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      1 /*
      2  * The case is designed to test min_free_kbytes tunable.
      3  *
      4  * The tune is used to control free memory, and system always
      5  * reserve min_free_kbytes memory at least.
      6  *
      7  * Since the tune is not too large or too little, which will
      8  * lead to the system hang, so I choose two cases, and test them
      9  * on all overcommit_memory policy, at the same time, compare
     10  * the current free memory with the tunable value repeatedly.
     11  *
     12  * a) default min_free_kbytes with all overcommit memory policy
     13  * b) 2x default value with all overcommit memory policy
     14  * c) 5% of MemFree or %2 MemTotal with all overcommit memory policy
     15  *
     16  ********************************************************************
     17  * Copyright (C) 2012 Red Hat, Inc.
     18  *
     19  * This program is free software; you can redistribute it and/or
     20  * modify it under the terms of version 2 of the GNU General Public
     21  * License as published by the Free Software Foundation.
     22  *
     23  * This program is distributed in the hope that it would be useful,
     24  * but WITHOUT ANY WARRANTY; without even the implied warranty of
     25  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.
     26  *
     27  * Further, this software is distributed without any warranty that it
     28  * is free of the rightful claim of any third person regarding
     29  * infringement or the like.  Any license provided herein, whether
     30  * implied or otherwise, applies only to this software file.  Patent
     31  * licenses, if any, provided herein do not apply to combinations of
     32  * this program with other software, or any other product whatsoever.
     33  *
     34  * You should have received a copy of the GNU General Public License
     35  * along with this program; if not, write the Free Software
     36  * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA
     37  * 02110-1301, USA.
     38  *
     39  * ********************************************************************
     40  */
     41 
     42 #include <sys/types.h>
     43 #include <sys/mman.h>
     44 #include <sys/wait.h>
     45 #include <errno.h>
     46 #include <fcntl.h>
     47 #include <signal.h>
     48 #include <stdio.h>
     49 #include <stdlib.h>
     50 #include "test.h"
     51 #include "mem.h"
     52 
     53 #define MAP_SIZE (1UL<<20)
     54 
     55 volatile int end;
     56 char *TCID = "min_free_kbytes";
     57 int TST_TOTAL = 1;
     58 static unsigned long default_tune;
     59 static unsigned long orig_overcommit;
     60 static unsigned long total_mem;
     61 
     62 static void test_tune(unsigned long overcommit_policy);
     63 static int eatup_mem(unsigned long overcommit_policy);
     64 static void check_monitor(void);
     65 static void sighandler(int signo LTP_ATTRIBUTE_UNUSED);
     66 
     67 int main(int argc, char *argv[])
     68 {
     69 	int lc, pid, status;
     70 	struct sigaction sa;
     71 
     72 	tst_parse_opts(argc, argv, NULL, NULL);
     73 
     74 	sa.sa_handler = sighandler;
     75 	if (sigemptyset(&sa.sa_mask) < 0)
     76 		tst_brkm(TBROK | TERRNO, cleanup, "sigemptyset");
     77 	sa.sa_flags = 0;
     78 	if (sigaction(SIGUSR1, &sa, NULL) < 0)
     79 		tst_brkm(TBROK | TERRNO, cleanup, "sigaction");
     80 
     81 	setup();
     82 
     83 	switch (pid = fork()) {
     84 	case -1:
     85 		tst_brkm(TBROK | TERRNO, cleanup, "fork");
     86 
     87 	case 0:
     88 		/* startup the check monitor */
     89 		check_monitor();
     90 		exit(0);
     91 	}
     92 
     93 	for (lc = 0; TEST_LOOPING(lc); lc++) {
     94 		tst_count = 0;
     95 
     96 		test_tune(2);
     97 		test_tune(0);
     98 		test_tune(1);
     99 	}
    100 
    101 	if (kill(pid, SIGUSR1) == -1)
    102 		tst_brkm(TBROK | TERRNO, cleanup, "kill %d", pid);
    103 	if (waitpid(pid, &status, WUNTRACED | WCONTINUED) == -1)
    104 		tst_brkm(TBROK | TERRNO, cleanup, "waitpid");
    105 	if (WIFEXITED(status) && WEXITSTATUS(status) != 0)
    106 		tst_resm(TFAIL,
    107 			 "check_monitor child exit with status: %d", status);
    108 
    109 	cleanup();
    110 	tst_exit();
    111 }
    112 
    113 static void test_tune(unsigned long overcommit_policy)
