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

/*
 * SPDX-License-Identifier: LGPL-2.1-only
 *
 * Copyright (C) 2005-2012 Mathieu Desnoyers <mathieu.desnoyers@efficios.com>
 *
 * Ring Buffer Library Synchronization Header (types).
 *
 * See ring_buffer_frontend.c for more information on wait-free algorithms.
 */

#ifndef _LTTNG_RING_BUFFER_FRONTEND_TYPES_H
#define _LTTNG_RING_BUFFER_FRONTEND_TYPES_H

#include <stdint.h>
#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;
	/* Extended options. */
	union {
		struct {
			int32_t blocking_timeout_ms;
		} s;
		char padding[RB_CHANNEL_PADDING];
	} u;
	/*
	 * 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 */
	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 */
	DECLARE_SHMP(uint64_t, ts_end);	/*
					 * timestamp_end per sub-buffer.
					 * Time is sampled by the
					 * switch_*_end() callbacks
					 * which are the last space
					 * reservation performed in the
					 * sub-buffer before it can be
					 * fully committed and
					 * delivered. This time value is
					 * then read by the deliver
					 * callback, performed by the
					 * last commit before the buffer
					 * becomes readable.
					 */
	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
852c2936	1	/*
c0c0989a	2	* SPDX-License-Identifier: LGPL-2.1-only
852c2936	3	*
e92f3e28 MD	4	* Copyright (C) 2005-2012 Mathieu Desnoyers <mathieu.desnoyers@efficios.com>
e92f3e28 MD	5	*
c0c0989a	6	* Ring Buffer Library Synchronization Header (types).
852c2936 MD	7	*
852c2936 MD	8	* See ring_buffer_frontend.c for more information on wait-free algorithms.
852c2936 MD	9	*/
852c2936 MD	10
c0c0989a MJ	11	#ifndef _LTTNG_RING_BUFFER_FRONTEND_TYPES_H
	12	#define _LTTNG_RING_BUFFER_FRONTEND_TYPES_H
	13
fb31eb73	14	#include <stdint.h>
a6352fd4	15	#include <string.h>
03d2d293	16	#include <time.h> /* for timer_t */
a6352fd4	17
14641deb MD	18	#include <urcu/list.h>
14641deb MD	19	#include <urcu/uatomic.h>
14641deb	20
4318ae1b	21	#include <lttng/ringbuffer-config.h>
44c72f10	22	#include <usterr-signal-safe.h>
4931a13e	23	#include "backend_types.h"
1d498196	24	#include "shm_internal.h"
03d2d293	25	#include "shm_types.h"
a3bb4b27	26	#include "vatomic.h"
852c2936 MD	27
	28	/*
	29	* A switch is done during tracing or as a final flush after tracing (so it
	30	* won't write in the new sub-buffer).
	31	*/
	32	enum switch_mode { SWITCH_ACTIVE, SWITCH_FLUSH };
	33
852c2936	34	/* channel: collection of per-cpu ring buffers. */
74d81a6c	35	#define RB_CHANNEL_PADDING 32
852c2936	36	struct channel {
14641deb	37	int record_disabled;
852c2936 MD	38	unsigned long commit_count_mask; /*
	39	* Commit count mask, removing
	40	* the MSBs corresponding to
	41	* bits used to represent the
	42	* subbuffer index.
	43	*/
	44
03d2d293 MD	45	unsigned long switch_timer_interval; /* Buffer flush (us) */
	46	timer_t switch_timer;
	47	int switch_timer_enabled;
	48
	49	unsigned long read_timer_interval; /* Reader wakeup (us) */
34a91bdb MD	50	timer_t read_timer;
	51	int read_timer_enabled;
	52
852c2936	53	int finalized; /* Has channel been finalized */
a3f61e7f	54	size_t priv_data_offset;
74d81a6c	55	unsigned int nr_streams; /* Number of streams */
03d2d293	56	struct lttng_ust_shm_handle *handle;
b2c5f61a MD	57	/* Extended options. */
	58	union {
	59	struct {
	60	int32_t blocking_timeout_ms;
	61	} s;
	62	char padding[RB_CHANNEL_PADDING];
	63	} u;
de85e7c3 MD	64	/*
	65	* Associated backend contains a variable-length array. Needs to
	66	* be last member.
