lttng: lib ring buffer clients

/*

 * ltt-ring-buffer-client-discard.c

 *

 * Copyright (C) 2010 - Mathieu Desnoyers <mathieu.desnoyers@efficios.com>

 *

 * LTTng lib ring buffer client (discard mode).

 *

 * Dual LGPL v2.1/GPL v2 license.

 */

#include <linux/module.h>

#include "ltt-tracer.h"

#define RING_BUFFER_MODE_TEMPLATE		RING_BUFFER_DISCARD

#define RING_BUFFER_MODE_TEMPLATE_STRING	"discard"

#define RING_BUFFER_OUTPUT_TEMPLATE		RING_BUFFER_SPLICE

#include "ltt-ring-buffer-client.h"

MODULE_LICENSE("GPL and additional rights");

MODULE_AUTHOR("Mathieu Desnoyers");

MODULE_DESCRIPTION("LTTng Ring Buffer Client Discard Mode");

/*

 * ltt-ring-buffer-client-discard.c

 *

 * Copyright (C) 2010 - Mathieu Desnoyers <mathieu.desnoyers@efficios.com>

 *

 * LTTng lib ring buffer client (discard mode).

 *

 * Dual LGPL v2.1/GPL v2 license.

 */

#include <linux/module.h>

#include "ltt-tracer.h"

#define RING_BUFFER_MODE_TEMPLATE		RING_BUFFER_DISCARD

#define RING_BUFFER_MODE_TEMPLATE_STRING	"discard-mmap"

#define RING_BUFFER_OUTPUT_TEMPLATE		RING_BUFFER_MMAP

#include "ltt-ring-buffer-client.h"

MODULE_LICENSE("GPL and additional rights");

MODULE_AUTHOR("Mathieu Desnoyers");

MODULE_DESCRIPTION("LTTng Ring Buffer Client Discard Mode");

/*

 * ltt-ring-buffer-client-overwrite.c

 *

 * Copyright (C) 2010 - Mathieu Desnoyers <mathieu.desnoyers@efficios.com>

 *

 * LTTng lib ring buffer client (overwrite mode).

 *

 * Dual LGPL v2.1/GPL v2 license.

 */

#include <linux/module.h>

#include "ltt-tracer.h"

#define RING_BUFFER_MODE_TEMPLATE		RING_BUFFER_OVERWRITE

#define RING_BUFFER_MODE_TEMPLATE_STRING	"overwrite-mmap"

#define RING_BUFFER_OUTPUT_TEMPLATE		RING_BUFFER_MMAP

#include "ltt-ring-buffer-client.h"

MODULE_LICENSE("GPL and additional rights");

MODULE_AUTHOR("Mathieu Desnoyers");

MODULE_DESCRIPTION("LTTng Ring Buffer Client Overwrite Mode");

/*

 * ltt-ring-buffer-client-overwrite.c

 *

 * Copyright (C) 2010 - Mathieu Desnoyers <mathieu.desnoyers@efficios.com>

 *

 * LTTng lib ring buffer client (overwrite mode).

 *

 * Dual LGPL v2.1/GPL v2 license.

 */

#include <linux/module.h>

#include "ltt-tracer.h"

#define RING_BUFFER_MODE_TEMPLATE		RING_BUFFER_OVERWRITE

#define RING_BUFFER_MODE_TEMPLATE_STRING	"overwrite"

#define RING_BUFFER_OUTPUT_TEMPLATE		RING_BUFFER_SPLICE

#include "ltt-ring-buffer-client.h"

MODULE_LICENSE("GPL and additional rights");

MODULE_AUTHOR("Mathieu Desnoyers");

MODULE_DESCRIPTION("LTTng Ring Buffer Client Overwrite Mode");

/*

 * ltt-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 "ltt-events.h"

#include "ltt-tracer.h"

#include "wrapper/ringbuffer/frontend_types.h"

/*

 * 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 ltt_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 ltt_channel *ltt_chan = channel_get_private(chan);

	struct ltt_event *event = ctx->priv;

	size_t orig_offset = offset;

	size_t padding;

	switch (ltt_chan->header_type) {

	case 1:	/* compact */

		padding = lib_ring_buffer_align(offset, ltt_alignof(uint32_t));

		offset += padding;

		if (!(ctx->rflags & (RING_BUFFER_RFLAG_FULL_TSC | LTT_RFLAG_EXTENDED))) {

			offset += sizeof(uint32_t);	/* id and timestamp */

		} else {

			/* Minimum space taken by 5-bit id */

			offset += sizeof(uint8_t);

