+++ /dev/null
-/*
- * lttng-ring-buffer-client.h
- *
- * Copyright (C) 2010 - Mathieu Desnoyers <mathieu.desnoyers@efficios.com>
- *
- * LTTng lib ring buffer client template.
- *
- * Dual LGPL v2.1/GPL v2 license.
- */
-
-#include <linux/module.h>
-#include <linux/types.h>
-#include "lib/bitfield.h"
-#include "wrapper/vmalloc.h" /* for wrapper_vmalloc_sync_all() */
-#include "wrapper/trace-clock.h"
-#include "lttng-events.h"
-#include "lttng-tracer.h"
-#include "wrapper/ringbuffer/frontend_types.h"
-
-#define LTTNG_COMPACT_EVENT_BITS 5
-#define LTTNG_COMPACT_TSC_BITS 27
-
-/*
- * Keep the natural field alignment for _each field_ within this structure if
- * you ever add/remove a field from this header. Packed attribute is not used
- * because gcc generates poor code on at least powerpc and mips. Don't ever
- * let gcc add padding between the structure elements.
- *
- * The guarantee we have with timestamps is that all the events in a
- * packet are included (inclusive) within the begin/end timestamps of
- * the packet. Another guarantee we have is that the "timestamp begin",
- * as well as the event timestamps, are monotonically increasing (never
- * decrease) when moving forward in a stream (physically). But this
- * guarantee does not apply to "timestamp end", because it is sampled at
- * commit time, which is not ordered with respect to space reservation.
- */
-
-struct packet_header {
- /* Trace packet header */
- uint32_t magic; /*
- * Trace magic number.
- * contains endianness information.
- */
- uint8_t uuid[16];
- uint32_t stream_id;
-
- struct {
- /* Stream packet context */
- uint64_t timestamp_begin; /* Cycle count at subbuffer start */
- uint64_t timestamp_end; /* Cycle count at subbuffer end */
- uint32_t events_discarded; /*
- * Events lost in this subbuffer since
- * the beginning of the trace.
- * (may overflow)
- */
- uint32_t content_size; /* Size of data in subbuffer */
- uint32_t packet_size; /* Subbuffer size (include padding) */
- uint32_t cpu_id; /* CPU id associated with stream */
- uint8_t header_end; /* End of header */
- } ctx;
-};
-
-
-static inline notrace u64 lib_ring_buffer_clock_read(struct channel *chan)
-{
- return trace_clock_read64();
-}
-
-static inline
-size_t ctx_get_size(size_t offset, struct lttng_ctx *ctx)
-{
- int i;
- size_t orig_offset = offset;
-
- if (likely(!ctx))
- return 0;
- for (i = 0; i < ctx->nr_fields; i++)
- offset += ctx->fields[i].get_size(offset);
- return offset - orig_offset;
-}
-
-static inline
-void ctx_record(struct lib_ring_buffer_ctx *bufctx,
- struct lttng_channel *chan,
- struct lttng_ctx *ctx)
-{
- int i;
-
- if (likely(!ctx))
- return;
- for (i = 0; i < ctx->nr_fields; i++)
- ctx->fields[i].record(&ctx->fields[i], bufctx, chan);
-}
-
-/*
- * record_header_size - Calculate the header size and padding necessary.
- * @config: ring buffer instance configuration
- * @chan: channel
- * @offset: offset in the write buffer
- * @pre_header_padding: padding to add before the header (output)
- * @ctx: reservation context
- *
- * Returns the event header size (including padding).
- *
- * The payload must itself determine its own alignment from the biggest type it
- * contains.
