[lttng-ust.git] / include / lttng / ringbuffer-config.h

/*
 * SPDX-License-Identifier: MIT
 *
 * Copyright (C) 2010 Mathieu Desnoyers <mathieu.desnoyers@efficios.com>
 *
 * Ring buffer configuration header. Note: after declaring the standard inline
 * functions, clients should also include linux/ringbuffer/api.h.
 */

#ifndef _LTTNG_RING_BUFFER_CONFIG_H
#define _LTTNG_RING_BUFFER_CONFIG_H

#include <errno.h>
#include "lttng/ust-tracer.h"
#include <stdint.h>
#include <stddef.h>
#include <urcu/arch.h>
#include <string.h>
#include "lttng/align.h"
#include <lttng/ust-compiler.h>

struct lttng_ust_lib_ring_buffer;
struct channel;
struct lttng_ust_lib_ring_buffer_config;
struct lttng_ust_lib_ring_buffer_ctx;
struct lttng_ust_shm_handle;

/*
 * Ring buffer client callbacks. Only used by slow path, never on fast path.
 * For the fast path, record_header_size(), ring_buffer_clock_read() should be
 * provided as inline functions too.  These may simply return 0 if not used by
 * the client.
 */
struct lttng_ust_lib_ring_buffer_client_cb {
	/* Mandatory callbacks */

	/* A static inline version is also required for fast path */
	uint64_t (*ring_buffer_clock_read) (struct channel *chan);
	size_t (*record_header_size) (const struct lttng_ust_lib_ring_buffer_config *config,
				      struct channel *chan, size_t offset,
				      size_t *pre_header_padding,
				      struct lttng_ust_lib_ring_buffer_ctx *ctx,
				      void *client_ctx);

	/* Slow path only, at subbuffer switch */
	size_t (*subbuffer_header_size) (void);
	void (*buffer_begin) (struct lttng_ust_lib_ring_buffer *buf, uint64_t tsc,
			      unsigned int subbuf_idx,
			      struct lttng_ust_shm_handle *handle);
	void (*buffer_end) (struct lttng_ust_lib_ring_buffer *buf, uint64_t tsc,
			    unsigned int subbuf_idx, unsigned long data_size,
			    struct lttng_ust_shm_handle *handle);

	/* Optional callbacks (can be set to NULL) */

	/* Called at buffer creation/finalize */
	int (*buffer_create) (struct lttng_ust_lib_ring_buffer *buf, void *priv,
			      int cpu, const char *name,
			      struct lttng_ust_shm_handle *handle);
	/*
	 * Clients should guarantee that no new reader handle can be opened
	 * after finalize.
	 */
	void (*buffer_finalize) (struct lttng_ust_lib_ring_buffer *buf,
				 void *priv, int cpu,
				 struct lttng_ust_shm_handle *handle);

	/*
	 * Extract header length, payload length and timestamp from event
	 * record. Used by buffer iterators. Timestamp is only used by channel
	 * iterator.
	 */
	void (*record_get) (const struct lttng_ust_lib_ring_buffer_config *config,
			    struct channel *chan, struct lttng_ust_lib_ring_buffer *buf,
			    size_t offset, size_t *header_len,
			    size_t *payload_len, uint64_t *timestamp,
			    struct lttng_ust_shm_handle *handle);
	/*
	 * Offset and size of content size field in client.
	 */
	void (*content_size_field) (const struct lttng_ust_lib_ring_buffer_config *config,
				size_t *offset, size_t *length);
	void (*packet_size_field) (const struct lttng_ust_lib_ring_buffer_config *config,
				size_t *offset, size_t *length);
};

