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.Dd August 23, 2020 29.Dt MINCORE 2 30.Os 31.Sh NAME 32.Nm mincore 33.Nd determine residency of memory pages 34.Sh LIBRARY 35.Lb libc 36.Sh SYNOPSIS 37.In sys/mman.h 38.Ft int 39.Fn mincore "const void *addr" "size_t len" "char *vec" 40.Sh DESCRIPTION 41The 42.Fn mincore 43system call determines whether each of the pages in the region beginning at 44.Fa addr 45and continuing for 46.Fa len 47bytes is resident or mapped, depending on the value of sysctl 48.Va vm.mincore_mapped . 49.\"The beginning address, 50.\".Fa addr , 51.\"is first rounded down to a multiple of the page size (see 52.\".Xr getpagesize 3 ) . 53.\"The end address, 54.\".Fa addr No + Fa len , 55.\"is rounded up to a multiple of the page size. 56The status is returned in the 57.Fa vec 58array, one character per page. 59Each character is either 0 if the page is not resident, or a combination of 60the following flags (defined in 61.In sys/mman.h ) : 62.Bl -tag -width ".Dv MINCORE_REFERENCED_OTHER" 63.It Dv MINCORE_INCORE 64Page is in core (resident). 65.It Dv MINCORE_REFERENCED 66Page has been referenced by us. 67.It Dv MINCORE_MODIFIED 68Page has been modified by us. 69.It Dv MINCORE_REFERENCED_OTHER 70Page has been referenced. 71.It Dv MINCORE_MODIFIED_OTHER 72Page has been modified. 73.It Dv MINCORE_PSIND(i) 74Page is part of a large 75.Pq Dq super 76page with size given by index 77.Dv i 78in the array returned by 79.Xr getpagesizes 3 . 80.It Dv MINCORE_SUPER 81A mask of the valid 82.Dv MINCORE_PSIND() 83values. 84If any bits in this mask are set, the page is part of a large 85.Pq Dq super 86page. 87.El 88.Pp 89The information returned by 90.Fn mincore 91may be out of date by the time the system call returns. 92The only way to ensure that a page is resident is to lock it into memory 93with the 94.Xr mlock 2 95system call. 96.Pp 97If the 98.Va vm.mincore_mapped 99sysctl is set to a non-zero value (default), only the current process' 100mappings of the pages in the specified virtual address range are examined. 101This does not preclude the system from returning 102.Dv MINCORE_REFERENCED_OTHER 103and 104.Dv MINCORE_MODIFIED_OTHER 105statuses. 106Otherwise, if the sysctl value is zero, all resident pages backing the 107specified address range are examined, regardless of the mapping state. 108.Sh IMPLEMENTATION NOTES 109Prior to the introduction of 110.Dv MINCORE_PSIND() 111in 112.Fx 13.0 , 113.Dv MINCORE_SUPER 114consisted of a single bit equal to 115.Dv MINCORE_PSIND(1) . 116In particular, applications compiled using the old value of 117.Dv MINCORE_SUPER 118will not identify large pages with size index 2 as being large pages. 119.Sh RETURN VALUES 120.Rv -std mincore 121.Sh ERRORS 122The 123.Fn mincore 124system call will fail if: 125.Bl -tag -width Er 126.It Bq Er ENOMEM 127The virtual address range specified by the 128.Fa addr 129and 130.Fa len 131arguments is not fully mapped. 132.It Bq Er EFAULT 133The 134.Fa vec 135argument points to an illegal address. 136.El 137.Sh SEE ALSO 138.Xr madvise 2 , 139.Xr mlock 2 , 140.Xr mprotect 2 , 141.Xr msync 2 , 142.Xr munmap 2 , 143.Xr getpagesize 3 , 144.Xr getpagesizes 3 145.Sh HISTORY 146The 147.Fn mincore 148system call first appeared in 149.Bx 4.4 . 150