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Commit | Line | Data |
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023695d9 SE |
1 | #include "util.h" |
2 | #include "../perf.h" | |
4b6ab94e | 3 | #include <subcmd/parse-options.h> |
023695d9 SE |
4 | #include "evsel.h" |
5 | #include "cgroup.h" | |
023695d9 | 6 | #include "evlist.h" |
aa8cc2f6 | 7 | #include <linux/stringify.h> |
023695d9 SE |
8 | |
9 | int nr_cgroups; | |
10 | ||
11 | static int | |
12 | cgroupfs_find_mountpoint(char *buf, size_t maxlen) | |
13 | { | |
14 | FILE *fp; | |
c168fbfb | 15 | char mountpoint[PATH_MAX + 1], tokens[PATH_MAX + 1], type[PATH_MAX + 1]; |
968ebff1 | 16 | char path_v1[PATH_MAX + 1], path_v2[PATH_MAX + 2], *path; |
621d2656 | 17 | char *token, *saved_ptr = NULL; |
023695d9 SE |
18 | |
19 | fp = fopen("/proc/mounts", "r"); | |
20 | if (!fp) | |
21 | return -1; | |
22 | ||
23 | /* | |
24 | * in order to handle split hierarchy, we need to scan /proc/mounts | |
25 | * and inspect every cgroupfs mount point to find one that has | |
26 | * perf_event subsystem | |
27 | */ | |
968ebff1 TH |
28 | path_v1[0] = '\0'; |
29 | path_v2[0] = '\0'; | |
30 | ||
aa8cc2f6 ACM |
31 | while (fscanf(fp, "%*s %"__stringify(PATH_MAX)"s %"__stringify(PATH_MAX)"s %" |
32 | __stringify(PATH_MAX)"s %*d %*d\n", | |
023695d9 SE |
33 | mountpoint, type, tokens) == 3) { |
34 | ||
968ebff1 | 35 | if (!path_v1[0] && !strcmp(type, "cgroup")) { |
023695d9 SE |
36 | |
37 | token = strtok_r(tokens, ",", &saved_ptr); | |
38 | ||
39 | while (token != NULL) { | |
40 | if (!strcmp(token, "perf_event")) { | |
968ebff1 | 41 | strcpy(path_v1, mountpoint); |
023695d9 SE |
42 | break; |
43 | } | |
44 | token = strtok_r(NULL, ",", &saved_ptr); | |
45 | } | |
46 | } | |
968ebff1 TH |
47 | |
48 | if (!path_v2[0] && !strcmp(type, "cgroup2")) | |
49 | strcpy(path_v2, mountpoint); | |
50 | ||
51 | if (path_v1[0] && path_v2[0]) | |
023695d9 SE |
52 | break; |
53 | } | |
54 | fclose(fp); | |
968ebff1 TH |
55 | |
56 | if (path_v1[0]) | |
57 | path = path_v1; | |
58 | else if (path_v2[0]) | |
59 | path = path_v2; | |
60 | else | |
023695d9 SE |
61 | return -1; |
62 | ||
968ebff1 TH |
63 | if (strlen(path) < maxlen) { |
64 | strcpy(buf, path); | |
023695d9 SE |
65 | return 0; |
66 | } | |
67 | return -1; | |
68 | } | |
69 | ||
70 | static int open_cgroup(char *name) | |
71 | { | |
c168fbfb ACM |
72 | char path[PATH_MAX + 1]; |
73 | char mnt[PATH_MAX + 1]; | |
023695d9 SE |
74 | int fd; |
75 | ||
76 | ||
c168fbfb | 77 | if (cgroupfs_find_mountpoint(mnt, PATH_MAX + 1)) |
023695d9 SE |
78 | return -1; |
79 | ||
c168fbfb | 80 | snprintf(path, PATH_MAX, "%s/%s", mnt, name); |
023695d9 SE |
81 | |
82 | fd = open(path, O_RDONLY); | |
83 | if (fd == -1) | |
84 | fprintf(stderr, "no access to cgroup %s\n", path); | |