			/* Align extended struct on largest member */

			offset += lib_ring_buffer_align(offset, ltt_alignof(uint64_t));

			offset += sizeof(uint32_t);	/* id */

			offset += lib_ring_buffer_align(offset, ltt_alignof(uint64_t));

			offset += sizeof(uint64_t);	/* timestamp */

		}

		break;

	case 2:	/* large */

		padding = lib_ring_buffer_align(offset, ltt_alignof(uint16_t));

		offset += padding;

		offset += sizeof(uint16_t);

		if (!(ctx->rflags & (RING_BUFFER_RFLAG_FULL_TSC | LTT_RFLAG_EXTENDED))) {

			offset += lib_ring_buffer_align(offset, ltt_alignof(uint32_t));

			offset += sizeof(uint32_t);	/* timestamp */

		} else {

			/* Align extended struct on largest member */

			offset += lib_ring_buffer_align(offset, ltt_alignof(uint64_t));

			offset += sizeof(uint32_t);	/* id */

			offset += lib_ring_buffer_align(offset, ltt_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, ltt_chan->ctx);

	*pre_header_padding = padding;

	return offset - orig_offset;

}

#include "wrapper/ringbuffer/api.h"

static

void ltt_write_event_header_slow(const struct lib_ring_buffer_config *config,

				 struct lib_ring_buffer_ctx *ctx,

				 uint32_t event_id);

/*

 * ltt_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 ltt_write_event_header(const struct lib_ring_buffer_config *config,

			    struct lib_ring_buffer_ctx *ctx,

			    uint32_t event_id)

{

	struct ltt_channel *ltt_chan = channel_get_private(ctx->chan);

	struct ltt_event *event = ctx->priv;

	if (unlikely(ctx->rflags))

		goto slow_path;

	switch (ltt_chan->header_type) {

	case 1:	/* compact */

	{

		uint32_t id_time = 0;

		bt_bitfield_write(&id_time, uint32_t, 0, 5, event_id);

		bt_bitfield_write(&id_time, uint32_t, 5, 27, 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, ltt_alignof(uint32_t));

		lib_ring_buffer_write(config, ctx, &timestamp, sizeof(timestamp));

		break;

	}

	default:

		WARN_ON_ONCE(1);

	}

	ctx_record(ctx, ltt_chan, ltt_chan->ctx);

	ctx_record(ctx, ltt_chan, event->ctx);

	lib_ring_buffer_align_ctx(ctx, ctx->largest_align);

	return;

slow_path:

	ltt_write_event_header_slow(config, ctx, event_id);

}

static

void ltt_write_event_header_slow(const struct lib_ring_buffer_config *config,

				 struct lib_ring_buffer_ctx *ctx,

				 uint32_t event_id)

{

	struct ltt_channel *ltt_chan = channel_get_private(ctx->chan);

	struct ltt_event *event = ctx->priv;

	switch (ltt_chan->header_type) {

	case 1:	/* compact */

		if (!(ctx->rflags & (RING_BUFFER_RFLAG_FULL_TSC | LTT_RFLAG_EXTENDED))) {

			uint32_t id_time = 0;

			bt_bitfield_write(&id_time, uint32_t, 0, 5, event_id);

			bt_bitfield_write(&id_time, uint32_t, 5, 27, 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, 5, 31);

			lib_ring_buffer_write(config, ctx, &id, sizeof(id));

			/* Align extended struct on largest member */

			lib_ring_buffer_align_ctx(ctx, ltt_alignof(uint64_t));

			lib_ring_buffer_write(config, ctx, &event_id, sizeof(event_id));

			lib_ring_buffer_align_ctx(ctx, ltt_alignof(uint64_t));

			lib_ring_buffer_write(config, ctx, &timestamp, sizeof(timestamp));

