From: Steven Rostedt <rostedt@goodmis.org>
To: Tom Zanussi <tom.zanussi@linux.intel.com>
Cc: tglx@linutronix.de, mhiramat@kernel.org, namhyung@kernel.org,
vedang.patel@intel.com, bigeasy@linutronix.de,
joel.opensrc@gmail.com, joelaf@google.com,
mathieu.desnoyers@efficios.com, baohong.liu@intel.com,
linux-kernel@vger.kernel.org, linux-rt-users@vger.kernel.org
Subject: Re: [PATCH v2 25/40] tracing: Add support for dynamic tracepoints
Date: Thu, 7 Sep 2017 18:02:26 -0400 [thread overview]
Message-ID: <20170907180226.1497e96c@gandalf.local.home> (raw)
In-Reply-To: <9f89af4588c84850a58edcf72d2591ba78906c30.1504642143.git.tom.zanussi@linux.intel.com>
On Tue, 5 Sep 2017 16:57:37 -0500
Tom Zanussi <tom.zanussi@linux.intel.com> wrote:
> The tracepoint infrastructure assumes statically-defined tracepoints
> and uses static_keys for tracepoint enablement. In order to define
> tracepoints on the fly, we need to have a dynamic counterpart.
Do we?
I believe the static keys should work just fine if you don't have any
defined static keys jumps, and they should work as a simple counter.
Could we do that instead of adding another variable to a structure that
is defined over a thousand times? Save us 4k of memory.
-- Steve
>
> Add a 'dynamic' flag to struct tracepoint along with accompanying
> logic for this purpose.
>
> Signed-off-by: Tom Zanussi <tom.zanussi@linux.intel.com>
> ---
> include/linux/tracepoint-defs.h | 1 +
> kernel/tracepoint.c | 18 +++++++++++++-----
> 2 files changed, 14 insertions(+), 5 deletions(-)
>
> diff --git a/include/linux/tracepoint-defs.h b/include/linux/tracepoint-defs.h
> index a031920..bc22d54 100644
> --- a/include/linux/tracepoint-defs.h
> +++ b/include/linux/tracepoint-defs.h
> @@ -32,6 +32,7 @@ struct tracepoint {
> int (*regfunc)(void);
> void (*unregfunc)(void);
> struct tracepoint_func __rcu *funcs;
> + bool dynamic;
> };
>
> #endif
> diff --git a/kernel/tracepoint.c b/kernel/tracepoint.c
> index 685c50a..1c5957f 100644
> --- a/kernel/tracepoint.c
> +++ b/kernel/tracepoint.c
> @@ -197,7 +197,9 @@ static int tracepoint_add_func(struct tracepoint *tp,
> struct tracepoint_func *old, *tp_funcs;
> int ret;
>
> - if (tp->regfunc && !static_key_enabled(&tp->key)) {
> + if (tp->regfunc &&
> + ((tp->dynamic && !(atomic_read(&tp->key.enabled) > 0)) ||
> + !static_key_enabled(&tp->key))) {
> ret = tp->regfunc();
> if (ret < 0)
> return ret;
> @@ -219,7 +221,9 @@ static int tracepoint_add_func(struct tracepoint *tp,
> * is used.
