1 // SPDX-License-Identifier: GPL-2.0
2 #define _GNU_SOURCE
3
4 #include <linux/limits.h>
5 #include <fcntl.h>
6 #include <stdio.h>
7 #include <stdlib.h>
8 #include <string.h>
9 #include <sys/stat.h>
10 #include <sys/types.h>
11 #include <unistd.h>
12 #include <sys/wait.h>
13 #include <errno.h>
14 #include <sys/sysinfo.h>
15 #include <pthread.h>
16
17 #include "../kselftest.h"
18 #include "cgroup_util.h"
19
20
21 /*
22 * Memory cgroup charging and vmstat data aggregation is performed using
23 * percpu batches 32 pages big (look at MEMCG_CHARGE_BATCH). So the maximum
24 * discrepancy between charge and vmstat entries is number of cpus multiplied
25 * by 32 pages multiplied by 2.
26 */
27 #define MAX_VMSTAT_ERROR (4096 * 32 * 2 * get_nprocs())
28
29
alloc_dcache(const char * cgroup,void * arg)30 static int alloc_dcache(const char *cgroup, void *arg)
31 {
32 unsigned long i;
33 struct stat st;
34 char buf[128];
35
36 for (i = 0; i < (unsigned long)arg; i++) {
37 snprintf(buf, sizeof(buf),
38 "/something-non-existent-with-a-long-name-%64lu-%d",
39 i, getpid());
40 stat(buf, &st);
41 }
42
43 return 0;
44 }
45
46 /*
47 * This test allocates 100000 of negative dentries with long names.
48 * Then it checks that "slab" in memory.stat is larger than 1M.
49 * Then it sets memory.high to 1M and checks that at least 1/2
50 * of slab memory has been reclaimed.
51 */
test_kmem_basic(const char * root)52 static int test_kmem_basic(const char *root)
53 {
54 int ret = KSFT_FAIL;
55 char *cg = NULL;
56 long slab0, slab1, current;
57
58 cg = cg_name(root, "kmem_basic_test");
59 if (!cg)
60 goto cleanup;
61
62 if (cg_create(cg))
63 goto cleanup;
64
65 if (cg_run(cg, alloc_dcache, (void *)100000))
66 goto cleanup;
67
68 slab0 = cg_read_key_long(cg, "memory.stat", "slab ");
69 if (slab0 < (1 << 20))
70 goto cleanup;
71
72 cg_write(cg, "memory.high", "1M");
73 slab1 = cg_read_key_long(cg, "memory.stat", "slab ");
74 if (slab1 <= 0)
75 goto cleanup;
76
77 current = cg_read_long(cg, "memory.current");
78 if (current <= 0)
79 goto cleanup;
80
81 if (slab1 < slab0 / 2 && current < slab0 / 2)
82 ret = KSFT_PASS;
83 cleanup:
84 cg_destroy(cg);
85 free(cg);
86
87 return ret;
88 }
89
alloc_kmem_fn(void * arg)90 static void *alloc_kmem_fn(void *arg)
91 {
92 alloc_dcache(NULL, (void *)100);
93 return NULL;
94 }
95
alloc_kmem_smp(const char * cgroup,void * arg)96 static int alloc_kmem_smp(const char *cgroup, void *arg)
97 {
98 int nr_threads = 2 * get_nprocs();
99 pthread_t *tinfo;
100 unsigned long i;
101 int ret = -1;
102
103 tinfo = calloc(nr_threads, sizeof(pthread_t));
104 if (tinfo == NULL)
105 return -1;
106
107 for (i = 0; i < nr_threads; i++) {
108 if (pthread_create(&tinfo[i], NULL, &alloc_kmem_fn,
109 (void *)i)) {
110 free(tinfo);
111 return -1;
112 }
113 }
114
115 for (i = 0; i < nr_threads; i++) {
116 ret = pthread_join(tinfo[i], NULL);
117 if (ret)
118 break;
119 }
120
121 free(tinfo);
122 return ret;
123 }
124
cg_run_in_subcgroups(const char * parent,int (* fn)(const char * cgroup,void * arg),void * arg,int times)125 static int cg_run_in_subcgroups(const char *parent,
126 int (*fn)(const char *cgroup, void *arg),
127 void *arg, int times)
128 {
129 char *child;
130 int i;
131
132 for (i = 0; i < times; i++) {
133 child = cg_name_indexed(parent, "child", i);
134 if (!child)
135 return -1;
136
137 if (cg_create(child)) {
138 cg_destroy(child);
139 free(child);
140 return -1;
141 }
142
143 if (cg_run(child, fn, NULL)) {
144 cg_destroy(child);
145 free(child);
146 return -1;
147 }
148
149 cg_destroy(child);
150 free(child);
151 }
152
153 return 0;
154 }
155
156 /*
157 * The test creates and destroys a large number of cgroups. In each cgroup it
158 * allocates some slab memory (mostly negative dentries) using 2 * NR_CPUS
159 * threads. Then it checks the sanity of numbers on the parent level:
160 * the total size of the cgroups should be roughly equal to
161 * anon + file + slab + kernel_stack.