		}

		break;

	case 2:	/* large */

	{

		if (!(ctx->rflags & (RING_BUFFER_RFLAG_FULL_TSC | LTT_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, ltt_alignof(uint32_t));

			lib_ring_buffer_write(config, ctx, &timestamp, 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, ltt_alignof(uint64_t));

			lib_ring_buffer_write(config, ctx, &event_id, sizeof(event_id));

			lib_ring_buffer_align_ctx(ctx, ltt_alignof(uint64_t));

			lib_ring_buffer_write(config, ctx, &timestamp, sizeof(timestamp));

		}

		break;

	}

	default:

		WARN_ON_ONCE(1);

	}

	ctx_record(ctx, ltt_chan, ltt_chan->ctx);

	ctx_record(ctx, ltt_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 ltt_channel *ltt_chan = channel_get_private(chan);

	struct ltt_session *session = ltt_chan->session;

	header->magic = CTF_MAGIC_NUMBER;

	memcpy(header->uuid, session->uuid.b, sizeof(session->uuid));

	header->stream_id = ltt_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 = 32,

	.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 ltt_channel *ltt_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, ltt_chan, buf_addr,

			      subbuf_size, num_subbuf, switch_timer_interval,

			      read_timer_interval);

}

static

void ltt_channel_destroy(struct channel *chan)

{

	channel_destroy(chan);

}

static

struct lib_ring_buffer *ltt_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 ltt_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 ltt_buffer_read_close(struct lib_ring_buffer *buf)

{

	lib_ring_buffer_release_read(buf);

}

static

int ltt_event_reserve(struct lib_ring_buffer_ctx *ctx,

		      uint32_t event_id)

{

	struct ltt_channel *ltt_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 (ltt_chan->header_type) {

	case 1:	/* compact */

		if (event_id > 30)

			ctx->rflags |= LTT_RFLAG_EXTENDED;

		break;

	case 2:	/* large */

		if (event_id > 65534)

			ctx->rflags |= LTT_RFLAG_EXTENDED;

		break;

	default:

		WARN_ON_ONCE(1);

	}

	ret = lib_ring_buffer_reserve(&client_config, ctx);

	if (ret)

		goto put;

	ltt_write_event_header(&client_config, ctx, event_id);

	return 0;

put:

	lib_ring_buffer_put_cpu(&client_config);

	return ret;

}

static

void ltt_event_commit(struct lib_ring_buffer_ctx *ctx)

{

	lib_ring_buffer_commit(&client_config, ctx);

	lib_ring_buffer_put_cpu(&client_config);

}

static

void ltt_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 ltt_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 ltt_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 *ltt_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 *ltt_get_hp_wait_queue(struct channel *chan)

{

	return &chan->hp_wait;

}

static

int ltt_is_finalized(struct channel *chan)

{

	return lib_ring_buffer_channel_is_finalized(chan);

}

static

int ltt_is_disabled(struct channel *chan)

{

	return lib_ring_buffer_channel_is_disabled(chan);

}

static struct ltt_transport ltt_relay_transport = {

	.name = "relay-" RING_BUFFER_MODE_TEMPLATE_STRING,

	.owner = THIS_MODULE,

	.ops = {

		.channel_create = _channel_create,

		.channel_destroy = ltt_channel_destroy,

		.buffer_read_open = ltt_buffer_read_open,

		.buffer_has_read_closed_stream =

			ltt_buffer_has_read_closed_stream,

		.buffer_read_close = ltt_buffer_read_close,

		.event_reserve = ltt_event_reserve,

		.event_commit = ltt_event_commit,

		.event_write = ltt_event_write,

		.event_write_from_user = ltt_event_write_from_user,

		.event_memset = ltt_event_memset,

		.packet_avail_size = NULL,	/* Would be racy anyway */

		.get_writer_buf_wait_queue = ltt_get_writer_buf_wait_queue,

		.get_hp_wait_queue = ltt_get_hp_wait_queue,

		.is_finalized = ltt_is_finalized,

		.is_disabled = ltt_is_disabled,

	},

};

static int __init ltt_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();

	ltt_transport_register(&ltt_relay_transport);

	return 0;

}

module_init(ltt_ring_buffer_client_init);

static void __exit ltt_ring_buffer_client_exit(void)

{

	ltt_transport_unregister(&ltt_relay_transport);

}

module_exit(ltt_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");