> */
> rcu_assign_pointer(tp->funcs, tp_funcs);
> - if (!static_key_enabled(&tp->key))
> + if (tp->dynamic && !(atomic_read(&tp->key.enabled) > 0))
> + atomic_inc(&tp->key.enabled);
> + else if (!tp->dynamic && !static_key_enabled(&tp->key))
> static_key_slow_inc(&tp->key);
> release_probes(old);
> return 0;
> @@ -246,10 +250,14 @@ static int tracepoint_remove_func(struct tracepoint *tp,
>
> if (!tp_funcs) {
> /* Removed last function */
> - if (tp->unregfunc && static_key_enabled(&tp->key))
> + if (tp->unregfunc &&
> + ((tp->dynamic && (atomic_read(&tp->key.enabled) > 0)) ||
> + static_key_enabled(&tp->key)))
> tp->unregfunc();
>
> - if (static_key_enabled(&tp->key))
> + if (tp->dynamic && (atomic_read(&tp->key.enabled) > 0))
> + atomic_dec(&tp->key.enabled);
> + else if (!tp->dynamic && static_key_enabled(&tp->key))
> static_key_slow_dec(&tp->key);
> }
> rcu_assign_pointer(tp->funcs, tp_funcs);
> @@ -258,7 +266,7 @@ static int tracepoint_remove_func(struct tracepoint *tp,
> }
>
> /**
> - * tracepoint_probe_register - Connect a probe to a tracepoint
> + * tracepoint_probe_register_prio - Connect a probe to a tracepoint
> * @tp: tracepoint
> * @probe: probe handler
> * @data: tracepoint data
next prev parent reply other threads:[~2017-09-07 22:02 UTC|newest]
Thread overview: 90+ messages / expand[flat|nested] mbox.gz Atom feed top
2017-09-05 21:57 [PATCH v2 00/40] tracing: Inter-event (e.g. latency) support Tom Zanussi
2017-09-05 21:57 ` [PATCH v2 01/40] tracing: Exclude 'generic fields' from histograms Tom Zanussi
2017-09-05 21:57 ` [PATCH v2 02/40] tracing: Add support to detect and avoid duplicates Tom Zanussi
2017-09-06 18:32 ` Steven Rostedt
2017-09-06 18:47 ` Steven Rostedt
2017-09-06 20:58 ` Patel, Vedang
2017-09-05 21:57 ` [PATCH v2 03/40] tracing: Remove code which merges duplicates Tom Zanussi
2017-09-05 21:57 ` [PATCH v2 04/40] tracing: Add hist_field_name() accessor Tom Zanussi
2017-09-05 21:57 ` [PATCH v2 05/40] tracing: Reimplement log2 Tom Zanussi
2017-09-05 21:57 ` [PATCH v2 06/40] ring-buffer: Add interface for setting absolute time stamps Tom Zanussi
2017-09-05 21:57 ` [PATCH v2 07/40] tracing: Apply absolute timestamps to instance max buffer Tom Zanussi
2017-09-06 19:57 ` Steven Rostedt
2017-09-07 0:49 ` Steven Rostedt
2017-09-07 1:15 ` Liu, Baohong
2017-09-05 21:57 ` [PATCH v2 08/40] ring-buffer: Redefine the unimplemented RINGBUF_TIME_TIME_STAMP Tom Zanussi
2017-09-07 14:35 ` Steven Rostedt
2017-09-07 15:05 ` Tom Zanussi
2017-09-05 21:57 ` [PATCH v2 09/40] tracing: Give event triggers access to ring_buffer_event Tom Zanussi
2017-09-05 21:57 ` [PATCH v2 10/40] tracing: Add ring buffer event param to hist field functions Tom Zanussi
2017-09-05 21:57 ` [PATCH v2 11/40] tracing: Increase tracing map KEYS_MAX size Tom Zanussi
2017-09-05 21:57 ` [PATCH v2 12/40] tracing: Break out hist trigger assignment parsing Tom Zanussi
2017-09-05 21:57 ` [PATCH v2 13/40] tracing: Make traceprobe parsing code reusable Tom Zanussi
2017-09-05 21:57 ` [PATCH v2 14/40] tracing: Add hist trigger timestamp support Tom Zanussi
2017-09-05 21:57 ` [PATCH v2 15/40] tracing: Add per-element variable support to tracing_map Tom Zanussi
2017-09-05 21:57 ` [PATCH v2 16/40] tracing: Add hist_data member to hist_field Tom Zanussi
2017-09-05 21:57 ` [PATCH v2 17/40] tracing: Add usecs modifier for hist trigger timestamps Tom Zanussi
2017-09-05 21:57 ` [PATCH v2 18/40] tracing: Add variable support to hist triggers Tom Zanussi
2017-09-05 21:57 ` [PATCH v2 19/40] tracing: Account for variables in named trigger compatibility Tom Zanussi
