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

#ifndef _LTTNG_RING_BUFFER_CONFIG_H
#define _LTTNG_RING_BUFFER_CONFIG_H

/*
 * lttng/ringbuffer-config.h
 *
 * 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.
 *
 * Permission is hereby granted, free of charge, to any person obtaining a copy
 * of this software and associated documentation files (the "Software"), to deal
 * in the Software without restriction, including without limitation the rights
 * to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
 * copies of the Software, and to permit persons to whom the Software is
 * furnished to do so, subject to the following conditions:
 *
 * The above copyright notice and this permission notice shall be included in
 * all copies or substantial portions of the Software.
 *
 * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
 * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
 * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
 * AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
 * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
 * OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
 * SOFTWARE.
 */

#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);

	/* 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);
};

/*
 * 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,		/* Overwrite when buffer full */
	RING_BUFFER_DISCARD,		/* 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 *))
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 */
	unsigned int padding1;		/* padding to realign on pointer */
	void *ip;			/* caller ip address */
	char padding2[LTTNG_UST_RING_BUFFER_CTX_PADDING];
};

/**
 * 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);
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)
{
	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->padding1 = 0;
	ctx->ip = 0;
	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 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
e92f3e28 MD	1	#ifndef _LTTNG_RING_BUFFER_CONFIG_H
e92f3e28 MD	2	#define _LTTNG_RING_BUFFER_CONFIG_H
a6352fd4 MD	3
a6352fd4 MD	4	/*
e92f3e28	5	* lttng/ringbuffer-config.h
a6352fd4 MD	6	*
	7	* Copyright (C) 2010 - Mathieu Desnoyers <mathieu.desnoyers@efficios.com>
	8	*
	9	* Ring buffer configuration header. Note: after declaring the standard inline
	10	* functions, clients should also include linux/ringbuffer/api.h.
	11	*
e92f3e28 MD	12	* Permission is hereby granted, free of charge, to any person obtaining a copy
	13	* of this software and associated documentation files (the "Software"), to deal
	14	* in the Software without restriction, including without limitation the rights
	15	* to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
	16	* copies of the Software, and to permit persons to whom the Software is
	17	* furnished to do so, subject to the following conditions:
a60d70e6	18	*
e92f3e28 MD	19	* The above copyright notice and this permission notice shall be included in
e92f3e28 MD	20	* all copies or substantial portions of the Software.
d2428e87 MD	21	*
	22	* THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
	23	* IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
	24	* FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
	25	* AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
	26	* LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
	27	* OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
	28	* SOFTWARE.
a6352fd4 MD	29	*/
	30
	31	#include <errno.h>
4318ae1b	32	#include "lttng/ust-tracer.h"
b728d87e MD	33	#include <stdint.h>
	34	#include <stddef.h>
	35	#include <urcu/arch.h>
2e707419	36	#include <string.h>
4318ae1b	37	#include "lttng/align.h"
a8909ba5	38	#include <lttng/ust-compiler.h>
a6352fd4	39
4cfec15c	40	struct lttng_ust_lib_ring_buffer;
a6352fd4	41	struct channel;
4cfec15c MD	42	struct lttng_ust_lib_ring_buffer_config;
4cfec15c MD	43	struct lttng_ust_lib_ring_buffer_ctx;
5a821cd6	44	struct lttng_ust_shm_handle;
a6352fd4 MD	45
	46	/*
	47	* Ring buffer client callbacks. Only used by slow path, never on fast path.
	48	* For the fast path, record_header_size(), ring_buffer_clock_read() should be
	49	* provided as inline functions too. These may simply return 0 if not used by
	50	* the client.
