[deliverable/lttng-ust.git] / libringbuffer / frontend_types.h

#ifndef _LTTNG_RING_BUFFER_FRONTEND_TYPES_H
#define _LTTNG_RING_BUFFER_FRONTEND_TYPES_H

/*
 * libringbuffer/frontend_types.h
 *
 * Ring Buffer Library Synchronization Header (types).
 *
 * Copyright (C) 2005-2012 Mathieu Desnoyers <mathieu.desnoyers@efficios.com>
 *
 * This library is free software; you can redistribute it and/or
 * modify it under the terms of the GNU Lesser General Public
 * License as published by the Free Software Foundation; only
 * version 2.1 of the License.
 *
 * This library is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
 * Lesser General Public License for more details.
 *
 * You should have received a copy of the GNU Lesser General Public
 * License along with this library; if not, write to the Free Software
 * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
 *
 * Author:
 *	Mathieu Desnoyers <mathieu.desnoyers@efficios.com>
 *
 * See ring_buffer_frontend.c for more information on wait-free algorithms.
 */

#include <string.h>
#include <time.h>	/* for timer_t */

#include <urcu/list.h>
#include <urcu/uatomic.h>

#include <lttng/ringbuffer-config.h>
#include <usterr-signal-safe.h>
#include "backend_types.h"
#include "shm_internal.h"
#include "shm_types.h"
#include "vatomic.h"

/*
 * A switch is done during tracing or as a final flush after tracing (so it
 * won't write in the new sub-buffer).
 */
enum switch_mode { SWITCH_ACTIVE, SWITCH_FLUSH };

/* channel: collection of per-cpu ring buffers. */
#define RB_CHANNEL_PADDING		32
struct channel {
	int record_disabled;
	unsigned long commit_count_mask;	/*
						 * Commit count mask, removing
						 * the MSBs corresponding to
						 * bits used to represent the
						 * subbuffer index.
						 */

	unsigned long switch_timer_interval;	/* Buffer flush (us) */
	timer_t switch_timer;
	int switch_timer_enabled;

	unsigned long read_timer_interval;	/* Reader wakeup (us) */
	timer_t read_timer;
	int read_timer_enabled;

	int finalized;				/* Has channel been finalized */
	size_t priv_data_offset;
	unsigned int nr_streams;		/* Number of streams */
	struct lttng_ust_shm_handle *handle;
	char padding[RB_CHANNEL_PADDING];
	/*
	 * Associated backend contains a variable-length array. Needs to
	 * be last member.
	 */
	struct channel_backend backend;		/* Associated backend */
} __attribute__((aligned(CAA_CACHE_LINE_SIZE)));

/* Per-subbuffer commit counters used on the hot path */
#define RB_COMMIT_COUNT_HOT_PADDING	16
struct commit_counters_hot {
	union v_atomic cc;		/* Commit counter */
	unsigned long cc_rseq;		/* Commit counter for rseq */
	union v_atomic seq;		/* Consecutive commits */
	char padding[RB_COMMIT_COUNT_HOT_PADDING];
} __attribute__((aligned(CAA_CACHE_LINE_SIZE)));

/* Per-subbuffer commit counters used only on cold paths */
#define RB_COMMIT_COUNT_COLD_PADDING	24
struct commit_counters_cold {
	union v_atomic cc_sb;		/* Incremented _once_ at sb switch */
	char padding[RB_COMMIT_COUNT_COLD_PADDING];
} __attribute__((aligned(CAA_CACHE_LINE_SIZE)));

/* ring buffer state */
#define RB_CRASH_DUMP_ABI_LEN		256
#define RB_RING_BUFFER_PADDING		60

