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Source at commit ec7cab4cbb721bff91ec924ec691efd8daf36579 created 12 years 8 months ago. By Maarten ter Huurne, MIPS: JZ4740: A320: Updated quickstart documentation. | |
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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 "debugfs.h" /* MAX_PATH, STR() */ |
7 | #include "evlist.h" |
8 | |
9 | int nr_cgroups; |
10 | |
11 | static int |
12 | cgroupfs_find_mountpoint(char *buf, size_t maxlen) |
13 | { |
14 | FILE *fp; |
15 | char mountpoint[MAX_PATH+1], tokens[MAX_PATH+1], type[MAX_PATH+1]; |
16 | char *token, *saved_ptr = NULL; |
17 | int found = 0; |
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 | */ |
28 | while (fscanf(fp, "%*s %"STR(MAX_PATH)"s %"STR(MAX_PATH)"s %" |
29 | STR(MAX_PATH)"s %*d %*d\n", |
30 | mountpoint, type, tokens) == 3) { |
31 | |
32 | if (!strcmp(type, "cgroup")) { |
33 | |
34 | token = strtok_r(tokens, ",", &saved_ptr); |
35 | |
36 | while (token != NULL) { |
37 | if (!strcmp(token, "perf_event")) { |
38 | found = 1; |
39 | break; |
40 | } |
41 | token = strtok_r(NULL, ",", &saved_ptr); |
42 | } |
43 | } |
44 | if (found) |
45 | break; |
46 | } |
47 | fclose(fp); |
48 | if (!found) |
49 | return -1; |
50 | |
51 | if (strlen(mountpoint) < maxlen) { |
52 | strcpy(buf, mountpoint); |
53 | return 0; |
54 | } |
55 | return -1; |
56 | } |
57 | |
58 | static int open_cgroup(char *name) |
59 | { |
60 | char path[MAX_PATH+1]; |
61 | char mnt[MAX_PATH+1]; |
62 | int fd; |
63 | |
64 | |
65 | if (cgroupfs_find_mountpoint(mnt, MAX_PATH+1)) |
66 | return -1; |
67 | |
68 | snprintf(path, MAX_PATH, "%s/%s", mnt, name); |
69 | |
70 | fd = open(path, O_RDONLY); |
71 | if (fd == -1) |
72 | fprintf(stderr, "no access to cgroup %s\n", path); |
73 | |
74 | return fd; |
75 | } |
76 | |
77 | static int add_cgroup(struct perf_evlist *evlist, char *str) |
78 | { |
79 | struct perf_evsel *counter; |
80 | struct cgroup_sel *cgrp = NULL; |
81 | int n; |
82 | /* |
83 | * check if cgrp is already defined, if so we reuse it |
84 | */ |
85 | list_for_each_entry(counter, &evlist->entries, node) { |
86 | cgrp = counter->cgrp; |
87 | if (!cgrp) |
88 | continue; |
89 | if (!strcmp(cgrp->name, str)) |
90 | break; |
91 | |
92 | cgrp = NULL; |
93 | } |
94 | |
95 | if (!cgrp) { |
96 | cgrp = zalloc(sizeof(*cgrp)); |
97 | if (!cgrp) |
98 | return -1; |
99 | |
100 | cgrp->name = str; |
101 | |
102 | cgrp->fd = open_cgroup(str); |
103 | if (cgrp->fd == -1) { |
104 | free(cgrp); |
105 | return -1; |
106 | } |
107 | } |
108 | |
109 | /* |
110 | * find corresponding event |
111 | * if add cgroup N, then need to find event N |
112 | */ |
113 | n = 0; |
114 | list_for_each_entry(counter, &evlist->entries, node) { |
115 | if (n == nr_cgroups) |
116 | goto found; |
117 | n++; |
118 | } |
119 | if (cgrp->refcnt == 0) |
120 | free(cgrp); |
121 | |
122 | return -1; |
123 | found: |
124 | cgrp->refcnt++; |
125 | counter->cgrp = cgrp; |
126 | return 0; |
127 | } |
128 | |
129 | void close_cgroup(struct cgroup_sel *cgrp) |
130 | { |
131 | if (!cgrp) |
132 | return; |
133 | |
134 | /* XXX: not reentrant */ |
135 | if (--cgrp->refcnt == 0) { |
136 | close(cgrp->fd); |
137 | free(cgrp->name); |
138 | free(cgrp); |
139 | } |
140 | } |
141 | |
142 | int parse_cgroups(const struct option *opt __used, const char *str, |
143 | int unset __used) |
144 | { |
145 | struct perf_evlist *evlist = *(struct perf_evlist **)opt->value; |
146 | const char *p, *e, *eos = str + strlen(str); |
147 | char *s; |
148 | int ret; |
149 | |
150 | if (list_empty(&evlist->entries)) { |
151 | fprintf(stderr, "must define events before cgroups\n"); |
152 | return -1; |
153 | } |
154 | |
155 | for (;;) { |
156 | p = strchr(str, ','); |
157 | e = p ? p : eos; |
158 | |
159 | /* allow empty cgroups, i.e., skip */ |
160 | if (e - str) { |
161 | /* termination added */ |
162 | s = strndup(str, e - str); |
163 | if (!s) |
164 | return -1; |
165 | ret = add_cgroup(evlist, s); |
166 | if (ret) { |
167 | free(s); |
168 | return -1; |
169 | } |
170 | } |
171 | /* nr_cgroups is increased een for empty cgroups */ |
172 | nr_cgroups++; |
173 | if (!p) |
174 | break; |
175 | str = p+1; |
176 | } |
177 | return 0; |
178 | } |
179 |
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