/*
 * Ring buffer instance configuration.
 *
 * Declare as "static const" within the client object to ensure the inline fast
 * paths can be optimized.
 *
 * alloc/sync pairs:
 *
 * RING_BUFFER_ALLOC_PER_CPU and RING_BUFFER_SYNC_PER_CPU :
 *   Per-cpu buffers with per-cpu synchronization. Tracing must be performed
 *   with preemption disabled (lib_ring_buffer_get_cpu() and
 *   lib_ring_buffer_put_cpu()).
 *
 * RING_BUFFER_ALLOC_PER_CPU and RING_BUFFER_SYNC_GLOBAL :
 *   Per-cpu buffer with global synchronization. Tracing can be performed with
 *   preemption enabled, statistically stays on the local buffers.
 *
 * RING_BUFFER_ALLOC_GLOBAL and RING_BUFFER_SYNC_PER_CPU :
 *   Should only be used for buffers belonging to a single thread or protected
 *   by mutual exclusion by the client. Note that periodical sub-buffer switch
 *   should be disabled in this kind of configuration.
 *
 * RING_BUFFER_ALLOC_GLOBAL and RING_BUFFER_SYNC_GLOBAL :
 *   Global shared buffer with global synchronization.
 *
 * wakeup:
 *
 * RING_BUFFER_WAKEUP_BY_TIMER uses per-cpu deferrable timers to poll the
 * buffers and wake up readers if data is ready. Mainly useful for tracers which
 * don't want to call into the wakeup code on the tracing path. Use in
 * combination with "read_timer_interval" channel_create() argument.
 *
 * RING_BUFFER_WAKEUP_BY_WRITER directly wakes up readers when a subbuffer is
 * ready to read. Lower latencies before the reader is woken up. Mainly suitable
 * for drivers.
 *
 * RING_BUFFER_WAKEUP_NONE does not perform any wakeup whatsoever. The client
 * has the responsibility to perform wakeups.
 */
#define LTTNG_UST_RING_BUFFER_CONFIG_PADDING	20

enum lttng_ust_lib_ring_buffer_alloc_types {
	RING_BUFFER_ALLOC_PER_CPU,
	RING_BUFFER_ALLOC_GLOBAL,
};

enum lttng_ust_lib_ring_buffer_sync_types {
	RING_BUFFER_SYNC_PER_CPU,	/* Wait-free */
	RING_BUFFER_SYNC_GLOBAL,	/* Lock-free */
};

enum lttng_ust_lib_ring_buffer_mode_types {
	RING_BUFFER_OVERWRITE = 0,	/* Overwrite when buffer full */
	RING_BUFFER_DISCARD = 1,	/* Discard when buffer full */
};

enum lttng_ust_lib_ring_buffer_output_types {
	RING_BUFFER_SPLICE,
	RING_BUFFER_MMAP,
	RING_BUFFER_READ,		/* TODO */
	RING_BUFFER_ITERATOR,
	RING_BUFFER_NONE,
};

enum lttng_ust_lib_ring_buffer_backend_types {
	RING_BUFFER_PAGE,
	RING_BUFFER_VMAP,		/* TODO */
	RING_BUFFER_STATIC,		/* TODO */
};

enum lttng_ust_lib_ring_buffer_oops_types {
	RING_BUFFER_NO_OOPS_CONSISTENCY,
	RING_BUFFER_OOPS_CONSISTENCY,
};

enum lttng_ust_lib_ring_buffer_ipi_types {
	RING_BUFFER_IPI_BARRIER,
	RING_BUFFER_NO_IPI_BARRIER,
};

enum lttng_ust_lib_ring_buffer_wakeup_types {
	RING_BUFFER_WAKEUP_BY_TIMER,	/* wake up performed by timer */
	RING_BUFFER_WAKEUP_BY_WRITER,	/*
					 * writer wakes up reader,
					 * not lock-free
					 * (takes spinlock).
					 */
};

struct lttng_ust_lib_ring_buffer_config {
	enum lttng_ust_lib_ring_buffer_alloc_types alloc;
	enum lttng_ust_lib_ring_buffer_sync_types sync;
	enum lttng_ust_lib_ring_buffer_mode_types mode;
	enum lttng_ust_lib_ring_buffer_output_types output;
	enum lttng_ust_lib_ring_buffer_backend_types backend;
	enum lttng_ust_lib_ring_buffer_oops_types oops;
	enum lttng_ust_lib_ring_buffer_ipi_types ipi;
	enum lttng_ust_lib_ring_buffer_wakeup_types wakeup;
	/*
	 * tsc_bits: timestamp bits saved at each record.
	 *   0 and 64 disable the timestamp compression scheme.
	 */
	unsigned int tsc_bits;
	struct lttng_ust_lib_ring_buffer_client_cb cb;
	/*
	 * client_type is used by the consumer process (which is in a
	 * different address space) to lookup the appropriate client
	 * callbacks and update the cb pointers.
	 */
	int client_type;
	int _unused1;
	const struct lttng_ust_lib_ring_buffer_client_cb *cb_ptr;
	char padding[LTTNG_UST_RING_BUFFER_CONFIG_PADDING];
};

