[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-context.h>
#include "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 lttng_ust_lib_ring_buffer_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 lttng_ust_lib_ring_buffer_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 lttng_ust_lib_ring_buffer_channel *__chan;	\
		int _____ret = caa_unlikely(cond);				\
		if (_____ret) {						\
			if (__rb_same_type(*(c), struct channel_backend))	\
				__chan = caa_container_of((void *) (c),	\
					struct lttng_ust_lib_ring_buffer_channel, \
					backend);			\
			else if (__rb_same_type(*(c),			\
					struct lttng_ust_lib_ring_buffer_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
0466ac28 MD	21	#include <lttng/ringbuffer-context.h>
0466ac28 MD	22	#include "ringbuffer-config.h"
44c72f10	23	#include <usterr-signal-safe.h>
4931a13e	24	#include "backend_types.h"
1d498196	25	#include "shm_internal.h"
03d2d293	26	#include "shm_types.h"
a3bb4b27	27	#include "vatomic.h"
852c2936 MD	28
	29	/*
	30	* A switch is done during tracing or as a final flush after tracing (so it
	31	* won't write in the new sub-buffer).
	32	*/
	33	enum switch_mode { SWITCH_ACTIVE, SWITCH_FLUSH };
	34
852c2936	35	/* channel: collection of per-cpu ring buffers. */
74d81a6c	36	#define RB_CHANNEL_PADDING 32
5198080d	37	struct lttng_ust_lib_ring_buffer_channel {
14641deb	38	int record_disabled;
852c2936 MD	39	unsigned long commit_count_mask; /*
	40	* Commit count mask, removing
	41	* the MSBs corresponding to
	42	* bits used to represent the
	43	* subbuffer index.
	44	*/
	45
03d2d293 MD	46	unsigned long switch_timer_interval; /* Buffer flush (us) */
	47	timer_t switch_timer;
	48	int switch_timer_enabled;
	49
	50	unsigned long read_timer_interval; /* Reader wakeup (us) */
34a91bdb MD	51	timer_t read_timer;
	52	int read_timer_enabled;
	53
852c2936	54	int finalized; /* Has channel been finalized */
a3f61e7f	55	size_t priv_data_offset;
74d81a6c	56	unsigned int nr_streams; /* Number of streams */
03d2d293	57	struct lttng_ust_shm_handle *handle;
b2c5f61a MD	58	/* Extended options. */
	59	union {
	60	struct {
	61	int32_t blocking_timeout_ms;
	62	} s;
	63	char padding[RB_CHANNEL_PADDING];
	64	} u;
de85e7c3 MD	65	/*
	66	* Associated backend contains a variable-length array. Needs to
	67	* be last member.
	68	*/
	69	struct channel_backend backend; /* Associated backend */
b728d87e	70	} __attribute__((aligned(CAA_CACHE_LINE_SIZE)));
852c2936 MD	71
852c2936 MD	72	/* Per-subbuffer commit counters used on the hot path */
3c8964ba	73	#define RB_COMMIT_COUNT_HOT_PADDING 16
852c2936 MD	74	struct commit_counters_hot {
	75	union v_atomic cc; /* Commit counter */
	76	union v_atomic seq; /* Consecutive commits */
3c8964ba	77	char padding[RB_COMMIT_COUNT_HOT_PADDING];
b728d87e	78	} __attribute__((aligned(CAA_CACHE_LINE_SIZE)));
852c2936 MD	79
852c2936 MD	80	/* Per-subbuffer commit counters used only on cold paths */
3c8964ba	81	#define RB_COMMIT_COUNT_COLD_PADDING 24
852c2936 MD	82	struct commit_counters_cold {
852c2936 MD	83	union v_atomic cc_sb; /* Incremented _once_ at sb switch */
3c8964ba	84	char padding[RB_COMMIT_COUNT_COLD_PADDING];
b728d87e	85	} __attribute__((aligned(CAA_CACHE_LINE_SIZE)));
852c2936	86
852c2936	87	/* ring buffer state */
a9ff648c MD	88	#define RB_CRASH_DUMP_ABI_LEN 256
	89	#define RB_RING_BUFFER_PADDING 60
	90
	91	#define RB_CRASH_DUMP_ABI_MAGIC_LEN 16
	92
	93	/*
	94	* The 128-bit magic number is xor'd in the process data so it does not
	95	* cause a false positive when searching for buffers by scanning memory.