	51	*/
4cfec15c	52	struct lttng_ust_lib_ring_buffer_client_cb {
a6352fd4 MD	53	/* Mandatory callbacks */
	54
	55	/* A static inline version is also required for fast path */
2fed87ae	56	uint64_t (ring_buffer_clock_read) (struct channel chan);
4cfec15c	57	size_t (record_header_size) (const struct lttng_ust_lib_ring_buffer_config config,
a6352fd4 MD	58	struct channel *chan, size_t offset,
a6352fd4 MD	59	size_t *pre_header_padding,
4cfec15c	60	struct lttng_ust_lib_ring_buffer_ctx *ctx);
a6352fd4 MD	61
	62	/* Slow path only, at subbuffer switch */
	63	size_t (*subbuffer_header_size) (void);
2fed87ae	64	void (buffer_begin) (struct lttng_ust_lib_ring_buffer buf, uint64_t tsc,
1d498196	65	unsigned int subbuf_idx,
38fae1d3	66	struct lttng_ust_shm_handle *handle);
2fed87ae	67	void (buffer_end) (struct lttng_ust_lib_ring_buffer buf, uint64_t tsc,
1d498196	68	unsigned int subbuf_idx, unsigned long data_size,
38fae1d3	69	struct lttng_ust_shm_handle *handle);
a6352fd4 MD	70
	71	/* Optional callbacks (can be set to NULL) */
	72
	73	/* Called at buffer creation/finalize */
4cfec15c	74	int (buffer_create) (struct lttng_ust_lib_ring_buffer buf, void *priv,
1d498196	75	int cpu, const char *name,
38fae1d3	76	struct lttng_ust_shm_handle *handle);
a6352fd4 MD	77	/*
	78	* Clients should guarantee that no new reader handle can be opened
	79	* after finalize.
	80	*/
4cfec15c	81	void (buffer_finalize) (struct lttng_ust_lib_ring_buffer buf,
1d498196	82	void *priv, int cpu,
38fae1d3	83	struct lttng_ust_shm_handle *handle);
a6352fd4 MD	84
	85	/*
	86	* Extract header length, payload length and timestamp from event
	87	* record. Used by buffer iterators. Timestamp is only used by channel
	88	* iterator.
	89	*/
4cfec15c MD	90	void (record_get) (const struct lttng_ust_lib_ring_buffer_config config,
4cfec15c MD	91	struct channel chan, struct lttng_ust_lib_ring_buffer buf,
a6352fd4	92	size_t offset, size_t *header_len,
2fed87ae	93	size_t payload_len, uint64_t timestamp,
38fae1d3	94	struct lttng_ust_shm_handle *handle);
a6352fd4 MD	95	};
	96
	97	/*
	98	* Ring buffer instance configuration.
	99	*
	100	* Declare as "static const" within the client object to ensure the inline fast
	101	* paths can be optimized.
	102	*
	103	* alloc/sync pairs:
	104	*
	105	* RING_BUFFER_ALLOC_PER_CPU and RING_BUFFER_SYNC_PER_CPU :
	106	* Per-cpu buffers with per-cpu synchronization. Tracing must be performed
	107	* with preemption disabled (lib_ring_buffer_get_cpu() and
	108	* lib_ring_buffer_put_cpu()).
	109	*
	110	* RING_BUFFER_ALLOC_PER_CPU and RING_BUFFER_SYNC_GLOBAL :
	111	* Per-cpu buffer with global synchronization. Tracing can be performed with
	112	* preemption enabled, statistically stays on the local buffers.
	113	*
	114	* RING_BUFFER_ALLOC_GLOBAL and RING_BUFFER_SYNC_PER_CPU :
	115	* Should only be used for buffers belonging to a single thread or protected
	116	* by mutual exclusion by the client. Note that periodical sub-buffer switch
	117	* should be disabled in this kind of configuration.
	118	*
	119	* RING_BUFFER_ALLOC_GLOBAL and RING_BUFFER_SYNC_GLOBAL :
	120	* Global shared buffer with global synchronization.
	121	*
	122	* wakeup:
	123	*
	124	* RING_BUFFER_WAKEUP_BY_TIMER uses per-cpu deferrable timers to poll the
	125	* buffers and wake up readers if data is ready. Mainly useful for tracers which
	126	* don't want to call into the wakeup code on the tracing path. Use in
	127	* combination with "read_timer_interval" channel_create() argument.