	67	*/
	68	struct channel_backend backend; /* Associated backend */
b728d87e	69	} __attribute__((aligned(CAA_CACHE_LINE_SIZE)));
852c2936 MD	70
852c2936 MD	71	/* Per-subbuffer commit counters used on the hot path */
3c8964ba	72	#define RB_COMMIT_COUNT_HOT_PADDING 16
852c2936 MD	73	struct commit_counters_hot {
	74	union v_atomic cc; /* Commit counter */
	75	union v_atomic seq; /* Consecutive commits */
3c8964ba	76	char padding[RB_COMMIT_COUNT_HOT_PADDING];
b728d87e	77	} __attribute__((aligned(CAA_CACHE_LINE_SIZE)));
852c2936 MD	78
852c2936 MD	79	/* Per-subbuffer commit counters used only on cold paths */
3c8964ba	80	#define RB_COMMIT_COUNT_COLD_PADDING 24
852c2936 MD	81	struct commit_counters_cold {
852c2936 MD	82	union v_atomic cc_sb; /* Incremented _once_ at sb switch */
3c8964ba	83	char padding[RB_COMMIT_COUNT_COLD_PADDING];
b728d87e	84	} __attribute__((aligned(CAA_CACHE_LINE_SIZE)));
852c2936	85
852c2936	86	/* ring buffer state */
a9ff648c MD	87	#define RB_CRASH_DUMP_ABI_LEN 256
	88	#define RB_RING_BUFFER_PADDING 60
	89
	90	#define RB_CRASH_DUMP_ABI_MAGIC_LEN 16
	91
	92	/*
	93	* The 128-bit magic number is xor'd in the process data so it does not
	94	* cause a false positive when searching for buffers by scanning memory.
	95	* The actual magic number is:
	96	* 0x17, 0x7B, 0xF1, 0x77, 0xBF, 0x17, 0x7B, 0xF1,
	97	* 0x77, 0xBF, 0x17, 0x7B, 0xF1, 0x77, 0xBF, 0x17,
	98	*/
	99	#define RB_CRASH_DUMP_ABI_MAGIC_XOR \
	100	{ \
	101	0x17 ^ 0xFF, 0x7B ^ 0xFF, 0xF1 ^ 0xFF, 0x77 ^ 0xFF, \
	102	0xBF ^ 0xFF, 0x17 ^ 0xFF, 0x7B ^ 0xFF, 0xF1 ^ 0xFF, \
	103	0x77 ^ 0xFF, 0xBF ^ 0xFF, 0x17 ^ 0xFF, 0x7B ^ 0xFF, \
	104	0xF1 ^ 0xFF, 0x77 ^ 0xFF, 0xBF ^ 0xFF, 0x17 ^ 0xFF, \
	105	}
	106
	107	#define RB_CRASH_ENDIAN 0x1234
	108
	109	#define RB_CRASH_DUMP_ABI_MAJOR 0
	110	#define RB_CRASH_DUMP_ABI_MINOR 0
	111
	112	enum lttng_crash_type {
	113	LTTNG_CRASH_TYPE_UST = 0,
	114	LTTNG_CRASH_TYPE_KERNEL = 1,
	115	};
	116
	117	struct lttng_crash_abi {
	118	uint8_t magic[RB_CRASH_DUMP_ABI_MAGIC_LEN];
	119	uint64_t mmap_length; /* Overall lenght of crash record */
	120	uint16_t endian; /*
	121	* { 0x12, 0x34 }: big endian
	122	* { 0x34, 0x12 }: little endian
	123	*/
	124	uint16_t major; /* Major number. */
	125	uint16_t minor; /* Minor number. */
	126	uint8_t word_size; /* Word size (bytes). */
	127	uint8_t layout_type; /* enum lttng_crash_type */
	128
	129	struct {
	130	uint32_t prod_offset;
	131	uint32_t consumed_offset;
	132	uint32_t commit_hot_array;
	133	uint32_t commit_hot_seq;
	134	uint32_t buf_wsb_array;
	135	uint32_t buf_wsb_id;
	136	uint32_t sb_array;
	137	uint32_t sb_array_shmp_offset;
	138	uint32_t sb_backend_p_offset;
	139	uint32_t content_size;
	140	uint32_t packet_size;
	141	} __attribute__((packed)) offset;
	142	struct {
	143	uint8_t prod_offset;
	144	uint8_t consumed_offset;
	145	uint8_t commit_hot_seq;
	146	uint8_t buf_wsb_id;
	147	uint8_t sb_array_shmp_offset;
	148	uint8_t sb_backend_p_offset;
	149	uint8_t content_size;
	150	uint8_t packet_size;
151	} __attribute__((packed)) length;
152	struct {
153	uint32_t commit_hot_array;
154	uint32_t buf_wsb_array;
155	uint32_t sb_array;
156	} __attribute__((packed)) stride;
157
158	uint64_t buf_size; /* Size of the buffer */
159	uint64_t subbuf_size; /* Sub-buffer size */
160	uint64_t num_subbuf; /* Number of sub-buffers for writer */
161	uint32_t mode; /* Buffer mode: 0: overwrite, 1: discard */
162	} __attribute__((packed));
163
4cfec15c	164	struct lttng_ust_lib_ring_buffer {
a9ff648c MD	165	/* First 32 bytes are for the buffer crash dump ABI */
	166	struct lttng_crash_abi crash_abi;
	167
	168	/* 32 bytes cache-hot cacheline */
	169	union v_atomic __attribute__((aligned(32))) offset;
	170	/* Current offset in the buffer */
a6352fd4	171	DECLARE_SHMP(struct commit_counters_hot, commit_hot);
852c2936	172	/* Commit count per sub-buffer */
14641deb	173	long consumed; /*
852c2936 MD	174	* Current offset in the buffer
	175	* standard atomic access (shared)
	176	*/
14641deb	177	int record_disabled;
a9ff648c MD	178	/* End of cache-hot 32 bytes cacheline */
a9ff648c MD	179
852c2936 MD	180	union v_atomic last_tsc; /*
	181	* Last timestamp written in the buffer.
