[lttng-dev] [UST PATCH 1/2] Specialize lttng_ust_lib_ring_buffer_client_cb

[Mathieu Desnoyers]

* Julien Desfossez (jdesfossez at efficios.com) wrote:
> Prepare the ring-buffer config to have custom callbacks. These custom
> callbacks are not related to the ring-buffer operations but allow
> applications to add custom functions.
> No additional feature or change in behaviour in this patch.
> 
> Signed-off-by: Julien Desfossez <jdesfossez at efficios.com>
> ---
>  include/lttng/ringbuffer-config.h                |    1 +
>  include/lttng/ust-events.h                       |    6 +++---
>  liblttng-ust/lttng-rb-clients.h                  |    8 ++++++++
>  liblttng-ust/lttng-ring-buffer-client.h          |   18 +++++++++++++++++-
>  liblttng-ust/lttng-ring-buffer-metadata-client.h |   18 +++++++++++++++++-
>  5 files changed, 46 insertions(+), 5 deletions(-)
>  create mode 100644 liblttng-ust/lttng-rb-clients.h
> 
> diff --git a/include/lttng/ringbuffer-config.h b/include/lttng/ringbuffer-config.h
> index 3b7d348..e81b827 100644
> --- a/include/lttng/ringbuffer-config.h
> +++ b/include/lttng/ringbuffer-config.h
> @@ -204,6 +204,7 @@ struct lttng_ust_lib_ring_buffer_config {
>  	 * callbacks and update the cb pointers.
>  	 */
>  	int client_type;
> +	const struct lttng_ust_lib_ring_buffer_client_cb *cb_ptr;
>  	char padding[LTTNG_UST_RING_BUFFER_CONFIG_PADDING];

we need to change the padding size.

>  };
>  
> diff --git a/include/lttng/ust-events.h b/include/lttng/ust-events.h
> index f40c044..153c0ff 100644
> --- a/include/lttng/ust-events.h
> +++ b/include/lttng/ust-events.h
> @@ -569,9 +569,9 @@ int lttng_add_ip_to_ctx(struct lttng_ctx **ctx);
>  void lttng_context_vtid_reset(void);
>  void lttng_context_vpid_reset(void);
>  
> -extern const struct lttng_ust_lib_ring_buffer_client_cb *lttng_client_callbacks_metadata;
> -extern const struct lttng_ust_lib_ring_buffer_client_cb *lttng_client_callbacks_discard;
> -extern const struct lttng_ust_lib_ring_buffer_client_cb *lttng_client_callbacks_overwrite;
> +extern const struct specialized_lttng_ust_lib_ring_buffer_client_cb *lttng_client_callbacks_metadata;
> +extern const struct specialized_lttng_ust_lib_ring_buffer_client_cb *lttng_client_callbacks_discard;
> +extern const struct specialized_lttng_ust_lib_ring_buffer_client_cb *lttng_client_callbacks_overwrite;
>  
>  struct lttng_transport *lttng_transport_find(const char *name);
>  
> diff --git a/liblttng-ust/lttng-rb-clients.h b/liblttng-ust/lttng-rb-clients.h
> new file mode 100644
> index 0000000..37fd842
> --- /dev/null
> +++ b/liblttng-ust/lttng-rb-clients.h
> @@ -0,0 +1,8 @@
> +#ifndef _LTTNG_RB_CLIENT_H
> +#define _LTTNG_RB_CLIENT_H

missing file copyright/license header.

> +
> +struct specialized_lttng_ust_lib_ring_buffer_client_cb {

maybe we could find another name than "specialized" ?

