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1 | #include "util.h" |
2 | #include "../perf.h" |
3 | #include "parse-options.h" |
4 | #include "evsel.h" |
5 | #include "cgroup.h" |
6 | #include "evlist.h" |
7 | |
8 | int nr_cgroups; |
9 | |
10 | static int |
11 | cgroupfs_find_mountpoint(char *buf, size_t maxlen) |
12 | { |
13 | FILE *fp; |
14 | char mountpoint[PATH_MAX + 1], tokens[PATH_MAX + 1], type[PATH_MAX + 1]; |
15 | char *token, *saved_ptr = NULL; |
16 | int found = 0; |
17 | |
18 | fp = fopen("/proc/mounts", "r"); |
19 | if (!fp) |
20 | return -1; |
21 | |
22 | /* |
23 | * in order to handle split hierarchy, we need to scan /proc/mounts |
24 | * and inspect every cgroupfs mount point to find one that has |
25 | * perf_event subsystem |
26 | */ |
27 | while (fscanf(fp, "%*s %"STR(PATH_MAX)"s %"STR(PATH_MAX)"s %" |
28 | STR(PATH_MAX)"s %*d %*d\n", |
29 | mountpoint, type, tokens) == 3) { |
30 | |
31 | if (!strcmp(type, "cgroup")) { |
32 | |
33 | token = strtok_r(tokens, ",", &saved_ptr); |
34 | |
35 | while (token != NULL) { |
36 | if (!strcmp(token, "perf_event")) { |
37 | found = 1; |
38 | break; |
39 | } |
40 | token = strtok_r(NULL, ",", &saved_ptr); |
41 | } |
42 | } |
43 | if (found) |
44 | break; |
45 | } |
46 | fclose(fp); |
47 | if (!found) |
48 | return -1; |
49 | |
50 | if (strlen(mountpoint) < maxlen) { |
51 | strcpy(buf, mountpoint); |
52 | return 0; |
53 | } |
54 | return -1; |
55 | } |
56 | |
57 | static int open_cgroup(char *name) |
58 | { |
59 | char path[PATH_MAX + 1]; |
60 | char mnt[PATH_MAX + 1]; |
61 | int fd; |
62 | |
63 | |
64 | if (cgroupfs_find_mountpoint(mnt, PATH_MAX + 1)) |
65 | return -1; |
66 | |
67 | snprintf(path, PATH_MAX, "%s/%s", mnt, name); |
68 | |
69 | fd = open(path, O_RDONLY); |
70 | if (fd == -1) |
71 | fprintf(stderr, "no access to cgroup %s\n", path); |
72 | |
73 | return fd; |
74 | } |
75 | |
76 | static int add_cgroup(struct perf_evlist *evlist, char *str) |
77 | { |
78 | struct perf_evsel *counter; |
79 | struct cgroup_sel *cgrp = NULL; |
80 | int n; |
81 | /* |
82 | * check if cgrp is already defined, if so we reuse it |
83 | */ |
84 | list_for_each_entry(counter, &evlist->entries, node) { |
85 | cgrp = counter->cgrp; |
86 | if (!cgrp) |
87 | continue; |
88 | if (!strcmp(cgrp->name, str)) |
89 | break; |
90 | |
91 | cgrp = NULL; |
92 | } |
93 | |
94 | if (!cgrp) { |
95 | cgrp = zalloc(sizeof(*cgrp)); |
96 | if (!cgrp) |
97 | return -1; |
98 | |
99 | cgrp->name = str; |
100 | |
101 | cgrp->fd = open_cgroup(str); |
102 | if (cgrp->fd == -1) { |
103 | free(cgrp); |
104 | return -1; |
105 | } |
106 | } |
107 | |
108 | /* |
109 | * find corresponding event |
110 | * if add cgroup N, then need to find event N |
111 | */ |
112 | n = 0; |
113 | list_for_each_entry(counter, &evlist->entries, node) { |
114 | if (n == nr_cgroups) |
115 | goto found; |
116 | n++; |
117 | } |
118 | if (cgrp->refcnt == 0) |
119 | free(cgrp); |
120 | |
121 | return -1; |
122 | found: |
123 | cgrp->refcnt++; |
124 | counter->cgrp = cgrp; |
125 | return 0; |
126 | } |
127 | |
128 | void close_cgroup(struct cgroup_sel *cgrp) |
129 | { |
130 | if (!cgrp) |
131 | return; |
132 | |
133 | /* XXX: not reentrant */ |
134 | if (--cgrp->refcnt == 0) { |
135 | close(cgrp->fd); |
136 | free(cgrp->name); |
137 | free(cgrp); |
138 | } |
139 | } |
140 | |
141 | int parse_cgroups(const struct option *opt __used, const char *str, |
142 | int unset __used) |
143 | { |
144 | struct perf_evlist *evlist = *(struct perf_evlist **)opt->value; |
145 | const char *p, *e, *eos = str + strlen(str); |
146 | char *s; |
147 | int ret; |
148 | |
149 | if (list_empty(&evlist->entries)) { |
150 | fprintf(stderr, "must define events before cgroups\n"); |
151 | return -1; |
152 | } |
153 | |
154 | for (;;) { |
155 | p = strchr(str, ','); |
156 | e = p ? p : eos; |
157 | |
158 | /* allow empty cgroups, i.e., skip */ |
159 | if (e - str) { |
160 | /* termination added */ |
161 | s = strndup(str, e - str); |
162 | if (!s) |
163 | return -1; |
164 | ret = add_cgroup(evlist, s); |
165 | if (ret) { |
166 | free(s); |
167 | return -1; |
168 | } |
169 | } |
170 | /* nr_cgroups is increased een for empty cgroups */ |
171 | nr_cgroups++; |
172 | if (!p) |
173 | break; |
174 | str = p+1; |
175 | } |
176 | return 0; |
177 | } |
178 |
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