1.\" $OpenBSD: mlockall.2,v 1.5 2008/06/26 05:42:05 ray Exp $ 2.\" $NetBSD: mlockall.2,v 1.6 2000/06/26 17:00:02 kleink Exp $ 3.\" 4.\" Copyright (c) 1999 The NetBSD Foundation, Inc. 5.\" All rights reserved. 6.\" 7.\" This code is derived from software contributed to The NetBSD Foundation 8.\" by Jason R. Thorpe of the Numerical Aerospace Simulation Facility, 9.\" NASA Ames Research Center. 10.\" 11.\" Redistribution and use in source and binary forms, with or without 12.\" modification, are permitted provided that the following conditions 13.\" are met: 14.\" 1. Redistributions of source code must retain the above copyright 15.\" notice, this list of conditions and the following disclaimer. 16.\" 2. Redistributions in binary form must reproduce the above copyright 17.\" notice, this list of conditions and the following disclaimer in the 18.\" documentation and/or other materials provided with the distribution. 19.\" 20.\" THIS SOFTWARE IS PROVIDED BY THE NETBSD FOUNDATION, INC. AND CONTRIBUTORS 21.\" ``AS IS'' AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED 22.\" TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR 23.\" PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE FOUNDATION OR CONTRIBUTORS 24.\" BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR 25.\" CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF 26.\" SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS 27.\" INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN 28.\" CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) 29.\" ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE 30.\" POSSIBILITY OF SUCH DAMAGE. 31.\" 32.Dd $Mdocdate: June 26 2008 $ 33.Dt MLOCKALL 2 34.Os 35.Sh NAME 36.Nm mlockall , 37.Nm munlockall 38.Nd lock (unlock) the address space of a process 39.Sh SYNOPSIS 40.Fd #include <sys/types.h> 41.Fd #include <sys/mman.h> 42.Ft int 43.Fn mlockall "int flags" 44.Ft int 45.Fn munlockall "void" 46.Sh DESCRIPTION 47The 48.Nm mlockall 49system call locks into memory the physical pages associated with the 50address space of a process until the address space is unlocked, the 51process exits, or execs another program image. 52.Pp 53The following flags affect the behavior of 54.Nm mlockall : 55.Bl -tag -width MCL_CURRENT 56.It Dv MCL_CURRENT 57Lock all pages currently mapped into the process's address space. 58.It Dv MCL_FUTURE 59Lock all pages mapped into the process's address space in the future, 60at the time the mapping is established. 61Note that this may cause future mappings to fail if those mappings 62cause resource limits to be exceeded. 63.El 64.Pp 65Since physical memory is a potentially scarce resource, processes are 66limited in how much they can lock down. 67A single process can lock the minimum of a system-wide 68.Dq wired pages 69limit and the per-process 70.Dv RLIMIT_MEMLOCK 71resource limit. 72.Pp 73The 74.Nm munlockall 75call unlocks any locked memory regions in the process address space. 76Any regions mapped after an 77.Nm munlockall 78call will not be locked. 79.Sh RETURN VALUES 80A return value of 0 indicates that the call 81succeeded and all pages in the range have either been locked or unlocked. 82A return value of -1 indicates an error occurred and the locked 83status of all pages in the range remains unchanged. 84In this case, the global location 85.Va errno 86is set to indicate the error. 87.Sh ERRORS 88.Fn mlockall 89will fail if: 90.Bl -tag -width Er 91.It Bq Er EINVAL 92The 93.Ar flags 94argument is zero or includes unimplemented flags or 95.Fa addr 96and 97.Fa size 98specify a region that would extend beyond the end of the address space. 99.It Bq Er ENOMEM 100Locking the indicated range would exceed either the system or per-process 101limit for locked memory. 102.It Bq Er EAGAIN 103Some or all of the memory mapped into the process's address space 104could not be locked when the call was made. 105.It Bq Er EPERM 106The calling process does not have the appropriate privileges to perform 107the requested operation. 108.El 109.Sh SEE ALSO 110.Xr mincore 2 , 111.Xr mlock 2 , 112.Xr mmap 2 , 113.Xr munmap 2 , 114.Xr setrlimit 2 115.Sh STANDARDS 116The 117.Fn mlockall 118and 119.Fn munlockall 120functions conform to 121.St -p1003.1b-93 . 122.Sh HISTORY 123The 124.Fn mlockall 125and 126.Fn munlockall 127functions first appeared in 128.Ox 2.9 . 129.Sh BUGS 130The per-process resource limit is a limit on the amount of virtual 131memory locked, while the system-wide limit is for the number of locked 132physical pages. 133Hence a process with two distinct locked mappings of the same physical page 134counts as 2 pages against the per-process limit and only as a single page 135in the system limit. 136