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 #include "../kselftest.h"
21 #define MAP_SIZE 1048576
25 struct map_list *next;
28 int read_memory_info(unsigned long *memfree, unsigned long *hugepagesize)
30 char buffer[256] = {0};
31 char *cmd = "cat /proc/meminfo | grep -i memfree | grep -o '[0-9]*'";
32 FILE *cmdfile = popen(cmd, "r");
34 if (!(fgets(buffer, sizeof(buffer), cmdfile))) {
35 perror("Failed to read meminfo\n");
41 *memfree = atoll(buffer);
42 cmd = "cat /proc/meminfo | grep -i hugepagesize | grep -o '[0-9]*'";
43 cmdfile = popen(cmd, "r");
45 if (!(fgets(buffer, sizeof(buffer), cmdfile))) {
46 perror("Failed to read meminfo\n");
51 *hugepagesize = atoll(buffer);
61 fd = open("/proc/sys/vm/compact_unevictable_allowed",
62 O_RDONLY | O_NONBLOCK);
64 perror("Failed to open\n"
65 "/proc/sys/vm/compact_unevictable_allowed\n");
69 if (read(fd, &allowed, sizeof(char)) != sizeof(char)) {
70 perror("Failed to read from\n"
71 "/proc/sys/vm/compact_unevictable_allowed\n");
83 int check_compaction(unsigned long mem_free, unsigned int hugepage_size)
86 int compaction_index = 0;
87 char initial_nr_hugepages[10] = {0};
88 char nr_hugepages[10] = {0};
90 /* We want to test with 80% of available memory. Else, OOM killer comes
92 mem_free = mem_free * 0.8;
94 fd = open("/proc/sys/vm/nr_hugepages", O_RDWR | O_NONBLOCK);
96 perror("Failed to open /proc/sys/vm/nr_hugepages");
100 if (read(fd, initial_nr_hugepages, sizeof(initial_nr_hugepages)) <= 0) {
101 perror("Failed to read from /proc/sys/vm/nr_hugepages");
105 /* Start with the initial condition of 0 huge pages*/
106 if (write(fd, "0", sizeof(char)) != sizeof(char)) {
107 perror("Failed to write 0 to /proc/sys/vm/nr_hugepages\n");
111 lseek(fd, 0, SEEK_SET);
113 /* Request a large number of huge pages. The Kernel will allocate
115 if (write(fd, "100000", (6*sizeof(char))) != (6*sizeof(char))) {
116 perror("Failed to write 100000 to /proc/sys/vm/nr_hugepages\n");
120 lseek(fd, 0, SEEK_SET);
122 if (read(fd, nr_hugepages, sizeof(nr_hugepages)) <= 0) {
123 perror("Failed to re-read from /proc/sys/vm/nr_hugepages\n");
127 /* We should have been able to request at least 1/3 rd of the memory in
129 compaction_index = mem_free/(atoi(nr_hugepages) * hugepage_size);
131 if (compaction_index > 3) {
132 printf("No of huge pages allocated = %d\n",
133 (atoi(nr_hugepages)));
134 fprintf(stderr, "ERROR: Less that 1/%d of memory is available\n"
135 "as huge pages\n", compaction_index);
139 printf("No of huge pages allocated = %d\n",
140 (atoi(nr_hugepages)));
142 lseek(fd, 0, SEEK_SET);
144 if (write(fd, initial_nr_hugepages, strlen(initial_nr_hugepages))
145 != strlen(initial_nr_hugepages)) {
146 perror("Failed to write value to /proc/sys/vm/nr_hugepages\n");
155 printf("Not OK. Compaction test failed.");
160 int main(int argc, char **argv)
163 struct map_list *list, *entry;
166 unsigned long mem_free = 0;
167 unsigned long hugepage_size = 0;
168 unsigned long mem_fragmentable = 0;
171 printf("Either the sysctl compact_unevictable_allowed is not\n"
172 "set to 1 or couldn't read the proc file.\n"
173 "Skipping the test\n");
177 lim.rlim_cur = RLIM_INFINITY;
178 lim.rlim_max = RLIM_INFINITY;
179 if (setrlimit(RLIMIT_MEMLOCK, &lim)) {
180 perror("Failed to set rlimit:\n");
184 page_size = getpagesize();
188 if (read_memory_info(&mem_free, &hugepage_size) != 0) {
189 printf("ERROR: Cannot read meminfo\n");
193 mem_fragmentable = mem_free * 0.8 / 1024;
195 while (mem_fragmentable > 0) {
196 map = mmap(NULL, MAP_SIZE, PROT_READ | PROT_WRITE,
197 MAP_ANONYMOUS | MAP_PRIVATE | MAP_LOCKED, -1, 0);
198 if (map == MAP_FAILED)
201 entry = malloc(sizeof(struct map_list));
203 munmap(map, MAP_SIZE);
210 /* Write something (in this case the address of the map) to
211 * ensure that KSM can't merge the mapped pages
213 for (i = 0; i < MAP_SIZE; i += page_size)
214 *(unsigned long *)(map + i) = (unsigned long)map + i;
219 for (entry = list; entry != NULL; entry = entry->next) {
220 munmap(entry->map, MAP_SIZE);
226 if (check_compaction(mem_free, hugepage_size) == 0)