Bump minimum kernel version to 2.6.30 to use EFD_SEMAPHORE
[lttng-tools.git] / src / bin / lttng-sessiond / fd-limit.cpp
1 /*
2 * Copyright (C) 2012 Mathieu Desnoyers <mathieu.desnoyers@efficios.com>
3 *
4 * SPDX-License-Identifier: GPL-2.0-only
5 *
6 */
7
8 #define _LGPL_SOURCE
9 #include <urcu/uatomic.h>
10 #include <sys/time.h>
11 #include <sys/resource.h>
12 #include <stdio.h>
13 #include "fd-limit.hpp"
14 #include <common/error.hpp>
15 #include <common/compat/errno.hpp>
16
17 /* total count of fd. */
18 static long fd_count;
19
20 /*
21 * threshold in % of number of fd allowed.
22 */
23 static long fd_threshold[LTTNG_FD_NR_TYPES] = {
24 75, /* LTTNG_FD_APPS */
25 };
26
27 static rlim_t max_nr_fd;
28
29 int lttng_fd_get(enum lttng_fd_type type, unsigned int nr)
30 {
31 long newval;
32
33 if (type >= LTTNG_FD_NR_TYPES) {
34 return -EINVAL;
35 }
36
37 newval = uatomic_add_return(&fd_count, (long) nr);
38 if ((long) (newval * 100)
39 - (long) (max_nr_fd * fd_threshold[type]) > 0) {
40 uatomic_sub(&fd_count, (long) nr);
41 return -EPERM;
42 }
43 return 0;
44 }
45
46 void lttng_fd_put(enum lttng_fd_type type __attribute__((unused)),
47 unsigned int nr)
48 {
49 uatomic_sub(&fd_count, (long) nr);
50 }
51
52 void lttng_fd_init(void)
53 {
54 struct rlimit rlim;
55 int ret;
56
57 ret = getrlimit(RLIMIT_NOFILE, &rlim);
58 if (ret < 0) {
59 PERROR("getrlimit");
60 }
61 max_nr_fd = rlim.rlim_cur;
62 }
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