Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1753211Ab3CRNLa (ORCPT ); Mon, 18 Mar 2013 09:11:30 -0400 Received: from merlin.infradead.org ([205.233.59.134]:45644 "EHLO merlin.infradead.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752985Ab3CRNL3 (ORCPT ); Mon, 18 Mar 2013 09:11:29 -0400 Message-ID: <1363612263.22553.12.camel@laptop> Subject: Re: [PATCH] perf: fix ring_buffer perf_output_space() boundary calculation From: Peter Zijlstra To: Stephane Eranian Cc: LKML , "mingo@elte.hu" , Jiri Olsa , =?ISO-8859-1?Q?Fr=E9d=E9ric?= Weisbecker Date: Mon, 18 Mar 2013 14:11:03 +0100 In-Reply-To: References: <20130318124847.GA2491@quad> <1363611569.22553.10.camel@laptop> Content-Type: text/plain; charset="UTF-8" X-Mailer: Evolution 3.6.2-0ubuntu0.1 Mime-Version: 1.0 Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 1032 Lines: 25 On Mon, 2013-03-18 at 14:03 +0100, Stephane Eranian wrote: > On Mon, Mar 18, 2013 at 1:59 PM, Peter Zijlstra wrote: > > 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. > > > Ok, that was not so clear to me. I think this if() statment deserves a comment. > I will add that in V2. Thanks; I suppose renaming the entire ->writable thing might be better though. Something like ->overwrite or so. -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/