NAME
vm_page_bits
,
vm_page_set_validclean
,
vm_page_clear_dirty
,
vm_page_set_invalid
,
vm_page_zero_invalid
,
vm_page_is_valid
,
vm_page_test_dirty
,
vm_page_dirty
,
vm_page_undirty
—
manage page clean and dirty
bits
SYNOPSIS
#include
<sys/param.h>
#include <vm/vm.h>
#include <vm/vm_page.h>
int
vm_page_bits
(int
base, int
size);
void
vm_page_set_validclean
(vm_page_t
m, int base,
int size);
void
vm_page_clear_dirty
(vm_page_t
m, int base,
int size);
void
vm_page_set_invalid
(vm_page_t
m, int base,
int size);
void
vm_page_zero_invalid
(vm_page_t
m, boolean_t
setvalid);
int
vm_page_is_valid
(vm_page_t
m, int base,
int size);
void
vm_page_test_dirty
(vm_page_t
m);
void
vm_page_dirty
(vm_page_t
m);
void
vm_page_undirty
(vm_page_t
m);
DESCRIPTION
vm_page_bits
()
calculates the bits representing the DEV_BSIZE
range
of bytes between base and size.
The byte range is expected to be within a single page, and if
size is zero, no bits will be set.
vm_page_set_validclean
()
flags the byte range between base and
size as valid and clean. The range is expected to be
DEV_BSIZE
aligned and no larger than
PAGE_SIZE
. If it is not properly aligned, any
unaligned chunks of the DEV_BSIZE
blocks at the
beginning and end of the range will be zeroed.
If base is zero and
size is one page, the modified bit in the page map is
cleared; as well, the VPO_NOSYNC
flag is
cleared.
vm_page_clear_dirty
()
clears the dirty bits within a page in the range between
base and size. The bits
representing the range are calculated by calling
vm_page_bits
().
vm_page_set_invalid
()
clears the bits in both the valid and dirty flags representing the
DEV_BSIZE
blocks between base
and size in the page. The bits are calculated by
calling vm_page_bits
(). As well as clearing the bits
within the page, the generation number within the object holding the page is
incremented.
vm_page_zero_invalid
()
zeroes all of the blocks within the page that are currently flagged as
invalid. If setvalid is TRUE
,
all of the valid bits within the page are set.
In some cases, such as NFS, the valid bits cannot be set in order to maintain cache consistency.
vm_page_is_valid
()
checks to determine if the all of the DEV_BSIZE
blocks between base and size of
the page are valid. If size is zero and the page is
entirely invalid vm_page_is_valid
() will return
TRUE
, in all other cases a size of zero will return
FALSE
.
vm_page_test_dirty
()
checks if a page has been modified via any of its physical maps, and if so,
flags the entire page as dirty. vm_page_dirty
() is
called to modify the dirty bits.
vm_page_dirty
()
flags the entire page as dirty. It is expected that the page is not
currently on the cache queue.
vm_page_undirty
()
clears all of the dirty bits in a page.
NOTES
None of these functions are allowed to block.
AUTHORS
This manual page was written by Chad David <davidc@acns.ab.ca>.