--- /dev/null
+/* Test selecting other page sizes for mmap/shmget.
+
+ Before running this huge pages for each huge page size must have been
+ reserved.
+ For large pages beyond MAX_ORDER (like 1GB on x86) boot options must be used.
+ Also shmmax must be increased.
+ And you need to run as root to work around some weird permissions in shm.
+ And nothing using huge pages should run in parallel.
+ When the program aborts you may need to clean up the shm segments with
+ ipcrm -m by hand, like this
+ sudo ipcs | awk '$1 == "0x00000000" {print $2}' | xargs -n1 sudo ipcrm -m
+ (warning this will remove all if someone else uses them) */
+
+#define _GNU_SOURCE 1
+#include <sys/mman.h>
+#include <stdlib.h>
+#include <stdio.h>
+#include <sys/ipc.h>
+#include <sys/shm.h>
+#include <sys/stat.h>
+#include <glob.h>
+#include <assert.h>
+#include <unistd.h>
+#include <stdarg.h>
+#include <string.h>
+
+#define err(x) perror(x), exit(1)
+
+#define MAP_HUGE_2MB (21 << MAP_HUGE_SHIFT)
+#define MAP_HUGE_1GB (30 << MAP_HUGE_SHIFT)
+#define MAP_HUGE_SHIFT 26
+#define MAP_HUGE_MASK 0x3f
+#define MAP_HUGETLB 0x40000
+
+#define SHM_HUGETLB 04000 /* segment will use huge TLB pages */
+#define SHM_HUGE_SHIFT 26
+#define SHM_HUGE_MASK 0x3f
+#define SHM_HUGE_2MB (21 << SHM_HUGE_SHIFT)
+#define SHM_HUGE_1GB (30 << SHM_HUGE_SHIFT)
+
+#define NUM_PAGESIZES 5
+
+#define NUM_PAGES 4
+
+#define Dprintf(fmt...) // printf(fmt)
+
+unsigned long page_sizes[NUM_PAGESIZES];
+int num_page_sizes;
+
+int ilog2(unsigned long v)
+{
+ int l = 0;
+ while ((1UL << l) < v)
+ l++;
+ return l;
+}
+
+void find_pagesizes(void)
+{
+ glob_t g;
+ int i;
+ glob("/sys/kernel/mm/hugepages/hugepages-*kB", 0, NULL, &g);
+ assert(g.gl_pathc <= NUM_PAGESIZES);
+ for (i = 0; i < g.gl_pathc; i++) {
+ sscanf(g.gl_pathv[i], "/sys/kernel/mm/hugepages/hugepages-%lukB",
+ &page_sizes[i]);
+ page_sizes[i] <<= 10;
+ printf("Found %luMB\n", page_sizes[i] >> 20);
+ }
+ num_page_sizes = g.gl_pathc;
+ globfree(&g);
+}
+
+unsigned long default_huge_page_size(void)
+{
+ unsigned long hps = 0;
+ char *line = NULL;
+ size_t linelen = 0;
+ FILE *f = fopen("/proc/meminfo", "r");
+ if (!f)
+ return 0;
+ while (getline(&line, &linelen, f) > 0) {
+ if (sscanf(line, "Hugepagesize: %lu kB", &hps) == 1) {
+ hps <<= 10;
+ break;
+ }
+ }
+ free(line);
+ return hps;
+}
+
+void show(unsigned long ps)
+{
+ char buf[100];
+ if (ps == getpagesize())
+ return;
+ printf("%luMB: ", ps >> 20);
+ fflush(stdout);
+ snprintf(buf, sizeof buf,
+ "cat /sys/kernel/mm/hugepages/hugepages-%lukB/free_hugepages",
+ ps >> 10);
+ system(buf);
+}
+
+unsigned long read_sysfs(int warn, char *fmt, ...)
