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.Dd May 13, 2019 32.Dt MLOCKALL 2 33.Os 34.Sh NAME 35.Nm mlockall , 36.Nm munlockall 37.Nd lock (unlock) the address space of a process 38.Sh LIBRARY 39.Lb libc 40.Sh SYNOPSIS 41.In sys/mman.h 42.Ft int 43.Fn mlockall "int flags" 44.Ft int 45.Fn munlockall "void" 46.Sh DESCRIPTION 47The 48.Fn 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.Fn mlockall : 55.Bl -tag -width ".Dv 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 70.Va vm.max_user_wired 71and the per-process 72.Dv RLIMIT_MEMLOCK 73resource limit. 74.Pp 75If 76.Va security.bsd.unprivileged_mlock 77is set to 0 these calls are only available to the super-user. 78If 79.Va vm.old_mlock 80is set to 1 the per-process 81.Dv RLIMIT_MEMLOCK 82resource limit will not be applied for 83.Fn mlockall 84calls. 85.Pp 86The 87.Fn munlockall 88call unlocks any locked memory regions in the process address space. 89Any regions mapped after an 90.Fn munlockall 91call will not be locked. 92.Sh RETURN VALUES 93A return value of 0 indicates that the call 94succeeded and all pages in the range have either been locked or unlocked. 95A return value of \-1 indicates an error occurred and the locked 96status of all pages in the range remains unchanged. 97In this case, the global location 98.Va errno 99is set to indicate the error. 100.Sh ERRORS 101.Fn mlockall 102will fail if: 103.Bl -tag -width Er 104.It Bq Er EINVAL 105The 106.Fa flags 107argument is zero, or includes unimplemented flags. 108.It Bq Er ENOMEM 109Locking the indicated range would exceed either the system or per-process 110limit for locked memory. 111.It Bq Er EAGAIN 112Some or all of the memory mapped into the process's address space 113could not be locked when the call was made. 114.It Bq Er EPERM 115The calling process does not have the appropriate privilege to perform 116the requested operation. 117.El 118.Sh SEE ALSO 119.Xr mincore 2 , 120.Xr mlock 2 , 121.Xr mmap 2 , 122.Xr munmap 2 , 123.Xr setrlimit 2 124.Sh STANDARDS 125The 126.Fn mlockall 127and 128.Fn munlockall 129functions are believed to conform to 130.St -p1003.1-2001 . 131.Sh HISTORY 132The 133.Fn mlockall 134and 135.Fn munlockall 136functions first appeared in 137.Fx 5.1 . 138.Sh BUGS 139The per-process and system-wide resource limits of locked memory apply 140to the amount of virtual memory locked, not the amount of locked physical 141pages. 142Hence two distinct locked mappings of the same physical page counts as 1432 pages aginst the system limit, and also against the per-process limit 144if both mappings belong to the same physical map. 145