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VM_PAGE_AFLAG(9) FreeBSD Kernel Developer's Manual VM_PAGE_AFLAG(9)
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>.