/*
 * ring buffer context
 *
 * Context passed to lib_ring_buffer_reserve(), lib_ring_buffer_commit(),
 * lib_ring_buffer_try_discard_reserve(), lib_ring_buffer_align_ctx() and
 * lib_ring_buffer_write().
 *
 * IMPORTANT: this structure is part of the ABI between the probe and
 * UST. Fields need to be only added at the end, never reordered, never
 * removed.
 */
#define LTTNG_UST_RING_BUFFER_CTX_PADDING	\
		(24 - sizeof(int) - sizeof(void *) - sizeof(void *))
struct lttng_ust_lib_ring_buffer_ctx {
	/* input received by lib_ring_buffer_reserve(), saved here. */
	struct channel *chan;		/* channel */
	void *priv;			/* client private data */
	struct lttng_ust_shm_handle *handle;	/* shared-memory handle */
	size_t data_size;		/* size of payload */
	int largest_align;		/*
					 * alignment of the largest element
					 * in the payload
					 */
	int cpu;			/* processor id */

	/* output from lib_ring_buffer_reserve() */
	struct lttng_ust_lib_ring_buffer *buf;	/*
					 * buffer corresponding to processor id
					 * for this channel
					 */
	size_t slot_size;		/* size of the reserved slot */
	unsigned long buf_offset;	/* offset following the record header */
	unsigned long pre_offset;	/*
					 * Initial offset position _before_
					 * the record is written. Positioned
					 * prior to record header alignment
					 * padding.
					 */
	uint64_t tsc;			/* time-stamp counter value */
	unsigned int rflags;		/* reservation flags */
	/*
	 * The field ctx_len is the length of struct
	 * lttng_ust_lib_ring_buffer_ctx as known by the user of
	 * lib_ring_buffer_ctx_init.
	 */
	unsigned int ctx_len;
	void *ip;			/* caller ip address */
	void *priv2;			/* 2nd priv data */
	char padding2[LTTNG_UST_RING_BUFFER_CTX_PADDING];
	/*
	 * This is the end of the initial fields expected by the original ABI
	 * between probes and UST. Only the fields above can be used if
	 * ctx_len is 0. Use the value of ctx_len to find out which of the
	 * following fields may be used.
	 */
	struct lttng_ust_lib_ring_buffer_backend_pages *backend_pages;
};

/**
 * lib_ring_buffer_ctx_init - initialize ring buffer context
 * @ctx: ring buffer context to initialize
 * @chan: channel
 * @priv: client private data
 * @data_size: size of record data payload
 * @largest_align: largest alignment within data payload types
 * @cpu: processor id
 */
static inline lttng_ust_notrace
void lib_ring_buffer_ctx_init(struct lttng_ust_lib_ring_buffer_ctx *ctx,
			      struct channel *chan, void *priv,
			      size_t data_size, int largest_align,
			      int cpu, struct lttng_ust_shm_handle *handle,
			      void *priv2);
static inline
void lib_ring_buffer_ctx_init(struct lttng_ust_lib_ring_buffer_ctx *ctx,
			      struct channel *chan, void *priv,
			      size_t data_size, int largest_align,
			      int cpu, struct lttng_ust_shm_handle *handle,
			      void *priv2)
{
	ctx->chan = chan;
	ctx->priv = priv;
	ctx->data_size = data_size;
	ctx->largest_align = largest_align;
	ctx->cpu = cpu;
	ctx->rflags = 0;
	ctx->handle = handle;
	ctx->ctx_len = sizeof(struct lttng_ust_lib_ring_buffer_ctx);
	ctx->ip = 0;
	ctx->priv2 = priv2;
	memset(ctx->padding2, 0, LTTNG_UST_RING_BUFFER_CTX_PADDING);
}

/*
 * Reservation flags.
 *
 * RING_BUFFER_RFLAG_FULL_TSC
 *
 * This flag is passed to record_header_size() and to the primitive used to
 * write the record header. It indicates that the full 64-bit time value is
 * needed in the record header. If this flag is not set, the record header needs
 * only to contain "tsc_bits" bit of time value.
 *
 * Reservation flags can be added by the client, starting from
 * "(RING_BUFFER_FLAGS_END << 0)". It can be used to pass information from
 * record_header_size() to lib_ring_buffer_write_record_header().
 */
#define	RING_BUFFER_RFLAG_FULL_TSC		(1U << 0)
#define RING_BUFFER_RFLAG_END			(1U << 1)

/*
 * We need to define RING_BUFFER_ALIGN_ATTR so it is known early at
 * compile-time. We have to duplicate the "config->align" information and the
 * definition here because config->align is used both in the slow and fast
 * paths, but RING_BUFFER_ALIGN_ATTR is only available for the client code.
 */
#ifdef RING_BUFFER_ALIGN

