->handle != NULL ||
(object->type != OBJT_DEFAULT &&
object->type != OBJT_SWAP) ||
(object->flags & OBJ_DEAD)) {
break;
}
if (
object->paging_in_progress != 0 ||
backing_object->paging_in_progress != 0
) {
vm_object_qcollapse(object);
break;
}
/*
* We know that we can either collapse the backing object (if
* the parent is the only reference to it) or (perhaps) have
* the parent bypass the object if the parent happens to shadow
* all the resident pages in the entire backing object.
*
* This is ignoring pager-backed pages such as swap pages.
* vm_object_backing_scan fails the shadowing test in this
* case.
*/
if (backing_object->ref_count == 1) {
/*
* If there is exactly one reference to the backing
* object, we can collapse it into the parent.
*/
vm_object_backing_scan(object, OBSC_COLLAPSE_WAIT);
/*
* Move the pager from backing_object to object.
*/
if (backing_object->type == OBJT_SWAP) {
vm_object_pip_add(backing_object, 1);
/*
* scrap the paging_offset junk and do a
* discrete copy. This also removes major
* assumptions about how the swap-pager
* works from where it doesn't belong. The
* new swapper is able to optimize the
* destroy-source case.
*/
vm_object_pip_add(object, 1);
swap_pager_copy(
backing_object,
object,
OFF_TO_IDX(object->backing_object_offset), TRUE);
vm_object_pip_wakeup(object);
vm_object_pip_wakeup(backing_object);
}
/*
* Object now shadows whatever backing_object did.
* Note that the reference to
* backing_object->backing_object moves from within
* backing_object to within object.
*/
TAILQ_REMOVE(
&object->backing_object->shadow_head,
object,
shadow_list
);
object->backing_object->shadow_count--;
object->backing_object->generation++;
if (backing_object->backing_object) {
TAILQ_REMOVE(
&backing_object->backing_object->shadow_head,
backing_object,
shadow_list
);
backing_object->backing_object->shadow_count--;
backing_object->backing_object->generation++;
}
object->backing_object = backing_object->backing_object;
if (object->backing_object) {
TAILQ_INSERT_TAIL(
&object->backing_object->shadow_head,
object,
shadow_list
);
object->backing_object->shadow_count++;
object->backing_object->generation++;
}
object->backing_object_offset +=
backing_object->backing_object_offset;
/*
* Discard backing_object.
*
* Since the backing object has no pages, no pager left,
* and no object references within it, all that is
* necessary is to dispose of it.
*/
KASSERT(backing_object->ref_count == 1, ("backing_object %p was somehow re-referenced during collapse!", backing_object));
KASSERT(TAILQ_FIRST(&backing_object->memq) == NULL, ("backing_object %p somehow has left over pages during collapse!", backing_object));
mtx_lock(&vm_object_list_mtx);
TAILQ_REMOVE(
&vm_object_list,
backing_object,
object_list
);
mtx_unlock(&vm_object_list_mtx);
uma_zfree(obj_zone, backing_object);
object_collapses++;
} else {
vm_object_t new_backing_object;
/*
* If we do not entirely shadow the backing object,
* there is nothing we can do so we give up.
*/
if (vm_object_backing_scan(object, OBSC_TEST_ALL_SHADOWED) == 0) {
break;
}
/*
* Make the parent shadow the next object in the
* chain. Deallocating backing_object will not remove
* it, since its reference count is at least 2.
*/
TAILQ_REMOVE(
&backing_object->shadow_head,
object,
shadow_list
);
backing_object->shadow_count--;
backing_object->generation++;
new_backing_object = backing_object->backing_object;
if ((object->backing_object = new_backing_object) != NULL) {
vm_object_reference(new_backing_object);
TAILQ_INSERT_TAIL(
&new_backing_object->shadow_head,
object,
shadow_list
);
new_backing_object->shadow_count++;
new_backing_object->generation++;
object->backing_object_offset +=
backing_object->backing_object_offset;
}
/*
* Drop the reference count on backing_object. Since
* its ref_count was at least 2, it will not vanish;
* so we don't need to call vm_object_deallocate, but
* we do anyway.
*/
vm_object_deallocate(backing_object);
object_bypasses++;
}
/*
* Try again with this object's new backing object.
*/
}
}
/*
* vm_object_page_remove: [internal]
*
* Removes all physical pages in the specified
* object range from the object's list of pages.
*
* The object must be locked.
*/
void
vm_object_page_remove(vm_object_t object, vm_pindex_t start, vm_pindex_t end, boolean_t clean_only)
{
vm_page_t p, next;
vm_pindex_t size;
int all;
if (object == NULL)
return;
mtx_lock(&Giant);
if (object->resident_page_count == 0) {
mtx_unlock(&Giant);
return;
}
all = ((end == 0) && (start == 0));
/*
* Since physically-backed objects do not use managed pages, we can't
* remove pages from the object (we must instead remove the page
* references, and then destroy the object).
