NAME    [Toc]    [Back]

     vm_page_hold, vm_page_unhold -- update a page's hold count

SYNOPSIS    [Toc]    [Back]

     #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    [Toc]    [Back]

     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 daemon.

SEE ALSO    [Toc]    [Back]

     vm_page_unwire(9), vm_page_wire(9)

AUTHORS    [Toc]    [Back]

     This manual page was written by Chad David <[email protected]>.


FreeBSD 5.2.1			 July 13, 2001			 FreeBSD 5.2.1