![Yannick Brosseau](/assets/img/avatar_default.png)
When setting back the initial value to nr_hugepages, the test was writing a length sizeof of the string and checking that strlen was writen. Since those values are not the same, use strlen in both place instead. Also make the error messages more explicit to help in future debugging. Signed-off-by: Yannick Brosseau <scientist@fb.com> Signed-off-by: Shuah Khan <shuahkh@osg.samsung.com>
226 lines
5 KiB
C
226 lines
5 KiB
C
/*
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*
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* A test for the patch "Allow compaction of unevictable pages".
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* With this patch we should be able to allocate at least 1/4
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* of RAM in huge pages. Without the patch much less is
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* allocated.
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*/
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#include <stdio.h>
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#include <stdlib.h>
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#include <sys/mman.h>
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#include <sys/resource.h>
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#include <fcntl.h>
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#include <errno.h>
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#include <unistd.h>
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#include <string.h>
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#define MAP_SIZE 1048576
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struct map_list {
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void *map;
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struct map_list *next;
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};
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int read_memory_info(unsigned long *memfree, unsigned long *hugepagesize)
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{
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char buffer[256] = {0};
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char *cmd = "cat /proc/meminfo | grep -i memfree | grep -o '[0-9]*'";
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FILE *cmdfile = popen(cmd, "r");
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if (!(fgets(buffer, sizeof(buffer), cmdfile))) {
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perror("Failed to read meminfo\n");
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return -1;
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}
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pclose(cmdfile);
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*memfree = atoll(buffer);
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cmd = "cat /proc/meminfo | grep -i hugepagesize | grep -o '[0-9]*'";
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cmdfile = popen(cmd, "r");
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if (!(fgets(buffer, sizeof(buffer), cmdfile))) {
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perror("Failed to read meminfo\n");
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return -1;
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}
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pclose(cmdfile);
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*hugepagesize = atoll(buffer);
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return 0;
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}
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int prereq(void)
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{
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char allowed;
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int fd;
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fd = open("/proc/sys/vm/compact_unevictable_allowed",
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O_RDONLY | O_NONBLOCK);
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if (fd < 0) {
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perror("Failed to open\n"
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"/proc/sys/vm/compact_unevictable_allowed\n");
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return -1;
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}
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if (read(fd, &allowed, sizeof(char)) != sizeof(char)) {
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perror("Failed to read from\n"
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"/proc/sys/vm/compact_unevictable_allowed\n");
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close(fd);
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return -1;
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}
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close(fd);
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if (allowed == '1')
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return 0;
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return -1;
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}
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int check_compaction(unsigned long mem_free, unsigned int hugepage_size)
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{
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int fd;
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int compaction_index = 0;
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char initial_nr_hugepages[10] = {0};
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char nr_hugepages[10] = {0};
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/* We want to test with 80% of available memory. Else, OOM killer comes
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in to play */
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mem_free = mem_free * 0.8;
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fd = open("/proc/sys/vm/nr_hugepages", O_RDWR | O_NONBLOCK);
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if (fd < 0) {
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perror("Failed to open /proc/sys/vm/nr_hugepages");
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return -1;
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}
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if (read(fd, initial_nr_hugepages, sizeof(initial_nr_hugepages)) <= 0) {
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perror("Failed to read from /proc/sys/vm/nr_hugepages");
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goto close_fd;
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}
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/* Start with the initial condition of 0 huge pages*/
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if (write(fd, "0", sizeof(char)) != sizeof(char)) {
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perror("Failed to write 0 to /proc/sys/vm/nr_hugepages\n");
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goto close_fd;
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}
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lseek(fd, 0, SEEK_SET);
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/* Request a large number of huge pages. The Kernel will allocate
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as much as it can */
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if (write(fd, "100000", (6*sizeof(char))) != (6*sizeof(char))) {
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perror("Failed to write 100000 to /proc/sys/vm/nr_hugepages\n");
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goto close_fd;
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}
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lseek(fd, 0, SEEK_SET);
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if (read(fd, nr_hugepages, sizeof(nr_hugepages)) <= 0) {
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perror("Failed to re-read from /proc/sys/vm/nr_hugepages\n");
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goto close_fd;
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}
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/* We should have been able to request at least 1/3 rd of the memory in
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huge pages */
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compaction_index = mem_free/(atoi(nr_hugepages) * hugepage_size);
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if (compaction_index > 3) {
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printf("No of huge pages allocated = %d\n",
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(atoi(nr_hugepages)));
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fprintf(stderr, "ERROR: Less that 1/%d of memory is available\n"
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"as huge pages\n", compaction_index);
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goto close_fd;
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}
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printf("No of huge pages allocated = %d\n",
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(atoi(nr_hugepages)));
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if (write(fd, initial_nr_hugepages, strlen(initial_nr_hugepages))
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!= strlen(initial_nr_hugepages)) {
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perror("Failed to write value to /proc/sys/vm/nr_hugepages\n");
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goto close_fd;
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}
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close(fd);
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return 0;
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close_fd:
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close(fd);
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printf("Not OK. Compaction test failed.");
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return -1;
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}
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int main(int argc, char **argv)
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{
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struct rlimit lim;
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struct map_list *list, *entry;
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size_t page_size, i;
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void *map = NULL;
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unsigned long mem_free = 0;
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unsigned long hugepage_size = 0;
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unsigned long mem_fragmentable = 0;
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if (prereq() != 0) {
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printf("Either the sysctl compact_unevictable_allowed is not\n"
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"set to 1 or couldn't read the proc file.\n"
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"Skipping the test\n");
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return 0;
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}
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lim.rlim_cur = RLIM_INFINITY;
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lim.rlim_max = RLIM_INFINITY;
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if (setrlimit(RLIMIT_MEMLOCK, &lim)) {
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perror("Failed to set rlimit:\n");
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return -1;
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}
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page_size = getpagesize();
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list = NULL;
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if (read_memory_info(&mem_free, &hugepage_size) != 0) {
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printf("ERROR: Cannot read meminfo\n");
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return -1;
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}
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mem_fragmentable = mem_free * 0.8 / 1024;
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while (mem_fragmentable > 0) {
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map = mmap(NULL, MAP_SIZE, PROT_READ | PROT_WRITE,
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MAP_ANONYMOUS | MAP_PRIVATE | MAP_LOCKED, -1, 0);
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if (map == MAP_FAILED)
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break;
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entry = malloc(sizeof(struct map_list));
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if (!entry) {
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munmap(map, MAP_SIZE);
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break;
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}
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entry->map = map;
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entry->next = list;
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list = entry;
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/* Write something (in this case the address of the map) to
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* ensure that KSM can't merge the mapped pages
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*/
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for (i = 0; i < MAP_SIZE; i += page_size)
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*(unsigned long *)(map + i) = (unsigned long)map + i;
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mem_fragmentable--;
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}
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for (entry = list; entry != NULL; entry = entry->next) {
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munmap(entry->map, MAP_SIZE);
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if (!entry->next)
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break;
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entry = entry->next;
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}
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if (check_compaction(mem_free, hugepage_size) == 0)
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return 0;
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return -1;
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}
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