#define RB_CRASH_DUMP_ABI_MAGIC_LEN	16

/*
 * The 128-bit magic number is xor'd in the process data so it does not
 * cause a false positive when searching for buffers by scanning memory.
 * The actual magic number is:
 *   0x17, 0x7B, 0xF1, 0x77, 0xBF, 0x17, 0x7B, 0xF1,
 *   0x77, 0xBF, 0x17, 0x7B, 0xF1, 0x77, 0xBF, 0x17,
 */
#define RB_CRASH_DUMP_ABI_MAGIC_XOR					\
	{								\
		0x17 ^ 0xFF, 0x7B ^ 0xFF, 0xF1 ^ 0xFF, 0x77 ^ 0xFF,	\
		0xBF ^ 0xFF, 0x17 ^ 0xFF, 0x7B ^ 0xFF, 0xF1 ^ 0xFF,	\
		0x77 ^ 0xFF, 0xBF ^ 0xFF, 0x17 ^ 0xFF, 0x7B ^ 0xFF,	\
		0xF1 ^ 0xFF, 0x77 ^ 0xFF, 0xBF ^ 0xFF, 0x17 ^ 0xFF,	\
	}

#define RB_CRASH_ENDIAN			0x1234

#define RB_CRASH_DUMP_ABI_MAJOR		0
#define RB_CRASH_DUMP_ABI_MINOR		0

enum lttng_crash_type {
	LTTNG_CRASH_TYPE_UST = 0,
	LTTNG_CRASH_TYPE_KERNEL = 1,
};

struct lttng_crash_abi {
	uint8_t magic[RB_CRASH_DUMP_ABI_MAGIC_LEN];
	uint64_t mmap_length;	/* Overall lenght of crash record */
	uint16_t endian;	/*
				 * { 0x12, 0x34 }: big endian
				 * { 0x34, 0x12 }: little endian
				 */
	uint16_t major;		/* Major number. */
	uint16_t minor;		/* Minor number. */
	uint8_t word_size;	/* Word size (bytes). */
	uint8_t layout_type;	/* enum lttng_crash_type */

	struct {
		uint32_t prod_offset;
		uint32_t consumed_offset;
		uint32_t commit_hot_array;
		uint32_t commit_hot_seq;
		uint32_t buf_wsb_array;
		uint32_t buf_wsb_id;
		uint32_t sb_array;
		uint32_t sb_array_shmp_offset;
		uint32_t sb_backend_p_offset;
		uint32_t content_size;
		uint32_t packet_size;
	} __attribute__((packed)) offset;
	struct {
		uint8_t prod_offset;
		uint8_t consumed_offset;
		uint8_t commit_hot_seq;
		uint8_t buf_wsb_id;
		uint8_t sb_array_shmp_offset;
		uint8_t sb_backend_p_offset;
		uint8_t content_size;
		uint8_t packet_size;
	} __attribute__((packed)) length;
	struct {
		uint32_t commit_hot_array;
		uint32_t buf_wsb_array;
		uint32_t sb_array;
	} __attribute__((packed)) stride;

	uint64_t buf_size;	/* Size of the buffer */
	uint64_t subbuf_size;	/* Sub-buffer size */
	uint64_t num_subbuf;	/* Number of sub-buffers for writer */
	uint32_t mode;		/* Buffer mode: 0: overwrite, 1: discard */
} __attribute__((packed));

struct lttng_ust_lib_ring_buffer {
	/* First 32 bytes are for the buffer crash dump ABI */
	struct lttng_crash_abi crash_abi;

	/* 32 bytes cache-hot cacheline */
	union v_atomic __attribute__((aligned(32))) offset;
					/* Current offset in the buffer */
	DECLARE_SHMP(struct commit_counters_hot, commit_hot);
					/* Commit count per sub-buffer */
	long consumed;			/*
					 * Current offset in the buffer
					 * standard atomic access (shared)
					 */
	int record_disabled;
	/* End of cache-hot 32 bytes cacheline */

	union v_atomic last_tsc;	/*
					 * Last timestamp written in the buffer.
					 */

