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 August 23, 2020 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_PSIND(i) 77Page is part of a large 78.Pq Dq super 79page with size given by index 80.Dv i 81in the array returned by 82.Xr getpagesizes 3 . 83.It Dv MINCORE_SUPER 84A mask of the valid 85.Dv MINCORE_PSIND() 86values. 87If any bits in this mask are set, the page is part of a large 88.Pq Dq super 89page. 90.El 91.Pp 92The information returned by 93.Fn mincore 94may be out of date by the time the system call returns. 95The only way to ensure that a page is resident is to lock it into memory 96with the 97.Xr mlock 2 98system call. 99.Pp 100If the 101.Va vm.mincore_mapped 102sysctl is set to a non-zero value (default), only the current process' 103mappings of the pages in the specified virtual address range are examined. 104This does not preclude the system from returning 105.Dv MINCORE_REFERENCED_OTHER 106and 107.Dv MINCORE_MODIFIED_OTHER 108statuses. 109Otherwise, if the sysctl value is zero, all resident pages backing the 110specified address range are examined, regardless of the mapping state. 111.Sh IMPLEMENTATION NOTES 112Prior to the introduction of 113.Dv MINCORE_PSIND() 114in 115.Fx 13.0 , 116.Dv MINCORE_SUPER 117consisted of a single bit equal to 118.Dv MINCORE_PSIND(1) . 119In particular, applications compiled using the old value of 120.Dv MINCORE_SUPER 121will not identify large pages with size index 2 as being large pages. 122.Sh RETURN VALUES 123.Rv -std mincore 124.Sh ERRORS 125The 126.Fn mincore 127system call will fail if: 128.Bl -tag -width Er 129.It Bq Er ENOMEM 130The virtual address range specified by the 131.Fa addr 132and 133.Fa len 134arguments is not fully mapped. 135.It Bq Er EFAULT 136The 137.Fa vec 138argument points to an illegal address. 139.El 140.Sh SEE ALSO 141.Xr madvise 2 , 142.Xr mlock 2 , 143.Xr mprotect 2 , 144.Xr msync 2 , 145.Xr munmap 2 , 146.Xr getpagesize 3 , 147.Xr getpagesizes 3 148.Sh HISTORY 149The 150.Fn mincore 151system call first appeared in 152.Bx 4.4 . 153