1 // SPDX-License-Identifier: GPL-2.0
4 * A test for the patch "Allow compaction of unevictable pages".
5 * With this patch we should be able to allocate at least 1/4
6 * of RAM in huge pages. Without the patch much less is
13 #include <sys/resource.h>
19 #define MAP_SIZE 1048576
23 struct map_list *next;
26 int read_memory_info(unsigned long *memfree, unsigned long *hugepagesize)
28 char buffer[256] = {0};
29 char *cmd = "cat /proc/meminfo | grep -i memfree | grep -o '[0-9]*'";
30 FILE *cmdfile = popen(cmd, "r");
32 if (!(fgets(buffer, sizeof(buffer), cmdfile))) {
33 perror("Failed to read meminfo\n");
39 *memfree = atoll(buffer);
40 cmd = "cat /proc/meminfo | grep -i hugepagesize | grep -o '[0-9]*'";
41 cmdfile = popen(cmd, "r");
43 if (!(fgets(buffer, sizeof(buffer), cmdfile))) {
44 perror("Failed to read meminfo\n");
49 *hugepagesize = atoll(buffer);
59 fd = open("/proc/sys/vm/compact_unevictable_allowed",
60 O_RDONLY | O_NONBLOCK);
62 perror("Failed to open\n"
63 "/proc/sys/vm/compact_unevictable_allowed\n");
67 if (read(fd, &allowed, sizeof(char)) != sizeof(char)) {
68 perror("Failed to read from\n"
69 "/proc/sys/vm/compact_unevictable_allowed\n");
81 int check_compaction(unsigned long mem_free, unsigned int hugepage_size)
84 int compaction_index = 0;
85 char initial_nr_hugepages[10] = {0};
86 char nr_hugepages[10] = {0};
88 /* We want to test with 80% of available memory. Else, OOM killer comes
90 mem_free = mem_free * 0.8;
92 fd = open("/proc/sys/vm/nr_hugepages", O_RDWR | O_NONBLOCK);
94 perror("Failed to open /proc/sys/vm/nr_hugepages");
98 if (read(fd, initial_nr_hugepages, sizeof(initial_nr_hugepages)) <= 0) {
99 perror("Failed to read from /proc/sys/vm/nr_hugepages");
103 /* Start with the initial condition of 0 huge pages*/
104 if (write(fd, "0", sizeof(char)) != sizeof(char)) {
105 perror("Failed to write 0 to /proc/sys/vm/nr_hugepages\n");
109 lseek(fd, 0, SEEK_SET);
111 /* Request a large number of huge pages. The Kernel will allocate
113 if (write(fd, "100000", (6*sizeof(char))) != (6*sizeof(char))) {
114 perror("Failed to write 100000 to /proc/sys/vm/nr_hugepages\n");
118 lseek(fd, 0, SEEK_SET);
120 if (read(fd, nr_hugepages, sizeof(nr_hugepages)) <= 0) {
121 perror("Failed to re-read from /proc/sys/vm/nr_hugepages\n");
125 /* We should have been able to request at least 1/3 rd of the memory in
127 compaction_index = mem_free/(atoi(nr_hugepages) * hugepage_size);
129 if (compaction_index > 3) {
130 printf("No of huge pages allocated = %d\n",
131 (atoi(nr_hugepages)));
132 fprintf(stderr, "ERROR: Less that 1/%d of memory is available\n"
133 "as huge pages\n", compaction_index);
137 printf("No of huge pages allocated = %d\n",
138 (atoi(nr_hugepages)));
140 lseek(fd, 0, SEEK_SET);
142 if (write(fd, initial_nr_hugepages, strlen(initial_nr_hugepages))
143 != strlen(initial_nr_hugepages)) {
144 perror("Failed to write value to /proc/sys/vm/nr_hugepages\n");
153 printf("Not OK. Compaction test failed.");
158 int main(int argc, char **argv)
161 struct map_list *list, *entry;
164 unsigned long mem_free = 0;
165 unsigned long hugepage_size = 0;
166 unsigned long mem_fragmentable = 0;
169 printf("Either the sysctl compact_unevictable_allowed is not\n"
170 "set to 1 or couldn't read the proc file.\n"
171 "Skipping the test\n");
175 lim.rlim_cur = RLIM_INFINITY;
176 lim.rlim_max = RLIM_INFINITY;
177 if (setrlimit(RLIMIT_MEMLOCK, &lim)) {
178 perror("Failed to set rlimit:\n");
182 page_size = getpagesize();
186 if (read_memory_info(&mem_free, &hugepage_size) != 0) {
187 printf("ERROR: Cannot read meminfo\n");
191 mem_fragmentable = mem_free * 0.8 / 1024;
193 while (mem_fragmentable > 0) {
194 map = mmap(NULL, MAP_SIZE, PROT_READ | PROT_WRITE,
195 MAP_ANONYMOUS | MAP_PRIVATE | MAP_LOCKED, -1, 0);
196 if (map == MAP_FAILED)
199 entry = malloc(sizeof(struct map_list));
201 munmap(map, MAP_SIZE);
208 /* Write something (in this case the address of the map) to
209 * ensure that KSM can't merge the mapped pages
211 for (i = 0; i < MAP_SIZE; i += page_size)
212 *(unsigned long *)(map + i) = (unsigned long)map + i;
217 for (entry = list; entry != NULL; entry = entry->next) {
218 munmap(entry->map, MAP_SIZE);
224 if (check_compaction(mem_free, hugepage_size) == 0)