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.\" $FreeBSD: src/share/man/man9/vm_fault_prefault.9,v 1.4.30.1.6.1 2010/12/21 17:09:25 kensmith Exp $
.\"
.Dd July 21, 2003
.Dt VM_FAULT_PREFAULT 9
.Os
.Sh NAME
.Nm vm_fault_prefault
.Nd cluster page faults into a process's address space
.Sh SYNOPSIS
.In sys/param.h
.In vm/vm.h
.In vm/pmap.h
.Ft void
.Fn vm_fault_prefault "pmap_t pmap" "vm_offset_t addra" "vm_map_entry_t entry"
.Sh DESCRIPTION
The
.Fn vm_fault_prefault
function provides a means of clustering pagefaults into a process's
address space.
It operates upon the physical map
.Fa pmap .
The
.Fa entry
argument specifies the entry to be prefaulted; the
.Fa addra
argument specifies the beginning of the mapping in the process's virtual
address space.
.Pp
It is typically called by
.Fn vm_fault
after the first page fault.
It benefits the
.Xr execve 2
system call by eliminating repetitive calls to
.Fn vm_fault ,
which would otherwise be made to bring the process's executable pages
into physical memory.
.Sh IMPLEMENTATION NOTES
This is a machine-independent function which calls the machine-dependent
.Xr pmap_is_prefaultable 9
helper function to determine if a page may be prefaulted into physical memory.
.Sh SEE ALSO
.Xr execve 2 ,
.Xr pmap_is_prefaultable 9
.Sh AUTHORS
This manual page was written by
.An Bruce M Simpson Aq bms@spc.org .