Commit | Line | Data |
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4e3c1b9b MD |
1 | /* |
2 | * ltt-events.c | |
3 | * | |
4 | * Copyright 2010 (c) - Mathieu Desnoyers <mathieu.desnoyers@efficios.com> | |
5 | * | |
6 | * Holds LTTng per-session event registry. | |
7 | */ | |
8 | ||
9 | #include <linux/module.h> | |
10 | #include "ltt-events.h" | |
11 | ||
12 | static LIST_HEAD(sessions); | |
13 | static DEFINE_MUTEX(sessions_mutex); | |
14 | static struct kmem_cache *event_cache; | |
15 | ||
abcca994 MD |
16 | static void synchronize_trace(void) |
17 | { | |
18 | synchronize_sched(); | |
19 | #ifdef CONFIG_PREEMPT_RT | |
20 | synchronize_rcu(); | |
21 | #endif | |
22 | } | |
23 | ||
baf20995 | 24 | struct ltt_session *ltt_session_create(void) |
4e3c1b9b MD |
25 | { |
26 | struct ltt_session *session; | |
27 | ||
28 | mutex_lock(&sessions_mutex); | |
baf20995 | 29 | session = kmalloc(sizeof(struct ltt_session)); |
4e3c1b9b MD |
30 | if (!session) |
31 | return NULL; | |
4e3c1b9b MD |
32 | INIT_LIST_HEAD(&session->chan); |
33 | list_add(&session->list, &sessions); | |
34 | mutex_unlock(&sessions_mutex); | |
35 | return session; | |
36 | ||
37 | exist: | |
38 | mutex_unlock(&sessions_mutex); | |
39 | return NULL; | |
40 | } | |
41 | ||
42 | int ltt_session_destroy(struct ltt_session *session) | |
43 | { | |
44 | struct ltt_channel *chan, *tmpchan; | |
45 | struct ltt_event *event, *tmpevent; | |
46 | ||
47 | mutex_lock(&sessions_mutex); | |
abcca994 MD |
48 | session->active = 0; |
49 | synchronize_trace(); /* Wait for in-flight events to complete */ | |
4e3c1b9b MD |
50 | list_for_each_entry_safe(event, tmpevent, &session->events, list) |
51 | _ltt_event_destroy(event); | |
52 | list_for_each_entry_safe(chan, tmpchan, &session->chan, list) | |
53 | _ltt_channel_destroy(chan); | |
54 | list_del(&session->list); | |
55 | mutex_unlock(&sessions_mutex); | |
56 | kfree(session); | |
57 | } | |
58 | ||
baf20995 | 59 | struct ltt_channel *ltt_channel_create(struct ltt_session *session, |
4e3c1b9b MD |
60 | int overwrite, void *buf_addr, |
61 | size_t subbuf_size, size_t num_subbuf, | |
62 | unsigned int switch_timer_interval, | |
63 | unsigned int read_timer_interval) | |
64 | { | |
65 | struct ltt_channel *chan; | |
66 | ||
67 | mutex_lock(&sessions_mutex); | |
e5382b6d MD |
68 | if (session->active) |
69 | goto active; /* Refuse to add channel to active session */ | |
baf20995 | 70 | chan = kmalloc(sizeof(struct ltt_channel), GFP_KERNEL); |
4e3c1b9b MD |
71 | if (!chan) |
72 | return NULL; | |
4e3c1b9b | 73 | chan->session = session; |
653fe716 | 74 | init_waitqueue_head(&chan->notify_wait); |
4e3c1b9b MD |
75 | |
76 | /* TODO: create rb channel */ | |
77 | list_add(&chan->list, &session->chan); | |
78 | mutex_unlock(&sessions_mutex); | |
79 | return chan; | |
80 | ||
81 | exist: | |
e5382b6d | 82 | active: |
4e3c1b9b MD |
83 | mutex_unlock(&sessions_mutex); |
84 | return NULL; | |
85 | } | |
86 | ||
87 | /* | |
88 | * Only used internally at session destruction. | |
89 | */ | |
90 | int _ltt_channel_destroy(struct ltt_channel *chan) | |
91 | { | |
abcca994 | 92 | /* TODO: destroy rb channel */ |
4e3c1b9b MD |
93 | list_del(&chan->list); |
94 | kfree(chan); | |
95 | } | |
96 | ||
e5382b6d MD |
97 | /* |
