VM_PAGE_HOLD(9) BSD Kernel Developer's Manual VM_PAGE_HOLD(9)NAME
vm_page_hold, vm_page_unhold — update a page's hold count
SYNOPSIS
#include <sys/param.h>
#include <vm/vm.h>
#include <vm/vm_page.h>
void
vm_page_hold(vm_page_t m);
void
vm_page_unhold(vm_page_t m);
DESCRIPTION
The vm_page_hold() function increases the hold count on a page. This
prevents the page daemon from freeing the page.
vm_page_hold() should only be used for very temporary wiring of a page,
as that page will not be considered for paging or reallocation for as
long as its hold count is greater than zero. Also note that while wired
pages are removed from whatever queue they are on, vm_page_hold() does
not affect the location of the page. If it is on a queue prior to the
call, it will still be there afterward.
If the page needs to be held for a long period of time, vm_page_wire(9)
should be used.
vm_page_unhold() function reduces the hold count on a page. If the hold
count is zero it is possible that the page will be freed by the page dae‐
mon.
SEE ALSOvm_page_unwire(9), vm_page_wire(9)AUTHORS
This manual page was written by Chad David ⟨davidc@acns.ab.ca⟩.
BSD July 13, 2001 BSD
