From a57b72b4b9e80a127d580f829df5808e9849dbaa Mon Sep 17 00:00:00 2001 From: Bruce M Simpson Date: Mon, 11 Aug 2003 07:16:21 +0000 Subject: [PATCH] Add the mlockall()/munlockall() system call manual page from NetBSD. PR: kern/42426, standards/54223 Obtained from: NetBSD Reviewed by: jake, alc Approved by: jake (mentor) MFC after: 2 weeks --- lib/libc/sys/mlockall.2 | 140 ++++++++++++++++++++++++++++++++++++++++ 1 file changed, 140 insertions(+) create mode 100644 lib/libc/sys/mlockall.2 diff --git a/lib/libc/sys/mlockall.2 b/lib/libc/sys/mlockall.2 new file mode 100644 index 000000000000..50cb1563e37c --- /dev/null +++ b/lib/libc/sys/mlockall.2 @@ -0,0 +1,140 @@ +.\" $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. +.\" 3. All advertising materials mentioning features or use of this software +.\" must display the following acknowledgement: +.\" This product includes software developed by the NetBSD +.\" Foundation, Inc. and its contributors. +.\" 4. Neither the name of The NetBSD Foundation nor the names of its +.\" contributors may be used to endorse or promote products derived +.\" from this software without specific prior written permission. +.\" +.\" 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 June 12, 1999 +.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 +.Nm 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 +.Nm mlockall : +.Bl -tag -width 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 +.Li RLIMIT_MEMLOCK +resource limit. +.Pp +The +.Nm munlockall +call unlocks any locked memory regions in the process address space. +Any regions mapped after an +.Nm 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 +.Ar 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.