1.\" $NetBSD: mlockall.2,v 1.11 2003/04/16 13:34:54 wiz Exp $ 2.\" 3.\" Copyright (c) 1999 The NetBSD Foundation, Inc. 4.\" All rights reserved. 5.\" 6.\" This code is derived from software contributed to The NetBSD Foundation 7.\" by Jason R. Thorpe of the Numerical Aerospace Simulation Facility, 8.\" NASA Ames Research Center. 9.\" 10.\" Redistribution and use in source and binary forms, with or without 11.\" modification, are permitted provided that the following conditions 12.\" are met: 13.\" 1. Redistributions of source code must retain the above copyright 14.\" notice, this list of conditions and the following disclaimer. 15.\" 2. Redistributions in binary form must reproduce the above copyright 16.\" notice, this list of conditions and the following disclaimer in the 17.\" documentation and/or other materials provided with the distribution. 18.\" 19.\" THIS SOFTWARE IS PROVIDED BY THE NETBSD FOUNDATION, INC. AND CONTRIBUTORS 20.\" ``AS IS'' AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED 21.\" TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR 22.\" PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE FOUNDATION OR CONTRIBUTORS 23.\" BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR 24.\" CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF 25.\" SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS 26.\" INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN 27.\" CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) 28.\" ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE 29.\" POSSIBILITY OF SUCH DAMAGE. 30.\" 31.\" $FreeBSD$ 32.\" 33.Dd May 13, 2019 34.Dt MLOCKALL 2 35.Os 36.Sh NAME 37.Nm mlockall , 38.Nm munlockall 39.Nd lock (unlock) the address space of a process 40.Sh LIBRARY 41.Lb libc 42.Sh SYNOPSIS 43.In sys/mman.h 44.Ft int 45.Fn mlockall "int flags" 46.Ft int 47.Fn munlockall "void" 48.Sh DESCRIPTION 49The 50.Fn mlockall 51system call locks into memory the physical pages associated with the 52address space of a process until the address space is unlocked, the 53process exits, or execs another program image. 54.Pp 55The following flags affect the behavior of 56.Fn mlockall : 57.Bl -tag -width ".Dv MCL_CURRENT" 58.It Dv MCL_CURRENT 59Lock all pages currently mapped into the process's address space. 60.It Dv MCL_FUTURE 61Lock all pages mapped into the process's address space in the future, 62at the time the mapping is established. 63Note that this may cause future mappings to fail if those mappings 64cause resource limits to be exceeded. 65.El 66.Pp 67Since physical memory is a potentially scarce resource, processes are 68limited in how much they can lock down. 69A single process can lock the minimum of a system-wide 70.Dq wired pages 71limit 72.Va vm.max_user_wired 73and the per-process 74.Dv RLIMIT_MEMLOCK 75resource limit. 76.Pp 77If 78.Va security.bsd.unprivileged_mlock 79is set to 0 these calls are only available to the super-user. 80If 81.Va vm.old_mlock 82is set to 1 the per-process 83.Dv RLIMIT_MEMLOCK 84resource limit will not be applied for 85.Fn mlockall 86calls. 87.Pp 88The 89.Fn munlockall 90call unlocks any locked memory regions in the process address space. 91Any regions mapped after an 92.Fn munlockall 93call will not be locked. 94.Sh RETURN VALUES 95A return value of 0 indicates that the call 96succeeded and all pages in the range have either been locked or unlocked. 97A return value of \-1 indicates an error occurred and the locked 98status of all pages in the range remains unchanged. 99In this case, the global location 100.Va errno 101is set to indicate the error. 102.Sh ERRORS 103.Fn mlockall 104will fail if: 105.Bl -tag -width Er 106.It Bq Er EINVAL 107The 108.Fa flags 109argument is zero, or includes unimplemented flags. 110.It Bq Er ENOMEM 111Locking the indicated range would exceed either the system or per-process 112limit for locked memory. 113.It Bq Er EAGAIN 114Some or all of the memory mapped into the process's address space 115could not be locked when the call was made. 116.It Bq Er EPERM 117The calling process does not have the appropriate privilege to perform 118the requested operation. 119.El 120.Sh SEE ALSO 121.Xr mincore 2 , 122.Xr mlock 2 , 123.Xr mmap 2 , 124.Xr munmap 2 , 125.Xr setrlimit 2 126.Sh STANDARDS 127The 128.Fn mlockall 129and 130.Fn munlockall 131functions are believed to conform to 132.St -p1003.1-2001 . 133.Sh HISTORY 134The 135.Fn mlockall 136and 137.Fn munlockall 138functions first appeared in 139.Fx 5.1 . 140.Sh BUGS 141The per-process and system-wide resource limits of locked memory apply 142to the amount of virtual memory locked, not the amount of locked physical 143pages. 144Hence two distinct locked mappings of the same physical page counts as 1452 pages aginst the system limit, and also against the per-process limit 146if both mappings belong to the same physical map. 147