NAME
uvm_pagealloc,
uvm_pagerealloc,
uvm_pagefree,
uvm_pglistalloc,
uvm_pglistfree,
uvm_page_physload —
physical memory allocator
SYNOPSIS
#include
<sys/param.h>
#include <uvm/uvm.h>
struct vm_page *
uvm_pagealloc(struct
uvm_object *uobj, voff_t
off, struct vm_anon
*anon, int
flags);
void
uvm_pagerealloc(struct
vm_page *pg, struct
uvm_object *newobj,
voff_t newoff);
void
uvm_pagefree(struct
vm_page *pg);
int
uvm_pglistalloc(psize_t
size, paddr_t low,
paddr_t high,
paddr_t alignment,
paddr_t boundary,
struct pglist *rlist,
int nsegs,
int flags);
void
uvm_pglistfree(struct
pglist *list);
void
uvm_page_physload(paddr_t
start, paddr_t end,
paddr_t avail_start,
paddr_t avail_end,
int free_list);
DESCRIPTION
The
uvm_pagealloc()
function allocates a page of memory at virtual address
off in either the object uobj or
the anonymous memory anon, or returns
NULL if no pages are free. Only one of
anon and uobj can be non
NULL. The flags can be any
of:
#define UVM_PGA_USERESERVE 0x0001 /* ok to use reserve pages */ #define UVM_PGA_ZERO 0x0002 /* returned page must be zeroed */
The UVM_PGA_USERESERVE flag means to
allocate a page even if that will result in the number of free pages being
lower than uvmexp.reserve_pagedaemon (if the current
thread is the pagedaemon) or uvmexp.reserve_kernel
(if the current thread is not the pagedaemon). The
UVM_PGA_ZERO flag causes the returned page to be
filled with zeroes, either by allocating it from a pool of pre-zeroed pages
or by zeroing it in-line as necessary.
The
uvm_pagerealloc()
function reallocates page pg to a new object
newobj, at a new offset
newoff.
The
uvm_pagefree()
function frees the physical page pg.
The
uvm_pglistalloc()
function allocates a list of pages for size size byte
under various constraints. low and
high describe the lowest and highest addresses
acceptable for the list. If alignment is non-zero, it
describes the required alignment of the list, in power-of-two notation. If
boundary is non-zero, no segment of the list may cross
this power-of-two boundary, relative to zero. nsegs is
the maximum number of physically contiguous segments. The allocated memory
is returned in the rlist list. The
flags can be any of:
#define UVM_PLA_WAITOK 0x0001 /* may sleep */ #define UVM_PLA_NOWAIT 0x0002 /* can't sleep */ #define UVM_PLA_ZERO 0x0004 /* zero all pages before returning */
The UVM_PLA_WAITOK flag means that the
function may sleep while trying to allocate the list of pages (this is
currently ignored). Conversely, the UVM_PLA_NOWAIT
flag signifies that the function may not sleep while allocating. It is an
error not to provide one of the above flags. Optionally, one may also
specify the UVM_PLA_ZERO flag to receive zeroed
memory in the page list.
The
uvm_pglistfree()
function frees the list of pages pointed to by
list.
The
uvm_page_physload()
function loads physical memory segments into VM space on the specified
free_list. uvm_page_physload()
must be called at system boot time to set up physical memory management
pages. The arguments describe the start and
end of the physical addresses of the segment, and the
available start and end addresses of pages not already in use.