# define RING_BUFFER_ALIGN_ATTR		/* Default arch alignment */

/*
 * Calculate the offset needed to align the type.
 * size_of_type must be non-zero.
 */
static inline lttng_ust_notrace
unsigned int lib_ring_buffer_align(size_t align_drift, size_t size_of_type);
static inline
unsigned int lib_ring_buffer_align(size_t align_drift, size_t size_of_type)
{
	return lttng_ust_offset_align(align_drift, size_of_type);
}

#else

# define RING_BUFFER_ALIGN_ATTR __attribute__((packed))

/*
 * Calculate the offset needed to align the type.
 * size_of_type must be non-zero.
 */
static inline lttng_ust_notrace
unsigned int lib_ring_buffer_align(size_t align_drift, size_t size_of_type);
static inline
unsigned int lib_ring_buffer_align(size_t align_drift, size_t size_of_type)
{
	return 0;
}

#endif

/**
 * lib_ring_buffer_align_ctx - Align context offset on "alignment"
 * @ctx: ring buffer context.
 */
static inline lttng_ust_notrace
void lib_ring_buffer_align_ctx(struct lttng_ust_lib_ring_buffer_ctx *ctx,
			   size_t alignment);
static inline
void lib_ring_buffer_align_ctx(struct lttng_ust_lib_ring_buffer_ctx *ctx,
			   size_t alignment)
{
	ctx->buf_offset += lib_ring_buffer_align(ctx->buf_offset,
						 alignment);
}

/*
 * lib_ring_buffer_check_config() returns 0 on success.
 * Used internally to check for valid configurations at channel creation.
 */
static inline lttng_ust_notrace
int lib_ring_buffer_check_config(const struct lttng_ust_lib_ring_buffer_config *config,
			     unsigned int switch_timer_interval,
			     unsigned int read_timer_interval);
static inline
int lib_ring_buffer_check_config(const struct lttng_ust_lib_ring_buffer_config *config,
			     unsigned int switch_timer_interval,
			     unsigned int read_timer_interval)
{
	if (config->alloc == RING_BUFFER_ALLOC_GLOBAL
	    && config->sync == RING_BUFFER_SYNC_PER_CPU
	    && switch_timer_interval)
		return -EINVAL;
	return 0;
}