	struct lttng_ust_lib_ring_buffer_backend backend;
					/* Associated backend */

	DECLARE_SHMP(struct commit_counters_cold, commit_cold);
					/* Commit count per sub-buffer */
	long active_readers;		/*
					 * Active readers count
					 * standard atomic access (shared)
					 */
					/* Dropped records */
	union v_atomic records_lost_full;	/* Buffer full */
	union v_atomic records_lost_wrap;	/* Nested wrap-around */
	union v_atomic records_lost_big;	/* Events too big */
	union v_atomic records_count;	/* Number of records written */
	union v_atomic records_overrun;	/* Number of overwritten records */
	//wait_queue_head_t read_wait;	/* reader buffer-level wait queue */
	int finalized;			/* buffer has been finalized */
	unsigned long get_subbuf_consumed;	/* Read-side consumed */
	unsigned long prod_snapshot;	/* Producer count snapshot */
	unsigned long cons_snapshot;	/* Consumer count snapshot */
	unsigned int get_subbuf:1;	/* Sub-buffer being held by reader */
	/* shmp pointer to self */
	DECLARE_SHMP(struct lttng_ust_lib_ring_buffer, self);
	char padding[RB_RING_BUFFER_PADDING];
} __attribute__((aligned(CAA_CACHE_LINE_SIZE)));

static inline
void *channel_get_private(struct channel *chan)
{
	return ((char *) chan) + chan->priv_data_offset;
}

#ifndef __rb_same_type
#define __rb_same_type(a, b)	__builtin_types_compatible_p(typeof(a), typeof(b))
#endif

/*
 * Issue warnings and disable channels upon internal error.
 * Can receive struct lttng_ust_lib_ring_buffer or struct lttng_ust_lib_ring_buffer_backend
 * parameters.
 */
#define CHAN_WARN_ON(c, cond)						\
	({								\
		struct channel *__chan;					\
		int _____ret = caa_unlikely(cond);				\
		if (_____ret) {						\
			if (__rb_same_type(*(c), struct channel_backend))	\
				__chan = caa_container_of((void *) (c),	\
							struct channel, \
							backend);	\
			else if (__rb_same_type(*(c), struct channel))	\
				__chan = (void *) (c);			\
			else						\
				BUG_ON(1);				\
			uatomic_inc(&__chan->record_disabled);		\
			WARN_ON(1);					\
		}							\
		_____ret = _____ret; /* For clang "unused result". */	\
	})

