1 // SPDX-License-Identifier: GPL-2.0
2 #include <err.h>
3 #include <stdio.h>
4 #include <stdlib.h>
5 #include <sys/prctl.h>
6
7 #include "futex.h"
8
9 #ifndef PR_FUTEX_HASH
10 #define PR_FUTEX_HASH 78
11 # define PR_FUTEX_HASH_SET_SLOTS 1
12 # define PR_FUTEX_HASH_GET_SLOTS 2
13 #endif // PR_FUTEX_HASH
14
futex_set_nbuckets_param(struct bench_futex_parameters * params)15 void futex_set_nbuckets_param(struct bench_futex_parameters *params)
16 {
17 int ret;
18
19 if (params->nbuckets < 0)
20 return;
21
22 ret = prctl(PR_FUTEX_HASH, PR_FUTEX_HASH_SET_SLOTS, params->nbuckets, 0);
23 if (ret) {
24 printf("Requesting %d hash buckets failed: %d/%m\n",
25 params->nbuckets, ret);
26 err(EXIT_FAILURE, "prctl(PR_FUTEX_HASH)");
27 }
28 }
29
futex_print_nbuckets(struct bench_futex_parameters * params)30 void futex_print_nbuckets(struct bench_futex_parameters *params)
31 {
32 char *futex_hash_mode;
33 int ret;
34
35 ret = prctl(PR_FUTEX_HASH, PR_FUTEX_HASH_GET_SLOTS);
36 if (params->nbuckets >= 0) {
37 if (ret != params->nbuckets) {
38 if (ret < 0) {
39 printf("Can't query number of buckets: %m\n");
40 err(EXIT_FAILURE, "prctl(PR_FUTEX_HASH)");
41 }
42 printf("Requested number of hash buckets does not currently used.\n");
43 printf("Requested: %d in usage: %d\n", params->nbuckets, ret);
44 err(EXIT_FAILURE, "prctl(PR_FUTEX_HASH)");
45 }
46 if (params->nbuckets == 0)
47 ret = asprintf(&futex_hash_mode, "Futex hashing: global hash");
48 else
49 ret = asprintf(&futex_hash_mode, "Futex hashing: %d hash buckets",
50 params->nbuckets);
51 } else {
52 if (ret <= 0) {
53 ret = asprintf(&futex_hash_mode, "Futex hashing: global hash");
54 } else {
55 ret = asprintf(&futex_hash_mode, "Futex hashing: auto resized to %d buckets",
56 ret);
57 }
58 }
59 if (ret < 0)
60 err(EXIT_FAILURE, "ENOMEM, futex_hash_mode");
61 printf("%s\n", futex_hash_mode);
62 free(futex_hash_mode);
63 }
64