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⟩.