#endif /* _LTTNG_RING_BUFFER_FRONTEND_TYPES_H */
Commit	Line	Data
e92f3e28 MD	1	#ifndef _LTTNG_RING_BUFFER_FRONTEND_TYPES_H
e92f3e28 MD	2	#define _LTTNG_RING_BUFFER_FRONTEND_TYPES_H
852c2936 MD	3
852c2936 MD	4	/*
e92f3e28	5	* libringbuffer/frontend_types.h
852c2936 MD	6	*
	7	* Ring Buffer Library Synchronization Header (types).
	8	*
e92f3e28 MD	9	* Copyright (C) 2005-2012 Mathieu Desnoyers <mathieu.desnoyers@efficios.com>
	10	*
	11	* This library is free software; you can redistribute it and/or
	12	* modify it under the terms of the GNU Lesser General Public
	13	* License as published by the Free Software Foundation; only
	14	* version 2.1 of the License.
	15	*
	16	* This library is distributed in the hope that it will be useful,
	17	* but WITHOUT ANY WARRANTY; without even the implied warranty of
	18	* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
	19	* Lesser General Public License for more details.
	20	*
	21	* You should have received a copy of the GNU Lesser General Public
	22	* License along with this library; if not, write to the Free Software
	23	* Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
	24	*
852c2936 MD	25	* Author:
	26	* Mathieu Desnoyers <mathieu.desnoyers@efficios.com>
	27	*
	28	* See ring_buffer_frontend.c for more information on wait-free algorithms.
852c2936 MD	29	*/
852c2936 MD	30
a6352fd4	31	#include <string.h>
03d2d293	32	#include <time.h> /* for timer_t */
a6352fd4	33
14641deb MD	34	#include <urcu/list.h>
14641deb MD	35	#include <urcu/uatomic.h>
14641deb	36
4318ae1b	37	#include <lttng/ringbuffer-config.h>
44c72f10	38	#include <usterr-signal-safe.h>
4931a13e	39	#include "backend_types.h"
1d498196	40	#include "shm_internal.h"
03d2d293	41	#include "shm_types.h"
a3bb4b27	42	#include "vatomic.h"
852c2936 MD	43
	44	/*
	45	* A switch is done during tracing or as a final flush after tracing (so it
	46	* won't write in the new sub-buffer).
	47	*/
	48	enum switch_mode { SWITCH_ACTIVE, SWITCH_FLUSH };
	49
852c2936	50	/* channel: collection of per-cpu ring buffers. */
74d81a6c	51	#define RB_CHANNEL_PADDING 32
852c2936	52	struct channel {
14641deb	53	int record_disabled;
852c2936 MD	54	unsigned long commit_count_mask; /*
	55	* Commit count mask, removing
	56	* the MSBs corresponding to
	57	* bits used to represent the
	58	* subbuffer index.
	59	*/
	60
03d2d293 MD	61	unsigned long switch_timer_interval; /* Buffer flush (us) */
	62	timer_t switch_timer;
	63	int switch_timer_enabled;
	64
	65	unsigned long read_timer_interval; /* Reader wakeup (us) */
34a91bdb MD	66	timer_t read_timer;
	67	int read_timer_enabled;
	68
852c2936	69	int finalized; /* Has channel been finalized */
a3f61e7f	70	size_t priv_data_offset;
74d81a6c	71	unsigned int nr_streams; /* Number of streams */
03d2d293	72	struct lttng_ust_shm_handle *handle;
74d81a6c	73	char padding[RB_CHANNEL_PADDING];
de85e7c3 MD	74	/*
	75	* Associated backend contains a variable-length array. Needs to
	76	* be last member.
	77	*/
	78	struct channel_backend backend; /* Associated backend */
b728d87e	79	} __attribute__((aligned(CAA_CACHE_LINE_SIZE)));
852c2936 MD	80
852c2936 MD	81	/* Per-subbuffer commit counters used on the hot path */
3c8964ba	82	#define RB_COMMIT_COUNT_HOT_PADDING 16
852c2936 MD	83	struct commit_counters_hot {
852c2936 MD	84	union v_atomic cc; /* Commit counter */