    114 {
    115 	int status;
    116 	int pid[3];
    117 	int ret, i;
    118 	unsigned long tune, memfree, memtotal;
    119 
    120 	set_sys_tune("overcommit_memory", overcommit_policy, 1);
    121 
    122 	for (i = 0; i < 3; i++) {
    123 		/* case1 */
    124 		if (i == 0)
    125 			set_sys_tune("min_free_kbytes", default_tune, 1);
    126 		/* case2 */
    127 		else if (i == 1) {
    128 			set_sys_tune("min_free_kbytes", 2 * default_tune, 1);
    129 			/* case3 */
    130 		} else {
    131 			memfree = read_meminfo("MemFree:");
    132 			memtotal = read_meminfo("MemTotal:");
    133 			tune = memfree / 20;
    134 			if (tune > (memtotal / 50))
    135 				tune = memtotal / 50;
    136 
    137 			set_sys_tune("min_free_kbytes", tune, 1);
    138 		}
    139 
    140 		fflush(stdout);
    141 		switch (pid[i] = fork()) {
    142 		case -1:
    143 			tst_brkm(TBROK | TERRNO, cleanup, "fork");
    144 		case 0:
    145 			ret = eatup_mem(overcommit_policy);
    146 			exit(ret);
    147 		}
    148 
    149 		if (waitpid(pid[i], &status, WUNTRACED | WCONTINUED) == -1)
    150 			tst_brkm(TBROK | TERRNO, cleanup, "waitpid");
    151 
    152 		if (overcommit_policy == 2) {
    153 			if (!WIFEXITED(status) || WEXITSTATUS(status) != 0)
    154 				tst_resm(TFAIL,
    155 					 "child unexpectedly failed: %d",
    156 					 status);
    157 		} else if (overcommit_policy == 1) {
    158 			if (!WIFSIGNALED(status) || WTERMSIG(status) != SIGKILL)
    159 #if __WORDSIZE == 32
    160 			{
    161 				if (total_mem < 3145728UL)
    162 #endif
    163 					tst_resm(TFAIL,
    164 						 "child unexpectedly failed: %d",
    165 						 status);
    166 #if __WORDSIZE == 32
    167 				/* in 32-bit system, a process allocate about 3Gb memory at most */
    168 				else
    169 					tst_resm(TINFO, "Child can't allocate "
    170 						 ">3Gb memory in 32bit system");
    171 			}
    172 #endif
    173 		} else {
    174 			if (WIFEXITED(status)) {
    175 				if (WEXITSTATUS(status) != 0) {
    176 					tst_resm(TFAIL, "child unexpectedly "
    177 						 "failed: %d", status);
    178 				}
    179 			} else if (!WIFSIGNALED(status) ||
    180 				   WTERMSIG(status) != SIGKILL) {
    181 				tst_resm(TFAIL,
    182 					 "child unexpectedly failed: %d",
    183 					 status);
    184 			}
    185 		}
    186 	}
    187 }
    188 
    189 static int eatup_mem(unsigned long overcommit_policy)
    190 {
    191 	int ret = 0;
    192 	unsigned long memfree;
    193 	void *addrs;
    194 
    195 	memfree = read_meminfo("MemFree:");
    196 	printf("memfree is %lu kB before eatup mem\n", memfree);
    197 	while (1) {
    198 		addrs = mmap(NULL, MAP_SIZE, PROT_READ | PROT_WRITE,
    199 			     MAP_ANONYMOUS | MAP_PRIVATE, -1, 0);
    200 		if (addrs == MAP_FAILED) {
    201 			if (overcommit_policy != 1 && errno != ENOMEM) {
    202 				perror("mmap");
    203 				ret = -1;
    204 			}
    205 			break;
    206 		}
    207 		memset(addrs, 1, MAP_SIZE);
    208 	}
    209 	memfree = read_meminfo("MemFree:");
    210 	printf("memfree is %lu kB after eatup mem\n", memfree);
    211 
    212 	return ret;
    213 }
    214 
    215 static void check_monitor(void)
    216 {
    217 	unsigned long tune;
    218 	unsigned long memfree;
    219 
    220 	while (end) {
    221 		memfree = read_meminfo("MemFree:");
    222 		tune = get_sys_tune("min_free_kbytes");
    223 
    224 		if (memfree < tune) {
    225 			tst_resm(TINFO, "MemFree is %lu kB, "
    226 				 "min_free_kbytes is %lu kB", memfree, tune);
    227 			tst_resm(TFAIL, "MemFree < min_free_kbytes");
    228 		}
    229 
    230 		sleep(2);
    231 	}
    232 }
    233 
    234 static void sighandler(int signo LTP_ATTRIBUTE_UNUSED)
    235 {
    236 	end = 1;
    237 }
    238 
    239 void setup(void)
    240 {
    241 	tst_require_root();
    242 	tst_sig(FORK, DEF_HANDLER, cleanup);
    243 	TEST_PAUSE;
    244 
    245 	total_mem = read_meminfo("MemTotal:") + read_meminfo("SwapTotal:");
    246 
    247 	default_tune = get_sys_tune("min_free_kbytes");
    248 	orig_overcommit = get_sys_tune("overcommit_memory");
    249 }
    250 
    251 void cleanup(void)
    252 {
    253 	set_sys_tune("min_free_kbytes", default_tune, 0);
    254 	set_sys_tune("overcommit_memory", orig_overcommit, 0);
    255 }
    256