1.\" Copyright (c) 1991, 1993 2.\" The Regents of the University of California. All rights reserved. 3.\" 4.\" Redistribution and use in source and binary forms, with or without 5.\" modification, are permitted provided that the following conditions 6.\" are met: 7.\" 1. Redistributions of source code must retain the above copyright 8.\" notice, this list of conditions and the following disclaimer. 9.\" 2. Redistributions in binary form must reproduce the above copyright 10.\" notice, this list of conditions and the following disclaimer in the 11.\" documentation and/or other materials provided with the distribution. 12.\" 3. Neither the name of the University nor the names of its contributors 13.\" may be used to endorse or promote products derived from this software 14.\" without specific prior written permission. 15.\" 16.\" THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND 17.\" ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE 18.\" IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE 19.\" ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE 20.\" FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL 21.\" DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS 22.\" OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) 23.\" HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT 24.\" LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY 25.\" OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF 26.\" SUCH DAMAGE. 27.\" 28.\" @(#)mincore.2 8.1 (Berkeley) 6/9/93 29.\" $FreeBSD$ 30.\" 31.Dd January 7, 2019 32.Dt MINCORE 2 33.Os 34.Sh NAME 35.Nm mincore 36.Nd determine residency of memory pages 37.Sh LIBRARY 38.Lb libc 39.Sh SYNOPSIS 40.In sys/mman.h 41.Ft int 42.Fn mincore "const void *addr" "size_t len" "char *vec" 43.Sh DESCRIPTION 44The 45.Fn mincore 46system call determines whether each of the pages in the region beginning at 47.Fa addr 48and continuing for 49.Fa len 50bytes is resident or mapped, depending on the value of sysctl 51.Va vm.mincore_mapped . 52.\"The beginning address, 53.\".Fa addr , 54.\"is first rounded down to a multiple of the page size (see 55.\".Xr getpagesize 3 ) . 56.\"The end address, 57.\".Fa addr No + Fa len , 58.\"is rounded up to a multiple of the page size. 59The status is returned in the 60.Fa vec 61array, one character per page. 62Each character is either 0 if the page is not resident, or a combination of 63the following flags (defined in 64.In sys/mman.h ) : 65.Bl -tag -width ".Dv MINCORE_REFERENCED_OTHER" 66.It Dv MINCORE_INCORE 67Page is in core (resident). 68.It Dv MINCORE_REFERENCED 69Page has been referenced by us. 70.It Dv MINCORE_MODIFIED 71Page has been modified by us. 72.It Dv MINCORE_REFERENCED_OTHER 73Page has been referenced. 74.It Dv MINCORE_MODIFIED_OTHER 75Page has been modified. 76.It Dv MINCORE_SUPER 77Page is part of a large 78.Pq Dq super 79page. 80.El 81.Pp 82The information returned by 83.Fn mincore 84may be out of date by the time the system call returns. 85The only way to ensure that a page is resident is to lock it into memory 86with the 87.Xr mlock 2 88system call. 89.Pp 90If the 91.Va vm.mincore_mapped 92sysctl is set to a non-zero value (default), only the current process' 93mappings of the pages in the specified virtual address range are examined. 94This does not preclude the system from returning 95.Dv MINCORE_REFERENCED_OTHER 96and 97.Dv MINCORE_MODIFIED_OTHER 98statuses. 99Otherwise, if the sysctl value is zero, all resident pages backing the 100specified address range are examined, regardless of the mapping state. 101.Sh RETURN VALUES 102.Rv -std mincore 103.Sh ERRORS 104The 105.Fn mincore 106system call will fail if: 107.Bl -tag -width Er 108.It Bq Er ENOMEM 109The virtual address range specified by the 110.Fa addr 111and 112.Fa len 113arguments is not fully mapped. 114.It Bq Er EFAULT 115The 116.Fa vec 117argument points to an illegal address. 118.El 119.Sh SEE ALSO 120.Xr madvise 2 , 121.Xr mlock 2 , 122.Xr mprotect 2 , 123.Xr msync 2 , 124.Xr munmap 2 , 125.Xr getpagesize 3 126.Sh HISTORY 127The 128.Fn mincore 129system call first appeared in 130.Bx 4.4 . 131