[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,
				      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
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,
e56bb47c MD	60	struct lttng_ust_lib_ring_buffer_ctx *ctx,
e56bb47c MD	61	void *client_ctx);
a6352fd4 MD	62
	63	/* Slow path only, at subbuffer switch */
	64	size_t (*subbuffer_header_size) (void);
2fed87ae	65	void (buffer_begin) (struct lttng_ust_lib_ring_buffer buf, uint64_t tsc,
1d498196	66	unsigned int subbuf_idx,
38fae1d3	67	struct lttng_ust_shm_handle *handle);
2fed87ae	68	void (buffer_end) (struct lttng_ust_lib_ring_buffer buf, uint64_t tsc,
1d498196	69	unsigned int subbuf_idx, unsigned long data_size,
38fae1d3	70	struct lttng_ust_shm_handle *handle);
a6352fd4 MD	71
	72	/* Optional callbacks (can be set to NULL) */
	73
	74	/* Called at buffer creation/finalize */
4cfec15c	75	int (buffer_create) (struct lttng_ust_lib_ring_buffer buf, void *priv,
1d498196	76	int cpu, const char *name,
38fae1d3	77	struct lttng_ust_shm_handle *handle);
a6352fd4 MD	78	/*
	79	* Clients should guarantee that no new reader handle can be opened
	80	* after finalize.
	81	*/
4cfec15c	82	void (buffer_finalize) (struct lttng_ust_lib_ring_buffer buf,
1d498196	83	void *priv, int cpu,
38fae1d3	84	struct lttng_ust_shm_handle *handle);
a6352fd4 MD	85
	86	/*
	87	* Extract header length, payload length and timestamp from event
	88	* record. Used by buffer iterators. Timestamp is only used by channel
	89	* iterator.
	90	*/
4cfec15c MD	91	void (record_get) (const struct lttng_ust_lib_ring_buffer_config config,
4cfec15c MD	92	struct channel chan, struct lttng_ust_lib_ring_buffer buf,
a6352fd4	93	size_t offset, size_t *header_len,
2fed87ae	94	size_t payload_len, uint64_t timestamp,
38fae1d3	95	struct lttng_ust_shm_handle *handle);
a9ff648c MD	96	/*
	97	* Offset and size of content size field in client.
	98	*/
	99	void (content_size_field) (const struct lttng_ust_lib_ring_buffer_config config,
	100	size_t offset, size_t length);
	101	void (packet_size_field) (const struct lttng_ust_lib_ring_buffer_config config,
	102	size_t offset, size_t length);
a6352fd4 MD	103	};
	104
	105	/*
	106	* Ring buffer instance configuration.
	107	*
	108	* Declare as "static const" within the client object to ensure the inline fast
	109	* paths can be optimized.
	110	*
	111	* alloc/sync pairs:
	112	*
	113	* RING_BUFFER_ALLOC_PER_CPU and RING_BUFFER_SYNC_PER_CPU :
	114	* Per-cpu buffers with per-cpu synchronization. Tracing must be performed
	115	* with preemption disabled (lib_ring_buffer_get_cpu() and
	116	* lib_ring_buffer_put_cpu()).
	117	*
	118	* RING_BUFFER_ALLOC_PER_CPU and RING_BUFFER_SYNC_GLOBAL :
	119	* Per-cpu buffer with global synchronization. Tracing can be performed with
	120	* preemption enabled, statistically stays on the local buffers.
	121	*
	122	* RING_BUFFER_ALLOC_GLOBAL and RING_BUFFER_SYNC_PER_CPU :
	123	* Should only be used for buffers belonging to a single thread or protected
	124	* by mutual exclusion by the client. Note that periodical sub-buffer switch
	125	* should be disabled in this kind of configuration.
	126	*
	127	* RING_BUFFER_ALLOC_GLOBAL and RING_BUFFER_SYNC_GLOBAL :
	128	* Global shared buffer with global synchronization.
	129	*
	130	* wakeup:
	131	*
	132	* RING_BUFFER_WAKEUP_BY_TIMER uses per-cpu deferrable timers to poll the
	133	* buffers and wake up readers if data is ready. Mainly useful for tracers which
	134	* don't want to call into the wakeup code on the tracing path. Use in
	135	* combination with "read_timer_interval" channel_create() argument.
