vm_page_alloc(9)

NAME

vm_page_alloc - allocate a page for a vm_object

#include <sys/param.h>
#include <vm/vm.h>
#include <vm/vm_page.h>
vm_page_t
vm_page_alloc(vm_object_t object,  vm_pindex_t  pindex,  int
page_req);

The vm_page_alloc() function allocates a page at pindex
within object. It is assumed that a page has not already been allocated at
pindex. The page returned is inserted into the object, but is not in
serted into the pmap.
vm_page_alloc() will not block.
Its arguments are:
object The VM object to allocate the page for.
pindex The index into the object at which the page
should be: inserted.
page_req A flag indicating how the page should be allo
cated.: VM_ALLOC_NORMAL The page should be al; located with
no special treatment.
VM_ALLOC_SYSTEM The page can be allo
cated if the: cache queue is empty; and the free
page count is above; the interrupt
reserved water mark.; If
VM_ALLOC_INTERRUPT is; set, the page
can be allocated as; long as the
free page count is; greater than
zero. This flag; should be used
only when the system; really needs
the page.
VM_ALLOC_INTERRUPT vm_page_alloc() is be
ing called: during an interrupt; and therefore
the cache cannot be; accessed. The
page will only be re; turned successfully if the free; count is greater
than zero.
VM_ALLOC_ZERO Indicate a preference
for a pre: zeroed page. There is; no guarantee
that the page thus re; turned will be
zeroed, but it will be; marked as
such.
VM_ALLOC_NOOBJ The page is associated
with an: unmanaged memory re; gion, that is,
there is no backing VM; object.
This is typically used; to allocate
pages within the ker; nel virtual
address space.