	96	* The actual magic number is:
	97	* 0x17, 0x7B, 0xF1, 0x77, 0xBF, 0x17, 0x7B, 0xF1,
	98	* 0x77, 0xBF, 0x17, 0x7B, 0xF1, 0x77, 0xBF, 0x17,
	99	*/
	100	#define RB_CRASH_DUMP_ABI_MAGIC_XOR \
	101	{ \
	102	0x17 ^ 0xFF, 0x7B ^ 0xFF, 0xF1 ^ 0xFF, 0x77 ^ 0xFF, \
	103	0xBF ^ 0xFF, 0x17 ^ 0xFF, 0x7B ^ 0xFF, 0xF1 ^ 0xFF, \
	104	0x77 ^ 0xFF, 0xBF ^ 0xFF, 0x17 ^ 0xFF, 0x7B ^ 0xFF, \
	105	0xF1 ^ 0xFF, 0x77 ^ 0xFF, 0xBF ^ 0xFF, 0x17 ^ 0xFF, \
	106	}
	107
	108	#define RB_CRASH_ENDIAN 0x1234
	109
	110	#define RB_CRASH_DUMP_ABI_MAJOR 0
	111	#define RB_CRASH_DUMP_ABI_MINOR 0
	112
	113	enum lttng_crash_type {
	114	LTTNG_CRASH_TYPE_UST = 0,
	115	LTTNG_CRASH_TYPE_KERNEL = 1,
	116	};
	117
	118	struct lttng_crash_abi {
	119	uint8_t magic[RB_CRASH_DUMP_ABI_MAGIC_LEN];
	120	uint64_t mmap_length; /* Overall lenght of crash record */
	121	uint16_t endian; /*
	122	* { 0x12, 0x34 }: big endian
	123	* { 0x34, 0x12 }: little endian
	124	*/
	125	uint16_t major; /* Major number. */
	126	uint16_t minor; /* Minor number. */
	127	uint8_t word_size; /* Word size (bytes). */
	128	uint8_t layout_type; /* enum lttng_crash_type */
	129
	130	struct {
	131	uint32_t prod_offset;
	132	uint32_t consumed_offset;
	133	uint32_t commit_hot_array;
	134	uint32_t commit_hot_seq;
	135	uint32_t buf_wsb_array;
	136	uint32_t buf_wsb_id;
	137	uint32_t sb_array;
	138	uint32_t sb_array_shmp_offset;
	139	uint32_t sb_backend_p_offset;
	140	uint32_t content_size;
	141	uint32_t packet_size;
	142	} __attribute__((packed)) offset;
	143	struct {
	144	uint8_t prod_offset;
	145	uint8_t consumed_offset;
	146	uint8_t commit_hot_seq;
	147	uint8_t buf_wsb_id;
	148	uint8_t sb_array_shmp_offset;
	149	uint8_t sb_backend_p_offset;
	150	uint8_t content_size;
	151	uint8_t packet_size;
152	} __attribute__((packed)) length;
153	struct {
154	uint32_t commit_hot_array;
155	uint32_t buf_wsb_array;
156	uint32_t sb_array;
157	} __attribute__((packed)) stride;
158
159	uint64_t buf_size; /* Size of the buffer */
160	uint64_t subbuf_size; /* Sub-buffer size */
161	uint64_t num_subbuf; /* Number of sub-buffers for writer */
162	uint32_t mode; /* Buffer mode: 0: overwrite, 1: discard */
163	} __attribute__((packed));
164
4cfec15c	165	struct lttng_ust_lib_ring_buffer {
a9ff648c MD	166	/* First 32 bytes are for the buffer crash dump ABI */
	167	struct lttng_crash_abi crash_abi;
	168
	169	/* 32 bytes cache-hot cacheline */
	170	union v_atomic __attribute__((aligned(32))) offset;
	171	/* Current offset in the buffer */
a6352fd4	172	DECLARE_SHMP(struct commit_counters_hot, commit_hot);
852c2936	173	/* Commit count per sub-buffer */
14641deb	174	long consumed; /*
852c2936 MD	175	* Current offset in the buffer
	176	* standard atomic access (shared)
	177	*/
14641deb	178	int record_disabled;
a9ff648c MD	179	/* End of cache-hot 32 bytes cacheline */
a9ff648c MD	180
852c2936 MD	181	union v_atomic last_tsc; /*
	182	* Last timestamp written in the buffer.
