2 * lttng-ring-buffer-client.h
4 * LTTng lib ring buffer client template.
6 * Copyright (C) 2010-2012 Mathieu Desnoyers <mathieu.desnoyers@efficios.com>
8 * This library is free software; you can redistribute it and/or
9 * modify it under the terms of the GNU Lesser General Public
10 * License as published by the Free Software Foundation; only
11 * version 2.1 of the License.
13 * This library is distributed in the hope that it will be useful,
14 * but WITHOUT ANY WARRANTY; without even the implied warranty of
15 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
16 * Lesser General Public License for more details.
18 * You should have received a copy of the GNU Lesser General Public
19 * License along with this library; if not, write to the Free Software
20 * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
23 #include <linux/module.h>
24 #include <linux/types.h>
25 #include "wrapper/vmalloc.h" /* for wrapper_vmalloc_sync_all() */
26 #include "lttng-events.h"
27 #include "lttng-tracer.h"
29 struct metadata_packet_header {
30 uint32_t magic; /* 0x75D11D57 */
31 uint8_t uuid[16]; /* Unique Universal Identifier */
32 uint32_t checksum; /* 0 if unused */
33 uint32_t content_size; /* in bits */
34 uint32_t packet_size; /* in bits */
35 uint8_t compression_scheme; /* 0 if unused */
36 uint8_t encryption_scheme; /* 0 if unused */
37 uint8_t checksum_scheme; /* 0 if unused */
38 uint8_t major; /* CTF spec major version number */
39 uint8_t minor; /* CTF spec minor version number */
40 uint8_t header_end[0];
43 struct metadata_record_header {
44 uint8_t header_end[0]; /* End of header */
47 static const struct lib_ring_buffer_config client_config;
50 u64 lib_ring_buffer_clock_read(struct channel *chan)
56 unsigned char record_header_size(const struct lib_ring_buffer_config *config,
57 struct channel *chan, size_t offset,
58 size_t *pre_header_padding,
59 struct lib_ring_buffer_ctx *ctx)
64 #include "wrapper/ringbuffer/api.h"
66 static u64 client_ring_buffer_clock_read(struct channel *chan)
72 size_t client_record_header_size(const struct lib_ring_buffer_config *config,
73 struct channel *chan, size_t offset,
74 size_t *pre_header_padding,
75 struct lib_ring_buffer_ctx *ctx)
81 * client_packet_header_size - called on buffer-switch to a new sub-buffer
83 * Return header size without padding after the structure. Don't use packed
84 * structure because gcc generates inefficient code on some architectures
87 static size_t client_packet_header_size(void)
89 return offsetof(struct metadata_packet_header, header_end);
92 static void client_buffer_begin(struct lib_ring_buffer *buf, u64 tsc,
93 unsigned int subbuf_idx)
95 struct channel *chan = buf->backend.chan;
96 struct metadata_packet_header *header =
97 (struct metadata_packet_header *)
98 lib_ring_buffer_offset_address(&buf->backend,
99 subbuf_idx * chan->backend.subbuf_size);
100 struct lttng_channel *lttng_chan = channel_get_private(chan);
101 struct lttng_session *session = lttng_chan->session;
103 header->magic = TSDL_MAGIC_NUMBER;
104 memcpy(header->uuid, session->uuid.b, sizeof(session->uuid));
105 header->checksum = 0; /* 0 if unused */
106 header->content_size = 0xFFFFFFFF; /* in bits, for debugging */
107 header->packet_size = 0xFFFFFFFF; /* in bits, for debugging */
108 header->compression_scheme = 0; /* 0 if unused */
109 header->encryption_scheme = 0; /* 0 if unused */
110 header->checksum_scheme = 0; /* 0 if unused */
111 header->major = CTF_SPEC_MAJOR;
112 header->minor = CTF_SPEC_MINOR;
116 * offset is assumed to never be 0 here : never deliver a completely empty
117 * subbuffer. data_size is between 1 and subbuf_size.
119 static void client_buffer_end(struct lib_ring_buffer *buf, u64 tsc,
120 unsigned int subbuf_idx, unsigned long data_size)
122 struct channel *chan = buf->backend.chan;
123 struct metadata_packet_header *header =
124 (struct metadata_packet_header *)
125 lib_ring_buffer_offset_address(&buf->backend,
126 subbuf_idx * chan->backend.subbuf_size);
127 unsigned long records_lost = 0;
129 header->content_size = data_size * CHAR_BIT; /* in bits */
130 header->packet_size = PAGE_ALIGN(data_size) * CHAR_BIT; /* in bits */
132 * We do not care about the records lost count, because the metadata
133 * channel waits and retry.
