+++ /dev/null
-/*
- * SPDX-License-Identifier: MIT
- *
- * Copyright (C) 2010-2021 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 <stdint.h>
-#include <stddef.h>
-#include <urcu/arch.h>
-#include <string.h>
-
-#include <lttng/ust-utils.h>
-#include <lttng/ust-compiler.h>
-#include <lttng/ust-tracer.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_private;
-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.
- *
- * 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];
-};
-
-/*
- * 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)
-
-/*
- * lib_ring_buffer_check_config() returns 0 on success.
- * Used internally to check for valid configurations at channel creation.
- */
-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)
- lttng_ust_notrace;
-
-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 __attribute__((unused)))
-{
- 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 */
projects / lttng-ust.git / blobdiff