Date: Wed, 16 Oct 2013 11:30:17 +0200
From: Ingo Molnar <mingo@kernel.org>
To: Stephane Eranian <eranian@google.com>
Cc: LKML <linux-kernel@vger.kernel.org>, "mingo@elte.hu" <mingo@elte.hu>,
        Peter Zijlstra <peterz@infradead.org>, David Ahern <dsahern@gmail.com>,
        Arnaldo Carvalho de Melo <acme@redhat.com>,
        "ak@linux.intel.com" <ak@linux.intel.com>,
        Jiri Olsa <jolsa@redhat.com>, Hugh Dickins <hughd@google.com>
Subject: Re: [PATCH] perf: revert PERF_RECORD_MMAP2 support
Message-ID: <20131016093017.GD23440@gmail.com>
References: <20131015161843.GA17653@quad>
 <20131016061502.GB21109@gmail.com>
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* Stephane Eranian <eranian@google.com> wrote:

> > For example by a simple patch that returns -EINVAL (or -ENOSYS) if the 
> > new flag is used - i.e. behaves like the old kernel in that regard - 
> > but leaves the rest in place. (the 'rest' will hopefully be fixed for 
> > v3.13)
>
> That's what I did in my initial revert patch. But it did not include the 
> perf tool revert.

Could the perf tool part have a minimal revert as well?

> I believe in the end, we will still go with the extended MMAP record and 
> not with the physical address (which adds a PERF_SAMPLE_*). So we can 
> leave the attr->mmap2 bit defined and return -EINVAL for now.

Yeah.

> As for the perf tool, we can remove everything and add that later on 
> because the layout of the MMAP2 record may change.

Yes - but can we keep the actual revert patch minimal? I.e. just prevent 
mmap2 records from being generated, or so.

Thanks,

	Ingo
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