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1// SPDX-License-Identifier: GPL-2.02/* Test selecting other page sizes for mmap/shmget.3 4 Before running this huge pages for each huge page size must have been5 reserved.6 For large pages beyond MAX_PAGE_ORDER (like 1GB on x86) boot options must7 be used. 1GB wouldn't be tested if it isn't available.8 Also shmmax must be increased.9 And you need to run as root to work around some weird permissions in shm.10 And nothing using huge pages should run in parallel.11 When the program aborts you may need to clean up the shm segments with12 ipcrm -m by hand, like this13 sudo ipcs | awk '$1 == "0x00000000" {print $2}' | xargs -n1 sudo ipcrm -m14 (warning this will remove all if someone else uses them) */15 16#define _GNU_SOURCE17#include <sys/mman.h>18#include <linux/mman.h>19#include <stdlib.h>20#include <stdio.h>21#include <sys/ipc.h>22#include <sys/shm.h>23#include <sys/stat.h>24#include <glob.h>25#include <assert.h>26#include <unistd.h>27#include <stdarg.h>28#include <string.h>29#include "vm_util.h"30#include "../kselftest.h"31 32#if !defined(MAP_HUGETLB)33#define MAP_HUGETLB 0x4000034#endif35 36#define SHM_HUGETLB 04000 /* segment will use huge TLB pages */37#ifndef SHM_HUGE_SHIFT38#define SHM_HUGE_SHIFT 2639#endif40#ifndef SHM_HUGE_MASK41#define SHM_HUGE_MASK 0x3f42#endif43#ifndef SHM_HUGE_2MB44#define SHM_HUGE_2MB (21 << SHM_HUGE_SHIFT)45#endif46#ifndef SHM_HUGE_1GB47#define SHM_HUGE_1GB (30 << SHM_HUGE_SHIFT)48#endif49 50#define NUM_PAGESIZES 551#define NUM_PAGES 452 53unsigned long page_sizes[NUM_PAGESIZES];54int num_page_sizes;55 56int ilog2(unsigned long v)57{58 int l = 0;59 while ((1UL << l) < v)60 l++;61 return l;62}63 64void show(unsigned long ps)65{66 char buf[100];67 68 if (ps == getpagesize())69 return;70 71 ksft_print_msg("%luMB: ", ps >> 20);72 73 fflush(stdout);74 snprintf(buf, sizeof buf,75 "cat /sys/kernel/mm/hugepages/hugepages-%lukB/free_hugepages",76 ps >> 10);77 system(buf);78}79 80unsigned long read_sysfs(int warn, char *fmt, ...)81{82 char *line = NULL;83 size_t linelen = 0;84 char buf[100];85 FILE *f;86 va_list ap;87 unsigned long val = 0;88 89 va_start(ap, fmt);90 vsnprintf(buf, sizeof buf, fmt, ap);91 va_end(ap);92 93 f = fopen(buf, "r");94 if (!f) {95 if (warn)96 ksft_print_msg("missing %s\n", buf);97 return 0;98 }99 if (getline(&line, &linelen, f) > 0) {100 sscanf(line, "%lu", &val);101 }102 fclose(f);103 free(line);104 return val;105}106 107unsigned long read_free(unsigned long ps)108{109 return read_sysfs(ps != getpagesize(),110 "/sys/kernel/mm/hugepages/hugepages-%lukB/free_hugepages",111 ps >> 10);112}113 114void test_mmap(unsigned long size, unsigned flags)115{116 char *map;117 unsigned long before, after;118 119 before = read_free(size);120 map = mmap(NULL, size*NUM_PAGES, PROT_READ|PROT_WRITE,121 MAP_PRIVATE|MAP_ANONYMOUS|MAP_HUGETLB|flags, -1, 0);122 if (map == MAP_FAILED)123 ksft_exit_fail_msg("mmap: %s\n", strerror(errno));124 125 memset(map, 0xff, size*NUM_PAGES);126 after = read_free(size);127 128 show(size);129 ksft_test_result(size == getpagesize() || (before - after) == NUM_PAGES,130 "%s mmap\n", __func__);131 132 if (munmap(map, size * NUM_PAGES))133 ksft_exit_fail_msg("%s: unmap %s\n", __func__, strerror(errno));134}135 136void test_shmget(unsigned long size, unsigned flags)137{138 int id;139 unsigned long before, after;140 struct shm_info i;141 char *map;142 143 before = read_free(size);144 id = shmget(IPC_PRIVATE, size * NUM_PAGES, IPC_CREAT|0600|flags);145 if (id < 0) {146 if (errno == EPERM) {147 ksft_test_result_skip("shmget requires root privileges: %s\n",148 strerror(errno));149 return;150 }151 ksft_exit_fail_msg("shmget: %s\n", strerror(errno));152 }153 154 if (shmctl(id, SHM_INFO, (void *)&i) < 0)155 ksft_exit_fail_msg("shmctl: %s\n", strerror(errno));156 157 map = shmat(id, NULL, 0600);158 if (map == MAP_FAILED)159 ksft_exit_fail_msg("shmat: %s\n", strerror(errno));160 161 shmctl(id, IPC_RMID, NULL);162 163 memset(map, 0xff, size*NUM_PAGES);164 after = read_free(size);165 166 show(size);167 ksft_test_result(size == getpagesize() || (before - after) == NUM_PAGES,168 "%s: mmap\n", __func__);169 if (shmdt(map))170 ksft_exit_fail_msg("%s: shmdt: %s\n", __func__, strerror(errno));171}172 173void find_pagesizes(void)174{175 unsigned long largest = getpagesize();176 int i;177 glob_t g;178 179 glob("/sys/kernel/mm/hugepages/hugepages-*kB", 0, NULL, &g);180 assert(g.gl_pathc <= NUM_PAGESIZES);181 for (i = 0; (i < g.gl_pathc) && (num_page_sizes < NUM_PAGESIZES); i++) {182 sscanf(g.gl_pathv[i], "/sys/kernel/mm/hugepages/hugepages-%lukB",183 &page_sizes[num_page_sizes]);184 page_sizes[num_page_sizes] <<= 10;185 ksft_print_msg("Found %luMB\n", page_sizes[i] >> 20);186 187 if (page_sizes[num_page_sizes] > largest)188 largest = page_sizes[i];189 190 if (read_free(page_sizes[num_page_sizes]) >= NUM_PAGES)191 num_page_sizes++;192 else193 ksft_print_msg("SKIP for size %lu MB as not enough huge pages, need %u\n",194 page_sizes[num_page_sizes] >> 20, NUM_PAGES);195 }196 globfree(&g);197 198 if (read_sysfs(0, "/proc/sys/kernel/shmmax") < NUM_PAGES * largest)199 ksft_exit_fail_msg("Please do echo %lu > /proc/sys/kernel/shmmax",200 largest * NUM_PAGES);201 202#if defined(__x86_64__)203 if (largest != 1U<<30) {204 ksft_exit_fail_msg("No GB pages available on x86-64\n"205 "Please boot with hugepagesz=1G hugepages=%d\n", NUM_PAGES);206 }207#endif208}209 210int main(void)211{212 unsigned default_hps = default_huge_page_size();213 int i;214 215 ksft_print_header();216 217 find_pagesizes();218 219 if (!num_page_sizes)220 ksft_finished();221 222 ksft_set_plan(2 * num_page_sizes + 3);223 224 for (i = 0; i < num_page_sizes; i++) {225 unsigned long ps = page_sizes[i];226 int arg = ilog2(ps) << MAP_HUGE_SHIFT;227 228 ksft_print_msg("Testing %luMB mmap with shift %x\n", ps >> 20, arg);229 test_mmap(ps, MAP_HUGETLB | arg);230 }231 232 ksft_print_msg("Testing default huge mmap\n");233 test_mmap(default_hps, MAP_HUGETLB);234 235 ksft_print_msg("Testing non-huge shmget\n");236 test_shmget(getpagesize(), 0);237 238 for (i = 0; i < num_page_sizes; i++) {239 unsigned long ps = page_sizes[i];240 int arg = ilog2(ps) << SHM_HUGE_SHIFT;241 ksft_print_msg("Testing %luMB shmget with shift %x\n", ps >> 20, arg);242 test_shmget(ps, SHM_HUGETLB | arg);243 }244 245 ksft_print_msg("default huge shmget\n");246 test_shmget(default_hps, SHM_HUGETLB);247 248 ksft_finished();249}250