- */
-static __inline__
-unsigned char record_header_size(const struct lib_ring_buffer_config *config,
- struct channel *chan, size_t offset,
- size_t *pre_header_padding,
- struct lib_ring_buffer_ctx *ctx)
-{
- struct lttng_channel *lttng_chan = channel_get_private(chan);
- struct lttng_event *event = ctx->priv;
- size_t orig_offset = offset;
- size_t padding;
-
- switch (lttng_chan->header_type) {
- case 1: /* compact */
- padding = lib_ring_buffer_align(offset, lttng_alignof(uint32_t));
- offset += padding;
- if (!(ctx->rflags & (RING_BUFFER_RFLAG_FULL_TSC | LTTNG_RFLAG_EXTENDED))) {
- offset += sizeof(uint32_t); /* id and timestamp */
- } else {
- /* Minimum space taken by LTTNG_COMPACT_EVENT_BITS id */
- offset += (LTTNG_COMPACT_EVENT_BITS + CHAR_BIT - 1) / CHAR_BIT;
- /* Align extended struct on largest member */
- offset += lib_ring_buffer_align(offset, lttng_alignof(uint64_t));
- offset += sizeof(uint32_t); /* id */
- offset += lib_ring_buffer_align(offset, lttng_alignof(uint64_t));
- offset += sizeof(uint64_t); /* timestamp */
- }
- break;
- case 2: /* large */
- padding = lib_ring_buffer_align(offset, lttng_alignof(uint16_t));
- offset += padding;
- offset += sizeof(uint16_t);
- if (!(ctx->rflags & (RING_BUFFER_RFLAG_FULL_TSC | LTTNG_RFLAG_EXTENDED))) {
- offset += lib_ring_buffer_align(offset, lttng_alignof(uint32_t));
- offset += sizeof(uint32_t); /* timestamp */
- } else {
- /* Align extended struct on largest member */
- offset += lib_ring_buffer_align(offset, lttng_alignof(uint64_t));
- offset += sizeof(uint32_t); /* id */
- offset += lib_ring_buffer_align(offset, lttng_alignof(uint64_t));
- offset += sizeof(uint64_t); /* timestamp */
- }
- break;
- default:
- padding = 0;
- WARN_ON_ONCE(1);
- }
- offset += ctx_get_size(offset, event->ctx);
- offset += ctx_get_size(offset, lttng_chan->ctx);
-
- *pre_header_padding = padding;
- return offset - orig_offset;
-}
-
-#include "wrapper/ringbuffer/api.h"
-
-static
-void lttng_write_event_header_slow(const struct lib_ring_buffer_config *config,
- struct lib_ring_buffer_ctx *ctx,
- uint32_t event_id);
-
-/*
- * lttng_write_event_header
- *
- * Writes the event header to the offset (already aligned on 32-bits).
- *
- * @config: ring buffer instance configuration
- * @ctx: reservation context
- * @event_id: event ID
- */
-static __inline__
-void lttng_write_event_header(const struct lib_ring_buffer_config *config,
- struct lib_ring_buffer_ctx *ctx,
- uint32_t event_id)
-{
- struct lttng_channel *lttng_chan = channel_get_private(ctx->chan);
- struct lttng_event *event = ctx->priv;
-
- if (unlikely(ctx->rflags))
- goto slow_path;
-
- switch (lttng_chan->header_type) {
- case 1: /* compact */
- {
- uint32_t id_time = 0;
-
- bt_bitfield_write(&id_time, uint32_t,
- 0,
- LTTNG_COMPACT_EVENT_BITS,
- event_id);
- bt_bitfield_write(&id_time, uint32_t,
- LTTNG_COMPACT_EVENT_BITS,
- LTTNG_COMPACT_TSC_BITS,
- ctx->tsc);
- lib_ring_buffer_write(config, ctx, &id_time, sizeof(id_time));
- break;
- }
- case 2: /* large */
- {
- uint32_t timestamp = (uint32_t) ctx->tsc;
- uint16_t id = event_id;
-
- lib_ring_buffer_write(config, ctx, &id, sizeof(id));
- lib_ring_buffer_align_ctx(ctx, lttng_alignof(uint32_t));
- lib_ring_buffer_write(config, ctx, ×tamp, sizeof(timestamp));
- break;
- }
- default:
- WARN_ON_ONCE(1);
- }
-
- ctx_record(ctx, lttng_chan, lttng_chan->ctx);
- ctx_record(ctx, lttng_chan, event->ctx);
- lib_ring_buffer_align_ctx(ctx, ctx->largest_align);
-
- return;
-
-slow_path:
- lttng_write_event_header_slow(config, ctx, event_id);
-}
-
-static
-void lttng_write_event_header_slow(const struct lib_ring_buffer_config *config,
- struct lib_ring_buffer_ctx *ctx,
- uint32_t event_id)
-{
- struct lttng_channel *lttng_chan = channel_get_private(ctx->chan);
