Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1757377AbcCXKnE (ORCPT ); Thu, 24 Mar 2016 06:43:04 -0400 Received: from casper.infradead.org ([85.118.1.10]:45085 "EHLO casper.infradead.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1757205AbcCXKm4 (ORCPT ); Thu, 24 Mar 2016 06:42:56 -0400 Date: Thu, 24 Mar 2016 11:42:44 +0100 From: Peter Zijlstra To: Will Deacon Cc: Wang Nan , mingo@redhat.com, linux-kernel@vger.kernel.org, He Kuang , Alexei Starovoitov , Arnaldo Carvalho de Melo , Brendan Gregg , Jiri Olsa , Masami Hiramatsu , Namhyung Kim , Zefan Li , pi3orama@163.com Subject: Re: [PATCH 2/5] perf core: Set event's default overflow_handler Message-ID: <20160324104244.GP6356@twins.programming.kicks-ass.net> References: <1457949585-191064-1-git-send-email-wangnan0@huawei.com> <1457949585-191064-3-git-send-email-wangnan0@huawei.com> <20160323175021.GK6356@twins.programming.kicks-ass.net> <20160323181348.GA2149@arm.com> <20160323192938.GM6356@twins.programming.kicks-ass.net> <20160324095802.GA9323@arm.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20160324095802.GA9323@arm.com> User-Agent: Mutt/1.5.21 (2012-12-30) Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 563 Lines: 10 On Thu, Mar 24, 2016 at 09:58:02AM +0000, Will Deacon wrote: > On Wed, Mar 23, 2016 at 08:29:38PM +0100, Peter Zijlstra wrote: > Not sure... I can imagine kgdb, for example, wanting to handle the stepping > itself. You also need to play clever tricks if you want to step through > LL/SC atomics, which the code here doesn't even try to handle (because > it involves disassembling the instructions and applying a bunch of > heuristics), so I imagine most debuggers wanting to take care of the step > themselves. Fair enough... right, a whole host of tricky this.