135 (void) lib_ring_buffer_get_records_lost_full(&client_config, buf);
136 records_lost += lib_ring_buffer_get_records_lost_wrap(&client_config, buf);
137 records_lost += lib_ring_buffer_get_records_lost_big(&client_config, buf);
138 WARN_ON_ONCE(records_lost != 0);
141 static int client_buffer_create(struct lib_ring_buffer *buf, void *priv,
142 int cpu, const char *name)
147 static void client_buffer_finalize(struct lib_ring_buffer *buf, void *priv, int cpu)
151 static const struct lib_ring_buffer_config client_config = {
152 .cb.ring_buffer_clock_read = client_ring_buffer_clock_read,
153 .cb.record_header_size = client_record_header_size,
154 .cb.subbuffer_header_size = client_packet_header_size,
155 .cb.buffer_begin = client_buffer_begin,
156 .cb.buffer_end = client_buffer_end,
157 .cb.buffer_create = client_buffer_create,
158 .cb.buffer_finalize = client_buffer_finalize,
161 .alloc = RING_BUFFER_ALLOC_GLOBAL,
162 .sync = RING_BUFFER_SYNC_GLOBAL,
163 .mode = RING_BUFFER_MODE_TEMPLATE,
164 .backend = RING_BUFFER_PAGE,
165 .output = RING_BUFFER_OUTPUT_TEMPLATE,
166 .oops = RING_BUFFER_OOPS_CONSISTENCY,
167 .ipi = RING_BUFFER_IPI_BARRIER,
168 .wakeup = RING_BUFFER_WAKEUP_BY_TIMER,
172 struct channel *_channel_create(const char *name,
173 struct lttng_channel *lttng_chan, void *buf_addr,
174 size_t subbuf_size, size_t num_subbuf,
175 unsigned int switch_timer_interval,
176 unsigned int read_timer_interval)
178 return channel_create(&client_config, name, lttng_chan, buf_addr,
179 subbuf_size, num_subbuf, switch_timer_interval,
180 read_timer_interval);
184 void lttng_channel_destroy(struct channel *chan)
186 channel_destroy(chan);
190 struct lib_ring_buffer *lttng_buffer_read_open(struct channel *chan)
192 struct lib_ring_buffer *buf;
194 buf = channel_get_ring_buffer(&client_config, chan, 0);
195 if (!lib_ring_buffer_open_read(buf))
201 int lttng_buffer_has_read_closed_stream(struct channel *chan)
203 struct lib_ring_buffer *buf;
206 for_each_channel_cpu(cpu, chan) {
207 buf = channel_get_ring_buffer(&client_config, chan, cpu);
208 if (!atomic_long_read(&buf->active_readers))
215 void lttng_buffer_read_close(struct lib_ring_buffer *buf)
217 lib_ring_buffer_release_read(buf);
221 int lttng_event_reserve(struct lib_ring_buffer_ctx *ctx, uint32_t event_id)
223 return lib_ring_buffer_reserve(&client_config, ctx);
227 void lttng_event_commit(struct lib_ring_buffer_ctx *ctx)
229 lib_ring_buffer_commit(&client_config, ctx);
233 void lttng_event_write(struct lib_ring_buffer_ctx *ctx, const void *src,
236 lib_ring_buffer_write(&client_config, ctx, src, len);
240 void lttng_event_write_from_user(struct lib_ring_buffer_ctx *ctx,
241 const void __user *src, size_t len)
243 lib_ring_buffer_copy_from_user_inatomic(&client_config, ctx, src, len);
247 void lttng_event_memset(struct lib_ring_buffer_ctx *ctx,
250 lib_ring_buffer_memset(&client_config, ctx, c, len);
254 size_t lttng_packet_avail_size(struct channel *chan)
257 unsigned long o_begin;
258 struct lib_ring_buffer *buf;
260 buf = chan->backend.buf; /* Only for global buffer ! */
261 o_begin = v_read(&client_config, &buf->offset);
262 if (subbuf_offset(o_begin, chan) != 0) {
263 return chan->backend.subbuf_size - subbuf_offset(o_begin, chan);
265 return chan->backend.subbuf_size - subbuf_offset(o_begin, chan)
266 - sizeof(struct metadata_packet_header);
271 wait_queue_head_t *lttng_get_writer_buf_wait_queue(struct channel *chan, int cpu)
273 struct lib_ring_buffer *buf = channel_get_ring_buffer(&client_config,
275 return &buf->write_wait;
279 wait_queue_head_t *lttng_get_hp_wait_queue(struct channel *chan)
281 return &chan->hp_wait;
285 int lttng_is_finalized(struct channel *chan)
287 return lib_ring_buffer_channel_is_finalized(chan);
291 int lttng_is_disabled(struct channel *chan)
293 return lib_ring_buffer_channel_is_disabled(chan);
296 static struct lttng_transport lttng_relay_transport = {
297 .name = "relay-" RING_BUFFER_MODE_TEMPLATE_STRING,
298 .owner = THIS_MODULE,
300 .channel_create = _channel_create,
301 .channel_destroy = lttng_channel_destroy,
302 .buffer_read_open = lttng_buffer_read_open,
303 .buffer_has_read_closed_stream =
304 lttng_buffer_has_read_closed_stream,
305 .buffer_read_close = lttng_buffer_read_close,
306 .event_reserve = lttng_event_reserve,
307 .event_commit = lttng_event_commit,
308 .event_write_from_user = lttng_event_write_from_user,
309 .event_memset = lttng_event_memset,
310 .event_write = lttng_event_write,
311 .packet_avail_size = lttng_packet_avail_size,
312 .get_writer_buf_wait_queue = lttng_get_writer_buf_wait_queue,
313 .get_hp_wait_queue = lttng_get_hp_wait_queue,
314 .is_finalized = lttng_is_finalized,
315 .is_disabled = lttng_is_disabled,
319 static int __init lttng_ring_buffer_client_init(void)
322 * This vmalloc sync all also takes care of the lib ring buffer
323 * vmalloc'd module pages when it is built as a module into LTTng.
325 wrapper_vmalloc_sync_all();
326 lttng_transport_register(<tng_relay_transport);
330 module_init(lttng_ring_buffer_client_init);
332 static void __exit lttng_ring_buffer_client_exit(void)
334 lttng_transport_unregister(<tng_relay_transport);
337 module_exit(lttng_ring_buffer_client_exit);
339 MODULE_LICENSE("GPL and additional rights");
340 MODULE_AUTHOR("Mathieu Desnoyers");
341 MODULE_DESCRIPTION("LTTng ring buffer " RING_BUFFER_MODE_TEMPLATE_STRING