- struct lttng_event *event = ctx->priv;
-
- switch (lttng_chan->header_type) {
- case 1: /* compact */
- if (!(ctx->rflags & (RING_BUFFER_RFLAG_FULL_TSC | LTTNG_RFLAG_EXTENDED))) {
- uint32_t id_time = 0;
-
- bt_bitfield_write(&id_time, uint32_t,
- 0,
- LTTNG_COMPACT_EVENT_BITS,
- event_id);
- bt_bitfield_write(&id_time, uint32_t,
- LTTNG_COMPACT_EVENT_BITS,
- LTTNG_COMPACT_TSC_BITS, ctx->tsc);
- lib_ring_buffer_write(config, ctx, &id_time, sizeof(id_time));
- } else {
- uint8_t id = 0;
- uint64_t timestamp = ctx->tsc;
-
- bt_bitfield_write(&id, uint8_t,
- 0,
- LTTNG_COMPACT_EVENT_BITS,
- 31);
- lib_ring_buffer_write(config, ctx, &id, sizeof(id));
- /* Align extended struct on largest member */
- lib_ring_buffer_align_ctx(ctx, lttng_alignof(uint64_t));
- lib_ring_buffer_write(config, ctx, &event_id, sizeof(event_id));
- lib_ring_buffer_align_ctx(ctx, lttng_alignof(uint64_t));
- lib_ring_buffer_write(config, ctx, ×tamp, sizeof(timestamp));
- }
- break;
- case 2: /* large */
- {
- if (!(ctx->rflags & (RING_BUFFER_RFLAG_FULL_TSC | LTTNG_RFLAG_EXTENDED))) {
- uint32_t timestamp = (uint32_t) ctx->tsc;
- uint16_t id = event_id;
-
- lib_ring_buffer_write(config, ctx, &id, sizeof(id));
- lib_ring_buffer_align_ctx(ctx, lttng_alignof(uint32_t));
- lib_ring_buffer_write(config, ctx, ×tamp, sizeof(timestamp));
- } else {
- uint16_t id = 65535;
- uint64_t timestamp = ctx->tsc;
-
- lib_ring_buffer_write(config, ctx, &id, sizeof(id));
- /* Align extended struct on largest member */
- lib_ring_buffer_align_ctx(ctx, lttng_alignof(uint64_t));
- lib_ring_buffer_write(config, ctx, &event_id, sizeof(event_id));
- lib_ring_buffer_align_ctx(ctx, lttng_alignof(uint64_t));
- lib_ring_buffer_write(config, ctx, ×tamp, sizeof(timestamp));
- }
- break;
- }
- default:
- WARN_ON_ONCE(1);
- }
- ctx_record(ctx, lttng_chan, lttng_chan->ctx);
- ctx_record(ctx, lttng_chan, event->ctx);
- lib_ring_buffer_align_ctx(ctx, ctx->largest_align);
-}
-
-static const struct lib_ring_buffer_config client_config;
-
-static u64 client_ring_buffer_clock_read(struct channel *chan)
-{
- return lib_ring_buffer_clock_read(chan);
-}
-
-static
-size_t client_record_header_size(const struct lib_ring_buffer_config *config,
- struct channel *chan, size_t offset,
- size_t *pre_header_padding,
- struct lib_ring_buffer_ctx *ctx)
-{
- return record_header_size(config, chan, offset,
- pre_header_padding, ctx);
-}
-
-/**
- * client_packet_header_size - called on buffer-switch to a new sub-buffer
- *
- * Return header size without padding after the structure. Don't use packed
- * structure because gcc generates inefficient code on some architectures
- * (powerpc, mips..)
- */
-static size_t client_packet_header_size(void)
-{
- return offsetof(struct packet_header, ctx.header_end);
-}
-
-static void client_buffer_begin(struct lib_ring_buffer *buf, u64 tsc,
- unsigned int subbuf_idx)
-{
- struct channel *chan = buf->backend.chan;
- struct packet_header *header =
- (struct packet_header *)
- lib_ring_buffer_offset_address(&buf->backend,
- subbuf_idx * chan->backend.subbuf_size);
- struct lttng_channel *lttng_chan = channel_get_private(chan);
- struct lttng_session *session = lttng_chan->session;
-
- header->magic = CTF_MAGIC_NUMBER;
- memcpy(header->uuid, session->uuid.b, sizeof(session->uuid));
- header->stream_id = lttng_chan->id;
- header->ctx.timestamp_begin = tsc;
- header->ctx.timestamp_end = 0;
- header->ctx.events_discarded = 0;
- header->ctx.content_size = 0xFFFFFFFF; /* for debugging */
- header->ctx.packet_size = 0xFFFFFFFF;
- header->ctx.cpu_id = buf->backend.cpu;
-}
-
-/*
- * offset is assumed to never be 0 here : never deliver a completely empty
- * subbuffer. data_size is between 1 and subbuf_size.