#endif /* _LTTNG_RING_BUFFER_CONFIG_H */
Commit	Line	Data
a6352fd4	1	/*
c0c0989a	2	* SPDX-License-Identifier: MIT
a6352fd4	3	*
c0c0989a	4	* Copyright (C) 2010 Mathieu Desnoyers <mathieu.desnoyers@efficios.com>
a6352fd4 MD	5	*
	6	* Ring buffer configuration header. Note: after declaring the standard inline
	7	* functions, clients should also include linux/ringbuffer/api.h.
a6352fd4 MD	8	*/
a6352fd4 MD	9
c0c0989a MJ	10	#ifndef _LTTNG_RING_BUFFER_CONFIG_H
	11	#define _LTTNG_RING_BUFFER_CONFIG_H
	12
a6352fd4	13	#include <errno.h>
4318ae1b	14	#include "lttng/ust-tracer.h"
b728d87e MD	15	#include <stdint.h>
	16	#include <stddef.h>
	17	#include <urcu/arch.h>
2e707419	18	#include <string.h>
4318ae1b	19	#include "lttng/align.h"
a8909ba5	20	#include <lttng/ust-compiler.h>
a6352fd4	21
4cfec15c	22	struct lttng_ust_lib_ring_buffer;
a6352fd4	23	struct channel;
4cfec15c MD	24	struct lttng_ust_lib_ring_buffer_config;
4cfec15c MD	25	struct lttng_ust_lib_ring_buffer_ctx;
5a821cd6	26	struct lttng_ust_shm_handle;
a6352fd4 MD	27
	28	/*
	29	* Ring buffer client callbacks. Only used by slow path, never on fast path.
	30	* For the fast path, record_header_size(), ring_buffer_clock_read() should be
	31	* provided as inline functions too. These may simply return 0 if not used by
	32	* the client.
	33	*/
4cfec15c	34	struct lttng_ust_lib_ring_buffer_client_cb {
a6352fd4 MD	35	/* Mandatory callbacks */
	36
	37	/* A static inline version is also required for fast path */
2fed87ae	38	uint64_t (ring_buffer_clock_read) (struct channel chan);
4cfec15c	39	size_t (record_header_size) (const struct lttng_ust_lib_ring_buffer_config config,
a6352fd4 MD	40	struct channel *chan, size_t offset,
a6352fd4 MD	41	size_t *pre_header_padding,
e56bb47c MD	42	struct lttng_ust_lib_ring_buffer_ctx *ctx,
e56bb47c MD	43	void *client_ctx);
a6352fd4 MD	44
	45	/* Slow path only, at subbuffer switch */
	46	size_t (*subbuffer_header_size) (void);
2fed87ae	47	void (buffer_begin) (struct lttng_ust_lib_ring_buffer buf, uint64_t tsc,
1d498196	48	unsigned int subbuf_idx,
38fae1d3	49	struct lttng_ust_shm_handle *handle);
2fed87ae	50	void (buffer_end) (struct lttng_ust_lib_ring_buffer buf, uint64_t tsc,
1d498196	51	unsigned int subbuf_idx, unsigned long data_size,
38fae1d3	52	struct lttng_ust_shm_handle *handle);
a6352fd4 MD	53
	54	/* Optional callbacks (can be set to NULL) */
	55
	56	/* Called at buffer creation/finalize */
4cfec15c	57	int (buffer_create) (struct lttng_ust_lib_ring_buffer buf, void *priv,
1d498196	58	int cpu, const char *name,
38fae1d3	59	struct lttng_ust_shm_handle *handle);
a6352fd4 MD	60	/*
	61	* Clients should guarantee that no new reader handle can be opened
	62	* after finalize.
	63	*/
4cfec15c	64	void (buffer_finalize) (struct lttng_ust_lib_ring_buffer buf,
1d498196	65	void *priv, int cpu,
38fae1d3	66	struct lttng_ust_shm_handle *handle);
a6352fd4 MD	67
	68	/*
	69	* Extract header length, payload length and timestamp from event
	70	* record. Used by buffer iterators. Timestamp is only used by channel
	71	* iterator.
	72	*/
4cfec15c MD	73	void (record_get) (const struct lttng_ust_lib_ring_buffer_config config,
4cfec15c MD	74	struct channel chan, struct lttng_ust_lib_ring_buffer buf,
a6352fd4	75	size_t offset, size_t *header_len,
2fed87ae	76	size_t payload_len, uint64_t timestamp,
38fae1d3	77	struct lttng_ust_shm_handle *handle);
a9ff648c MD	78	/*
	79	* Offset and size of content size field in client.
	80	*/
	81	void (content_size_field) (const struct lttng_ust_lib_ring_buffer_config config,
	82	size_t offset, size_t length);
	83	void (packet_size_field) (const struct lttng_ust_lib_ring_buffer_config config,
	84	size_t offset, size_t length);
a6352fd4 MD	85	};
	86
	87	/*
	88	* Ring buffer instance configuration.
	89	*
	90	* Declare as "static const" within the client object to ensure the inline fast
