[lttng-dev] [PATCH] Fix: baddr_statedump tracepoint registration
Mathieu Desnoyers
mathieu.desnoyers at efficios.com
Mon Dec 16 08:39:38 EST 2013
Hi Paul,
I rewrote the patch to use a reference counting approach instead.
The effect should be the same. Here is the commit:
commit f0cc794d37abf59b4b8079612c7aa03dc305d92f
Author: Mathieu Desnoyers <mathieu.desnoyers at efficios.com>
Date: Mon Dec 16 08:36:06 2013 -0500
Fix: baddr_statedump tracepoint registration
Make sure that the ust_baddr_statedump probe is registered prior to
using the tracepoint in lttng_ust_baddr_statedump(). This fix solves the
issue that in rare cases the very first ust_baddr_statedump events were
missing.
Use a reference counting approach that allows constructors/destructors
of the probe to be called many times, as long as the number of calls to
constructor matches the number of calls to destructor.
Reported-by: Paul Woegerer <paul_woegerer at mentor.com>
Signed-off-by: Mathieu Desnoyers <mathieu.desnoyers at efficios.com>
Thanks,
Mathieu
----- Original Message -----
> From: "Paul Woegerer" <paul_woegerer at mentor.com>
> To: "mathieu desnoyers" <mathieu.desnoyers at efficios.com>, lttng-dev at lists.lttng.org
> Sent: Friday, December 13, 2013 8:12:02 AM
> Subject: [PATCH] Fix: baddr_statedump tracepoint registration
>
> Also make sure that the ust_baddr_statedump probe get registered prior
> to using the tracepoint in lttng_ust_baddr_statedump(). This fix solves
> the issue that in rare cases the very first ust_baddr_statedump events
> were missing.
>
> Signed-off-by: Paul Woegerer <paul_woegerer at mentor.com>
> ---
> include/lttng/ust-tracepoint-event.h | 10 ++++++++++
> liblttng-ust/Makefile.am | 1 -
> liblttng-ust/lttng-ust-baddr.c | 15 +++++++++++++++
> liblttng-ust/ust_baddr_statedump.c | 22 ----------------------
> 4 files changed, 25 insertions(+), 23 deletions(-)
> delete mode 100644 liblttng-ust/ust_baddr_statedump.c
>
> diff --git a/include/lttng/ust-tracepoint-event.h
> b/include/lttng/ust-tracepoint-event.h
> index be58030..b48cd74 100644
> --- a/include/lttng/ust-tracepoint-event.h
> +++ b/include/lttng/ust-tracepoint-event.h
> @@ -694,6 +694,10 @@ static struct lttng_probe_desc
> _TP_COMBINE_TOKENS(__probe_desc___, TRACEPOINT_PR
> * linking the probe statically.
> */
>
> +#ifndef BADDR_EXPLICIT_PROBE_REGISTER
> +#define BADDR_EXPLICIT_PROBE_REGISTER do {} while (0)
> +#endif
> +
> /* Reset all macros within TRACEPOINT_EVENT */
> #include <lttng/ust-tracepoint-event-reset.h>
> static void lttng_ust_notrace __attribute__((constructor))
> @@ -703,6 +707,8 @@ _TP_COMBINE_TOKENS(__lttng_events_init__,
> TRACEPOINT_PROVIDER)(void)
> {
> int ret;
>
> + BADDR_EXPLICIT_PROBE_REGISTER;
> +
> /*
> * __tracepoint_provider_check_ ## TRACEPOINT_PROVIDER() is a
> * static inline function that ensures every probe PROVIDER
> @@ -724,7 +730,11 @@ _TP_COMBINE_TOKENS(__lttng_events_exit__,
> TRACEPOINT_PROVIDER)(void);
> static void
> _TP_COMBINE_TOKENS(__lttng_events_exit__, TRACEPOINT_PROVIDER)(void)
> {
> + BADDR_EXPLICIT_PROBE_REGISTER;
> +
> lttng_probe_unregister(&_TP_COMBINE_TOKENS(__probe_desc___,
> TRACEPOINT_PROVIDER));
> }
>
> +#undef BADDR_EXPLICIT_PROBE_REGISTER
> +
> int _TP_COMBINE_TOKENS(__tracepoint_provider_, TRACEPOINT_PROVIDER);
> diff --git a/liblttng-ust/Makefile.am b/liblttng-ust/Makefile.am
> index b165c32..e9022d8 100644
> --- a/liblttng-ust/Makefile.am
> +++ b/liblttng-ust/Makefile.am
> @@ -37,7 +37,6 @@ liblttng_ust_runtime_la_SOURCES = \
> lttng-hash-helper.h \
> lttng-ust-baddr.c \
> lttng-ust-baddr.h \
> - ust_baddr_statedump.c \
> ust_baddr_statedump.h \
> tracepoint-internal.h \
> clock.h \
> diff --git a/liblttng-ust/lttng-ust-baddr.c b/liblttng-ust/lttng-ust-baddr.c
> index b7843e2..d39e9e8 100644
> --- a/liblttng-ust/lttng-ust-baddr.c
> +++ b/liblttng-ust/lttng-ust-baddr.c
> @@ -35,6 +35,15 @@
> #include "lttng-tracer-core.h"
> #include "lttng-ust-baddr.h"
>
> +#define TRACEPOINT_CREATE_PROBES
> +#define TP_SESSION_CHECK
> +static int explicit_probe_register;
> +#define BADDR_EXPLICIT_PROBE_REGISTER \
> +do { \
> + if (!explicit_probe_register) \
> + return; \
> +} while (0)
> +
> #define TRACEPOINT_DEFINE
> #include "ust_baddr_statedump.h"
>
> @@ -199,10 +208,16 @@ void lttng_ust_baddr_statedump_init(void)
> {
> __tracepoints__init();
> __tracepoints__ptrs_init();
> + explicit_probe_register = 1;
> + __lttng_events_init__ust_baddr_statedump();
> + explicit_probe_register = 0;
> }
>
> void lttng_ust_baddr_statedump_destroy(void)
> {
> + explicit_probe_register = 1;
> + __lttng_events_exit__ust_baddr_statedump();
> + explicit_probe_register = 0;
> __tracepoints__ptrs_destroy();
> __tracepoints__destroy();
> }
> diff --git a/liblttng-ust/ust_baddr_statedump.c
> b/liblttng-ust/ust_baddr_statedump.c
> deleted file mode 100644
> index 9097008..0000000
> --- a/liblttng-ust/ust_baddr_statedump.c
> +++ /dev/null
> @@ -1,22 +0,0 @@
> -/*
> - * Copyright (C) 2013 Paul Woegerer <paul_woegerer at mentor.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; either
> - * version 2.1 of the License, or (at your option) any later version.
> - *
> - * 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
> - */
> -
> -#define _LGPL_SOURCE
> -#define TRACEPOINT_CREATE_PROBES
> -#define TP_SESSION_CHECK
> -#include "ust_baddr_statedump.h"
> --
> 1.8.5
>
>
--
Mathieu Desnoyers
EfficiOS Inc.
http://www.efficios.com
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