Re: [PATCH -tip v3 04/10] perf probe: Query basic types fromdebuginfo

From: Arnaldo Carvalho de Melo
Date: Mon Apr 12 2010 - 13:45:43 EST


Em Mon, Apr 12, 2010 at 01:17:15PM -0400, Masami Hiramatsu escreveu:
> Query the basic type information (byte-size and signed-flag) from
> debuginfo and pass that to kprobe-tracer. This is especially useful
> for tracing the members of data structure, because each member has
> different byte-size on the memory.
>
> Signed-off-by: Masami Hiramatsu <mhiramat@xxxxxxxxxx>
> Cc: Ingo Molnar <mingo@xxxxxxx>
> Cc: Paul Mackerras <paulus@xxxxxxxxx>
> Cc: Arnaldo Carvalho de Melo <acme@xxxxxxxxxx>
> Cc: Peter Zijlstra <peterz@xxxxxxxxxxxxx>
> Cc: Mike Galbraith <efault@xxxxxx>
> Cc: Frederic Weisbecker <fweisbec@xxxxxxxxx>
> ---
>
> tools/perf/util/probe-event.c | 9 +++++
> tools/perf/util/probe-event.h | 1 +
> tools/perf/util/probe-finder.c | 78 ++++++++++++++++++++++++++++++++++++----
> 3 files changed, 80 insertions(+), 8 deletions(-)
>
> diff --git a/tools/perf/util/probe-event.c b/tools/perf/util/probe-event.c
> index 19de8b7..05ca4a9 100644
> --- a/tools/perf/util/probe-event.c
> +++ b/tools/perf/util/probe-event.c
> @@ -740,6 +740,13 @@ static int synthesize_kprobe_trace_arg(struct kprobe_trace_arg *arg,
> buf += ret;
> buflen -= ret;
> }
> + /* Print argument type */
> + if (arg->type) {
> + ret = e_snprintf(buf, buflen, ":%s", arg->type);
> + if (ret <= 0)
> + return ret;
> + buf += ret;
> + }
>
> return buf - tmp;
> }
> @@ -848,6 +855,8 @@ void clear_kprobe_trace_event(struct kprobe_trace_event *tev)
> free(tev->args[i].name);
> if (tev->args[i].value)
> free(tev->args[i].value);
> + if (tev->args[i].type)
> + free(tev->args[i].type);

It follows the existing style but as kfree, free() also can cope with
NULL pointers, so unconditionally calling free is a shorter form, but
this can be fixed later, possibily in a big cleanup in all of
tools/perf.

- Arnaldo
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