[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 lttng_ust_lib_ring_buffer_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 lttng_ust_lib_ring_buffer_channel *chan);
	size_t (*record_header_size) (const struct lttng_ust_lib_ring_buffer_config *config,
				      struct lttng_ust_lib_ring_buffer_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 lttng_ust_lib_ring_buffer_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	64
struct lttng_ust_lib_ring_buffer_ctx {
	uint32_t struct_size;		/* Size of this structure. */

	/* input received by lib_ring_buffer_reserve(), saved here. */
	struct lttng_ust_lib_ring_buffer_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 */
	void *ip;			/* caller ip address */
	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 lttng_ust_lib_ring_buffer_channel *chan,
			      void *priv, size_t data_size, int largest_align,
			      int cpu, struct lttng_ust_shm_handle *handle);
static inline
void lib_ring_buffer_ctx_init(struct lttng_ust_lib_ring_buffer_ctx *ctx,
			      struct lttng_ust_lib_ring_buffer_channel *chan,
			      void *priv, size_t data_size, int largest_align,
			      int cpu, struct lttng_ust_shm_handle *handle)
{
	ctx->struct_size = sizeof(struct lttng_ust_lib_ring_buffer_ctx);
	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->ip = 0;
}

/*
 * 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;
5198080d	23	struct lttng_ust_lib_ring_buffer_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 */
5198080d	38	uint64_t (ring_buffer_clock_read) (struct lttng_ust_lib_ring_buffer_channel chan);
4cfec15c	39	size_t (record_header_size) (const struct lttng_ust_lib_ring_buffer_config config,
5198080d MJ	40	struct lttng_ust_lib_ring_buffer_channel *chan,
5198080d MJ	41	size_t offset,
a6352fd4	42	size_t *pre_header_padding,
e56bb47c MD	43	struct lttng_ust_lib_ring_buffer_ctx *ctx,
e56bb47c MD	44	void *client_ctx);
a6352fd4 MD	45
	46	/* Slow path only, at subbuffer switch */
	47	size_t (*subbuffer_header_size) (void);
2fed87ae	48	void (buffer_begin) (struct lttng_ust_lib_ring_buffer buf, uint64_t tsc,
1d498196	49	unsigned int subbuf_idx,
38fae1d3	50	struct lttng_ust_shm_handle *handle);
2fed87ae	51	void (buffer_end) (struct lttng_ust_lib_ring_buffer buf, uint64_t tsc,
1d498196	52	unsigned int subbuf_idx, unsigned long data_size,
38fae1d3	53	struct lttng_ust_shm_handle *handle);
a6352fd4 MD	54
	55	/* Optional callbacks (can be set to NULL) */
	56
	57	/* Called at buffer creation/finalize */
4cfec15c	58	int (buffer_create) (struct lttng_ust_lib_ring_buffer buf, void *priv,
1d498196	59	int cpu, const char *name,
38fae1d3	60	struct lttng_ust_shm_handle *handle);
a6352fd4 MD	61	/*
	62	* Clients should guarantee that no new reader handle can be opened
	63	* after finalize.
	64	*/
4cfec15c	65	void (buffer_finalize) (struct lttng_ust_lib_ring_buffer buf,
1d498196	66	void *priv, int cpu,
38fae1d3	67	struct lttng_ust_shm_handle *handle);
a6352fd4 MD	68
	69	/*
	70	* Extract header length, payload length and timestamp from event
	71	* record. Used by buffer iterators. Timestamp is only used by channel
	72	* iterator.
	73	*/
4cfec15c	74	void (record_get) (const struct lttng_ust_lib_ring_buffer_config config,
5198080d MJ	75	struct lttng_ust_lib_ring_buffer_channel *chan,
5198080d MJ	76	struct lttng_ust_lib_ring_buffer *buf,
a6352fd4	77	size_t offset, size_t *header_len,
2fed87ae	78	size_t payload_len, uint64_t timestamp,
38fae1d3	79	struct lttng_ust_shm_handle *handle);
a9ff648c MD	80	/*
	81	* Offset and size of content size field in client.
	82	*/
	83	void (content_size_field) (const struct lttng_ust_lib_ring_buffer_config config,
	84	size_t offset, size_t length);
	85	void (packet_size_field) (const struct lttng_ust_lib_ring_buffer_config config,
	86	size_t offset, size_t length);
a6352fd4 MD	87	};
	88
	89	/*
	90	* Ring buffer instance configuration.
	91	*
	92	* Declare as "static const" within the client object to ensure the inline fast
	93	* paths can be optimized.