3ea36dea	85	unsigned long cc_rseq; /* Commit counter for rseq */
852c2936	86	union v_atomic seq; /* Consecutive commits */
3c8964ba	87	char padding[RB_COMMIT_COUNT_HOT_PADDING];
b728d87e	88	} __attribute__((aligned(CAA_CACHE_LINE_SIZE)));
852c2936 MD	89
852c2936 MD	90	/* Per-subbuffer commit counters used only on cold paths */
3c8964ba	91	#define RB_COMMIT_COUNT_COLD_PADDING 24
852c2936 MD	92	struct commit_counters_cold {
852c2936 MD	93	union v_atomic cc_sb; /* Incremented _once_ at sb switch */
3c8964ba	94	char padding[RB_COMMIT_COUNT_COLD_PADDING];
b728d87e	95	} __attribute__((aligned(CAA_CACHE_LINE_SIZE)));
852c2936	96
852c2936	97	/* ring buffer state */
a9ff648c MD	98	#define RB_CRASH_DUMP_ABI_LEN 256
	99	#define RB_RING_BUFFER_PADDING 60
	100
	101	#define RB_CRASH_DUMP_ABI_MAGIC_LEN 16
	102
	103	/*
	104	* The 128-bit magic number is xor'd in the process data so it does not
	105	* cause a false positive when searching for buffers by scanning memory.
	106	* The actual magic number is:
	107	* 0x17, 0x7B, 0xF1, 0x77, 0xBF, 0x17, 0x7B, 0xF1,
	108	* 0x77, 0xBF, 0x17, 0x7B, 0xF1, 0x77, 0xBF, 0x17,
	109	*/
	110	#define RB_CRASH_DUMP_ABI_MAGIC_XOR \
	111	{ \
	112	0x17 ^ 0xFF, 0x7B ^ 0xFF, 0xF1 ^ 0xFF, 0x77 ^ 0xFF, \
	113	0xBF ^ 0xFF, 0x17 ^ 0xFF, 0x7B ^ 0xFF, 0xF1 ^ 0xFF, \
	114	0x77 ^ 0xFF, 0xBF ^ 0xFF, 0x17 ^ 0xFF, 0x7B ^ 0xFF, \
	115	0xF1 ^ 0xFF, 0x77 ^ 0xFF, 0xBF ^ 0xFF, 0x17 ^ 0xFF, \
	116	}
	117
	118	#define RB_CRASH_ENDIAN 0x1234
	119
	120	#define RB_CRASH_DUMP_ABI_MAJOR 0
	121	#define RB_CRASH_DUMP_ABI_MINOR 0
	122
	123	enum lttng_crash_type {
	124	LTTNG_CRASH_TYPE_UST = 0,
	125	LTTNG_CRASH_TYPE_KERNEL = 1,
	126	};
	127
	128	struct lttng_crash_abi {
	129	uint8_t magic[RB_CRASH_DUMP_ABI_MAGIC_LEN];
	130	uint64_t mmap_length; /* Overall lenght of crash record */
	131	uint16_t endian; /*
	132	* { 0x12, 0x34 }: big endian
	133	* { 0x34, 0x12 }: little endian
	134	*/
	135	uint16_t major; /* Major number. */
	136	uint16_t minor; /* Minor number. */
	137	uint8_t word_size; /* Word size (bytes). */
	138	uint8_t layout_type; /* enum lttng_crash_type */
	139
	140	struct {
	141	uint32_t prod_offset;
	142	uint32_t consumed_offset;
	143	uint32_t commit_hot_array;
	144	uint32_t commit_hot_seq;
	145	uint32_t buf_wsb_array;
	146	uint32_t buf_wsb_id;
	147	uint32_t sb_array;
	148	uint32_t sb_array_shmp_offset;
	149	uint32_t sb_backend_p_offset;
	150	uint32_t content_size;
	151	uint32_t packet_size;
	152	} __attribute__((packed)) offset;
	153	struct {
	154	uint8_t prod_offset;
	155	uint8_t consumed_offset;
	156	uint8_t commit_hot_seq;
	157	uint8_t buf_wsb_id;
	158	uint8_t sb_array_shmp_offset;
	159	uint8_t sb_backend_p_offset;
	160	uint8_t content_size;
	161	uint8_t packet_size;
162	} __attribute__((packed)) length;
163	struct {
164	uint32_t commit_hot_array;
165	uint32_t buf_wsb_array;
166	uint32_t sb_array;
167	} __attribute__((packed)) stride;
168
169	uint64_t buf_size; /* Size of the buffer */
170	uint64_t subbuf_size; /* Sub-buffer size */
171	uint64_t num_subbuf; /* Number of sub-buffers for writer */
172	uint32_t mode; /* Buffer mode: 0: overwrite, 1: discard */
173	} __attribute__((packed));
174
4cfec15c	175	struct lttng_ust_lib_ring_buffer {
a9ff648c MD	176	/* First 32 bytes are for the buffer crash dump ABI */