Thanks,

Mathieu

> +	struct lttng_ust_lib_ring_buffer_client_cb parent;
> +};
> +
> +#endif /* _LTTNG_RB_CLIENT_H */
> diff --git a/liblttng-ust/lttng-ring-buffer-client.h b/liblttng-ust/lttng-ring-buffer-client.h
> index 72b6d2c..94db97e 100644
> --- a/liblttng-ust/lttng-ring-buffer-client.h
> +++ b/liblttng-ust/lttng-ring-buffer-client.h
> @@ -161,6 +161,7 @@ unsigned char record_header_size(const struct lttng_ust_lib_ring_buffer_config *
>  }
>  
>  #include "../libringbuffer/api.h"
> +#include "lttng-rb-clients.h"
>  
>  static
>  void lttng_write_event_header_slow(const struct lttng_ust_lib_ring_buffer_config *config,
> @@ -385,6 +386,19 @@ static void client_buffer_finalize(struct lttng_ust_lib_ring_buffer *buf, void *
>  {
>  }
>  
> +static const
> +struct specialized_lttng_ust_lib_ring_buffer_client_cb client_cb = {
> +	.parent = {
> +		.ring_buffer_clock_read = client_ring_buffer_clock_read,
> +		.record_header_size = client_record_header_size,
> +		.subbuffer_header_size = client_packet_header_size,
> +		.buffer_begin = client_buffer_begin,
> +		.buffer_end = client_buffer_end,
> +		.buffer_create = client_buffer_create,
> +		.buffer_finalize = client_buffer_finalize,
> +	},
> +};
> +
>  static const struct lttng_ust_lib_ring_buffer_config client_config = {
>  	.cb.ring_buffer_clock_read = client_ring_buffer_clock_read,
>  	.cb.record_header_size = client_record_header_size,
> @@ -404,9 +418,11 @@ static const struct lttng_ust_lib_ring_buffer_config client_config = {
>  	.ipi = RING_BUFFER_NO_IPI_BARRIER,
>  	.wakeup = LTTNG_CLIENT_WAKEUP,
>  	.client_type = LTTNG_CLIENT_TYPE,
> +
> +	.cb_ptr = &client_cb.parent,
>  };
>  
> -const struct lttng_ust_lib_ring_buffer_client_cb *LTTNG_CLIENT_CALLBACKS = &client_config.cb;
> +const struct specialized_lttng_ust_lib_ring_buffer_client_cb *LTTNG_CLIENT_CALLBACKS = &client_cb;
>  
>  static
>  struct lttng_channel *_channel_create(const char *name,
> diff --git a/liblttng-ust/lttng-ring-buffer-metadata-client.h b/liblttng-ust/lttng-ring-buffer-metadata-client.h
> index 89f2620..5098f21 100644
> --- a/liblttng-ust/lttng-ring-buffer-metadata-client.h
> +++ b/liblttng-ust/lttng-ring-buffer-metadata-client.h
> @@ -61,6 +61,7 @@ unsigned char record_header_size(const struct lttng_ust_lib_ring_buffer_config *
>  }
>  
>  #include "../libringbuffer/api.h"
> +#include "lttng-rb-clients.h"
>  
>  static uint64_t client_ring_buffer_clock_read(struct channel *chan)
>  {
> @@ -153,6 +154,19 @@ static void client_buffer_finalize(struct lttng_ust_lib_ring_buffer *buf,
>  {
>  }
>  
> +static const
> +struct specialized_lttng_ust_lib_ring_buffer_client_cb client_cb = {
> +	.parent = {
> +		.ring_buffer_clock_read = client_ring_buffer_clock_read,
> +		.record_header_size = client_record_header_size,
> +		.subbuffer_header_size = client_packet_header_size,
> +		.buffer_begin = client_buffer_begin,
> +		.buffer_end = client_buffer_end,
> +		.buffer_create = client_buffer_create,
> +		.buffer_finalize = client_buffer_finalize,
> +	},
> +};
> +
>  static const struct lttng_ust_lib_ring_buffer_config client_config = {
>  	.cb.ring_buffer_clock_read = client_ring_buffer_clock_read,
>  	.cb.record_header_size = client_record_header_size,
> @@ -172,9 +186,11 @@ static const struct lttng_ust_lib_ring_buffer_config client_config = {
>  	.ipi = RING_BUFFER_NO_IPI_BARRIER,
>  	.wakeup = RING_BUFFER_WAKEUP_BY_WRITER,
>  	.client_type = LTTNG_CLIENT_TYPE,
> +
> +	 .cb_ptr = &client_cb.parent,
>  };
>  
> -const struct lttng_ust_lib_ring_buffer_client_cb *LTTNG_CLIENT_CALLBACKS = &client_config.cb;
> +const struct specialized_lttng_ust_lib_ring_buffer_client_cb *LTTNG_CLIENT_CALLBACKS = &client_cb;
>  
>  static
>  struct lttng_channel *_channel_create(const char *name,
> -- 
> 1.7.10.4
> 

-- 
Mathieu Desnoyers
EfficiOS Inc.
http://www.efficios.com