162 */
test_kmem_memcg_deletion(const char * root)163 static int test_kmem_memcg_deletion(const char *root)
164 {
165 long current, slab, anon, file, kernel_stack, sum;
166 int ret = KSFT_FAIL;
167 char *parent;
168
169 parent = cg_name(root, "kmem_memcg_deletion_test");
170 if (!parent)
171 goto cleanup;
172
173 if (cg_create(parent))
174 goto cleanup;
175
176 if (cg_write(parent, "cgroup.subtree_control", "+memory"))
177 goto cleanup;
178
179 if (cg_run_in_subcgroups(parent, alloc_kmem_smp, NULL, 100))
180 goto cleanup;
181
182 current = cg_read_long(parent, "memory.current");
183 slab = cg_read_key_long(parent, "memory.stat", "slab ");
184 anon = cg_read_key_long(parent, "memory.stat", "anon ");
185 file = cg_read_key_long(parent, "memory.stat", "file ");
186 kernel_stack = cg_read_key_long(parent, "memory.stat", "kernel_stack ");
187 if (current < 0 || slab < 0 || anon < 0 || file < 0 ||
188 kernel_stack < 0)
189 goto cleanup;
190
191 sum = slab + anon + file + kernel_stack;
192 if (abs(sum - current) < MAX_VMSTAT_ERROR) {
193 ret = KSFT_PASS;
194 } else {
195 printf("memory.current = %ld\n", current);
196 printf("slab + anon + file + kernel_stack = %ld\n", sum);
197 printf("slab = %ld\n", slab);
198 printf("anon = %ld\n", anon);
199 printf("file = %ld\n", file);
200 printf("kernel_stack = %ld\n", kernel_stack);
201 }
202
203 cleanup:
204 cg_destroy(parent);
205 free(parent);
206
207 return ret;
208 }
209
210 /*
211 * The test reads the entire /proc/kpagecgroup. If the operation went
212 * successfully (and the kernel didn't panic), the test is treated as passed.
213 */
test_kmem_proc_kpagecgroup(const char * root)214 static int test_kmem_proc_kpagecgroup(const char *root)
215 {
216 unsigned long buf[128];
217 int ret = KSFT_FAIL;
218 ssize_t len;
219 int fd;
220
221 fd = open("/proc/kpagecgroup", O_RDONLY);
222 if (fd < 0)
223 return ret;
224
225 do {
226 len = read(fd, buf, sizeof(buf));
227 } while (len > 0);
228
229 if (len == 0)
230 ret = KSFT_PASS;
231
232 close(fd);
233 return ret;
234 }
235
pthread_wait_fn(void * arg)236 static void *pthread_wait_fn(void *arg)
237 {
238 sleep(100);
239 return NULL;
240 }
241
spawn_1000_threads(const char * cgroup,void * arg)242 static int spawn_1000_threads(const char *cgroup, void *arg)
243 {
244 int nr_threads = 1000;
245 pthread_t *tinfo;
246 unsigned long i;
247 long stack;
248 int ret = -1;
249
250 tinfo = calloc(nr_threads, sizeof(pthread_t));
251 if (tinfo == NULL)
252 return -1;
253
254 for (i = 0; i < nr_threads; i++) {
255 if (pthread_create(&tinfo[i], NULL, &pthread_wait_fn,
256 (void *)i)) {
257 free(tinfo);
258 return(-1);
259 }
260 }
261
262 stack = cg_read_key_long(cgroup, "memory.stat", "kernel_stack ");
263 if (stack >= 4096 * 1000)
264 ret = 0;
265
266 free(tinfo);
267 return ret;
268 }
269
270 /*
271 * The test spawns a process, which spawns 1000 threads. Then it checks
272 * that memory.stat's kernel_stack is at least 1000 pages large.
273 */
test_kmem_kernel_stacks(const char * root)274 static int test_kmem_kernel_stacks(const char *root)
275 {
276 int ret = KSFT_FAIL;
277 char *cg = NULL;
278
279 cg = cg_name(root, "kmem_kernel_stacks_test");
280 if (!cg)
281 goto cleanup;
282
283 if (cg_create(cg))
284 goto cleanup;
285
286 if (cg_run(cg, spawn_1000_threads, NULL))
287 goto cleanup;
288
289 ret = KSFT_PASS;
290 cleanup:
291 cg_destroy(cg);
292 free(cg);
293
294 return ret;
295 }
296
297 /*
298 * This test sequentionally creates 30 child cgroups, allocates some
299 * kernel memory in each of them, and deletes them. Then it checks
300 * that the number of dying cgroups on the parent level is 0.