	128	*
	129	* RING_BUFFER_WAKEUP_BY_WRITER directly wakes up readers when a subbuffer is
	130	* ready to read. Lower latencies before the reader is woken up. Mainly suitable
	131	* for drivers.
	132	*
	133	* RING_BUFFER_WAKEUP_NONE does not perform any wakeup whatsoever. The client
	134	* has the responsibility to perform wakeups.
	135	*/
82b9bde8	136	#define LTTNG_UST_RING_BUFFER_CONFIG_PADDING 20
46d52200 ZT	137
	138	enum lttng_ust_lib_ring_buffer_alloc_types {
	139	RING_BUFFER_ALLOC_PER_CPU,
	140	RING_BUFFER_ALLOC_GLOBAL,
	141	};
	142
	143	enum lttng_ust_lib_ring_buffer_sync_types {
	144	RING_BUFFER_SYNC_PER_CPU, /* Wait-free */
	145	RING_BUFFER_SYNC_GLOBAL, /* Lock-free */
	146	};
	147
	148	enum lttng_ust_lib_ring_buffer_mode_types {
	149	RING_BUFFER_OVERWRITE, /* Overwrite when buffer full */
	150	RING_BUFFER_DISCARD, /* Discard when buffer full */
	151	};
	152
	153	enum lttng_ust_lib_ring_buffer_output_types {
	154	RING_BUFFER_SPLICE,
	155	RING_BUFFER_MMAP,
	156	RING_BUFFER_READ, /* TODO */
	157	RING_BUFFER_ITERATOR,
	158	RING_BUFFER_NONE,
	159	};
	160
	161	enum lttng_ust_lib_ring_buffer_backend_types {
	162	RING_BUFFER_PAGE,
	163	RING_BUFFER_VMAP, /* TODO */
	164	RING_BUFFER_STATIC, /* TODO */
	165	};
	166
	167	enum lttng_ust_lib_ring_buffer_oops_types {
	168	RING_BUFFER_NO_OOPS_CONSISTENCY,
	169	RING_BUFFER_OOPS_CONSISTENCY,
	170	};
	171
	172	enum lttng_ust_lib_ring_buffer_ipi_types {
	173	RING_BUFFER_IPI_BARRIER,
	174	RING_BUFFER_NO_IPI_BARRIER,
	175	};
	176
	177	enum lttng_ust_lib_ring_buffer_wakeup_types {
	178	RING_BUFFER_WAKEUP_BY_TIMER, /* wake up performed by timer */
	179	RING_BUFFER_WAKEUP_BY_WRITER, /*
	180	* writer wakes up reader,
	181	* not lock-free
	182	* (takes spinlock).
	183	*/
	184	};
	185
4cfec15c	186	struct lttng_ust_lib_ring_buffer_config {
46d52200 ZT	187	enum lttng_ust_lib_ring_buffer_alloc_types alloc;
	188	enum lttng_ust_lib_ring_buffer_sync_types sync;
	189	enum lttng_ust_lib_ring_buffer_mode_types mode;
	190	enum lttng_ust_lib_ring_buffer_output_types output;
	191	enum lttng_ust_lib_ring_buffer_backend_types backend;
	192	enum lttng_ust_lib_ring_buffer_oops_types oops;
	193	enum lttng_ust_lib_ring_buffer_ipi_types ipi;
	194	enum lttng_ust_lib_ring_buffer_wakeup_types wakeup;
a6352fd4 MD	195	/*
	196	* tsc_bits: timestamp bits saved at each record.
	197	* 0 and 64 disable the timestamp compression scheme.
	198	*/
	199	unsigned int tsc_bits;
4cfec15c	200	struct lttng_ust_lib_ring_buffer_client_cb cb;
c1fca457 MD	201	/*
	202	* client_type is used by the consumer process (which is in a
	203	* different address space) to lookup the appropriate client
	204	* callbacks and update the cb pointers.
