Message-ID: <1363611569.22553.10.camel@laptop>
Subject: Re: [PATCH] perf: fix ring_buffer perf_output_space() boundary
 calculation
From: Peter Zijlstra <peterz@infradead.org>
To: Stephane Eranian <eranian@google.com>
Cc: linux-kernel@vger.kernel.org, mingo@elte.hu, jolsa@redhat.com,
        fweisbec@gmail.com
Date: Mon, 18 Mar 2013 13:59:29 +0100
In-Reply-To: <20130318124847.GA2491@quad>
References: <20130318124847.GA2491@quad>
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On Mon, 2013-03-18 at 13:48 +0100, Stephane Eranian wrote:
>         if (!rb->writable)
> -               return true;
> +               return false;


writable means user writable (VM_WRITE); the difference is that a
!VM_WRITE buffer will simply over-write its own tail whereas a VM_WRITE
buffer will drop events.

So returning true for !VM_WRITE makes sense, there's always space.

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