*/
KASSERT(object->type != OBJT_PHYS, ("attempt to remove pages from a physical object"));
vm_object_pip_add(object, 1);
again:
vm_page_lock_queues();
size = end - start;
if (all || size > object->resident_page_count / 4) {
for (p = TAILQ_FIRST(&object->memq); p != NULL; p = next) {
next = TAILQ_NEXT(p, listq);
if (all || ((start <= p->pindex) && (p->pindex < end))) {
if (p->wire_count != 0) {
pmap_remove_all(p);
if (!clean_only)
p->valid = 0;
continue;
}
/*
* The busy flags are only cleared at
* interrupt -- minimize the spl transitions
*/
if (vm_page_sleep_if_busy(p, TRUE, "vmopar"))
goto again;
if (clean_only && p->valid) {
vm_page_test_dirty(p);
if (p->valid & p->dirty)
continue;
}
vm_page_busy(p);
pmap_remove_all(p);
vm_page_free(p);
}
}
} else {
while (size > 0) {
if ((p = vm_page_lookup(object, start)) != NULL) {
if (p->wire_count != 0) {
pmap_remove_all(p);
if (!clean_only)
p->valid = 0;
start += 1;
size -= 1;
continue;
}
/*
* The busy flags are only cleared at
* interrupt -- minimize the spl transitions
*/
if (vm_page_sleep_if_busy(p, TRUE, "vmopar"))
goto again;
if (clean_only && p->valid) {
vm_page_test_dirty(p);
if (p->valid & p->dirty) {
start += 1;
size -= 1;
continue;
}
}
vm_page_busy(p);
pmap_remove_all(p);
vm_page_free(p);
}
start += 1;
size -= 1;
}
}
vm_page_unlock_queues();
vm_object_pip_wakeup(object);
mtx_unlock(&Giant);
}
/*
* Routine: vm_object_coalesce
* Function: Coalesces two objects backing up adjoining
* regions of memory into a single object.
*
* returns TRUE if objects were combined.
*
* NOTE: Only works at the moment if the second object is NULL -
* if it's not, which object do we lock first?
*
* Parameters:
* prev_object First object to coalesce
* prev_offset Offset into prev_object
* next_object Second object into coalesce
* next_offset Offset into next_object
*
* prev_size Size of reference to prev_object
* next_size Size of reference to next_object
*
* Conditions:
* The object must *not* be locked.
*/
boolean_t
vm_object_coalesce(vm_object_t prev_object, vm_pindex_t prev_pindex,
vm_size_t prev_size, vm_size_t next_size)
{
vm_pindex_t next_pindex;
if (prev_object == NULL)
return (TRUE);
vm_object_lock(prev_object);
if (prev_object->type != OBJT_DEFAULT &&
prev_object->type != OBJT_SWAP) {
vm_object_unlock(prev_object);
return (FALSE);
}
/*
* Try to collapse the object first
*/
vm_object_collapse(prev_object);
/*
* Can't coalesce if: . more than one reference . paged out . shadows
* another object . has a copy elsewhere (any of which mean that the
* pages not mapped to prev_entry may be in use anyway)
*/
if (prev_object->backing_object != NULL) {
vm_object_unlock(prev_object);
return (FALSE);
}
prev_size >>= PAGE_SHIFT;
next_size >>= PAGE_SHIFT;
next_pindex = prev_pindex + prev_size;
if ((prev_object->ref_count > 1) &&
(prev_object->size != next_pindex)) {
vm_object_unlock(prev_object);
return (FALSE);
}
/*
* Remove any pages that may still be in the object from a previous
* deallocation.
*/
if (next_pindex < prev_object->size) {
vm_object_page_remove(prev_object,
next_pindex,
next_pindex + next_size, FALSE);
if (prev_object->type == OBJT_SWAP)
swap_pager_freespace(prev_object,
next_pindex, next_size);
}
/*
* Extend the object if necessary.
*/
if (next_pindex + next_size > prev_object->size)
prev_object->size = next_pindex + next_size;
vm_object_unlock(prev_object);
return (TRUE);
}
void
vm_object_set_writeable_dirty(vm_object_t object)
{
struct vnode *vp;
vm_object_set_flag(object, OBJ_WRITEABLE|OBJ_MIGHTBEDIRTY);
if (object->type == OBJT_VNODE &&
(vp = (struct vnode *)object->handle) != NULL) {
VI_LOCK(vp);
if ((vp->v_iflag & VI_OBJDIRTY) == 0)
vp->v_iflag |= VI_OBJDIRTY;
VI_UNLOCK(vp);
}
}
#ifdef ENABLE_VFS_IOOPT
/*
* Experimental support for zero-copy I/O
*
* Performs the copy_on_write operations necessary to allow the virtual copies
* into user space to work. This has to be called for write(2) system calls
* from other processes, file unlinking, and file size shrinkage.
