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1 /******************************************************************************/
2 /*                                                                            */
3 /* Copyright (c) 2009 FUJITSU LIMITED                                         */
4 /*                                                                            */
5 /* This program is free software;  you can redistribute it and/or modify      */
6 /* it under the terms of the GNU General Public License as published by       */
7 /* the Free Software Foundation; either version 2 of the License, or          */
8 /* (at your option) any later version.                                        */
9 /*                                                                            */
10 /* This program is distributed in the hope that it will be useful,            */
11 /* but WITHOUT ANY WARRANTY;  without even the implied warranty of            */
12 /* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See                  */
13 /* the GNU General Public License for more details.                           */
14 /*                                                                            */
15 /* You should have received a copy of the GNU General Public License          */
16 /* along with this program;  if not, write to the Free Software               */
17 /* Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA    */
18 /*                                                                            */
19 /* Author: Miao Xie <miaox@cn.fujitsu.com>                                    */
20 /*                                                                            */
21 /******************************************************************************/
22 
23 #include <sys/mman.h>
24 #include <err.h>
25 #include <errno.h>
26 #include <libgen.h>
27 #include <stdio.h>
28 #include <stdlib.h>
29 #include <string.h>
30 #include <unistd.h>
31 
32 int unit = 1024 * 1024;
33 
34 //argv[1] memory use(M) (>0)
35 
main(int argc,char * argv[])36 int main(int argc, char *argv[])
37 {
38 	long int use;
39 	if (argc != 2) {
40 		fprintf(stderr, "usage: %s mmap-size-in-kB", basename(argv[0]));
41 		exit(1);
42 	}
43 	if ((use = strtol(argv[1], NULL, 10)) < 0) {
44 		errx(EINVAL, "Invalid mmap size specified (must be a long "
45 		     "int greater than 1)");
46 	}
47 
48 	long int pagesize = getpagesize();
49 	long int mmap_block = use * unit / 10 / pagesize;
50 	long int total_block = 0;
51 
52 	while (pagesize * mmap_block > 2 * unit) {
53 		unsigned long *addr = mmap(NULL, pagesize * mmap_block,
54 					   PROT_READ | PROT_WRITE,
55 					   MAP_PRIVATE | MAP_ANONYMOUS, -1, 0);
56 		if (addr == MAP_FAILED) {
57 			mmap_block = mmap_block / 2;
58 			continue;
59 		}
60 		memset(addr, 0xF7, pagesize * mmap_block);
61 		total_block += mmap_block;
62 		if (total_block * pagesize >= use * unit)
63 			break;
64 	}
65 	return 0;
66 }
67