linux-kernel - Re: [PATCH 12/25] perf tools: Try to load vmlinux from buildid database

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Date:   Thu, 26 Nov 2020 14:50:08 -0300
From:   Arnaldo Carvalho de Melo <acme@...nel.org>
To:     Jiri Olsa <jolsa@...nel.org>
Cc:     lkml <linux-kernel@...r.kernel.org>,
        Peter Zijlstra <a.p.zijlstra@...llo.nl>,
        Ingo Molnar <mingo@...nel.org>,
        Mark Rutland <mark.rutland@....com>,
        Namhyung Kim <namhyung@...nel.org>,
        Alexander Shishkin <alexander.shishkin@...ux.intel.com>,
        Michael Petlan <mpetlan@...hat.com>,
        Song Liu <songliubraving@...com>,
        Ian Rogers <irogers@...gle.com>,
        Stephane Eranian <eranian@...gle.com>,
        Alexey Budankov <alexey.budankov@...ux.intel.com>,
        Andi Kleen <ak@...ux.intel.com>,
        Adrian Hunter <adrian.hunter@...el.com>
Subject: Re: [PATCH 12/25] perf tools: Try to load vmlinux from buildid
 database

Em Thu, Nov 26, 2020 at 06:00:13PM +0100, Jiri Olsa escreveu:
> Currently we don't check on kernel's vmlinux the same way as
> we do for normal binaries, but we either look for kallsyms
> file in build id database or check on known vmlinux locations
> (plus some other optional paths).
> 
> This patch adds the check for standard build id binary location,
> so we are ready once we start to store it there from debuginfod
> in following changes.

Thanks, applied.

- Arnaldo

 
> Signed-off-by: Jiri Olsa <jolsa@...nel.org>
> ---
>  tools/perf/util/build-id.c | 13 ++++++++++---
>  tools/perf/util/build-id.h |  2 ++
>  tools/perf/util/symbol.c   | 16 ++++++++++++++++
>  3 files changed, 28 insertions(+), 3 deletions(-)
> 
> diff --git a/tools/perf/util/build-id.c b/tools/perf/util/build-id.c
> index 4a391f13f40d..1fd58703c2d4 100644
> --- a/tools/perf/util/build-id.c
> +++ b/tools/perf/util/build-id.c
> @@ -261,10 +261,9 @@ static const char *build_id_cache__basename(bool is_kallsyms, bool is_vdso,
>  	    "debug" : "elf"));
>  }
>  
> -char *dso__build_id_filename(const struct dso *dso, char *bf, size_t size,
> -			     bool is_debug)
> +char *__dso__build_id_filename(const struct dso *dso, char *bf, size_t size,
> +			       bool is_debug, bool is_kallsyms)
>  {
> -	bool is_kallsyms = dso__is_kallsyms((struct dso *)dso);
>  	bool is_vdso = dso__is_vdso((struct dso *)dso);
>  	char sbuild_id[SBUILD_ID_SIZE];
>  	char *linkname;
> @@ -293,6 +292,14 @@ char *dso__build_id_filename(const struct dso *dso, char *bf, size_t size,
>  	return bf;
>  }
>  
> +char *dso__build_id_filename(const struct dso *dso, char *bf, size_t size,
> +			     bool is_debug)
> +{
> +	bool is_kallsyms = dso__is_kallsyms((struct dso *)dso);
> +
> +	return __dso__build_id_filename(dso, bf, size, is_debug, is_kallsyms);
> +}
> +
>  #define dsos__for_each_with_build_id(pos, head)	\
>  	list_for_each_entry(pos, head, node)	\
>  		if (!pos->has_build_id)		\
> diff --git a/tools/perf/util/build-id.h b/tools/perf/util/build-id.h
> index d53415feaf69..f1a2f67df6e4 100644
> --- a/tools/perf/util/build-id.h
> +++ b/tools/perf/util/build-id.h
> @@ -29,6 +29,8 @@ char *build_id_cache__kallsyms_path(const char *sbuild_id, char *bf,
>  
>  char *dso__build_id_filename(const struct dso *dso, char *bf, size_t size,
>  			     bool is_debug);
> +char *__dso__build_id_filename(const struct dso *dso, char *bf, size_t size,
> +			       bool is_debug, bool is_kallsyms);
>  
>  int build_id__mark_dso_hit(struct perf_tool *tool, union perf_event *event,
>  			   struct perf_sample *sample, struct evsel *evsel,
> diff --git a/tools/perf/util/symbol.c b/tools/perf/util/symbol.c
> index 0d14abdf3d72..64a039cbba1b 100644
> --- a/tools/perf/util/symbol.c
> +++ b/tools/perf/util/symbol.c
> @@ -2189,6 +2189,8 @@ static int dso__load_kernel_sym(struct dso *dso, struct map *map)
>  	int err;
>  	const char *kallsyms_filename = NULL;
>  	char *kallsyms_allocated_filename = NULL;
> +	char *filename = NULL;
> +
>  	/*
>  	 * Step 1: if the user specified a kallsyms or vmlinux filename, use
>  	 * it and only it, reporting errors to the user if it cannot be used.
> @@ -2213,6 +2215,20 @@ static int dso__load_kernel_sym(struct dso *dso, struct map *map)
>  		return dso__load_vmlinux(dso, map, symbol_conf.vmlinux_name, false);
>  	}
>  
> +	/*
> +	 * Before checking on common vmlinux locations, check if it's
> +	 * stored as standard build id binary (not kallsyms) under
> +	 * .debug cache.
> +	 */
> +	if (!symbol_conf.ignore_vmlinux_buildid)
> +		filename = __dso__build_id_filename(dso, NULL, 0, false, false);
> +	if (filename != NULL) {
> +		err = dso__load_vmlinux(dso, map, filename, true);
> +		if (err > 0)
> +			return err;
> +		free(filename);
> +	}
> +
>  	if (!symbol_conf.ignore_vmlinux && vmlinux_path != NULL) {
>  		err = dso__load_vmlinux_path(dso, map);
>  		if (err > 0)
> -- 
> 2.26.2
> 

-- 

- Arnaldo