	91	* paths can be optimized.
	92	*
	93	* alloc/sync pairs:
	94	*
	95	* RING_BUFFER_ALLOC_PER_CPU and RING_BUFFER_SYNC_PER_CPU :
	96	* Per-cpu buffers with per-cpu synchronization. Tracing must be performed
	97	* with preemption disabled (lib_ring_buffer_get_cpu() and
	98	* lib_ring_buffer_put_cpu()).
	99	*
	100	* RING_BUFFER_ALLOC_PER_CPU and RING_BUFFER_SYNC_GLOBAL :
	101	* Per-cpu buffer with global synchronization. Tracing can be performed with
	102	* preemption enabled, statistically stays on the local buffers.
	103	*
	104	* RING_BUFFER_ALLOC_GLOBAL and RING_BUFFER_SYNC_PER_CPU :
	105	* Should only be used for buffers belonging to a single thread or protected
	106	* by mutual exclusion by the client. Note that periodical sub-buffer switch
	107	* should be disabled in this kind of configuration.
	108	*
	109	* RING_BUFFER_ALLOC_GLOBAL and RING_BUFFER_SYNC_GLOBAL :
	110	* Global shared buffer with global synchronization.
	111	*
	112	* wakeup:
	113	*
	114	* RING_BUFFER_WAKEUP_BY_TIMER uses per-cpu deferrable timers to poll the
	115	* buffers and wake up readers if data is ready. Mainly useful for tracers which
	116	* don't want to call into the wakeup code on the tracing path. Use in
	117	* combination with "read_timer_interval" channel_create() argument.
	118	*
	119	* RING_BUFFER_WAKEUP_BY_WRITER directly wakes up readers when a subbuffer is
	120	* ready to read. Lower latencies before the reader is woken up. Mainly suitable
	121	* for drivers.
	122	*
	123	* RING_BUFFER_WAKEUP_NONE does not perform any wakeup whatsoever. The client
	124	* has the responsibility to perform wakeups.
	125	*/
82b9bde8	126	#define LTTNG_UST_RING_BUFFER_CONFIG_PADDING 20
46d52200 ZT	127
	128	enum lttng_ust_lib_ring_buffer_alloc_types {
	129	RING_BUFFER_ALLOC_PER_CPU,
	130	RING_BUFFER_ALLOC_GLOBAL,
	131	};
	132
	133	enum lttng_ust_lib_ring_buffer_sync_types {
	134	RING_BUFFER_SYNC_PER_CPU, /* Wait-free */
	135	RING_BUFFER_SYNC_GLOBAL, /* Lock-free */
	136	};
	137
	138	enum lttng_ust_lib_ring_buffer_mode_types {
a9ff648c MD	139	RING_BUFFER_OVERWRITE = 0, /* Overwrite when buffer full */
a9ff648c MD	140	RING_BUFFER_DISCARD = 1, /* Discard when buffer full */
46d52200 ZT	141	};
	142
	143	enum lttng_ust_lib_ring_buffer_output_types {
	144	RING_BUFFER_SPLICE,
	145	RING_BUFFER_MMAP,
	146	RING_BUFFER_READ, /* TODO */
	147	RING_BUFFER_ITERATOR,
	148	RING_BUFFER_NONE,
	149	};
	150
	151	enum lttng_ust_lib_ring_buffer_backend_types {
	152	RING_BUFFER_PAGE,
	153	RING_BUFFER_VMAP, /* TODO */
	154	RING_BUFFER_STATIC, /* TODO */
	155	};
	156
	157	enum lttng_ust_lib_ring_buffer_oops_types {
	158	RING_BUFFER_NO_OOPS_CONSISTENCY,
	159	RING_BUFFER_OOPS_CONSISTENCY,
	160	};
	161
	162	enum lttng_ust_lib_ring_buffer_ipi_types {
	163	RING_BUFFER_IPI_BARRIER,
	164	RING_BUFFER_NO_IPI_BARRIER,
	165	};
	166
	167	enum lttng_ust_lib_ring_buffer_wakeup_types {
	168	RING_BUFFER_WAKEUP_BY_TIMER, /* wake up performed by timer */
	169	RING_BUFFER_WAKEUP_BY_WRITER, /*
	170	* writer wakes up reader,
	171	* not lock-free
	172	* (takes spinlock).
	173	*/
	174	};
	175
4cfec15c	176	struct lttng_ust_lib_ring_buffer_config {
46d52200 ZT	177	enum lttng_ust_lib_ring_buffer_alloc_types alloc;
	178	enum lttng_ust_lib_ring_buffer_sync_types sync;
	179	enum lttng_ust_lib_ring_buffer_mode_types mode;
	180	enum lttng_ust_lib_ring_buffer_output_types output;
	181	enum lttng_ust_lib_ring_buffer_backend_types backend;
	182	enum lttng_ust_lib_ring_buffer_oops_types oops;
	183	enum lttng_ust_lib_ring_buffer_ipi_types ipi;
	184	enum lttng_ust_lib_ring_buffer_wakeup_types wakeup;
a6352fd4 MD	185	/*
	186	* tsc_bits: timestamp bits saved at each record.
	187	* 0 and 64 disable the timestamp compression scheme.
	188	*/
	189	unsigned int tsc_bits;
4cfec15c	190	struct lttng_ust_lib_ring_buffer_client_cb cb;