+{
+ char *line = NULL;
+ size_t linelen = 0;
+ char buf[100];
+ FILE *f;
+ va_list ap;
+ unsigned long val = 0;
+
+ va_start(ap, fmt);
+ vsnprintf(buf, sizeof buf, fmt, ap);
+ va_end(ap);
+
+ f = fopen(buf, "r");
+ if (!f) {
+ if (warn)
+ printf("missing %s\n", buf);
+ return 0;
+ }
+ if (getline(&line, &linelen, f) > 0) {
+ sscanf(line, "%lu", &val);
+ }
+ fclose(f);
+ free(line);
+ return val;
+}
+
+unsigned long read_free(unsigned long ps)
+{
+ return read_sysfs(ps != getpagesize(),
+ "/sys/kernel/mm/hugepages/hugepages-%lukB/free_hugepages",
+ ps >> 10);
+}
+
+void test_mmap(unsigned long size, unsigned flags)
+{
+ char *map;
+ unsigned long before, after;
+ int err;
+
+ before = read_free(size);
+ map = mmap(NULL, size*NUM_PAGES, PROT_READ|PROT_WRITE,
+ MAP_PRIVATE|MAP_ANONYMOUS|MAP_HUGETLB|flags, 0, 0);
+
+ if (map == (char *)-1) err("mmap");
+ memset(map, 0xff, size*NUM_PAGES);
+ after = read_free(size);
+ Dprintf("before %lu after %lu diff %ld size %lu\n",
+ before, after, before - after, size);
+ assert(size == getpagesize() || (before - after) == NUM_PAGES);
+ show(size);
+ err = munmap(map, size);
+ assert(!err);
+}
+
+void test_shmget(unsigned long size, unsigned flags)
+{
+ int id;
+ unsigned long before, after;
+ int err;
+
+ before = read_free(size);
+ id = shmget(IPC_PRIVATE, size * NUM_PAGES, IPC_CREAT|0600|flags);
+ if (id < 0) err("shmget");
+
+ struct shm_info i;
+ if (shmctl(id, SHM_INFO, (void *)&i) < 0) err("shmctl");
+ Dprintf("alloc %lu res %lu\n", i.shm_tot, i.shm_rss);
+
+
+ Dprintf("id %d\n", id);
+ char *map = shmat(id, NULL, 0600);
+ if (map == (char*)-1) err("shmat");
+
+ shmctl(id, IPC_RMID, NULL);
+
+ memset(map, 0xff, size*NUM_PAGES);
+ after = read_free(size);
+
+ Dprintf("before %lu after %lu diff %ld size %lu\n",
+ before, after, before - after, size);
+ assert(size == getpagesize() || (before - after) == NUM_PAGES);
+ show(size);
+ err = shmdt(map);
+ assert(!err);
+}
+
+void sanity_checks(void)
+{
+ int i;
+ unsigned long largest = getpagesize();
+
+ for (i = 0; i < num_page_sizes; i++) {
+ if (page_sizes[i] > largest)
+ largest = page_sizes[i];
+
+ if (read_free(page_sizes[i]) < NUM_PAGES) {
+ printf("Not enough huge pages for page size %lu MB, need %u\n",
+ page_sizes[i] >> 20,
+ NUM_PAGES);
+ exit(0);
+ }
+ }
+
+ if (read_sysfs(0, "/proc/sys/kernel/shmmax") < NUM_PAGES * largest) {
+ printf("Please do echo %lu > /proc/sys/kernel/shmmax", largest * NUM_PAGES);
+ exit(0);
+ }
+
+#if defined(__x86_64__)
+ if (largest != 1U<<30) {
+ printf("No GB pages available on x86-64\n"
+ "Please boot with hugepagesz=1G hugepages=%d\n", NUM_PAGES);
+ exit(0);
+ }
+#endif
+}
+
+int main(void)
+{
+ int i;
+ unsigned default_hps = default_huge_page_size();
+
+ find_pagesizes();
+
+ sanity_checks();
+
+ for (i = 0; i < num_page_sizes; i++) {
+ unsigned long ps = page_sizes[i];
+ int arg = ilog2(ps) << MAP_HUGE_SHIFT;
+ printf("Testing %luMB mmap with shift %x\n", ps >> 20, arg);
+ test_mmap(ps, MAP_HUGETLB | arg);
+ }
+ printf("Testing default huge mmap\n");
+ test_mmap(default_hps, SHM_HUGETLB);
+
+ puts("Testing non-huge shmget");
+ test_shmget(getpagesize(), 0);
+
+ for (i = 0; i < num_page_sizes; i++) {
+ unsigned long ps = page_sizes[i];
+ int arg = ilog2(ps) << SHM_HUGE_SHIFT;
+ printf("Testing %luMB shmget with shift %x\n", ps >> 20, arg);
+ test_shmget(ps, SHM_HUGETLB | arg);
+ }
+ puts("default huge shmget");
+ test_shmget(default_hps, SHM_HUGETLB);
+
+ return 0;
+}
projects / karo-tx-linux.git / commitdiff