2017-09-07 16:40 ` Steven Rostedt
2017-09-07 17:00 ` Tom Zanussi
2017-09-05 21:57 ` [PATCH v2 20/40] tracing: Add simple expression support to hist triggers Tom Zanussi
2017-09-07 16:46 ` Steven Rostedt
2017-09-07 17:01 ` Tom Zanussi
2017-09-05 21:57 ` [PATCH v2 21/40] tracing: Generalize per-element hist trigger data Tom Zanussi
2017-09-07 17:56 ` Steven Rostedt
2017-09-07 18:14 ` Tom Zanussi
2017-09-05 21:57 ` [PATCH v2 22/40] tracing: Pass tracing_map_elt to hist_field accessor functions Tom Zanussi
2017-09-05 21:57 ` [PATCH v2 23/40] tracing: Add hist_field 'type' field Tom Zanussi
2017-09-05 21:57 ` [PATCH v2 24/40] tracing: Add variable reference handling to hist triggers Tom Zanussi
2017-09-05 21:57 ` [PATCH v2 25/40] tracing: Add support for dynamic tracepoints Tom Zanussi
2017-09-05 23:29 ` Mathieu Desnoyers
2017-09-06 2:35 ` Tom Zanussi
2017-09-07 22:02 ` Steven Rostedt [this message]
2017-09-08 14:18 ` Tom Zanussi
2017-09-05 21:57 ` [PATCH v2 26/40] tracing: Add hist trigger action hook Tom Zanussi
2017-09-05 21:57 ` [PATCH v2 27/40] tracing: Add support for 'synthetic' events Tom Zanussi
2017-09-07 23:40 ` Steven Rostedt
2017-09-08 14:30 ` Tom Zanussi
2017-09-05 21:57 ` [PATCH v2 28/40] tracing: Add support for 'field variables' Tom Zanussi
2017-09-07 23:43 ` Steven Rostedt
2017-09-08 15:37 ` Tom Zanussi
2017-09-05 21:57 ` [PATCH v2 29/40] tracing: Add 'onmatch' hist trigger action support Tom Zanussi
2017-09-05 21:57 ` [PATCH v2 30/40] tracing: Add 'onmax' " Tom Zanussi
2017-09-05 21:57 ` [PATCH v2 31/40] tracing: Allow whitespace to surround hist trigger filter Tom Zanussi
2017-09-08 18:50 ` Steven Rostedt
2017-09-08 19:08 ` Tom Zanussi
2017-09-05 21:57 ` [PATCH v2 32/40] tracing: Add cpu field for hist triggers Tom Zanussi
2017-09-08 19:08 ` Steven Rostedt
2017-09-08 19:35 ` Tom Zanussi
2017-09-05 21:57 ` [PATCH v2 33/40] tracing: Add hist trigger support for variable reference aliases Tom Zanussi
2017-09-08 19:09 ` Steven Rostedt
2017-09-08 19:41 ` Tom Zanussi
2017-09-05 21:57 ` [PATCH v2 34/40] tracing: Add 'last error' error facility for hist triggers Tom Zanussi
2017-09-08 19:25 ` Steven Rostedt
2017-09-08 19:44 ` Tom Zanussi
2017-09-05 21:57 ` [PATCH v2 35/40] tracing: Reverse the order event_mutex/trace_types_lock are taken Tom Zanussi
2017-09-08 19:31 ` Steven Rostedt
2017-09-08 19:41 ` Steven Rostedt
2017-09-08 20:00 ` Steven Rostedt
2017-09-05 21:57 ` [PATCH v2 36/40] tracing: Remove lookups from tracing_map hitcount Tom Zanussi
2017-09-12 2:16 ` Masami Hiramatsu
2017-09-12 14:16 ` Tom Zanussi
2017-09-05 21:57 ` [PATCH v2 37/40] tracing: Add inter-event hist trigger Documentation Tom Zanussi
2017-09-20 14:44 ` Julia Cartwright
2017-09-20 17:15 ` Tom Zanussi
2017-09-05 21:57 ` [PATCH v2 38/40] tracing: Make tracing_set_clock() non-static Tom Zanussi
2017-09-12 2:18 ` Masami Hiramatsu
2017-09-12 14:18 ` Tom Zanussi
2017-09-05 21:57 ` [PATCH v2 39/40] tracing: Add a clock attribute for hist triggers Tom Zanussi
2017-09-05 21:57 ` [PATCH v2 40/40] tracing: Add trace_event_buffer_reserve() variant that allows recursion Tom Zanussi
2017-09-07 22:29 ` kbuild test robot
2017-09-07 22:35 ` kbuild test robot
2017-09-08 20:27 ` Steven Rostedt
2017-09-08 20:41 ` Tom Zanussi
2017-09-12 1:50 ` [PATCH v2 00/40] tracing: Inter-event (e.g. latency) support Masami Hiramatsu
2017-09-12 14:14 ` Tom Zanussi
2017-09-19 16:31 ` Steven Rostedt
2017-09-19 18:44 ` Tom Zanussi
2017-09-21 20:20 ` Steven Rostedt
2017-09-21 21:11 ` Tom Zanussi
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