	136	*
	137	* RING_BUFFER_WAKEUP_BY_WRITER directly wakes up readers when a subbuffer is
	138	* ready to read. Lower latencies before the reader is woken up. Mainly suitable
	139	* for drivers.
	140	*
	141	* RING_BUFFER_WAKEUP_NONE does not perform any wakeup whatsoever. The client
	142	* has the responsibility to perform wakeups.
	143	*/
82b9bde8	144	#define LTTNG_UST_RING_BUFFER_CONFIG_PADDING 20
46d52200 ZT	145
	146	enum lttng_ust_lib_ring_buffer_alloc_types {
	147	RING_BUFFER_ALLOC_PER_CPU,
	148	RING_BUFFER_ALLOC_GLOBAL,
	149	};
	150
	151	enum lttng_ust_lib_ring_buffer_sync_types {
	152	RING_BUFFER_SYNC_PER_CPU, /* Wait-free */
	153	RING_BUFFER_SYNC_GLOBAL, /* Lock-free */
	154	};
	155
	156	enum lttng_ust_lib_ring_buffer_mode_types {
a9ff648c MD	157	RING_BUFFER_OVERWRITE = 0, /* Overwrite when buffer full */
a9ff648c MD	158	RING_BUFFER_DISCARD = 1, /* Discard when buffer full */
46d52200 ZT	159	};
	160
	161	enum lttng_ust_lib_ring_buffer_output_types {
	162	RING_BUFFER_SPLICE,
	163	RING_BUFFER_MMAP,
	164	RING_BUFFER_READ, /* TODO */
	165	RING_BUFFER_ITERATOR,
	166	RING_BUFFER_NONE,
	167	};
	168
	169	enum lttng_ust_lib_ring_buffer_backend_types {
	170	RING_BUFFER_PAGE,
	171	RING_BUFFER_VMAP, /* TODO */
	172	RING_BUFFER_STATIC, /* TODO */
	173	};
	174
	175	enum lttng_ust_lib_ring_buffer_oops_types {
	176	RING_BUFFER_NO_OOPS_CONSISTENCY,
	177	RING_BUFFER_OOPS_CONSISTENCY,
	178	};
	179
	180	enum lttng_ust_lib_ring_buffer_ipi_types {
	181	RING_BUFFER_IPI_BARRIER,
	182	RING_BUFFER_NO_IPI_BARRIER,
	183	};
	184
	185	enum lttng_ust_lib_ring_buffer_wakeup_types {
	186	RING_BUFFER_WAKEUP_BY_TIMER, /* wake up performed by timer */
	187	RING_BUFFER_WAKEUP_BY_WRITER, /*
	188	* writer wakes up reader,
	189	* not lock-free
	190	* (takes spinlock).
	191	*/
	192	};
	193
4cfec15c	194	struct lttng_ust_lib_ring_buffer_config {
46d52200 ZT	195	enum lttng_ust_lib_ring_buffer_alloc_types alloc;
	196	enum lttng_ust_lib_ring_buffer_sync_types sync;
	197	enum lttng_ust_lib_ring_buffer_mode_types mode;
	198	enum lttng_ust_lib_ring_buffer_output_types output;
	199	enum lttng_ust_lib_ring_buffer_backend_types backend;
	200	enum lttng_ust_lib_ring_buffer_oops_types oops;
	201	enum lttng_ust_lib_ring_buffer_ipi_types ipi;
	202	enum lttng_ust_lib_ring_buffer_wakeup_types wakeup;
a6352fd4 MD	203	/*
	204	* tsc_bits: timestamp bits saved at each record.
	205	* 0 and 64 disable the timestamp compression scheme.
	206	*/
	207	unsigned int tsc_bits;
4cfec15c	208	struct lttng_ust_lib_ring_buffer_client_cb cb;
c1fca457 MD	209	/*
	210	* client_type is used by the consumer process (which is in a
	211	* different address space) to lookup the appropriate client
	212	* callbacks and update the cb pointers.
	213	*/
	214	int client_type;
82b9bde8 JD	215	int _unused1;
82b9bde8 JD	216	const struct lttng_ust_lib_ring_buffer_client_cb *cb_ptr;
2e707419	217	char padding[LTTNG_UST_RING_BUFFER_CONFIG_PADDING];
a6352fd4 MD	218	};
	219
	220	/*
	221	* ring buffer context
	222	*
	223	* Context passed to lib_ring_buffer_reserve(), lib_ring_buffer_commit(),
	224	* lib_ring_buffer_try_discard_reserve(), lib_ring_buffer_align_ctx() and
	225	* lib_ring_buffer_write().
