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b2441318 | 1 | // SPDX-License-Identifier: GPL-2.0 |
fcc1f2d5 AK |
2 | /* Test selecting other page sizes for mmap/shmget. |
3 | ||
4 | Before running this huge pages for each huge page size must have been | |
5 | reserved. | |
6 | For large pages beyond MAX_ORDER (like 1GB on x86) boot options must be used. | |
7 | Also shmmax must be increased. | |
8 | And you need to run as root to work around some weird permissions in shm. | |
9 | And nothing using huge pages should run in parallel. | |
10 | When the program aborts you may need to clean up the shm segments with | |
11 | ipcrm -m by hand, like this | |
12 | sudo ipcs | awk '$1 == "0x00000000" {print $2}' | xargs -n1 sudo ipcrm -m | |
13 | (warning this will remove all if someone else uses them) */ | |
14 | ||
15 | #define _GNU_SOURCE 1 | |
16 | #include <sys/mman.h> | |
17 | #include <stdlib.h> | |
18 | #include <stdio.h> | |
19 | #include <sys/ipc.h> | |
20 | #include <sys/shm.h> | |
21 | #include <sys/stat.h> | |
22 | #include <glob.h> | |
23 | #include <assert.h> | |
24 | #include <unistd.h> | |
25 | #include <stdarg.h> | |
26 | #include <string.h> | |
27 | ||
28 | #define err(x) perror(x), exit(1) | |
29 | ||
30 | #define MAP_HUGE_2MB (21 << MAP_HUGE_SHIFT) | |
31 | #define MAP_HUGE_1GB (30 << MAP_HUGE_SHIFT) | |
32 | #define MAP_HUGE_SHIFT 26 | |
33 | #define MAP_HUGE_MASK 0x3f | |
a4351cb5 | 34 | #if !defined(MAP_HUGETLB) |
fcc1f2d5 | 35 | #define MAP_HUGETLB 0x40000 |
a4351cb5 | 36 | #endif |
fcc1f2d5 AK |
37 | |
38 | #define SHM_HUGETLB 04000 /* segment will use huge TLB pages */ | |
39 | #define SHM_HUGE_SHIFT 26 | |
40 | #define SHM_HUGE_MASK 0x3f | |
41 | #define SHM_HUGE_2MB (21 << SHM_HUGE_SHIFT) | |
42 | #define SHM_HUGE_1GB (30 << SHM_HUGE_SHIFT) | |
43 | ||
44 | #define NUM_PAGESIZES 5 | |
45 | ||
46 | #define NUM_PAGES 4 | |
47 | ||
48 | #define Dprintf(fmt...) // printf(fmt) | |
49 | ||
50 | unsigned long page_sizes[NUM_PAGESIZES]; | |
51 | int num_page_sizes; | |
52 | ||
53 | int ilog2(unsigned long v) | |
54 | { | |
55 | int l = 0; | |
56 | while ((1UL << l) < v) | |
57 | l++; | |
58 | return l; | |
59 | } | |
60 | ||
61 | void find_pagesizes(void) | |
62 | { | |
63 | glob_t g; | |
64 | int i; | |
65 | glob("/sys/kernel/mm/hugepages/hugepages-*kB", 0, NULL, &g); | |
66 | assert(g.gl_pathc <= NUM_PAGESIZES); | |
67 | for (i = 0; i < g.gl_pathc; i++) { | |
68 | sscanf(g.gl_pathv[i], "/sys/kernel/mm/hugepages/hugepages-%lukB", | |
69 | &page_sizes[i]); | |
70 | page_sizes[i] <<= 10; | |
71 | printf("Found %luMB\n", page_sizes[i] >> 20); | |
72 | } | |
73 | num_page_sizes = g.gl_pathc; | |
74 | globfree(&g); | |
75 | } | |
76 | ||
77 | unsigned long default_huge_page_size(void) | |
78 | { | |
79 | unsigned long hps = 0; | |
80 | char *line = NULL; | |
81 | size_t linelen = 0; | |
82 | FILE *f = fopen("/proc/meminfo", "r"); | |
83 | if (!f) | |
84 | return 0; | |
85 | while (getline(&line, &linelen, f) > 0) { | |
86 | if (sscanf(line, "Hugepagesize: %lu kB", &hps) == 1) { | |
87 | hps <<= 10; | |
88 | break; | |
89 | } | |
90 | } | |
91 | free(line); | |
92 | return hps; | |
93 | } | |
94 | ||
95 | void show(unsigned long ps) | |
96 | { | |
97 | char buf[100]; | |
98 | if (ps == getpagesize()) | |
99 | return; | |
100 | printf("%luMB: ", ps >> 20); | |
101 | fflush(stdout); | |
102 | snprintf(buf, sizeof buf, | |
103 | "cat /sys/kernel/mm/hugepages/hugepages-%lukB/free_hugepages", | |
104 | ps >> 10); | |
105 | system(buf); | |
106 | } | |
107 | ||
108 | unsigned long read_sysfs(int warn, char *fmt, ...) | |
109 | { | |
110 | char *line = NULL; | |
111 | size_t linelen = 0; | |
112 | char buf[100]; | |
113 | FILE *f; | |
114 | va_list ap; | |
115 | unsigned long val = 0; | |
116 | ||
117 | va_start(ap, fmt); | |
118 | vsnprintf(buf, sizeof buf, fmt, ap); | |
119 | va_end(ap); | |
120 | ||
121 | f = fopen(buf, "r"); | |
122 | if (!f) { | |
123 | if (warn) | |
124 | printf("missing %s\n", buf); | |
125 | return 0; | |
126 | } | |
127 | if (getline(&line, &linelen, f) > 0) { | |
128 | sscanf(line, "%lu", &val); | |
129 | } | |
