From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1760452Ab0FRKbR (ORCPT ); Fri, 18 Jun 2010 06:31:17 -0400 Received: from mx2.mail.elte.hu ([157.181.151.9]:52853 "EHLO mx2.mail.elte.hu" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1759218Ab0FRKbP (ORCPT ); Fri, 18 Jun 2010 06:31:15 -0400 Date: Fri, 18 Jun 2010 12:30:58 +0200 From: Ingo Molnar To: Andi Kleen Cc: Don Zickus , Hidetoshi Seto , Huang Ying , Fr??d??ric Weisbecker , Peter Zijlstra , "H. Peter Anvin" , linux-kernel@vger.kernel.org Subject: Re: [RFC 1/3] Unified NMI delayed call mechanism Message-ID: <20100618103058.GA8934@elte.hu> References: <1276334896-7075-1-git-send-email-ying.huang@intel.com> <20100612102558.GA4000@elte.hu> <4C15A5D1.1040104@jp.fujitsu.com> <20100614135403.GH4894@redhat.com> <20100614144403.GA369@basil.fritz.box> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20100614144403.GA369@basil.fritz.box> User-Agent: Mutt/1.5.20 (2009-08-17) X-ELTE-SpamScore: 1.0 X-ELTE-SpamLevel: s X-ELTE-SpamCheck: no X-ELTE-SpamVersion: ELTE 2.0 X-ELTE-SpamCheck-Details: score=1.0 required=5.9 tests=BAYES_50 autolearn=no SpamAssassin version=3.2.5 1.0 BAYES_50 BODY: Bayesian spam probability is 40 to 60% [score: 0.4509] Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org * Andi Kleen wrote: > > I think the perf event subsytem can log events in NMI context already and > > deliver them to userspace when the NMI is done. This is why I think Ingo > > wants MCE to be updated to sit on top of the perf event subsytem to avoid > > re-invent everything again. > > perf is not solving the problem this is trying to solve. That is why i requested to extend the events backend. That will unify more of the code than the first few steps achieved by these three patches - and offers the functionality to all code that uses the events framework. > [...] > > perf does not fit into this because it has no way to process such an event > inside the kernel. It 'does not fit' into the events backend only if you pretend that it is impossible or undesirable to have a delayed, in-context callback mechanism implemented there. If you look at it more closely you'll notice that in reality it's not only possible but that it is also a pretty natural fit. Thanks, Ingo