180901e6 MD	226	*
	227	* IMPORTANT: this structure is part of the ABI between the probe and
	228	* UST. Fields need to be only added at the end, never reordered, never
	229	* removed.
a6352fd4	230	*/
96f85541	231	#define LTTNG_UST_RING_BUFFER_CTX_PADDING \
53569322	232	(24 - sizeof(int) - sizeof(void ) - sizeof(void ))
4cfec15c	233	struct lttng_ust_lib_ring_buffer_ctx {
a6352fd4 MD	234	/* input received by lib_ring_buffer_reserve(), saved here. */
	235	struct channel chan; / channel */
	236	void priv; / client private data */
38fae1d3	237	struct lttng_ust_shm_handle handle; / shared-memory handle */
a6352fd4 MD	238	size_t data_size; /* size of payload */
	239	int largest_align; /*
	240	* alignment of the largest element
	241	* in the payload
	242	*/
	243	int cpu; /* processor id */
	244
	245	/* output from lib_ring_buffer_reserve() */
4cfec15c	246	struct lttng_ust_lib_ring_buffer buf; /
a6352fd4 MD	247	* buffer corresponding to processor id
	248	* for this channel
	249	*/
	250	size_t slot_size; /* size of the reserved slot */
	251	unsigned long buf_offset; /* offset following the record header */
	252	unsigned long pre_offset; /*
	253	* Initial offset position _before_
	254	* the record is written. Positioned
	255	* prior to record header alignment
	256	* padding.
	257	*/
2fed87ae	258	uint64_t tsc; /* time-stamp counter value */
a6352fd4	259	unsigned int rflags; /* reservation flags */
82cd0cfd MD	260	/*
	261	* The field ctx_len is the length of struct
	262	* lttng_ust_lib_ring_buffer_ctx as known by the user of
	263	* lib_ring_buffer_ctx_init.
	264	*/
	265	unsigned int ctx_len;
96f85541	266	void ip; / caller ip address */
53569322	267	void priv2; / 2nd priv data */
96f85541	268	char padding2[LTTNG_UST_RING_BUFFER_CTX_PADDING];
82cd0cfd MD	269	/*
	270	* This is the end of the initial fields expected by the original ABI
	271	* between probes and UST. Only the fields above can be used if
	272	* ctx_len is 0. Use the value of ctx_len to find out which of the
	273	* following fields may be used.
	274	*/
a3492932	275	struct lttng_ust_lib_ring_buffer_backend_pages *backend_pages;
a6352fd4 MD	276	};
	277
	278	/**
	279	* lib_ring_buffer_ctx_init - initialize ring buffer context
	280	* @ctx: ring buffer context to initialize
	281	* @chan: channel
	282	* @priv: client private data
	283	* @data_size: size of record data payload
	284	* @largest_align: largest alignment within data payload types
	285	* @cpu: processor id
	286	*/
a8909ba5 PW	287	static inline lttng_ust_notrace
	288	void lib_ring_buffer_ctx_init(struct lttng_ust_lib_ring_buffer_ctx *ctx,
	289	struct channel chan, void priv,
	290	size_t data_size, int largest_align,
53569322 MD	291	int cpu, struct lttng_ust_shm_handle *handle,
53569322 MD	292	void *priv2);
a6352fd4	293	static inline
4cfec15c	294	void lib_ring_buffer_ctx_init(struct lttng_ust_lib_ring_buffer_ctx *ctx,
a6352fd4 MD	295	struct channel chan, void priv,
a6352fd4 MD	296	size_t data_size, int largest_align,
53569322 MD	297	int cpu, struct lttng_ust_shm_handle *handle,
53569322 MD	298	void *priv2)
a6352fd4 MD	299	{
	300	ctx->chan = chan;
	301	ctx->priv = priv;
	302	ctx->data_size = data_size;
	303	ctx->largest_align = largest_align;
	304	ctx->cpu = cpu;
	305	ctx->rflags = 0;
1d498196	306	ctx->handle = handle;
82cd0cfd	307	ctx->ctx_len = sizeof(struct lttng_ust_lib_ring_buffer_ctx);
96f85541	308	ctx->ip = 0;
53569322	309	ctx->priv2 = priv2;
96f85541	310	memset(ctx->padding2, 0, LTTNG_UST_RING_BUFFER_CTX_PADDING);
a6352fd4 MD	311	}
	312
	313	/*
	314	* Reservation flags.
