linux-kernel - Re: [PATCH] perf machine: Search for modules in %s/lib/modules/%s

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Date:	Wed, 30 Apr 2014 08:46:38 +0900
From:	Namhyung Kim <namhyung@...nel.org>
To:	Jiri Olsa <jolsa@...hat.com>
Cc:	Richard Yao <ryao@...too.org>,
	Peter Zijlstra <a.p.zijlstra@...llo.nl>,
	Paul Mackerras <paulus@...ba.org>,
	Arnaldo Carvalho de Melo <acme@...stprotocols.net>,
	Adrian Hunter <adrian.hunter@...el.com>,
	David Ahern <dsahern@...il.com>,
	Stephane Eranian <eranian@...gle.com>,
	Frederic Weisbecker <fweisbec@...il.com>,
	linux-kernel@...r.kernel.org
Subject: Re: [PATCH] perf machine: Search for modules in %s/lib/modules/%s

Hi Jiri,

On Tue, 29 Apr 2014 10:06:17 +0200, Jiri Olsa wrote:
> On Sun, Apr 27, 2014 at 12:05:56PM +0200, Jiri Olsa wrote:
>> On Sat, Apr 26, 2014 at 01:17:55PM -0400, Richard Yao wrote:
>> > Modules installed outside of the kernel's build system should go into
>> > "%s/lib/modules/%s/extra", but at present, perf will only look at them
>> > when they are in "%s/lib/modules/%s/kernel". Lets encourage good
>> > citizenship by relaxing this requirement to "%s/lib/modules/%s". This
>> > way open source modules that are out-of-tree have no incentive to start
>> > populating a directory reserved for in-kernel modules and I can stop
>> > hex-editing my system's perf binary when profiling OSS out-of-tree
>> > modules.
>> > 
>> > Feedback from Namhyung Kim correctly revealed that the hex-edits that I
>> > had been doing meant that perf was also traversing the build and source
>> > symlinks in %s/lib/modules/%s. That is undesireable, so we explicitly
>> > exclude them from traversal with a minor tweak to the traversal routine.
>> 
>> looks good to me, Namhyung?
>
> just realized Namhyung wasn't CC-ed on this one ;-)

:)

Well, I still prefer the symlink check with lstat(), I can live with
this, so:

  Acked-by: Namhyung kim <namhyung@...nel.org>

Thanks,
Namhyung

>
>> 
>> thanks,
>> jirka
>> 
>> > 
>> > Signed-off-by: Richard Yao <ryao@...too.org>
>> > ---
>> >  tools/perf/util/machine.c | 16 ++++++++++++----
>> >  1 file changed, 12 insertions(+), 4 deletions(-)
>> > 
>> > diff --git a/tools/perf/util/machine.c b/tools/perf/util/machine.c
>> > index a53cd0b..27c2a5e 100644
>> > --- a/tools/perf/util/machine.c
>> > +++ b/tools/perf/util/machine.c
>> > @@ -717,7 +717,7 @@ static char *get_kernel_version(const char *root_dir)
>> >  }
>> >  
>> >  static int map_groups__set_modules_path_dir(struct map_groups *mg,
>> > -				const char *dir_name)
>> > +				const char *dir_name, int depth)
>> >  {
>> >  	struct dirent *dent;
>> >  	DIR *dir = opendir(dir_name);
>> > @@ -742,7 +742,15 @@ static int map_groups__set_modules_path_dir(struct map_groups *mg,
>> >  			    !strcmp(dent->d_name, ".."))
>> >  				continue;
>> >  
>> > -			ret = map_groups__set_modules_path_dir(mg, path);
>> > +			/* Do not follow top-level source and build symlinks */
>> > +			if (depth == 0) {
>> > +				if (!strcmp(dent->d_name, "source") ||
>> > +				    !strcmp(dent->d_name, "build"))
>> > +					continue;
>> > +			}
>> > +
>> > +			ret = map_groups__set_modules_path_dir(mg, path,
>> > +							       depth + 1);
>> >  			if (ret < 0)
>> >  				goto out;
>> >  		} else {
>> > @@ -786,11 +794,11 @@ static int machine__set_modules_path(struct machine *machine)
>> >  	if (!version)
>> >  		return -1;
>> >  
>> > -	snprintf(modules_path, sizeof(modules_path), "%s/lib/modules/%s/kernel",
>> > +	snprintf(modules_path, sizeof(modules_path), "%s/lib/modules/%s",
>> >  		 machine->root_dir, version);
>> >  	free(version);
>> >  
>> > -	return map_groups__set_modules_path_dir(&machine->kmaps, modules_path);
>> > +	return map_groups__set_modules_path_dir(&machine->kmaps, modules_path, 0);
>> >  }
>> >  
>> >  static int machine__create_module(void *arg, const char *name, u64 start)
>> > -- 
>> > 1.8.3.2
>> > 
>> --
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