	94	*
	95	* alloc/sync pairs:
	96	*
	97	* RING_BUFFER_ALLOC_PER_CPU and RING_BUFFER_SYNC_PER_CPU :
	98	* Per-cpu buffers with per-cpu synchronization. Tracing must be performed
	99	* with preemption disabled (lib_ring_buffer_get_cpu() and
	100	* lib_ring_buffer_put_cpu()).
	101	*
	102	* RING_BUFFER_ALLOC_PER_CPU and RING_BUFFER_SYNC_GLOBAL :
	103	* Per-cpu buffer with global synchronization. Tracing can be performed with
	104	* preemption enabled, statistically stays on the local buffers.
	105	*
	106	* RING_BUFFER_ALLOC_GLOBAL and RING_BUFFER_SYNC_PER_CPU :
	107	* Should only be used for buffers belonging to a single thread or protected
	108	* by mutual exclusion by the client. Note that periodical sub-buffer switch
	109	* should be disabled in this kind of configuration.
	110	*
	111	* RING_BUFFER_ALLOC_GLOBAL and RING_BUFFER_SYNC_GLOBAL :
	112	* Global shared buffer with global synchronization.
	113	*
	114	* wakeup:
	115	*
	116	* RING_BUFFER_WAKEUP_BY_TIMER uses per-cpu deferrable timers to poll the
	117	* buffers and wake up readers if data is ready. Mainly useful for tracers which
	118	* don't want to call into the wakeup code on the tracing path. Use in
	119	* combination with "read_timer_interval" channel_create() argument.
	120	*
	121	* RING_BUFFER_WAKEUP_BY_WRITER directly wakes up readers when a subbuffer is
	122	* ready to read. Lower latencies before the reader is woken up. Mainly suitable
	123	* for drivers.
	124	*
	125	* RING_BUFFER_WAKEUP_NONE does not perform any wakeup whatsoever. The client
	126	* has the responsibility to perform wakeups.
	127	*/
82b9bde8	128	#define LTTNG_UST_RING_BUFFER_CONFIG_PADDING 20
46d52200 ZT	129
	130	enum lttng_ust_lib_ring_buffer_alloc_types {
	131	RING_BUFFER_ALLOC_PER_CPU,
	132	RING_BUFFER_ALLOC_GLOBAL,
	133	};
	134
	135	enum lttng_ust_lib_ring_buffer_sync_types {
	136	RING_BUFFER_SYNC_PER_CPU, /* Wait-free */
	137	RING_BUFFER_SYNC_GLOBAL, /* Lock-free */
	138	};
	139
	140	enum lttng_ust_lib_ring_buffer_mode_types {
a9ff648c MD	141	RING_BUFFER_OVERWRITE = 0, /* Overwrite when buffer full */
a9ff648c MD	142	RING_BUFFER_DISCARD = 1, /* Discard when buffer full */
46d52200 ZT	143	};
	144
	145	enum lttng_ust_lib_ring_buffer_output_types {
	146	RING_BUFFER_SPLICE,
	147	RING_BUFFER_MMAP,
	148	RING_BUFFER_READ, /* TODO */
	149	RING_BUFFER_ITERATOR,
	150	RING_BUFFER_NONE,
	151	};
	152
	153	enum lttng_ust_lib_ring_buffer_backend_types {
	154	RING_BUFFER_PAGE,
	155	RING_BUFFER_VMAP, /* TODO */
	156	RING_BUFFER_STATIC, /* TODO */
	157	};
	158
	159	enum lttng_ust_lib_ring_buffer_oops_types {
	160	RING_BUFFER_NO_OOPS_CONSISTENCY,
	161	RING_BUFFER_OOPS_CONSISTENCY,
	162	};
	163
	164	enum lttng_ust_lib_ring_buffer_ipi_types {
	165	RING_BUFFER_IPI_BARRIER,
	166	RING_BUFFER_NO_IPI_BARRIER,
	167	};
	168
	169	enum lttng_ust_lib_ring_buffer_wakeup_types {
	170	RING_BUFFER_WAKEUP_BY_TIMER, /* wake up performed by timer */
	171	RING_BUFFER_WAKEUP_BY_WRITER, /*
	172	* writer wakes up reader,
	173	* not lock-free
	174	* (takes spinlock).
	175	*/
	176	};
	177
4cfec15c	178	struct lttng_ust_lib_ring_buffer_config {
46d52200 ZT	179	enum lttng_ust_lib_ring_buffer_alloc_types alloc;
	180	enum lttng_ust_lib_ring_buffer_sync_types sync;
	181	enum lttng_ust_lib_ring_buffer_mode_types mode;
	182	enum lttng_ust_lib_ring_buffer_output_types output;
	183	enum lttng_ust_lib_ring_buffer_backend_types backend;
	184	enum lttng_ust_lib_ring_buffer_oops_types oops;
	185	enum lttng_ust_lib_ring_buffer_ipi_types ipi;
	186	enum lttng_ust_lib_ring_buffer_wakeup_types wakeup;
a6352fd4 MD	187	/*
	188	* tsc_bits: timestamp bits saved at each record.
