d8561f0a50
like the mlock(2) manual page says. Update mlock(2) to say that hitting RLIMIT_MEMLOCK results in ENOMEM, not EAGAIN. MFC after: 1 month
136 lines
4.3 KiB
Groff
136 lines
4.3 KiB
Groff
.\" $NetBSD: mlockall.2,v 1.11 2003/04/16 13:34:54 wiz Exp $
|
|
.\"
|
|
.\" Copyright (c) 1999 The NetBSD Foundation, Inc.
|
|
.\" All rights reserved.
|
|
.\"
|
|
.\" This code is derived from software contributed to The NetBSD Foundation
|
|
.\" by Jason R. Thorpe of the Numerical Aerospace Simulation Facility,
|
|
.\" NASA Ames Research Center.
|
|
.\"
|
|
.\" Redistribution and use in source and binary forms, with or without
|
|
.\" modification, are permitted provided that the following conditions
|
|
.\" are met:
|
|
.\" 1. Redistributions of source code must retain the above copyright
|
|
.\" notice, this list of conditions and the following disclaimer.
|
|
.\" 2. Redistributions in binary form must reproduce the above copyright
|
|
.\" notice, this list of conditions and the following disclaimer in the
|
|
.\" documentation and/or other materials provided with the distribution.
|
|
.\"
|
|
.\" THIS SOFTWARE IS PROVIDED BY THE NETBSD FOUNDATION, INC. AND CONTRIBUTORS
|
|
.\" ``AS IS'' AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED
|
|
.\" TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR
|
|
.\" PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE FOUNDATION OR CONTRIBUTORS
|
|
.\" BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
|
|
.\" CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
|
|
.\" SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
|
|
.\" INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
|
|
.\" CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
|
|
.\" ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
|
|
.\" POSSIBILITY OF SUCH DAMAGE.
|
|
.\"
|
|
.\" $FreeBSD$
|
|
.\"
|
|
.Dd July 27, 2010
|
|
.Dt MLOCKALL 2
|
|
.Os
|
|
.Sh NAME
|
|
.Nm mlockall ,
|
|
.Nm munlockall
|
|
.Nd lock (unlock) the address space of a process
|
|
.Sh LIBRARY
|
|
.Lb libc
|
|
.Sh SYNOPSIS
|
|
.In sys/mman.h
|
|
.Ft int
|
|
.Fn mlockall "int flags"
|
|
.Ft int
|
|
.Fn munlockall "void"
|
|
.Sh DESCRIPTION
|
|
The
|
|
.Fn mlockall
|
|
system call locks into memory the physical pages associated with the
|
|
address space of a process until the address space is unlocked, the
|
|
process exits, or execs another program image.
|
|
.Pp
|
|
The following flags affect the behavior of
|
|
.Fn mlockall :
|
|
.Bl -tag -width ".Dv MCL_CURRENT"
|
|
.It Dv MCL_CURRENT
|
|
Lock all pages currently mapped into the process's address space.
|
|
.It Dv MCL_FUTURE
|
|
Lock all pages mapped into the process's address space in the future,
|
|
at the time the mapping is established.
|
|
Note that this may cause future mappings to fail if those mappings
|
|
cause resource limits to be exceeded.
|
|
.El
|
|
.Pp
|
|
Since physical memory is a potentially scarce resource, processes are
|
|
limited in how much they can lock down.
|
|
A single process can lock the minimum of a system-wide
|
|
.Dq wired pages
|
|
limit and the per-process
|
|
.Dv RLIMIT_MEMLOCK
|
|
resource limit.
|
|
.Pp
|
|
These calls are only available to the super-user.
|
|
.Pp
|
|
The
|
|
.Fn munlockall
|
|
call unlocks any locked memory regions in the process address space.
|
|
Any regions mapped after an
|
|
.Fn munlockall
|
|
call will not be locked.
|
|
.Sh RETURN VALUES
|
|
A return value of 0 indicates that the call
|
|
succeeded and all pages in the range have either been locked or unlocked.
|
|
A return value of \-1 indicates an error occurred and the locked
|
|
status of all pages in the range remains unchanged.
|
|
In this case, the global location
|
|
.Va errno
|
|
is set to indicate the error.
|
|
.Sh ERRORS
|
|
.Fn mlockall
|
|
will fail if:
|
|
.Bl -tag -width Er
|
|
.It Bq Er EINVAL
|
|
The
|
|
.Fa flags
|
|
argument is zero, or includes unimplemented flags.
|
|
.It Bq Er ENOMEM
|
|
Locking the indicated range would exceed either the system or per-process
|
|
limit for locked memory.
|
|
.It Bq Er EAGAIN
|
|
Some or all of the memory mapped into the process's address space
|
|
could not be locked when the call was made.
|
|
.It Bq Er EPERM
|
|
The calling process does not have the appropriate privilege to perform
|
|
the requested operation.
|
|
.El
|
|
.Sh SEE ALSO
|
|
.Xr mincore 2 ,
|
|
.Xr mlock 2 ,
|
|
.Xr mmap 2 ,
|
|
.Xr munmap 2 ,
|
|
.Xr setrlimit 2
|
|
.Sh STANDARDS
|
|
The
|
|
.Fn mlockall
|
|
and
|
|
.Fn munlockall
|
|
functions are believed to conform to
|
|
.St -p1003.1-2001 .
|
|
.Sh HISTORY
|
|
The
|
|
.Fn mlockall
|
|
and
|
|
.Fn munlockall
|
|
functions first appeared in
|
|
.Fx 5.1 .
|
|
.Sh BUGS
|
|
The per-process resource limit is a limit on the amount of virtual
|
|
memory locked, while the system-wide limit is for the number of locked
|
|
physical pages.
|
|
Hence a process with two distinct locked mappings of the same physical page
|
|
counts as 2 pages against the per-process limit and as only a single page
|
|
in the system limit.
|