VM_PAGE_IO_START(9)

NAME

     vm_page_io_start, vm_page_io_finish -- ready or unready a page for I/O

SYNOPSIS

     #include <sys/param.h>
     #include <vm/vm.h>
     #include <vm/vm_page.h>

     void
     vm_page_io_start(vm_page_t m);

     void
     vm_page_io_finish(vm_page_t m);

DESCRIPTION

     The vm_page_io_start() function prepares the page for I/O by incrementing
     its busy flag by one.

     The vm_page_io_finish() function lowers the busy count on the page by
     one, if the resulting busy count is zero, a wakeup(9) will be issued if
     the page has been marked PG_WANTED.  A page is typically marked PG_WANTED
     by a thread to register its interest in the page to either complete I/O
     or becoming available for general use.

AUTHORS

     This man page was written by Chad David <davidc@acns.ab.ca> and Alfred
     Perlstein <alfred@FreeBSD.org>.