c1fca457 MD	191	/*
	192	* client_type is used by the consumer process (which is in a
	193	* different address space) to lookup the appropriate client
	194	* callbacks and update the cb pointers.
	195	*/
	196	int client_type;
82b9bde8 JD	197	int _unused1;
82b9bde8 JD	198	const struct lttng_ust_lib_ring_buffer_client_cb *cb_ptr;
2e707419	199	char padding[LTTNG_UST_RING_BUFFER_CONFIG_PADDING];
a6352fd4 MD	200	};
	201
	202	/*
	203	* ring buffer context
	204	*
	205	* Context passed to lib_ring_buffer_reserve(), lib_ring_buffer_commit(),
	206	* lib_ring_buffer_try_discard_reserve(), lib_ring_buffer_align_ctx() and
	207	* lib_ring_buffer_write().
180901e6 MD	208	*
	209	* IMPORTANT: this structure is part of the ABI between the probe and
	210	* UST. Fields need to be only added at the end, never reordered, never
	211	* removed.
a6352fd4	212	*/
96f85541	213	#define LTTNG_UST_RING_BUFFER_CTX_PADDING \
53569322	214	(24 - sizeof(int) - sizeof(void ) - sizeof(void ))
4cfec15c	215	struct lttng_ust_lib_ring_buffer_ctx {
a6352fd4 MD	216	/* input received by lib_ring_buffer_reserve(), saved here. */
	217	struct channel chan; / channel */
	218	void priv; / client private data */
38fae1d3	219	struct lttng_ust_shm_handle handle; / shared-memory handle */
a6352fd4 MD	220	size_t data_size; /* size of payload */
	221	int largest_align; /*
	222	* alignment of the largest element
	223	* in the payload
	224	*/
	225	int cpu; /* processor id */
	226
	227	/* output from lib_ring_buffer_reserve() */
4cfec15c	228	struct lttng_ust_lib_ring_buffer buf; /
a6352fd4 MD	229	* buffer corresponding to processor id
	230	* for this channel
	231	*/
	232	size_t slot_size; /* size of the reserved slot */
	233	unsigned long buf_offset; /* offset following the record header */
	234	unsigned long pre_offset; /*
	235	* Initial offset position _before_
	236	* the record is written. Positioned
	237	* prior to record header alignment
	238	* padding.
	239	*/
2fed87ae	240	uint64_t tsc; /* time-stamp counter value */
a6352fd4	241	unsigned int rflags; /* reservation flags */
82cd0cfd MD	242	/*
	243	* The field ctx_len is the length of struct
	244	* lttng_ust_lib_ring_buffer_ctx as known by the user of
	245	* lib_ring_buffer_ctx_init.
	246	*/
	247	unsigned int ctx_len;
96f85541	248	void ip; / caller ip address */
53569322	249	void priv2; / 2nd priv data */
96f85541	250	char padding2[LTTNG_UST_RING_BUFFER_CTX_PADDING];
82cd0cfd MD	251	/*
	252	* This is the end of the initial fields expected by the original ABI
	253	* between probes and UST. Only the fields above can be used if
	254	* ctx_len is 0. Use the value of ctx_len to find out which of the
	255	* following fields may be used.
	256	*/
a3492932	257	struct lttng_ust_lib_ring_buffer_backend_pages *backend_pages;
a6352fd4 MD	258	};
	259
	260	/**
	261	* lib_ring_buffer_ctx_init - initialize ring buffer context
	262	* @ctx: ring buffer context to initialize
	263	* @chan: channel
	264	* @priv: client private data
	265	* @data_size: size of record data payload
	266	* @largest_align: largest alignment within data payload types
	267	* @cpu: processor id
	268	*/
a8909ba5 PW	269	static inline lttng_ust_notrace
	270	void lib_ring_buffer_ctx_init(struct lttng_ust_lib_ring_buffer_ctx *ctx,
	271	struct channel chan, void priv,
	272	size_t data_size, int largest_align,
53569322 MD	273	int cpu, struct lttng_ust_shm_handle *handle,
53569322 MD	274	void *priv2);
a6352fd4	275	static inline
4cfec15c	276	void lib_ring_buffer_ctx_init(struct lttng_ust_lib_ring_buffer_ctx *ctx,
a6352fd4 MD	277	struct channel chan, void priv,
a6352fd4 MD	278	size_t data_size, int largest_align,
53569322 MD	279	int cpu, struct lttng_ust_shm_handle *handle,
53569322 MD	280	void *priv2)
a6352fd4 MD	281	{
	282	ctx->chan = chan;
	283	ctx->priv = priv;
	284	ctx->data_size = data_size;
