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Add new pager type, OBJT_MGTDEVICE. It provides the device pager

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which carries fictitous managed pages. In particular, the consumers of
the new object type can remove all mappings of the device page with
pmap_remove_all().

The range of physical addresses used for fake page allocation shall be
registered with vm_phys_fictitious_reg_range() interface to allow the
PHYS_TO_VM_PAGE() to work in pmap.

Most likely, only i386 and amd64 pmaps can handle fictitious managed
pages right now.

Sponsored by:	The FreeBSD Foundation
Reviewed by:	alc
MFC after:	1 month
This commit is contained in:
Konstantin Belousov 2012-05-12 20:49:58 +00:00
parent ecb0bac9ab
commit b7ac5a8571
Notes: svn2git 2020-12-20 02:59:44 +00:00 
svn path=/head/; revision=235375
4 changed files with 50 additions and 10 deletions
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54
sys/vm/device_pager.c
View File

@ -61,6 +61,7 @@ static void dev_pager_putpages(vm_object_t, vm_page_t *, int,
boolean_t, int *);
static boolean_t dev_pager_haspage(vm_object_t, vm_pindex_t, int *,
int *);
static void dev_pager_free_page(vm_object_t object, vm_page_t m);
/* list of device pager objects */
static struct pagerlst dev_pager_object_list;
@ -76,6 +77,14 @@ struct pagerops devicepagerops = {
.pgo_haspage = dev_pager_haspage,
};
struct pagerops mgtdevicepagerops = {
.pgo_alloc = dev_pager_alloc,
.pgo_dealloc = dev_pager_dealloc,
.pgo_getpages = dev_pager_getpages,
.pgo_putpages = dev_pager_putpages,
.pgo_haspage = dev_pager_haspage,
};
static int old_dev_pager_ctor(void *handle, vm_ooffset_t size, vm_prot_t prot,
vm_ooffset_t foff, struct ucred *cred, u_short *color);
static void old_dev_pager_dtor(void *handle);
@ -115,7 +124,7 @@ cdev_pager_allocate(void *handle, enum obj_type tp, struct cdev_pager_ops *ops,
vm_pindex_t pindex;
u_short color;
if (tp != OBJT_DEVICE)
if (tp != OBJT_DEVICE && tp != OBJT_MGTDEVICE)
return (NULL);
/*
@ -196,6 +205,24 @@ cdev_pager_free_page(vm_object_t object, vm_page_t m)
{
VM_OBJECT_LOCK_ASSERT(object, MA_OWNED);
if (object->type == OBJT_MGTDEVICE) {
KASSERT((m->oflags & VPO_UNMANAGED) == 0, ("unmanaged %p", m));
pmap_remove_all(m);
vm_page_lock(m);
vm_page_remove(m);
vm_page_unlock(m);
} else if (object->type == OBJT_DEVICE)
dev_pager_free_page(object, m);
}
static void
dev_pager_free_page(vm_object_t object, vm_page_t m)
{
VM_OBJECT_LOCK_ASSERT(object, MA_OWNED);
KASSERT((object->type == OBJT_DEVICE &&
(m->oflags & VPO_UNMANAGED) != 0),
("Managed device or page obj %p m %p", object, m));
TAILQ_REMOVE(&object->un_pager.devp.devp_pglist, m, pageq);
vm_page_putfake(m);
}
@ -213,11 +240,15 @@ dev_pager_dealloc(object)
TAILQ_REMOVE(&dev_pager_object_list, object, pager_object_list);
mtx_unlock(&dev_pager_mtx);
VM_OBJECT_LOCK(object);
/*
* Free up our fake pages.
*/
while ((m = TAILQ_FIRST(&object->un_pager.devp.devp_pglist)) != NULL)
cdev_pager_free_page(object, m);
if (object->type == OBJT_DEVICE) {
/*
* Free up our fake pages.
*/
while ((m = TAILQ_FIRST(&object->un_pager.devp.devp_pglist))
!= NULL)
dev_pager_free_page(object, m);
}
}
static int
@ -240,8 +271,15 @@ dev_pager_getpages(vm_object_t object, vm_page_t *ma, int count, int reqpage)
}
if (error == VM_PAGER_OK) {
TAILQ_INSERT_TAIL(&object->un_pager.devp.devp_pglist,
ma[reqpage], pageq);
KASSERT((object->type == OBJT_DEVICE &&
(ma[reqpage]->oflags & VPO_UNMANAGED) != 0) ||
(object->type == OBJT_MGTDEVICE &&
(ma[reqpage]->oflags & VPO_UNMANAGED) == 0),
("Wrong page type %p %p", ma[reqpage], object));
if (object->type == OBJT_DEVICE) {
TAILQ_INSERT_TAIL(&object->un_pager.devp.devp_pglist,
ma[reqpage], pageq);
}
}
return (error);

2
sys/vm/vm.h
View File

@ -83,7 +83,7 @@ typedef u_char vm_prot_t; /* protection codes */
#define VM_PROT_DEFAULT VM_PROT_ALL
enum obj_type { OBJT_DEFAULT, OBJT_SWAP, OBJT_VNODE, OBJT_DEVICE, OBJT_PHYS,
OBJT_DEAD, OBJT_SG };
OBJT_DEAD, OBJT_SG, OBJT_MGTDEVICE };
typedef u_char objtype_t;
union vm_map_object;

3
sys/vm/vm_pager.c
View File

@ -159,7 +159,8 @@ struct pagerops *pagertab[] = {
&devicepagerops, /* OBJT_DEVICE */
&physpagerops, /* OBJT_PHYS */
&deadpagerops, /* OBJT_DEAD */
&sgpagerops /* OBJT_SG */
&sgpagerops, /* OBJT_SG */
&mgtdevicepagerops, /* OBJT_MGTDEVICE */
};
static const int npagers = sizeof(pagertab) / sizeof(pagertab[0]);

1
sys/vm/vm_pager.h
View File

@ -71,6 +71,7 @@ extern struct pagerops vnodepagerops;
extern struct pagerops devicepagerops;
extern struct pagerops physpagerops;
extern struct pagerops sgpagerops;
extern struct pagerops mgtdevicepagerops;
/*
* get/put return values