/*
* lttng-ring-buffer-client.h
*
* LTTng lib ring buffer client template.
*
* Copyright (C) 2010-2012 Mathieu Desnoyers <mathieu.desnoyers@efficios.com>
*
* This library is free software; you can redistribute it and/or
* modify it under the terms of the GNU Lesser General Public
* License as published by the Free Software Foundation; only
* version 2.1 of the License.
*
* This library is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
* Lesser General Public License for more details.
*
* You should have received a copy of the GNU Lesser General Public
* License along with this library; if not, write to the Free Software
* Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
*/
#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 */
uint64_t content_size; /* Size of data in subbuffer */
uint64_t packet_size; /* Subbuffer size (include padding) */
unsigned long events_discarded; /*
* Events lost in this subbuffer since
* the beginning of the trace.
* (may overflow)
*/
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.content_size = ~0ULL; /* for debugging */
header->ctx.packet_size = ~0ULL;
header->ctx.events_discarded = 0;
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 =
(uint64_t) data_size * CHAR_BIT; /* in bits */
header->ctx.packet_size =
(uint64_t) 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_inatomic(&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");