	285	ctx->largest_align = largest_align;
	286	ctx->cpu = cpu;
	287	ctx->rflags = 0;
1d498196	288	ctx->handle = handle;
82cd0cfd	289	ctx->ctx_len = sizeof(struct lttng_ust_lib_ring_buffer_ctx);
96f85541	290	ctx->ip = 0;
53569322	291	ctx->priv2 = priv2;
96f85541	292	memset(ctx->padding2, 0, LTTNG_UST_RING_BUFFER_CTX_PADDING);
a6352fd4 MD	293	}
	294
	295	/*
	296	* Reservation flags.
	297	*
	298	* RING_BUFFER_RFLAG_FULL_TSC
	299	*
	300	* This flag is passed to record_header_size() and to the primitive used to
	301	* write the record header. It indicates that the full 64-bit time value is
	302	* needed in the record header. If this flag is not set, the record header needs
	303	* only to contain "tsc_bits" bit of time value.
	304	*
	305	* Reservation flags can be added by the client, starting from
	306	* "(RING_BUFFER_FLAGS_END << 0)". It can be used to pass information from
	307	* record_header_size() to lib_ring_buffer_write_record_header().
	308	*/
	309	#define RING_BUFFER_RFLAG_FULL_TSC (1U << 0)
	310	#define RING_BUFFER_RFLAG_END (1U << 1)
	311
	312	/*
	313	* We need to define RING_BUFFER_ALIGN_ATTR so it is known early at
	314	* compile-time. We have to duplicate the "config->align" information and the
	315	* definition here because config->align is used both in the slow and fast
	316	* paths, but RING_BUFFER_ALIGN_ATTR is only available for the client code.
	317	*/
	318	#ifdef RING_BUFFER_ALIGN
	319
	320	# define RING_BUFFER_ALIGN_ATTR /* Default arch alignment */
	321
	322	/*
	323	* Calculate the offset needed to align the type.
	324	* size_of_type must be non-zero.
	325	*/
a8909ba5 PW	326	static inline lttng_ust_notrace
a8909ba5 PW	327	unsigned int lib_ring_buffer_align(size_t align_drift, size_t size_of_type);
a6352fd4 MD	328	static inline
	329	unsigned int lib_ring_buffer_align(size_t align_drift, size_t size_of_type)
	330	{
b72687b8	331	return lttng_ust_offset_align(align_drift, size_of_type);
a6352fd4 MD	332	}
	333
	334	#else
	335
	336	# define RING_BUFFER_ALIGN_ATTR __attribute__((packed))
	337
	338	/*
	339	* Calculate the offset needed to align the type.
	340	* size_of_type must be non-zero.
	341	*/
a8909ba5 PW	342	static inline lttng_ust_notrace
a8909ba5 PW	343	unsigned int lib_ring_buffer_align(size_t align_drift, size_t size_of_type);
a6352fd4 MD	344	static inline
	345	unsigned int lib_ring_buffer_align(size_t align_drift, size_t size_of_type)
	346	{
	347	return 0;
	348	}
	349
	350	#endif
	351
	352	/**
	353	* lib_ring_buffer_align_ctx - Align context offset on "alignment"
	354	* @ctx: ring buffer context.
	355	*/
a8909ba5 PW	356	static inline lttng_ust_notrace
	357	void lib_ring_buffer_align_ctx(struct lttng_ust_lib_ring_buffer_ctx *ctx,
	358	size_t alignment);
a6352fd4	359	static inline
4cfec15c	360	void lib_ring_buffer_align_ctx(struct lttng_ust_lib_ring_buffer_ctx *ctx,
a6352fd4 MD	361	size_t alignment)
	362	{
	363	ctx->buf_offset += lib_ring_buffer_align(ctx->buf_offset,
	364	alignment);
	365	}
	366
	367	/*
	368	* lib_ring_buffer_check_config() returns 0 on success.
	369	* Used internally to check for valid configurations at channel creation.
	370	*/
a8909ba5 PW	371	static inline lttng_ust_notrace
	372	int lib_ring_buffer_check_config(const struct lttng_ust_lib_ring_buffer_config *config,
	373	unsigned int switch_timer_interval,
	374	unsigned int read_timer_interval);
a6352fd4	375	static inline
4cfec15c	376	int lib_ring_buffer_check_config(const struct lttng_ust_lib_ring_buffer_config *config,
a6352fd4 MD	377	unsigned int switch_timer_interval,
	378	unsigned int read_timer_interval)
	379	{
	380	if (config->alloc == RING_BUFFER_ALLOC_GLOBAL
	381	&& config->sync == RING_BUFFER_SYNC_PER_CPU
	382	&& switch_timer_interval)
	383	return -EINVAL;
	384	return 0;
	385	}
	386
e92f3e28	387	#endif /* _LTTNG_RING_BUFFER_CONFIG_H */