85 | ||
86 | return fd; | |
87 | } | |
88 | ||
89 | static int add_cgroup(struct perf_evlist *evlist, char *str) | |
90 | { | |
91 | struct perf_evsel *counter; | |
92 | struct cgroup_sel *cgrp = NULL; | |
93 | int n; | |
94 | /* | |
95 | * check if cgrp is already defined, if so we reuse it | |
96 | */ | |
e5cadb93 | 97 | evlist__for_each_entry(evlist, counter) { |
023695d9 SE |
98 | cgrp = counter->cgrp; |
99 | if (!cgrp) | |
100 | continue; | |
101 | if (!strcmp(cgrp->name, str)) | |
102 | break; | |
103 | ||
104 | cgrp = NULL; | |
105 | } | |
106 | ||
107 | if (!cgrp) { | |
108 | cgrp = zalloc(sizeof(*cgrp)); | |
109 | if (!cgrp) | |
110 | return -1; | |
111 | ||
112 | cgrp->name = str; | |
113 | ||
114 | cgrp->fd = open_cgroup(str); | |
115 | if (cgrp->fd == -1) { | |
116 | free(cgrp); | |
117 | return -1; | |
118 | } | |
119 | } | |
120 | ||
121 | /* | |
122 | * find corresponding event | |
123 | * if add cgroup N, then need to find event N | |
124 | */ | |
125 | n = 0; | |
e5cadb93 | 126 | evlist__for_each_entry(evlist, counter) { |
023695d9 SE |
127 | if (n == nr_cgroups) |
128 | goto found; | |
129 | n++; | |
130 | } | |
79c5fe6d | 131 | if (refcount_read(&cgrp->refcnt) == 0) |
023695d9 SE |
132 | free(cgrp); |
133 | ||
134 | return -1; | |
135 | found: | |
79c5fe6d | 136 | refcount_inc(&cgrp->refcnt); |
023695d9 SE |
137 | counter->cgrp = cgrp; |
138 | return 0; | |
139 | } | |
140 | ||
141 | void close_cgroup(struct cgroup_sel *cgrp) | |
142 | { | |
79c5fe6d | 143 | if (cgrp && refcount_dec_and_test(&cgrp->refcnt)) { |
023695d9 | 144 | close(cgrp->fd); |
74cf249d | 145 | zfree(&cgrp->name); |
023695d9 SE |
146 | free(cgrp); |
147 | } | |
148 | } | |
149 | ||
1d037ca1 IT |
150 | int parse_cgroups(const struct option *opt __maybe_unused, const char *str, |
151 | int unset __maybe_unused) | |
023695d9 SE |
152 | { |
153 | struct perf_evlist *evlist = *(struct perf_evlist **)opt->value; | |
154 | const char *p, *e, *eos = str + strlen(str); | |
155 | char *s; | |
156 | int ret; | |
157 | ||
158 | if (list_empty(&evlist->entries)) { | |
159 | fprintf(stderr, "must define events before cgroups\n"); | |
160 | return -1; | |
161 | } | |
162 | ||
163 | for (;;) { | |
164 | p = strchr(str, ','); | |
165 | e = p ? p : eos; | |
166 | ||
167 | /* allow empty cgroups, i.e., skip */ | |
168 | if (e - str) { | |
169 | /* termination added */ | |
170 | s = strndup(str, e - str); | |
171 | if (!s) | |
172 | return -1; | |
173 | ret = add_cgroup(evlist, s); | |
174 | if (ret) { | |
175 | free(s); | |
176 | return -1; | |
177 | } | |
178 | } | |
179 | /* nr_cgroups is increased een for empty cgroups */ | |
180 | nr_cgroups++; | |
181 | if (!p) | |
182 | break; | |
183 | str = p+1; | |
184 | } | |
185 | return 0; | |
186 | } |