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From:   Arnaldo Carvalho de Melo <arnaldo.melo@gmail.com>
Date:   Mon, 18 May 2020 11:19:15 -0300
To:     Jiri Olsa <jolsa@kernel.org>
Cc:     lkml <linux-kernel@vger.kernel.org>,
        Ingo Molnar <mingo@kernel.org>,
        Namhyung Kim <namhyung@kernel.org>,
        Alexander Shishkin <alexander.shishkin@linux.intel.com>,
        Peter Zijlstra <a.p.zijlstra@chello.nl>,
        Michael Petlan <mpetlan@redhat.com>
Subject: Re: [RFC] perf trace: Fix compilation error for make NO_LIBBPF=1
 DEBUG=1
Message-ID: <20200518141915.GA24211@kernel.org>
References: <20200518141027.3765877-1-jolsa@kernel.org>
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Em Mon, May 18, 2020 at 04:10:27PM +0200, Jiri Olsa escreveu:
> I haven't tested if this breaks some perf trace functionality,
> hence RFC ;-)

Thanks for the patch, looks ok, applying, please let me know if you need
to do something else with it.

- Arnaldo
 
> The perf compilation fails for NO_LIBBPF=1 DEBUG=1 with:
> 
>   $ make NO_LIBBPF=1 DEBUG=1
>     BUILD:   Doing 'make -j8' parallel build
>     CC       builtin-trace.o
>     LD       perf-in.o
>     LINK     perf
>   /usr/bin/ld: perf-in.o: in function `trace__find_bpf_map_by_name':
>   /home/jolsa/kernel/linux-perf/tools/perf/builtin-trace.c:4608: undefined reference to `bpf_object__find_map_by_name'
>   collect2: error: ld returned 1 exit status
>   make[2]: *** [Makefile.perf:631: perf] Error 1
>   make[1]: *** [Makefile.perf:225: sub-make] Error 2
>   make: *** [Makefile:70: all] Error 2
> 
> Moving trace__find_bpf_map_by_name calls under HAVE_LIBBPF_SUPPORT
> ifdef and add make test for this.
> 
> Signed-off-by: Jiri Olsa <jolsa@kernel.org>
> ---
>  tools/perf/builtin-trace.c | 54 ++++++++++++++++++++++++--------------
>  tools/perf/tests/make      |  1 +
>  2 files changed, 35 insertions(+), 20 deletions(-)
> 
> diff --git a/tools/perf/builtin-trace.c b/tools/perf/builtin-trace.c
> index 56bcf1ab19f8..61bafca1018a 100644
> --- a/tools/perf/builtin-trace.c
> +++ b/tools/perf/builtin-trace.c
> @@ -3174,6 +3174,26 @@ static int trace__set_ev_qualifier_tp_filter(struct trace *trace)
>  }
>  
>  #ifdef HAVE_LIBBPF_SUPPORT
> +static struct bpf_map *trace__find_bpf_map_by_name(struct trace *trace, const char *name)
> +{
> +	if (trace->bpf_obj == NULL)
> +		return NULL;
> +
> +	return bpf_object__find_map_by_name(trace->bpf_obj, name);
> +}
> +
> +static void trace__set_bpf_map_filtered_pids(struct trace *trace)
> +{
> +	trace->filter_pids.map = trace__find_bpf_map_by_name(trace, "pids_filtered");
> +}
> +
> +static void trace__set_bpf_map_syscalls(struct trace *trace)
> +{
> +	trace->syscalls.map = trace__find_bpf_map_by_name(trace, "syscalls");
> +	trace->syscalls.prog_array.sys_enter = trace__find_bpf_map_by_name(trace, "syscalls_sys_enter");
> +	trace->syscalls.prog_array.sys_exit  = trace__find_bpf_map_by_name(trace, "syscalls_sys_exit");
> +}
> +
>  static struct bpf_program *trace__find_bpf_program_by_title(struct trace *trace, const char *name)
>  {
>  	if (trace->bpf_obj == NULL)
> @@ -3512,6 +3532,20 @@ static void trace__delete_augmented_syscalls(struct trace *trace)
>  	trace->bpf_obj = NULL;
>  }
>  #else // HAVE_LIBBPF_SUPPORT
> +static struct bpf_map *trace__find_bpf_map_by_name(struct trace *trace __maybe_unused,
> +						   const char *name __maybe_unused)
> +{
> +	return NULL;
> +}
> +
> +static void trace__set_bpf_map_filtered_pids(struct trace *trace __maybe_unused)
> +{
> +}
> +
> +static void trace__set_bpf_map_syscalls(struct trace *trace __maybe_unused)
> +{
> +}
> +
>  static int trace__set_ev_qualifier_bpf_filter(struct trace *trace __maybe_unused)
>  {
>  	return 0;
> @@ -4600,26 +4634,6 @@ static int trace__parse_cgroups(const struct option *opt, const char *str, int u
>  	return 0;
>  }
>  
> -static struct bpf_map *trace__find_bpf_map_by_name(struct trace *trace, const char *name)
> -{
> -	if (trace->bpf_obj == NULL)
> -		return NULL;
> -
> -	return bpf_object__find_map_by_name(trace->bpf_obj, name);
> -}
> -
> -static void trace__set_bpf_map_filtered_pids(struct trace *trace)
> -{
> -	trace->filter_pids.map = trace__find_bpf_map_by_name(trace, "pids_filtered");
> -}
> -
> -static void trace__set_bpf_map_syscalls(struct trace *trace)
> -{
> -	trace->syscalls.map = trace__find_bpf_map_by_name(trace, "syscalls");
> -	trace->syscalls.prog_array.sys_enter = trace__find_bpf_map_by_name(trace, "syscalls_sys_enter");
> -	trace->syscalls.prog_array.sys_exit  = trace__find_bpf_map_by_name(trace, "syscalls_sys_exit");
> -}
> -
>  static int trace__config(const char *var, const char *value, void *arg)
>  {
>  	struct trace *trace = arg;
> diff --git a/tools/perf/tests/make b/tools/perf/tests/make
> index 5d0c3a9c47a1..c3c59def9f87 100644
> --- a/tools/perf/tests/make
> +++ b/tools/perf/tests/make
> @@ -84,6 +84,7 @@ make_no_libaudit    := NO_LIBAUDIT=1
>  make_no_libbionic   := NO_LIBBIONIC=1
>  make_no_auxtrace    := NO_AUXTRACE=1
>  make_no_libbpf	    := NO_LIBBPF=1
> +make_no_libbpf_DEBUG := NO_LIBBPF=1 DEBUG=1
>  make_no_libcrypto   := NO_LIBCRYPTO=1
>  make_with_babeltrace:= LIBBABELTRACE=1
>  make_no_sdt	    := NO_SDT=1
> -- 
> 2.25.4
> 

-- 

- Arnaldo