1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
|
/* SPDX-License-Identifier: LGPL-2.1+ */
#include "alloc-util.h"
#include "cgroup-util.h"
#include "limits-util.h"
#include "memory-util.h"
#include "parse-util.h"
#include "process-util.h"
#include "procfs-util.h"
#include "string-util.h"
uint64_t physical_memory(void) {
_cleanup_free_ char *root = NULL, *value = NULL;
uint64_t mem, lim;
size_t ps;
long sc;
int r;
/* We return this as uint64_t in case we are running as 32bit process on a 64bit kernel with huge amounts of
* memory.
*
* In order to support containers nicely that have a configured memory limit we'll take the minimum of the
* physically reported amount of memory and the limit configured for the root cgroup, if there is any. */
sc = sysconf(_SC_PHYS_PAGES);
assert(sc > 0);
ps = page_size();
mem = (uint64_t) sc * (uint64_t) ps;
r = cg_get_root_path(&root);
if (r < 0) {
log_debug_errno(r, "Failed to determine root cgroup, ignoring cgroup memory limit: %m");
return mem;
}
r = cg_all_unified();
if (r < 0) {
log_debug_errno(r, "Failed to determine root unified mode, ignoring cgroup memory limit: %m");
return mem;
}
if (r > 0) {
r = cg_get_attribute("memory", root, "memory.max", &value);
if (r == -ENOENT) /* Field does not exist on the system's top-level cgroup, hence don't
* complain. (Note that it might exist on our own root though, if we live
* in a cgroup namespace, hence check anyway instead of not even
* trying.) */
return mem;
if (r < 0) {
log_debug_errno(r, "Failed to read memory.max cgroup attribute, ignoring cgroup memory limit: %m");
return mem;
}
if (streq(value, "max"))
return mem;
} else {
r = cg_get_attribute("memory", root, "memory.limit_in_bytes", &value);
if (r < 0) {
log_debug_errno(r, "Failed to read memory.limit_in_bytes cgroup attribute, ignoring cgroup memory limit: %m");
return mem;
}
}
r = safe_atou64(value, &lim);
if (r < 0) {
log_debug_errno(r, "Failed to parse cgroup memory limit '%s', ignoring: %m", value);
return mem;
}
if (lim == UINT64_MAX)
return mem;
/* Make sure the limit is a multiple of our own page size */
lim /= ps;
lim *= ps;
return MIN(mem, lim);
}
uint64_t physical_memory_scale(uint64_t v, uint64_t max) {
uint64_t p, m, ps, r;
assert(max > 0);
/* Returns the physical memory size, multiplied by v divided by max. Returns UINT64_MAX on overflow. On success
* the result is a multiple of the page size (rounds down). */
ps = page_size();
assert(ps > 0);
p = physical_memory() / ps;
assert(p > 0);
m = p * v;
if (m / p != v)
return UINT64_MAX;
m /= max;
r = m * ps;
if (r / ps != m)
return UINT64_MAX;
return r;
}
uint64_t system_tasks_max(void) {
uint64_t a = TASKS_MAX, b = TASKS_MAX;
_cleanup_free_ char *root = NULL;
int r;
/* Determine the maximum number of tasks that may run on this system. We check three sources to determine this
* limit:
*
* a) the maximum tasks value the kernel allows on this architecture
* b) the cgroups pids_max attribute for the system
* c) the kernel's configured maximum PID value
*
* And then pick the smallest of the three */
r = procfs_tasks_get_limit(&a);
if (r < 0)
log_debug_errno(r, "Failed to read maximum number of tasks from /proc, ignoring: %m");
r = cg_get_root_path(&root);
if (r < 0)
log_debug_errno(r, "Failed to determine cgroup root path, ignoring: %m");
else {
r = cg_get_attribute_as_uint64("pids", root, "pids.max", &b);
if (r < 0)
log_debug_errno(r, "Failed to read pids.max attribute of cgroup root, ignoring: %m");
}
return MIN3(TASKS_MAX,
a <= 0 ? TASKS_MAX : a,
b <= 0 ? TASKS_MAX : b);
}
uint64_t system_tasks_max_scale(uint64_t v, uint64_t max) {
uint64_t t, m;
assert(max > 0);
/* Multiply the system's task value by the fraction v/max. Hence, if max==100 this calculates percentages
* relative to the system's maximum number of tasks. Returns UINT64_MAX on overflow. */
t = system_tasks_max();
assert(t > 0);
m = t * v;
if (m / t != v) /* overflow? */
return UINT64_MAX;
return m / max;
}
|
