linux-kernel - Re: [PATCH perf/core v5 02/15] perf-buildid-cache: Use path/to/bin/buildid/elf instead of path/to/bin/buildid

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Message-Id: <20160428105150.d13b50f0ed3cae33b587c865@kernel.org>
Date:	Thu, 28 Apr 2016 10:51:50 +0900
From:	Masami Hiramatsu <mhiramat@...nel.org>
To:	Arnaldo Carvalho de Melo <acme@...nel.org>
Cc:	linux-kernel@...r.kernel.org, Namhyung Kim <namhyung@...nel.org>,
	Peter Zijlstra <peterz@...radead.org>,
	Ingo Molnar <mingo@...hat.com>,
	Hemant Kumar <hemant@...ux.vnet.ibm.com>,
	Ananth N Mavinakayanahalli <ananth@...ux.vnet.ibm.com>
Subject: Re: [PATCH perf/core v5 02/15] perf-buildid-cache: Use
 path/to/bin/buildid/elf instead of path/to/bin/buildid

On Wed, 27 Apr 2016 18:23:50 -0300
Arnaldo Carvalho de Melo <acme@...nel.org> wrote:

> Em Thu, Apr 28, 2016 at 03:37:23AM +0900, Masami Hiramatsu escreveu:
> > From: Masami Hiramatsu <masami.hiramatsu.pt@...achi.com>
> > 
> > Use path/to/bin/buildid/elf instead of path/to/bin/buildid
> > to store corresponding elf binary.
> > This also stores vdso in buildid/vdso, kallsyms in buildid/kallsyms.
> > 
> > Note that the existing caches are not updated until user adds
> > or updates the cache. Anyway, if there is the old style build-id
> > cache it falls back to use it. (IOW, it is backward compatible)
> > 
> > Signed-off-by: Masami Hiramatsu <masami.hiramatsu.pt@...achi.com>
> > Signed-off-by: Masami Hiramatsu <mhiramat@...nel.org>
> > ---
> >  Changes in v5:
> >   - Support old style buildid caches.
> 
> > +	/* Remove old style build-id cache */
> > +	if (__is_regular_file(dir_name))
> > +		if (unlink(dir_name))
> > +			goto out_free;
> 
> Shouldn't this just fail and require the user to use --force/-f or purge
> first?

No, I don't think so, because the old style build-id is useless for
probe-cache in anyway, and after applying this patch, perf can use
new one seemlessly. So let just renew it :)

Thank you,

-- 
Masami Hiramatsu <mhiramat@...nel.org>