	205	*/
	206	int client_type;
82b9bde8 JD	207	int _unused1;
82b9bde8 JD	208	const struct lttng_ust_lib_ring_buffer_client_cb *cb_ptr;
2e707419	209	char padding[LTTNG_UST_RING_BUFFER_CONFIG_PADDING];
a6352fd4 MD	210	};
	211
	212	/*
	213	* ring buffer context
	214	*
	215	* Context passed to lib_ring_buffer_reserve(), lib_ring_buffer_commit(),
	216	* lib_ring_buffer_try_discard_reserve(), lib_ring_buffer_align_ctx() and
	217	* lib_ring_buffer_write().
180901e6 MD	218	*
	219	* IMPORTANT: this structure is part of the ABI between the probe and
	220	* UST. Fields need to be only added at the end, never reordered, never
	221	* removed.
a6352fd4	222	*/
96f85541 MD	223	#define LTTNG_UST_RING_BUFFER_CTX_PADDING \
96f85541 MD	224	(24 - sizeof(int) - sizeof(void *))
4cfec15c	225	struct lttng_ust_lib_ring_buffer_ctx {
a6352fd4 MD	226	/* input received by lib_ring_buffer_reserve(), saved here. */
	227	struct channel chan; / channel */
	228	void priv; / client private data */
38fae1d3	229	struct lttng_ust_shm_handle handle; / shared-memory handle */
a6352fd4 MD	230	size_t data_size; /* size of payload */
	231	int largest_align; /*
	232	* alignment of the largest element
	233	* in the payload
	234	*/
	235	int cpu; /* processor id */
	236
	237	/* output from lib_ring_buffer_reserve() */
4cfec15c	238	struct lttng_ust_lib_ring_buffer buf; /
a6352fd4 MD	239	* buffer corresponding to processor id
	240	* for this channel
	241	*/
	242	size_t slot_size; /* size of the reserved slot */
	243	unsigned long buf_offset; /* offset following the record header */
	244	unsigned long pre_offset; /*
	245	* Initial offset position _before_
	246	* the record is written. Positioned
	247	* prior to record header alignment
	248	* padding.
	249	*/
2fed87ae	250	uint64_t tsc; /* time-stamp counter value */
a6352fd4	251	unsigned int rflags; /* reservation flags */
96f85541 MD	252	unsigned int padding1; /* padding to realign on pointer */
	253	void ip; / caller ip address */
	254	char padding2[LTTNG_UST_RING_BUFFER_CTX_PADDING];
a6352fd4 MD	255	};
	256
	257	/**
	258	* lib_ring_buffer_ctx_init - initialize ring buffer context
	259	* @ctx: ring buffer context to initialize
	260	* @chan: channel
	261	* @priv: client private data
	262	* @data_size: size of record data payload
	263	* @largest_align: largest alignment within data payload types
	264	* @cpu: processor id
	265	*/
a8909ba5 PW	266	static inline lttng_ust_notrace
	267	void lib_ring_buffer_ctx_init(struct lttng_ust_lib_ring_buffer_ctx *ctx,
	268	struct channel chan, void priv,
	269	size_t data_size, int largest_align,
	270	int cpu, struct lttng_ust_shm_handle *handle);
a6352fd4	271	static inline
4cfec15c	272	void lib_ring_buffer_ctx_init(struct lttng_ust_lib_ring_buffer_ctx *ctx,
a6352fd4 MD	273	struct channel chan, void priv,
a6352fd4 MD	274	size_t data_size, int largest_align,
38fae1d3	275	int cpu, struct lttng_ust_shm_handle *handle)
a6352fd4 MD	276	{
	277	ctx->chan = chan;
	278	ctx->priv = priv;
	279	ctx->data_size = data_size;
	280	ctx->largest_align = largest_align;
	281	ctx->cpu = cpu;
	282	ctx->rflags = 0;
1d498196	283	ctx->handle = handle;
96f85541 MD	284	ctx->padding1 = 0;
	285	ctx->ip = 0;
	286	memset(ctx->padding2, 0, LTTNG_UST_RING_BUFFER_CTX_PADDING);
a6352fd4 MD	287	}
	288
	289	/*
	290	* Reservation flags.