301 */
test_kmem_dead_cgroups(const char * root)302 static int test_kmem_dead_cgroups(const char *root)
303 {
304 int ret = KSFT_FAIL;
305 char *parent;
306 long dead;
307 int i;
308
309 parent = cg_name(root, "kmem_dead_cgroups_test");
310 if (!parent)
311 goto cleanup;
312
313 if (cg_create(parent))
314 goto cleanup;
315
316 if (cg_write(parent, "cgroup.subtree_control", "+memory"))
317 goto cleanup;
318
319 if (cg_run_in_subcgroups(parent, alloc_dcache, (void *)100, 30))
320 goto cleanup;
321
322 for (i = 0; i < 5; i++) {
323 dead = cg_read_key_long(parent, "cgroup.stat",
324 "nr_dying_descendants ");
325 if (dead == 0) {
326 ret = KSFT_PASS;
327 break;
328 }
329 /*
330 * Reclaiming cgroups might take some time,
331 * let's wait a bit and repeat.
332 */
333 sleep(1);
334 }
335
336 cleanup:
337 cg_destroy(parent);
338 free(parent);
339
340 return ret;
341 }
342
343 /*
344 * This test creates a sub-tree with 1000 memory cgroups.
345 * Then it checks that the memory.current on the parent level
346 * is greater than 0 and approximates matches the percpu value
347 * from memory.stat.
348 */
test_percpu_basic(const char * root)349 static int test_percpu_basic(const char *root)
350 {
351 int ret = KSFT_FAIL;
352 char *parent, *child;
353 long current, percpu;
354 int i;
355
356 parent = cg_name(root, "percpu_basic_test");
357 if (!parent)
358 goto cleanup;
359
360 if (cg_create(parent))
361 goto cleanup;
362
363 if (cg_write(parent, "cgroup.subtree_control", "+memory"))
364 goto cleanup;
365
366 for (i = 0; i < 1000; i++) {
367 child = cg_name_indexed(parent, "child", i);
368 if (!child)
369 return -1;
370
371 if (cg_create(child))
372 goto cleanup_children;
373
374 free(child);
375 }
376
377 current = cg_read_long(parent, "memory.current");
378 percpu = cg_read_key_long(parent, "memory.stat", "percpu ");
379
380 if (current > 0 && percpu > 0 && abs(current - percpu) <
381 MAX_VMSTAT_ERROR)
382 ret = KSFT_PASS;
383 else
384 printf("memory.current %ld\npercpu %ld\n",
385 current, percpu);
386
387 cleanup_children:
388 for (i = 0; i < 1000; i++) {
389 child = cg_name_indexed(parent, "child", i);
390 cg_destroy(child);
391 free(child);
392 }
393
394 cleanup:
395 cg_destroy(parent);
396 free(parent);
397
398 return ret;
399 }
400
401 #define T(x) { x, #x }
402 struct kmem_test {
403 int (*fn)(const char *root);
404 const char *name;
405 } tests[] = {
406 T(test_kmem_basic),
407 T(test_kmem_memcg_deletion),
408 T(test_kmem_proc_kpagecgroup),
409 T(test_kmem_kernel_stacks),
410 T(test_kmem_dead_cgroups),
411 T(test_percpu_basic),
412 };
413 #undef T
414
main(int argc,char ** argv)415 int main(int argc, char **argv)
416 {
417 char root[PATH_MAX];
418 int i, ret = EXIT_SUCCESS;
419
420 if (cg_find_unified_root(root, sizeof(root)))
421 ksft_exit_skip("cgroup v2 isn't mounted\n");
422
423 /*
424 * Check that memory controller is available:
425 * memory is listed in cgroup.controllers
426 */
427 if (cg_read_strstr(root, "cgroup.controllers", "memory"))
428 ksft_exit_skip("memory controller isn't available\n");
429
430 if (cg_read_strstr(root, "cgroup.subtree_control", "memory"))
431 if (cg_write(root, "cgroup.subtree_control", "+memory"))
432 ksft_exit_skip("Failed to set memory controller\n");
433
434 for (i = 0; i < ARRAY_SIZE(tests); i++) {
435 switch (tests[i].fn(root)) {
436 case KSFT_PASS:
437 ksft_test_result_pass("%s\n", tests[i].name);
438 break;
439 case KSFT_SKIP:
440 ksft_test_result_skip("%s\n", tests[i].name);
441 break;
442 default:
443 ret = EXIT_FAILURE;
444 ksft_test_result_fail("%s\n", tests[i].name);
445 break;
446 }
447 }
448
449 return ret;
450 }
451