130 | fclose(f); | |
131 | free(line); | |
132 | return val; | |
133 | } | |
134 | ||
135 | unsigned long read_free(unsigned long ps) | |
136 | { | |
137 | return read_sysfs(ps != getpagesize(), | |
138 | "/sys/kernel/mm/hugepages/hugepages-%lukB/free_hugepages", | |
139 | ps >> 10); | |
140 | } | |
141 | ||
142 | void test_mmap(unsigned long size, unsigned flags) | |
143 | { | |
144 | char *map; | |
145 | unsigned long before, after; | |
146 | int err; | |
147 | ||
148 | before = read_free(size); | |
149 | map = mmap(NULL, size*NUM_PAGES, PROT_READ|PROT_WRITE, | |
70d1a4e6 | 150 | MAP_PRIVATE|MAP_ANONYMOUS|MAP_HUGETLB|flags, -1, 0); |
fcc1f2d5 AK |
151 | |
152 | if (map == (char *)-1) err("mmap"); | |
153 | memset(map, 0xff, size*NUM_PAGES); | |
154 | after = read_free(size); | |
155 | Dprintf("before %lu after %lu diff %ld size %lu\n", | |
156 | before, after, before - after, size); | |
157 | assert(size == getpagesize() || (before - after) == NUM_PAGES); | |
158 | show(size); | |
159 | err = munmap(map, size); | |
160 | assert(!err); | |
161 | } | |
162 | ||
163 | void test_shmget(unsigned long size, unsigned flags) | |
164 | { | |
165 | int id; | |
166 | unsigned long before, after; | |
167 | int err; | |
168 | ||
169 | before = read_free(size); | |
170 | id = shmget(IPC_PRIVATE, size * NUM_PAGES, IPC_CREAT|0600|flags); | |
171 | if (id < 0) err("shmget"); | |
172 | ||
173 | struct shm_info i; | |
174 | if (shmctl(id, SHM_INFO, (void *)&i) < 0) err("shmctl"); | |
175 | Dprintf("alloc %lu res %lu\n", i.shm_tot, i.shm_rss); | |
176 | ||
177 | ||
178 | Dprintf("id %d\n", id); | |
179 | char *map = shmat(id, NULL, 0600); | |
180 | if (map == (char*)-1) err("shmat"); | |
181 | ||
182 | shmctl(id, IPC_RMID, NULL); | |
183 | ||
184 | memset(map, 0xff, size*NUM_PAGES); | |
185 | after = read_free(size); | |
186 | ||
187 | Dprintf("before %lu after %lu diff %ld size %lu\n", | |
188 | before, after, before - after, size); | |
189 | assert(size == getpagesize() || (before - after) == NUM_PAGES); | |
190 | show(size); | |
191 | err = shmdt(map); | |
192 | assert(!err); | |
193 | } | |
194 | ||
195 | void sanity_checks(void) | |
196 | { | |
197 | int i; | |
198 | unsigned long largest = getpagesize(); | |
199 | ||
200 | for (i = 0; i < num_page_sizes; i++) { | |
201 | if (page_sizes[i] > largest) | |
202 | largest = page_sizes[i]; | |
203 | ||
204 | if (read_free(page_sizes[i]) < NUM_PAGES) { | |
205 | printf("Not enough huge pages for page size %lu MB, need %u\n", | |
206 | page_sizes[i] >> 20, | |
207 | NUM_PAGES); | |
208 | exit(0); | |
209 | } | |
210 | } | |
211 | ||
212 | if (read_sysfs(0, "/proc/sys/kernel/shmmax") < NUM_PAGES * largest) { | |
213 | printf("Please do echo %lu > /proc/sys/kernel/shmmax", largest * NUM_PAGES); | |
214 | exit(0); | |
215 | } | |
216 | ||
217 | #if defined(__x86_64__) | |
218 | if (largest != 1U<<30) { | |
219 | printf("No GB pages available on x86-64\n" | |
220 | "Please boot with hugepagesz=1G hugepages=%d\n", NUM_PAGES); | |
221 | exit(0); | |
222 | } | |
223 | #endif | |
224 | } | |
225 | ||
226 | int main(void) | |
227 | { | |
228 | int i; | |
229 | unsigned default_hps = default_huge_page_size(); | |
230 | ||
231 | find_pagesizes(); | |
232 | ||
233 | sanity_checks(); | |
234 | ||
235 | for (i = 0; i < num_page_sizes; i++) { | |
236 | unsigned long ps = page_sizes[i]; | |
237 | int arg = ilog2(ps) << MAP_HUGE_SHIFT; | |
238 | printf("Testing %luMB mmap with shift %x\n", ps >> 20, arg); | |
239 | test_mmap(ps, MAP_HUGETLB | arg); | |
240 | } | |
241 | printf("Testing default huge mmap\n"); | |
242 | test_mmap(default_hps, SHM_HUGETLB); | |
243 | ||
244 | puts("Testing non-huge shmget"); | |
245 | test_shmget(getpagesize(), 0); | |
246 | ||
247 | for (i = 0; i < num_page_sizes; i++) { | |
248 | unsigned long ps = page_sizes[i]; | |
249 | int arg = ilog2(ps) << SHM_HUGE_SHIFT; | |
250 | printf("Testing %luMB shmget with shift %x\n", ps >> 20, arg); | |
251 | test_shmget(ps, SHM_HUGETLB | arg); | |
252 | } | |
253 | puts("default huge shmget"); | |
254 | test_shmget(default_hps, SHM_HUGETLB); | |
255 | ||
256 | return 0; | |
257 | } |