- */
-static void client_buffer_end(struct lib_ring_buffer *buf, u64 tsc,
- unsigned int subbuf_idx, unsigned long data_size)
-{
- struct channel *chan = buf->backend.chan;
- struct packet_header *header =
- (struct packet_header *)
- lib_ring_buffer_offset_address(&buf->backend,
- subbuf_idx * chan->backend.subbuf_size);
- unsigned long records_lost = 0;
-
- header->ctx.timestamp_end = tsc;
- header->ctx.content_size = data_size * CHAR_BIT; /* in bits */
- header->ctx.packet_size = PAGE_ALIGN(data_size) * CHAR_BIT; /* in bits */
- records_lost += lib_ring_buffer_get_records_lost_full(&client_config, buf);
- records_lost += lib_ring_buffer_get_records_lost_wrap(&client_config, buf);
- records_lost += lib_ring_buffer_get_records_lost_big(&client_config, buf);
- header->ctx.events_discarded = records_lost;
-}
-
-static int client_buffer_create(struct lib_ring_buffer *buf, void *priv,
- int cpu, const char *name)
-{
- return 0;
-}
-
-static void client_buffer_finalize(struct lib_ring_buffer *buf, void *priv, int cpu)
-{
-}
-
-static const struct lib_ring_buffer_config client_config = {
- .cb.ring_buffer_clock_read = client_ring_buffer_clock_read,
- .cb.record_header_size = client_record_header_size,
- .cb.subbuffer_header_size = client_packet_header_size,
- .cb.buffer_begin = client_buffer_begin,
- .cb.buffer_end = client_buffer_end,
- .cb.buffer_create = client_buffer_create,
- .cb.buffer_finalize = client_buffer_finalize,
-
- .tsc_bits = LTTNG_COMPACT_TSC_BITS,
- .alloc = RING_BUFFER_ALLOC_PER_CPU,
- .sync = RING_BUFFER_SYNC_PER_CPU,
- .mode = RING_BUFFER_MODE_TEMPLATE,
- .backend = RING_BUFFER_PAGE,
- .output = RING_BUFFER_OUTPUT_TEMPLATE,
- .oops = RING_BUFFER_OOPS_CONSISTENCY,
- .ipi = RING_BUFFER_IPI_BARRIER,
- .wakeup = RING_BUFFER_WAKEUP_BY_TIMER,
-};
-
-static
-struct channel *_channel_create(const char *name,
- struct lttng_channel *lttng_chan, void *buf_addr,
- size_t subbuf_size, size_t num_subbuf,
- unsigned int switch_timer_interval,
- unsigned int read_timer_interval)
-{
- return channel_create(&client_config, name, lttng_chan, buf_addr,
- subbuf_size, num_subbuf, switch_timer_interval,
- read_timer_interval);
-}
-
-static
-void lttng_channel_destroy(struct channel *chan)
-{
- channel_destroy(chan);
-}
-
-static
-struct lib_ring_buffer *lttng_buffer_read_open(struct channel *chan)
-{
- struct lib_ring_buffer *buf;
- int cpu;
-
- for_each_channel_cpu(cpu, chan) {
- buf = channel_get_ring_buffer(&client_config, chan, cpu);
- if (!lib_ring_buffer_open_read(buf))
- return buf;
- }
- return NULL;
-}
-
-static
-int lttng_buffer_has_read_closed_stream(struct channel *chan)
-{
- struct lib_ring_buffer *buf;
- int cpu;
-
- for_each_channel_cpu(cpu, chan) {
- buf = channel_get_ring_buffer(&client_config, chan, cpu);
- if (!atomic_long_read(&buf->active_readers))
- return 1;
- }
- return 0;
-}
-
-static
-void lttng_buffer_read_close(struct lib_ring_buffer *buf)
-{
- lib_ring_buffer_release_read(buf);
-}
-
-static
-int lttng_event_reserve(struct lib_ring_buffer_ctx *ctx,
- uint32_t event_id)
-{
- struct lttng_channel *lttng_chan = channel_get_private(ctx->chan);
- int ret, cpu;
-
- cpu = lib_ring_buffer_get_cpu(&client_config);
- if (cpu < 0)
- return -EPERM;
- ctx->cpu = cpu;
-