	291	*
	292	* RING_BUFFER_RFLAG_FULL_TSC
	293	*
	294	* This flag is passed to record_header_size() and to the primitive used to
	295	* write the record header. It indicates that the full 64-bit time value is
	296	* needed in the record header. If this flag is not set, the record header needs
	297	* only to contain "tsc_bits" bit of time value.
	298	*
	299	* Reservation flags can be added by the client, starting from
	300	* "(RING_BUFFER_FLAGS_END << 0)". It can be used to pass information from
	301	* record_header_size() to lib_ring_buffer_write_record_header().
	302	*/
	303	#define RING_BUFFER_RFLAG_FULL_TSC (1U << 0)
	304	#define RING_BUFFER_RFLAG_END (1U << 1)
	305
	306	/*
	307	* We need to define RING_BUFFER_ALIGN_ATTR so it is known early at
	308	* compile-time. We have to duplicate the "config->align" information and the
	309	* definition here because config->align is used both in the slow and fast
	310	* paths, but RING_BUFFER_ALIGN_ATTR is only available for the client code.
	311	*/
	312	#ifdef RING_BUFFER_ALIGN
	313
	314	# define RING_BUFFER_ALIGN_ATTR /* Default arch alignment */
	315
	316	/*
	317	* Calculate the offset needed to align the type.
	318	* size_of_type must be non-zero.
	319	*/
a8909ba5 PW	320	static inline lttng_ust_notrace
a8909ba5 PW	321	unsigned int lib_ring_buffer_align(size_t align_drift, size_t size_of_type);
a6352fd4 MD	322	static inline
	323	unsigned int lib_ring_buffer_align(size_t align_drift, size_t size_of_type)
	324	{
	325	return offset_align(align_drift, size_of_type);
	326	}
	327
	328	#else
	329
	330	# define RING_BUFFER_ALIGN_ATTR __attribute__((packed))
	331
	332	/*
	333	* Calculate the offset needed to align the type.
	334	* size_of_type must be non-zero.
	335	*/
a8909ba5 PW	336	static inline lttng_ust_notrace
a8909ba5 PW	337	unsigned int lib_ring_buffer_align(size_t align_drift, size_t size_of_type);
a6352fd4 MD	338	static inline
	339	unsigned int lib_ring_buffer_align(size_t align_drift, size_t size_of_type)
	340	{
	341	return 0;
	342	}
	343
	344	#endif
	345
	346	/**
	347	* lib_ring_buffer_align_ctx - Align context offset on "alignment"
	348	* @ctx: ring buffer context.
	349	*/
a8909ba5 PW	350	static inline lttng_ust_notrace
	351	void lib_ring_buffer_align_ctx(struct lttng_ust_lib_ring_buffer_ctx *ctx,
	352	size_t alignment);
a6352fd4	353	static inline
4cfec15c	354	void lib_ring_buffer_align_ctx(struct lttng_ust_lib_ring_buffer_ctx *ctx,
a6352fd4 MD	355	size_t alignment)
	356	{
	357	ctx->buf_offset += lib_ring_buffer_align(ctx->buf_offset,
	358	alignment);
	359	}
	360
	361	/*
	362	* lib_ring_buffer_check_config() returns 0 on success.
	363	* Used internally to check for valid configurations at channel creation.
	364	*/
a8909ba5 PW	365	static inline lttng_ust_notrace
	366	int lib_ring_buffer_check_config(const struct lttng_ust_lib_ring_buffer_config *config,
	367	unsigned int switch_timer_interval,
	368	unsigned int read_timer_interval);
a6352fd4	369	static inline
4cfec15c	370	int lib_ring_buffer_check_config(const struct lttng_ust_lib_ring_buffer_config *config,
a6352fd4 MD	371	unsigned int switch_timer_interval,
	372	unsigned int read_timer_interval)
	373	{
	374	if (config->alloc == RING_BUFFER_ALLOC_GLOBAL
	375	&& config->sync == RING_BUFFER_SYNC_PER_CPU
	376	&& switch_timer_interval)
	377	return -EINVAL;
	378	return 0;
	379	}
	380
e92f3e28	381	#endif /* _LTTNG_RING_BUFFER_CONFIG_H */