*/
void
vm_freeze_copyopts(vm_object_t object, vm_pindex_t froma, vm_pindex_t toa)
{
int rv;
vm_object_t robject;
vm_pindex_t idx;
GIANT_REQUIRED;
if ((object == NULL) ||
((object->flags & OBJ_OPT) == 0))
return;
if (object->shadow_count > object->ref_count)
panic("vm_freeze_copyopts: sc > rc");
while ((robject = TAILQ_FIRST(&object->shadow_head)) != NULL) {
vm_pindex_t bo_pindex;
vm_page_t m_in, m_out;
bo_pindex = OFF_TO_IDX(robject->backing_object_offset);
vm_object_reference(robject);
vm_object_pip_wait(robject, "objfrz");
if (robject->ref_count == 1) {
vm_object_deallocate(robject);
continue;
}
vm_object_pip_add(robject, 1);
for (idx = 0; idx < robject->size; idx++) {
m_out = vm_page_grab(robject, idx,
VM_ALLOC_NORMAL | VM_ALLOC_RETRY);
if (m_out->valid == 0) {
m_in = vm_page_grab(object, bo_pindex + idx,
VM_ALLOC_NORMAL | VM_ALLOC_RETRY);
vm_page_lock_queues();
if (m_in->valid == 0) {
vm_page_unlock_queues();
rv = vm_pager_get_pages(object, &m_in, 1, 0);
if (rv != VM_PAGER_OK) {
printf("vm_freeze_copyopts: cannot read page from file: %lx\n", (long)m_in->pindex);
continue;
}
vm_page_lock_queues();
vm_page_deactivate(m_in);
}
pmap_remove_all(m_in);
vm_page_unlock_queues();
pmap_copy_page(m_in, m_out);
m_out->valid = m_in->valid;
vm_page_dirty(m_out);
vm_page_lock_queues();
vm_page_activate(m_out);
vm_page_unlock_queues();
vm_page_wakeup(m_in);
}
vm_page_wakeup(m_out);
}
object->shadow_count--;
object->ref_count--;
TAILQ_REMOVE(&object->shadow_head, robject, shadow_list);
robject->backing_object = NULL;
robject->backing_object_offset = 0;
vm_object_pip_wakeup(robject);
vm_object_deallocate(robject);
}
vm_object_clear_flag(object, OBJ_OPT);
}
#endif
#include "opt_ddb.h"
#ifdef DDB
#include <sys/kernel.h>
#include <sys/cons.h>
#include <ddb/ddb.h>
static int
_vm_object_in_map(vm_map_t map, vm_object_t object, vm_map_entry_t entry)
{
vm_map_t tmpm;
vm_map_entry_t tmpe;
vm_object_t obj;
int entcount;
if (map == 0)
return 0;
if (entry == 0) {
tmpe = map->header.next;
entcount = map->nentries;
while (entcount-- && (tmpe != &map->header)) {
if (_vm_object_in_map(map, object, tmpe)) {
return 1;
}
tmpe = tmpe->next;
}
} else if (entry->eflags & MAP_ENTRY_IS_SUB_MAP) {
tmpm = entry->object.sub_map;
tmpe = tmpm->header.next;
entcount = tmpm->nentries;
while (entcount-- && tmpe != &tmpm->header) {
if (_vm_object_in_map(tmpm, object, tmpe)) {
return 1;
}
tmpe = tmpe->next;
}
} else if ((obj = entry->object.vm_object) != NULL) {
for (; obj; obj = obj->backing_object)
if (obj == object) {
return 1;
}
}
return 0;
}
static int
vm_object_in_map(vm_object_t object)
{
struct proc *p;
/* sx_slock(&allproc_lock); */
LIST_FOREACH(p, &allproc, p_list) {
if (!p->p_vmspace /* || (p->p_flag & (P_SYSTEM|P_WEXIT)) */)
continue;
if (_vm_object_in_map(&p->p_vmspace->vm_map, object, 0)) {
/* sx_sunlock(&allproc_lock); */
return 1;
}
}
/* sx_sunlock(&allproc_lock); */
if (_vm_object_in_map(kernel_map, object, 0))
return 1;
if (_vm_object_in_map(kmem_map, object, 0))
return 1;
if (_vm_object_in_map(pager_map, object, 0))
return 1;
if (_vm_object_in_map(buffer_map, object, 0))
return 1;
return 0;
}
DB_SHOW_COMMAND(vmochk, vm_object_check)
{
vm_object_t object;
/*
* make sure that internal objs are in a map somewhere
* and none have zero ref counts.