	315	*
	316	* RING_BUFFER_RFLAG_FULL_TSC
	317	*
	318	* This flag is passed to record_header_size() and to the primitive used to
	319	* write the record header. It indicates that the full 64-bit time value is
	320	* needed in the record header. If this flag is not set, the record header needs
	321	* only to contain "tsc_bits" bit of time value.
	322	*
	323	* Reservation flags can be added by the client, starting from
	324	* "(RING_BUFFER_FLAGS_END << 0)". It can be used to pass information from
	325	* record_header_size() to lib_ring_buffer_write_record_header().
	326	*/
	327	#define RING_BUFFER_RFLAG_FULL_TSC (1U << 0)
	328	#define RING_BUFFER_RFLAG_END (1U << 1)
	329
	330	/*
	331	* We need to define RING_BUFFER_ALIGN_ATTR so it is known early at
	332	* compile-time. We have to duplicate the "config->align" information and the
	333	* definition here because config->align is used both in the slow and fast
	334	* paths, but RING_BUFFER_ALIGN_ATTR is only available for the client code.
	335	*/
	336	#ifdef RING_BUFFER_ALIGN
	337
	338	# define RING_BUFFER_ALIGN_ATTR /* Default arch alignment */
	339
	340	/*
	341	* Calculate the offset needed to align the type.
	342	* size_of_type must be non-zero.
	343	*/
a8909ba5 PW	344	static inline lttng_ust_notrace
a8909ba5 PW	345	unsigned int lib_ring_buffer_align(size_t align_drift, size_t size_of_type);
a6352fd4 MD	346	static inline
	347	unsigned int lib_ring_buffer_align(size_t align_drift, size_t size_of_type)
	348	{
b72687b8	349	return lttng_ust_offset_align(align_drift, size_of_type);
a6352fd4 MD	350	}
	351
	352	#else
	353
	354	# define RING_BUFFER_ALIGN_ATTR __attribute__((packed))
	355
	356	/*
	357	* Calculate the offset needed to align the type.
	358	* size_of_type must be non-zero.
	359	*/
a8909ba5 PW	360	static inline lttng_ust_notrace
a8909ba5 PW	361	unsigned int lib_ring_buffer_align(size_t align_drift, size_t size_of_type);
a6352fd4 MD	362	static inline
	363	unsigned int lib_ring_buffer_align(size_t align_drift, size_t size_of_type)
	364	{
	365	return 0;
	366	}
	367
	368	#endif
	369
	370	/**
	371	* lib_ring_buffer_align_ctx - Align context offset on "alignment"
	372	* @ctx: ring buffer context.
	373	*/
a8909ba5 PW	374	static inline lttng_ust_notrace
	375	void lib_ring_buffer_align_ctx(struct lttng_ust_lib_ring_buffer_ctx *ctx,
	376	size_t alignment);
a6352fd4	377	static inline
4cfec15c	378	void lib_ring_buffer_align_ctx(struct lttng_ust_lib_ring_buffer_ctx *ctx,
a6352fd4 MD	379	size_t alignment)
	380	{
	381	ctx->buf_offset += lib_ring_buffer_align(ctx->buf_offset,
	382	alignment);
	383	}
	384
	385	/*
	386	* lib_ring_buffer_check_config() returns 0 on success.
	387	* Used internally to check for valid configurations at channel creation.
	388	*/
a8909ba5 PW	389	static inline lttng_ust_notrace
	390	int lib_ring_buffer_check_config(const struct lttng_ust_lib_ring_buffer_config *config,
	391	unsigned int switch_timer_interval,
	392	unsigned int read_timer_interval);
a6352fd4	393	static inline
4cfec15c	394	int lib_ring_buffer_check_config(const struct lttng_ust_lib_ring_buffer_config *config,
a6352fd4 MD	395	unsigned int switch_timer_interval,
	396	unsigned int read_timer_interval)
	397	{
	398	if (config->alloc == RING_BUFFER_ALLOC_GLOBAL
	399	&& config->sync == RING_BUFFER_SYNC_PER_CPU
	400	&& switch_timer_interval)
	401	return -EINVAL;
	402	return 0;
	403	}
	404
e92f3e28	405	#endif /* _LTTNG_RING_BUFFER_CONFIG_H */