	182	*/
	183
a9ff648c MD	184	struct lttng_ust_lib_ring_buffer_backend backend;
a9ff648c MD	185	/* Associated backend */
852c2936	186
a6352fd4	187	DECLARE_SHMP(struct commit_counters_cold, commit_cold);
852c2936	188	/* Commit count per sub-buffer */
6c737d05 MD	189	DECLARE_SHMP(uint64_t, ts_end); /*
	190	* timestamp_end per sub-buffer.
	191	* Time is sampled by the
	192	* switch_*_end() callbacks
	193	* which are the last space
	194	* reservation performed in the
	195	* sub-buffer before it can be
	196	* fully committed and
	197	* delivered. This time value is
	198	* then read by the deliver
	199	* callback, performed by the
	200	* last commit before the buffer
	201	* becomes readable.
	202	*/
14641deb	203	long active_readers; /*
852c2936 MD	204	* Active readers count
	205	* standard atomic access (shared)
	206	*/
	207	/* Dropped records */
	208	union v_atomic records_lost_full; /* Buffer full */
	209	union v_atomic records_lost_wrap; /* Nested wrap-around */
	210	union v_atomic records_lost_big; /* Events too big */
	211	union v_atomic records_count; /* Number of records written */
	212	union v_atomic records_overrun; /* Number of overwritten records */
14641deb	213	//wait_queue_head_t read_wait; /* reader buffer-level wait queue */
852c2936	214	int finalized; /* buffer has been finalized */
852c2936 MD	215	unsigned long get_subbuf_consumed; /* Read-side consumed */
	216	unsigned long prod_snapshot; /* Producer count snapshot */
	217	unsigned long cons_snapshot; /* Consumer count snapshot */
34a91bdb	218	unsigned int get_subbuf:1; /* Sub-buffer being held by reader */
5d61a504	219	/* shmp pointer to self */
4cfec15c	220	DECLARE_SHMP(struct lttng_ust_lib_ring_buffer, self);
3c8964ba	221	char padding[RB_RING_BUFFER_PADDING];
b728d87e	222	} __attribute__((aligned(CAA_CACHE_LINE_SIZE)));
852c2936 MD	223
	224	static inline
	225	void channel_get_private(struct channel chan)
	226	{
a3f61e7f	227	return ((char *) chan) + chan->priv_data_offset;
852c2936 MD	228	}
852c2936 MD	229
0d4aa2df MD	230	#ifndef __rb_same_type
	231	#define __rb_same_type(a, b) __builtin_types_compatible_p(typeof(a), typeof(b))
	232	#endif
	233
852c2936 MD	234	/*
852c2936 MD	235	* Issue warnings and disable channels upon internal error.
4cfec15c	236	* Can receive struct lttng_ust_lib_ring_buffer or struct lttng_ust_lib_ring_buffer_backend
852c2936 MD	237	* parameters.
	238	*/
	239	#define CHAN_WARN_ON(c, cond) \
	240	({ \
	241	struct channel *__chan; \
b5a3dfa5	242	int _____ret = caa_unlikely(cond); \
852c2936	243	if (_____ret) { \
0d4aa2df	244	if (__rb_same_type(*(c), struct channel_backend)) \
14641deb	245	__chan = caa_container_of((void *) (c), \
852c2936 MD	246	struct channel, \
852c2936 MD	247	backend); \
0d4aa2df	248	else if (__rb_same_type(*(c), struct channel)) \
852c2936 MD	249	__chan = (void *) (c); \
	250	else \
	251	BUG_ON(1); \
14641deb	252	uatomic_inc(&__chan->record_disabled); \
852c2936 MD	253	WARN_ON(1); \
852c2936 MD	254	} \
257ecc17	255	_____ret = _____ret; /* For clang "unused result". */ \
852c2936 MD	256	})
852c2936 MD	257
e92f3e28	258	#endif /* _LTTNG_RING_BUFFER_FRONTEND_TYPES_H */