*/
TAILQ_FOREACH(object, &vm_object_list, object_list) {
if (object->handle == NULL &&
(object->type == OBJT_DEFAULT || object->type == OBJT_SWAP)) {
if (object->ref_count == 0) {
db_printf("vmochk: internal obj has zero ref count: %ld\n",
(long)object->size);
}
if (!vm_object_in_map(object)) {
db_printf(
"vmochk: internal obj is not in a map: "
"ref: %d, size: %lu: 0x%lx, backing_object: %p\n",
object->ref_count, (u_long)object->size,
(u_long)object->size,
(void *)object->backing_object);
}
}
}
}
/*
* vm_object_print: [ debug ]
*/
DB_SHOW_COMMAND(object, vm_object_print_static)
{
/* XXX convert args. */
vm_object_t object = (vm_object_t)addr;
boolean_t full = have_addr;
vm_page_t p;
/* XXX count is an (unused) arg. Avoid shadowing it. */
#define count was_count
int count;
if (object == NULL)
return;
db_iprintf(
"Object %p: type=%d, size=0x%jx, res=%d, ref=%d, flags=0x%x\n",
object, (int)object->type, (uintmax_t)object->size,
object->resident_page_count, object->ref_count, object->flags);
db_iprintf(" sref=%d, backing_object(%d)=(%p)+0x%jx\n",
object->shadow_count,
object->backing_object ? object->backing_object->ref_count : 0,
object->backing_object, (uintmax_t)object->backing_object_offset);
if (!full)
return;
db_indent += 2;
count = 0;
TAILQ_FOREACH(p, &object->memq, listq) {
if (count == 0)
db_iprintf("memory:=");
else if (count == 6) {
db_printf("\n");
db_iprintf(" ...");
count = 0;
} else
db_printf(",");
count++;
db_printf("(off=0x%jx,page=0x%jx)",
(uintmax_t)p->pindex, (uintmax_t)VM_PAGE_TO_PHYS(p));
}
if (count != 0)
db_printf("\n");
db_indent -= 2;
}
/* XXX. */
#undef count
/* XXX need this non-static entry for calling from vm_map_print. */
void
vm_object_print(
/* db_expr_t */ long addr,
boolean_t have_addr,
/* db_expr_t */ long count,
char *modif)
{
vm_object_print_static(addr, have_addr, count, modif);
}
DB_SHOW_COMMAND(vmopag, vm_object_print_pages)
{
vm_object_t object;
int nl = 0;
int c;
TAILQ_FOREACH(object, &vm_object_list, object_list) {
vm_pindex_t idx, fidx;
vm_pindex_t osize;
vm_offset_t pa = -1, padiff;
int rcount;
vm_page_t m;
db_printf("new object: %p\n", (void *)object);
if (nl > 18) {
c = cngetc();
if (c != ' ')
return;
nl = 0;
}
nl++;
rcount = 0;
fidx = 0;
osize = object->size;
if (osize > 128)
osize = 128;
for (idx = 0; idx < osize; idx++) {
m = vm_page_lookup(object, idx);
if (m == NULL) {
if (rcount) {
db_printf(" index(%ld)run(%d)pa(0x%lx)\n",
(long)fidx, rcount, (long)pa);
if (nl > 18) {
c = cngetc();
if (c != ' ')
return;
nl = 0;
}
nl++;
rcount = 0;
}
continue;
}
if (rcount &&
(VM_PAGE_TO_PHYS(m) == pa + rcount * PAGE_SIZE)) {
++rcount;
continue;
}
if (rcount) {
padiff = pa + rcount * PAGE_SIZE - VM_PAGE_TO_PHYS(m);
padiff >>= PAGE_SHIFT;
padiff &= PQ_L2_MASK;
if (padiff == 0) {
pa = VM_PAGE_TO_PHYS(m) - rcount * PAGE_SIZE;
++rcount;
continue;
}
db_printf(" index(%ld)run(%d)pa(0x%lx)",
(long)fidx, rcount, (long)pa);
db_printf("pd(%ld)\n", (long)padiff);
if (nl > 18) {
c = cngetc();
if (c != ' ')
return;
nl = 0;
}
nl++;
}
fidx = idx;
pa = VM_PAGE_TO_PHYS(m);
rcount = 1;
}
if (rcount) {
db_printf(" index(%ld)run(%d)pa(0x%lx)\n",
(long)fidx, rcount, (long)pa);
if (nl > 18) {
c = cngetc();
if (c != ' ')
return;
nl = 0;
}
nl++;
}
}
}
#endif /* DDB */
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