	183	*/
	184
a9ff648c MD	185	struct lttng_ust_lib_ring_buffer_backend backend;
a9ff648c MD	186	/* Associated backend */
852c2936	187
a6352fd4	188	DECLARE_SHMP(struct commit_counters_cold, commit_cold);
852c2936	189	/* Commit count per sub-buffer */
6c737d05 MD	190	DECLARE_SHMP(uint64_t, ts_end); /*
	191	* timestamp_end per sub-buffer.
	192	* Time is sampled by the
	193	* switch_*_end() callbacks
	194	* which are the last space
	195	* reservation performed in the
	196	* sub-buffer before it can be
	197	* fully committed and
	198	* delivered. This time value is
	199	* then read by the deliver
	200	* callback, performed by the
	201	* last commit before the buffer
	202	* becomes readable.
	203	*/
14641deb	204	long active_readers; /*
852c2936 MD	205	* Active readers count
	206	* standard atomic access (shared)
	207	*/
	208	/* Dropped records */
	209	union v_atomic records_lost_full; /* Buffer full */
	210	union v_atomic records_lost_wrap; /* Nested wrap-around */
	211	union v_atomic records_lost_big; /* Events too big */
	212	union v_atomic records_count; /* Number of records written */
	213	union v_atomic records_overrun; /* Number of overwritten records */
14641deb	214	//wait_queue_head_t read_wait; /* reader buffer-level wait queue */
852c2936	215	int finalized; /* buffer has been finalized */
852c2936 MD	216	unsigned long get_subbuf_consumed; /* Read-side consumed */
	217	unsigned long prod_snapshot; /* Producer count snapshot */
	218	unsigned long cons_snapshot; /* Consumer count snapshot */
34a91bdb	219	unsigned int get_subbuf:1; /* Sub-buffer being held by reader */
5d61a504	220	/* shmp pointer to self */
4cfec15c	221	DECLARE_SHMP(struct lttng_ust_lib_ring_buffer, self);
3c8964ba	222	char padding[RB_RING_BUFFER_PADDING];
b728d87e	223	} __attribute__((aligned(CAA_CACHE_LINE_SIZE)));
852c2936 MD	224
852c2936 MD	225	static inline
5198080d	226	void channel_get_private(struct lttng_ust_lib_ring_buffer_channel chan)
852c2936	227	{
a3f61e7f	228	return ((char *) chan) + chan->priv_data_offset;
852c2936 MD	229	}
852c2936 MD	230
0d4aa2df MD	231	#ifndef __rb_same_type
	232	#define __rb_same_type(a, b) __builtin_types_compatible_p(typeof(a), typeof(b))
	233	#endif
	234
852c2936 MD	235	/*
852c2936 MD	236	* Issue warnings and disable channels upon internal error.
4cfec15c	237	* Can receive struct lttng_ust_lib_ring_buffer or struct lttng_ust_lib_ring_buffer_backend
852c2936 MD	238	* parameters.
	239	*/
	240	#define CHAN_WARN_ON(c, cond) \
	241	({ \
5198080d	242	struct lttng_ust_lib_ring_buffer_channel *__chan; \
b5a3dfa5	243	int _____ret = caa_unlikely(cond); \
852c2936	244	if (_____ret) { \
0d4aa2df	245	if (__rb_same_type(*(c), struct channel_backend)) \
14641deb	246	__chan = caa_container_of((void *) (c), \
5198080d MJ	247	struct lttng_ust_lib_ring_buffer_channel, \
	248	backend); \
	249	else if (__rb_same_type(*(c), \
	250	struct lttng_ust_lib_ring_buffer_channel)) \
852c2936 MD	251	__chan = (void *) (c); \
	252	else \
	253	BUG_ON(1); \
14641deb	254	uatomic_inc(&__chan->record_disabled); \
852c2936 MD	255	WARN_ON(1); \
852c2936 MD	256	} \
257ecc17	257	_____ret = _____ret; /* For clang "unused result". */ \
852c2936 MD	258	})
852c2936 MD	259
e92f3e28	260	#endif /* _LTTNG_RING_BUFFER_FRONTEND_TYPES_H */