NAME¶
vm_page_aflag_clear
,
vm_page_aflag_set
,
vm_page_reference
—
change page atomic flags
SYNOPSIS¶
#include
<sys/param.h>
#include
<vm/vm.h>
#include
<vm/vm_page.h>
void
vm_page_aflag_clear
(
vm_page_t
m,
uint8_t
bits);
void
vm_page_aflag_set
(
vm_page_t
m,
uint8_t
bits);
void
vm_page_reference
(
vm_page_t
m);
DESCRIPTION¶
The
vm_page_aflag_clear
() atomically clears
the specified bits on the page's
aflags.
The
vm_page_aflag_set
() atomically sets the
specified bits on the page's
aflags.
The
vm_page_reference
(
m)
call is the same as
vm_page_aflag_set(m, PGA_REFERENCED);
and is the recommended way to mark the page as referenced from third-party
kernel modules.
These functions neither block nor require any locks to be held around the calls
for correctness.
The functions arguments are:
- m
- The page whose aflags are updated.
- bits
- The bits that are set or cleared on the page's flags.
The following
aflags can be set or cleared:
- PGA_REFERENCED
- The bit may be set to indicate that the page has been recently accessed.
For instance, pmap(9) sets this bit to
reflect the accessed attribute of the page mapping typically updated by
processor's memory management unit on the page access.
- PGA_WRITEABLE
- A writeable mapping for the page may exist.
Both
PGA_REFERENCED
and
PGA_WRITEABLE
bits are only valid for the
managed pages.
AUTHORS¶
This manual page was written by
Chad David
⟨davidc@acns.ab.ca⟩.