98 | * Supports event creation while tracing session is active. | |
99 | */ | |
4e3c1b9b | 100 | struct ltt_event *ltt_event_create(struct ltt_channel *chan, char *name, |
baf20995 MD |
101 | enum instrum_type itype, |
102 | void *probe, void *filter) | |
4e3c1b9b MD |
103 | { |
104 | struct ltt_event *event; | |
3d084699 | 105 | int ret; |
4e3c1b9b MD |
106 | |
107 | mutex_lock(&sessions_mutex); | |
e5382b6d MD |
108 | if (chan->free_event_id == -1UL) |
109 | goto full; | |
4e3c1b9b MD |
110 | /* |
111 | * This is O(n^2) (for each event loop called at event creation). | |
112 | * Might require a hash if we have lots of events. | |
113 | */ | |
114 | list_for_each_entry(event, &chan->session->events, list) | |
115 | if (!strcmp(event->name, name)) | |
116 | goto exist; | |
117 | event = kmem_cache_zalloc(events_cache, GFP_KERNEL); | |
118 | if (!event) | |
119 | goto cache_error; | |
120 | event->name = kmalloc(strlen(name) + 1, GFP_KERNEL); | |
121 | if (!event->name) | |
122 | goto error; | |
123 | strcpy(event->name, name); | |
124 | event->chan = chan; | |
baf20995 | 125 | event->probe = probe; |
4e3c1b9b | 126 | event->filter = filter; |
e5382b6d | 127 | event->id = chan->free_event_id++; |
baf20995 | 128 | event->itype = itype; |
4e3c1b9b | 129 | mutex_unlock(&sessions_mutex); |
e5382b6d MD |
130 | /* Populate ltt_event structure before tracepoint registration. */ |
131 | smp_wmb(); | |
baf20995 MD |
132 | switch (itype) { |
133 | case INSTRUM_TRACEPOINTS: | |
134 | ret = tracepoint_probe_register(name, probe, event); | |
135 | break; | |
136 | default: | |
137 | WARN_ON_ONCE(1); | |
138 | } | |
4e3c1b9b MD |
139 | return event; |
140 | ||
141 | error: | |
142 | kmem_cache_free(event); | |
143 | cache_error: | |
144 | exist: | |
e5382b6d | 145 | full: |
4e3c1b9b MD |
146 | mutex_unlock(&sessions_mutex); |
147 | return NULL; | |
148 | } | |
149 | ||
150 | /* | |
151 | * Only used internally at session destruction. | |
152 | */ | |
153 | int _ltt_event_destroy(struct ltt_event *event) | |
154 | { | |
baf20995 MD |
155 | switch (event->itype) { |
156 | case INSTRUM_TRACEPOINTS: | |
157 | ret = tracepoint_probe_unregister(name, event->probe, event); | |
158 | break; | |
159 | default: | |
160 | WARN_ON_ONCE(1); | |
161 | } | |
4e3c1b9b MD |
162 | kfree(event->name); |
163 | kmem_cache_free(event); | |
164 | } | |
165 | ||
166 | static int __init ltt_events_init(void) | |
167 | { | |
168 | int ret; | |
169 | ||
170 | events_cache = KMEM_CACHE(ltt_event, 0); | |
171 | if (!events_cache) | |
172 | return -ENOMEM; | |
92e94819 MD |
173 | |
174 | /* TODO: show ABI to userspace */ | |
175 | ||
4e3c1b9b MD |
176 | return 0; |
177 | } | |
178 | ||
179 | static void __exit ltt_events_exit(void) | |
180 | { | |
92e94819 MD |
181 | struct ltt_session *session, *tmpsession; |
182 | ||
183 | /* TODO: hide ABI from userspace, wait for callers to release refs. */ | |
184 | ||
185 | list_for_each_entry_safe(session, tmpsession, &sessions, list) | |
186 | ltt_session_destroy(session); | |
4e3c1b9b MD |
187 | kmem_cache_destroy(events_cache); |
188 | } | |
92e94819 MD |
189 | |
190 | MODULE_LICENSE("GPL and additional rights"); | |
191 | MODULE_AUTHOR("Mathieu Desnoyers <mathieu.desnoyers@efficios.com>"); | |
192 | MODULE_DESCRIPTION("LTTng Events"); |