[lttng-dev] [UST PATCH 1/2] Specialize lttng_ust_lib_ring_buffer_client_cb
Mathieu Desnoyers
mathieu.desnoyers at efficios.com
Fri Aug 16 14:47:00 EDT 2013
* 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 | 4 +++-
> include/lttng/ust-events.h | 6 ++---
> liblttng-ust/Makefile.am | 1 +
> liblttng-ust/lttng-rb-clients.h | 26 ++++++++++++++++++++++
> liblttng-ust/lttng-ring-buffer-client.h | 18 ++++++++++++++-
> liblttng-ust/lttng-ring-buffer-metadata-client.h | 18 ++++++++++++++-
> 6 files changed, 67 insertions(+), 6 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..afb1310 100644
> --- a/include/lttng/ringbuffer-config.h
> +++ b/include/lttng/ringbuffer-config.h
> @@ -133,7 +133,8 @@ struct lttng_ust_lib_ring_buffer_client_cb {
> * RING_BUFFER_WAKEUP_NONE does not perform any wakeup whatsoever. The client
> * has the responsibility to perform wakeups.
> */
just to be on the safe side (this structure is not packed):
> -#define LTTNG_UST_RING_BUFFER_CONFIG_PADDING 32
> +#define LTTNG_UST_RING_BUFFER_CONFIG_PADDING \
> + (32 - sizeof(const struct lttng_ust_lib_ring_buffer_client_cb *))
>
#define LTTNG_UST_RING_BUFFER_CONFIG_PADDING 20
(32 - 4 - 8, worse case)
> enum lttng_ust_lib_ring_buffer_alloc_types {
> RING_BUFFER_ALLOC_PER_CPU,
> @@ -204,6 +205,7 @@ struct lttng_ust_lib_ring_buffer_config {
> * callbacks and update the cb pointers.
> */
> int client_type;
int _unused1;
(because int client_type has a structure that contains pointers, so
we'll have padding added on 64-bit archs) It's better to explicitly
enforce the padding. (yes, this should have been packed form the
start. Too late.)
Thanks,
Mathieu
> + const struct lttng_ust_lib_ring_buffer_client_cb *cb_ptr;
> char padding[LTTNG_UST_RING_BUFFER_CONFIG_PADDING];
> };
>
> diff --git a/include/lttng/ust-events.h b/include/lttng/ust-events.h
> index f40c044..74a3bc6 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 lttng_ust_client_lib_ring_buffer_client_cb *lttng_client_callbacks_metadata;
> +extern const struct lttng_ust_client_lib_ring_buffer_client_cb *lttng_client_callbacks_discard;
> +extern const struct lttng_ust_client_lib_ring_buffer_client_cb *lttng_client_callbacks_overwrite;
>
> struct lttng_transport *lttng_transport_find(const char *name);
>
> diff --git a/liblttng-ust/Makefile.am b/liblttng-ust/Makefile.am
> index 1e6401a..5a43cf5 100644
> --- a/liblttng-ust/Makefile.am
> +++ b/liblttng-ust/Makefile.am
> @@ -47,6 +47,7 @@ liblttng_ust_support_la_SOURCES = \
> lttng-tracer.h \
> lttng-tracer-core.h \
> ust-core.c \
> + lttng-rb-clients.h \
> lttng-ring-buffer-client.h \
> lttng-ring-buffer-client-discard.c \
> lttng-ring-buffer-client-discard-rt.c \
> diff --git a/liblttng-ust/lttng-rb-clients.h b/liblttng-ust/lttng-rb-clients.h
> new file mode 100644
> index 0000000..c9a1619
> --- /dev/null
> +++ b/liblttng-ust/lttng-rb-clients.h
> @@ -0,0 +1,26 @@
> +#ifndef _LTTNG_RB_CLIENT_H
> +#define _LTTNG_RB_CLIENT_H
> +
> +/*
> + * Copyright (c) 2013 - Mathieu Desnoyers <mathieu.desnoyers at 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
> + */
> +
> +struct lttng_ust_client_lib_ring_buffer_client_cb {
> + 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..383fce0 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 lttng_ust_client_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 lttng_ust_client_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..0d2a1f8 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 lttng_ust_client_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 lttng_ust_client_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
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