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Date: Thu, 14 May 2015 13:38:21 +0200
From: Jiri Olsa <jolsa@redhat.com>
To: Ingo Molnar <mingo@kernel.org>
Cc: Milos Vyletel <milos@redhat.com>, Peter Zijlstra <a.p.zijlstra@chello.nl>,
        Paul Mackerras <paulus@samba.org>, Ingo Molnar <mingo@redhat.com>,
        Arnaldo Carvalho de Melo <acme@kernel.org>,
        Masami Hiramatsu <masami.hiramatsu.pt@hitachi.com>,
        Namhyung Kim <namhyung@kernel.org>, Jiri Olsa <jolsa@kernel.org>,
        He Kuang <hekuang@huawei.com>, Adrian Hunter <adrian.hunter@intel.com>,
        "open list:PERFORMANCE EVENT..." <linux-kernel@vger.kernel.org>
Subject: Re: [PATCH 2/2] perf/tools: put new buildid locks to use
Message-ID: <20150514113821.GB1313@krava.redhat.com>
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 <20150514104059.GA27771@gmail.com>
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On Thu, May 14, 2015 at 12:40:59PM +0200, Ingo Molnar wrote:
> 
> * Milos Vyletel <milos@redhat.com> wrote:
> 
> > Use new read/write locks when accesing buildid directory on places where
> > we may race if multiple instances are run simultaneously.
> 
> Dunno, this will create locking interaction between multiple instances 
> of perf - hanging each other, etc.
> 
> And it seems unnecessary: the buildid hierarchy is already spread out. 
> What kind of races might there be?

there was just recently one fixed by commit:
  0635b0f71424 perf tools: Fix race in build_id_cache__add_s()

havent checked the final patch yet, but the idea is to
protect us from similar bugs

jirka