	189	* 0 and 64 disable the timestamp compression scheme.
	190	*/
	191	unsigned int tsc_bits;
4cfec15c	192	struct lttng_ust_lib_ring_buffer_client_cb cb;
c1fca457 MD	193	/*
	194	* client_type is used by the consumer process (which is in a
	195	* different address space) to lookup the appropriate client
	196	* callbacks and update the cb pointers.
	197	*/
	198	int client_type;
82b9bde8 JD	199	int _unused1;
82b9bde8 JD	200	const struct lttng_ust_lib_ring_buffer_client_cb *cb_ptr;
2e707419	201	char padding[LTTNG_UST_RING_BUFFER_CONFIG_PADDING];
a6352fd4 MD	202	};
	203
	204	/*
	205	* ring buffer context
	206	*
	207	* Context passed to lib_ring_buffer_reserve(), lib_ring_buffer_commit(),
	208	* lib_ring_buffer_try_discard_reserve(), lib_ring_buffer_align_ctx() and
	209	* lib_ring_buffer_write().
180901e6 MD	210	*
	211	* IMPORTANT: this structure is part of the ABI between the probe and
	212	* UST. Fields need to be only added at the end, never reordered, never
	213	* removed.
a6352fd4	214	*/
2b7080aa	215	#define LTTNG_UST_RING_BUFFER_CTX_PADDING 64
4cfec15c	216	struct lttng_ust_lib_ring_buffer_ctx {
2b7080aa MD	217	uint32_t struct_size; /* Size of this structure. */
2b7080aa MD	218
a6352fd4	219	/* input received by lib_ring_buffer_reserve(), saved here. */
5198080d	220	struct lttng_ust_lib_ring_buffer_channel chan; / channel */
a6352fd4	221	void priv; / client private data */
38fae1d3	222	struct lttng_ust_shm_handle handle; / shared-memory handle */
a6352fd4 MD	223	size_t data_size; /* size of payload */
	224	int largest_align; /*
	225	* alignment of the largest element
	226	* in the payload
	227	*/
	228	int cpu; /* processor id */
	229
	230	/* output from lib_ring_buffer_reserve() */
4cfec15c	231	struct lttng_ust_lib_ring_buffer buf; /
a6352fd4 MD	232	* buffer corresponding to processor id
	233	* for this channel
	234	*/
	235	size_t slot_size; /* size of the reserved slot */
	236	unsigned long buf_offset; /* offset following the record header */
	237	unsigned long pre_offset; /*
	238	* Initial offset position _before_
	239	* the record is written. Positioned
	240	* prior to record header alignment
	241	* padding.
	242	*/
2fed87ae	243	uint64_t tsc; /* time-stamp counter value */
a6352fd4	244	unsigned int rflags; /* reservation flags */
96f85541	245	void ip; / caller ip address */
a3492932	246	struct lttng_ust_lib_ring_buffer_backend_pages *backend_pages;
a6352fd4 MD	247	};
	248
	249	/**
	250	* lib_ring_buffer_ctx_init - initialize ring buffer context
	251	* @ctx: ring buffer context to initialize
	252	* @chan: channel
	253	* @priv: client private data
	254	* @data_size: size of record data payload
	255	* @largest_align: largest alignment within data payload types
	256	* @cpu: processor id
	257	*/
a8909ba5 PW	258	static inline lttng_ust_notrace
a8909ba5 PW	259	void lib_ring_buffer_ctx_init(struct lttng_ust_lib_ring_buffer_ctx *ctx,
5198080d MJ	260	struct lttng_ust_lib_ring_buffer_channel *chan,
5198080d MJ	261	void *priv, size_t data_size, int largest_align,
2b7080aa	262	int cpu, struct lttng_ust_shm_handle *handle);
a6352fd4	263	static inline
4cfec15c	264	void lib_ring_buffer_ctx_init(struct lttng_ust_lib_ring_buffer_ctx *ctx,
5198080d MJ	265	struct lttng_ust_lib_ring_buffer_channel *chan,
5198080d MJ	266	void *priv, size_t data_size, int largest_align,
2b7080aa	267	int cpu, struct lttng_ust_shm_handle *handle)
a6352fd4	268	{
2b7080aa	269	ctx->struct_size = sizeof(struct lttng_ust_lib_ring_buffer_ctx);
a6352fd4 MD	270	ctx->chan = chan;
	271	ctx->priv = priv;
	272	ctx->data_size = data_size;
	273	ctx->largest_align = largest_align;
	274	ctx->cpu = cpu;
	275	ctx->rflags = 0;
1d498196	276	ctx->handle = handle;
96f85541	277	ctx->ip = 0;
a6352fd4 MD	278	}
	279
	280	/*
	281	* Reservation flags.
