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