Line data Source code
1 : /* SPDX-License-Identifier: LGPL-2.1+ */
2 :
3 : #include "alloc-util.h"
4 : #include "cgroup-util.h"
5 : #include "limits-util.h"
6 : #include "memory-util.h"
7 : #include "parse-util.h"
8 : #include "process-util.h"
9 : #include "procfs-util.h"
10 : #include "string-util.h"
11 :
12 38 : uint64_t physical_memory(void) {
13 38 : _cleanup_free_ char *root = NULL, *value = NULL;
14 : uint64_t mem, lim;
15 : size_t ps;
16 : long sc;
17 : int r;
18 :
19 : /* We return this as uint64_t in case we are running as 32bit process on a 64bit kernel with huge amounts of
20 : * memory.
21 : *
22 : * In order to support containers nicely that have a configured memory limit we'll take the minimum of the
23 : * physically reported amount of memory and the limit configured for the root cgroup, if there is any. */
24 :
25 38 : sc = sysconf(_SC_PHYS_PAGES);
26 38 : assert(sc > 0);
27 :
28 38 : ps = page_size();
29 38 : mem = (uint64_t) sc * (uint64_t) ps;
30 :
31 38 : r = cg_get_root_path(&root);
32 38 : if (r < 0) {
33 0 : log_debug_errno(r, "Failed to determine root cgroup, ignoring cgroup memory limit: %m");
34 0 : return mem;
35 : }
36 :
37 38 : r = cg_all_unified();
38 38 : if (r < 0) {
39 0 : log_debug_errno(r, "Failed to determine root unified mode, ignoring cgroup memory limit: %m");
40 0 : return mem;
41 : }
42 38 : if (r > 0) {
43 0 : r = cg_get_attribute("memory", root, "memory.max", &value);
44 0 : if (r < 0) {
45 0 : log_debug_errno(r, "Failed to read memory.max cgroup attribute, ignoring cgroup memory limit: %m");
46 0 : return mem;
47 : }
48 :
49 0 : if (streq(value, "max"))
50 0 : return mem;
51 : } else {
52 38 : r = cg_get_attribute("memory", root, "memory.limit_in_bytes", &value);
53 38 : if (r < 0) {
54 0 : log_debug_errno(r, "Failed to read memory.limit_in_bytes cgroup attribute, ignoring cgroup memory limit: %m");
55 0 : return mem;
56 : }
57 : }
58 :
59 38 : r = safe_atou64(value, &lim);
60 38 : if (r < 0) {
61 0 : log_debug_errno(r, "Failed to parse cgroup memory limit '%s', ignoring: %m", value);
62 0 : return mem;
63 : }
64 38 : if (lim == UINT64_MAX)
65 0 : return mem;
66 :
67 : /* Make sure the limit is a multiple of our own page size */
68 38 : lim /= ps;
69 38 : lim *= ps;
70 :
71 38 : return MIN(mem, lim);
72 : }
73 :
74 15 : uint64_t physical_memory_scale(uint64_t v, uint64_t max) {
75 : uint64_t p, m, ps, r;
76 :
77 15 : assert(max > 0);
78 :
79 : /* Returns the physical memory size, multiplied by v divided by max. Returns UINT64_MAX on overflow. On success
80 : * the result is a multiple of the page size (rounds down). */
81 :
82 15 : ps = page_size();
83 15 : assert(ps > 0);
84 :
85 15 : p = physical_memory() / ps;
86 15 : assert(p > 0);
87 :
88 15 : m = p * v;
89 15 : if (m / p != v)
90 1 : return UINT64_MAX;
91 :
92 14 : m /= max;
93 :
94 14 : r = m * ps;
95 14 : if (r / ps != m)
96 0 : return UINT64_MAX;
97 :
98 14 : return r;
99 : }
100 :
101 16 : uint64_t system_tasks_max(void) {
102 :
103 16 : uint64_t a = TASKS_MAX, b = TASKS_MAX;
104 32 : _cleanup_free_ char *root = NULL;
105 : int r;
106 :
107 : /* Determine the maximum number of tasks that may run on this system. We check three sources to determine this
108 : * limit:
109 : *
110 : * a) the maximum tasks value the kernel allows on this architecture
111 : * b) the cgroups pids_max attribute for the system
112 : * c) the kernel's configured maximum PID value
113 : *
114 : * And then pick the smallest of the three */
115 :
116 16 : r = procfs_tasks_get_limit(&a);
117 16 : if (r < 0)
118 0 : log_debug_errno(r, "Failed to read maximum number of tasks from /proc, ignoring: %m");
119 :
120 16 : r = cg_get_root_path(&root);
121 16 : if (r < 0)
122 0 : log_debug_errno(r, "Failed to determine cgroup root path, ignoring: %m");
123 : else {
124 16 : _cleanup_free_ char *value = NULL;
125 :
126 16 : r = cg_get_attribute("pids", root, "pids.max", &value);
127 16 : if (r < 0)
128 16 : log_debug_errno(r, "Failed to read pids.max attribute of cgroup root, ignoring: %m");
129 0 : else if (!streq(value, "max")) {
130 0 : r = safe_atou64(value, &b);
131 0 : if (r < 0)
132 0 : log_debug_errno(r, "Failed to parse pids.max attribute of cgroup root, ignoring: %m");
133 : }
134 : }
135 :
136 16 : return MIN3(TASKS_MAX,
137 : a <= 0 ? TASKS_MAX : a,
138 : b <= 0 ? TASKS_MAX : b);
139 : }
140 :
141 14 : uint64_t system_tasks_max_scale(uint64_t v, uint64_t max) {
142 : uint64_t t, m;
143 :
144 14 : assert(max > 0);
145 :
146 : /* Multiply the system's task value by the fraction v/max. Hence, if max==100 this calculates percentages
147 : * relative to the system's maximum number of tasks. Returns UINT64_MAX on overflow. */
148 :
149 14 : t = system_tasks_max();
150 14 : assert(t > 0);
151 :
152 14 : m = t * v;
153 14 : if (m / t != v) /* overflow? */
154 1 : return UINT64_MAX;
155 :
156 13 : return m / max;
157 : }
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