	282	*
	283	* RING_BUFFER_RFLAG_FULL_TSC
	284	*
	285	* This flag is passed to record_header_size() and to the primitive used to
	286	* write the record header. It indicates that the full 64-bit time value is
	287	* needed in the record header. If this flag is not set, the record header needs
	288	* only to contain "tsc_bits" bit of time value.
	289	*
	290	* Reservation flags can be added by the client, starting from
	291	* "(RING_BUFFER_FLAGS_END << 0)". It can be used to pass information from
	292	* record_header_size() to lib_ring_buffer_write_record_header().
	293	*/
	294	#define RING_BUFFER_RFLAG_FULL_TSC (1U << 0)
	295	#define RING_BUFFER_RFLAG_END (1U << 1)
	296
	297	/*
	298	* We need to define RING_BUFFER_ALIGN_ATTR so it is known early at
	299	* compile-time. We have to duplicate the "config->align" information and the
	300	* definition here because config->align is used both in the slow and fast
	301	* paths, but RING_BUFFER_ALIGN_ATTR is only available for the client code.
	302	*/
	303	#ifdef RING_BUFFER_ALIGN
	304
	305	# define RING_BUFFER_ALIGN_ATTR /* Default arch alignment */
	306
	307	/*
	308	* Calculate the offset needed to align the type.
	309	* size_of_type must be non-zero.
	310	*/
a8909ba5 PW	311	static inline lttng_ust_notrace
a8909ba5 PW	312	unsigned int lib_ring_buffer_align(size_t align_drift, size_t size_of_type);
a6352fd4 MD	313	static inline
	314	unsigned int lib_ring_buffer_align(size_t align_drift, size_t size_of_type)
	315	{
b72687b8	316	return lttng_ust_offset_align(align_drift, size_of_type);
a6352fd4 MD	317	}
	318
	319	#else
	320
	321	# define RING_BUFFER_ALIGN_ATTR __attribute__((packed))
	322
	323	/*
	324	* Calculate the offset needed to align the type.
	325	* size_of_type must be non-zero.
	326	*/
a8909ba5 PW	327	static inline lttng_ust_notrace
a8909ba5 PW	328	unsigned int lib_ring_buffer_align(size_t align_drift, size_t size_of_type);
a6352fd4 MD	329	static inline
	330	unsigned int lib_ring_buffer_align(size_t align_drift, size_t size_of_type)
	331	{
	332	return 0;
	333	}
	334
	335	#endif
	336
	337	/**
	338	* lib_ring_buffer_align_ctx - Align context offset on "alignment"
	339	* @ctx: ring buffer context.
	340	*/
a8909ba5 PW	341	static inline lttng_ust_notrace
	342	void lib_ring_buffer_align_ctx(struct lttng_ust_lib_ring_buffer_ctx *ctx,
	343	size_t alignment);
a6352fd4	344	static inline
4cfec15c	345	void lib_ring_buffer_align_ctx(struct lttng_ust_lib_ring_buffer_ctx *ctx,
a6352fd4 MD	346	size_t alignment)
	347	{
	348	ctx->buf_offset += lib_ring_buffer_align(ctx->buf_offset,
	349	alignment);
	350	}
	351
	352	/*
	353	* lib_ring_buffer_check_config() returns 0 on success.
	354	* Used internally to check for valid configurations at channel creation.
	355	*/
a8909ba5 PW	356	static inline lttng_ust_notrace
	357	int lib_ring_buffer_check_config(const struct lttng_ust_lib_ring_buffer_config *config,
	358	unsigned int switch_timer_interval,
	359	unsigned int read_timer_interval);
a6352fd4	360	static inline
4cfec15c	361	int lib_ring_buffer_check_config(const struct lttng_ust_lib_ring_buffer_config *config,
a6352fd4 MD	362	unsigned int switch_timer_interval,
	363	unsigned int read_timer_interval)
	364	{
	365	if (config->alloc == RING_BUFFER_ALLOC_GLOBAL
	366	&& config->sync == RING_BUFFER_SYNC_PER_CPU
	367	&& switch_timer_interval)
	368	return -EINVAL;
	369	return 0;
	370	}
	371
e92f3e28	372	#endif /* _LTTNG_RING_BUFFER_CONFIG_H */