	177	struct lttng_crash_abi crash_abi;
	178
	179	/* 32 bytes cache-hot cacheline */
	180	union v_atomic __attribute__((aligned(32))) offset;
	181	/* Current offset in the buffer */
a6352fd4	182	DECLARE_SHMP(struct commit_counters_hot, commit_hot);
852c2936	183	/* Commit count per sub-buffer */
14641deb	184	long consumed; /*
852c2936 MD	185	* Current offset in the buffer
	186	* standard atomic access (shared)
	187	*/
14641deb	188	int record_disabled;
a9ff648c MD	189	/* End of cache-hot 32 bytes cacheline */
a9ff648c MD	190
852c2936 MD	191	union v_atomic last_tsc; /*
	192	* Last timestamp written in the buffer.
	193	*/
	194
a9ff648c MD	195	struct lttng_ust_lib_ring_buffer_backend backend;
a9ff648c MD	196	/* Associated backend */
852c2936	197
a6352fd4	198	DECLARE_SHMP(struct commit_counters_cold, commit_cold);
852c2936	199	/* Commit count per sub-buffer */
14641deb	200	long active_readers; /*
852c2936 MD	201	* Active readers count
	202	* standard atomic access (shared)
	203	*/
	204	/* Dropped records */
	205	union v_atomic records_lost_full; /* Buffer full */
	206	union v_atomic records_lost_wrap; /* Nested wrap-around */
	207	union v_atomic records_lost_big; /* Events too big */
	208	union v_atomic records_count; /* Number of records written */
	209	union v_atomic records_overrun; /* Number of overwritten records */
14641deb	210	//wait_queue_head_t read_wait; /* reader buffer-level wait queue */
852c2936	211	int finalized; /* buffer has been finalized */
852c2936 MD	212	unsigned long get_subbuf_consumed; /* Read-side consumed */
	213	unsigned long prod_snapshot; /* Producer count snapshot */
	214	unsigned long cons_snapshot; /* Consumer count snapshot */
34a91bdb	215	unsigned int get_subbuf:1; /* Sub-buffer being held by reader */
5d61a504	216	/* shmp pointer to self */
4cfec15c	217	DECLARE_SHMP(struct lttng_ust_lib_ring_buffer, self);
3c8964ba	218	char padding[RB_RING_BUFFER_PADDING];
b728d87e	219	} __attribute__((aligned(CAA_CACHE_LINE_SIZE)));
852c2936 MD	220
	221	static inline
	222	void channel_get_private(struct channel chan)
	223	{
a3f61e7f	224	return ((char *) chan) + chan->priv_data_offset;
852c2936 MD	225	}
852c2936 MD	226
0d4aa2df MD	227	#ifndef __rb_same_type
	228	#define __rb_same_type(a, b) __builtin_types_compatible_p(typeof(a), typeof(b))
	229	#endif
	230
852c2936 MD	231	/*
852c2936 MD	232	* Issue warnings and disable channels upon internal error.
4cfec15c	233	* Can receive struct lttng_ust_lib_ring_buffer or struct lttng_ust_lib_ring_buffer_backend
852c2936 MD	234	* parameters.
	235	*/
	236	#define CHAN_WARN_ON(c, cond) \
	237	({ \
	238	struct channel *__chan; \
b5a3dfa5	239	int _____ret = caa_unlikely(cond); \
852c2936	240	if (_____ret) { \
0d4aa2df	241	if (__rb_same_type(*(c), struct channel_backend)) \
14641deb	242	__chan = caa_container_of((void *) (c), \
852c2936 MD	243	struct channel, \
852c2936 MD	244	backend); \
0d4aa2df	245	else if (__rb_same_type(*(c), struct channel)) \
852c2936 MD	246	__chan = (void *) (c); \
	247	else \
	248	BUG_ON(1); \
14641deb	249	uatomic_inc(&__chan->record_disabled); \
852c2936 MD	250	WARN_ON(1); \
852c2936 MD	251	} \
257ecc17	252	_____ret = _____ret; /* For clang "unused result". */ \
852c2936 MD	253	})
852c2936 MD	254
e92f3e28	255	#endif /* _LTTNG_RING_BUFFER_FRONTEND_TYPES_H */