- switch (lttng_chan->header_type) {
- case 1: /* compact */
- if (event_id > 30)
- ctx->rflags |= LTTNG_RFLAG_EXTENDED;
- break;
- case 2: /* large */
- if (event_id > 65534)
- ctx->rflags |= LTTNG_RFLAG_EXTENDED;
- break;
- default:
- WARN_ON_ONCE(1);
- }
-
- ret = lib_ring_buffer_reserve(&client_config, ctx);
- if (ret)
- goto put;
- lttng_write_event_header(&client_config, ctx, event_id);
- return 0;
-put:
- lib_ring_buffer_put_cpu(&client_config);
- return ret;
-}
-
-static
-void lttng_event_commit(struct lib_ring_buffer_ctx *ctx)
-{
- lib_ring_buffer_commit(&client_config, ctx);
- lib_ring_buffer_put_cpu(&client_config);
-}
-
-static
-void lttng_event_write(struct lib_ring_buffer_ctx *ctx, const void *src,
- size_t len)
-{
- lib_ring_buffer_write(&client_config, ctx, src, len);
-}
-
-static
-void lttng_event_write_from_user(struct lib_ring_buffer_ctx *ctx,
- const void __user *src, size_t len)
-{
- lib_ring_buffer_copy_from_user(&client_config, ctx, src, len);
-}
-
-static
-void lttng_event_memset(struct lib_ring_buffer_ctx *ctx,
- int c, size_t len)
-{
- lib_ring_buffer_memset(&client_config, ctx, c, len);
-}
-
-static
-wait_queue_head_t *lttng_get_writer_buf_wait_queue(struct channel *chan, int cpu)
-{
- struct lib_ring_buffer *buf = channel_get_ring_buffer(&client_config,
- chan, cpu);
- return &buf->write_wait;
-}
-
-static
-wait_queue_head_t *lttng_get_hp_wait_queue(struct channel *chan)
-{
- return &chan->hp_wait;
-}
-
-static
-int lttng_is_finalized(struct channel *chan)
-{
- return lib_ring_buffer_channel_is_finalized(chan);
-}
-
-static
-int lttng_is_disabled(struct channel *chan)
-{
- return lib_ring_buffer_channel_is_disabled(chan);
-}
-
-static struct lttng_transport lttng_relay_transport = {
- .name = "relay-" RING_BUFFER_MODE_TEMPLATE_STRING,
- .owner = THIS_MODULE,
- .ops = {
- .channel_create = _channel_create,
- .channel_destroy = lttng_channel_destroy,
- .buffer_read_open = lttng_buffer_read_open,
- .buffer_has_read_closed_stream =
- lttng_buffer_has_read_closed_stream,
- .buffer_read_close = lttng_buffer_read_close,
- .event_reserve = lttng_event_reserve,
- .event_commit = lttng_event_commit,
- .event_write = lttng_event_write,
- .event_write_from_user = lttng_event_write_from_user,
- .event_memset = lttng_event_memset,
- .packet_avail_size = NULL, /* Would be racy anyway */
- .get_writer_buf_wait_queue = lttng_get_writer_buf_wait_queue,
- .get_hp_wait_queue = lttng_get_hp_wait_queue,
- .is_finalized = lttng_is_finalized,
- .is_disabled = lttng_is_disabled,
- },
-};
-
-static int __init lttng_ring_buffer_client_init(void)
-{
- /*
- * This vmalloc sync all also takes care of the lib ring buffer
- * vmalloc'd module pages when it is built as a module into LTTng.
- */
- wrapper_vmalloc_sync_all();
- lttng_transport_register(<tng_relay_transport);
- return 0;
-}
-
-module_init(lttng_ring_buffer_client_init);
-
-static void __exit lttng_ring_buffer_client_exit(void)
-{
- lttng_transport_unregister(<tng_relay_transport);
-}
-
-module_exit(lttng_ring_buffer_client_exit);
-
-MODULE_LICENSE("GPL and additional rights");
-MODULE_AUTHOR("Mathieu Desnoyers");
-MODULE_DESCRIPTION("LTTng ring buffer " RING_BUFFER_MODE_TEMPLATE_STRING
- " client");
projects / lttng-modules.git / blobdiff