Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1755195AbYGWKOE (ORCPT ); Wed, 23 Jul 2008 06:14:04 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1752978AbYGWKNy (ORCPT ); Wed, 23 Jul 2008 06:13:54 -0400 Received: from bombadil.infradead.org ([18.85.46.34]:49575 "EHLO bombadil.infradead.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752849AbYGWKNx (ORCPT ); Wed, 23 Jul 2008 06:13:53 -0400 Date: Wed, 23 Jul 2008 06:13:10 -0400 From: Christoph Hellwig To: Avi Kivity Cc: Christoph Hellwig , Peter Zijlstra , Jan Kiszka , Mathieu Desnoyers , akpm@linux-foundation.org, Ingo Molnar , linux-kernel@vger.kernel.org, kvm@vger.kernel.org, "Feng(Eric) Liu" Subject: Re: [patch 4/4] KVM-trace port to tracepoints Message-ID: <20080723101310.GA30309@infradead.org> References: <20080717160003.359557938@polymtl.ca> <487F7800.4010502@siemens.com> <20080717172853.GB29855@Krystal> <488604F8.1040008@siemens.com> <48862B01.7070907@qumranet.com> <1216799346.7257.125.camel@twins> <4886E6FD.4090200@qumranet.com> <1216803303.7257.138.camel@twins> <20080723100314.GA2847@infradead.org> <48870329.2080401@qumranet.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <48870329.2080401@qumranet.com> User-Agent: Mutt/1.5.18 (2008-05-17) X-SRS-Rewrite: SMTP reverse-path rewritten from by bombadil.infradead.org See http://www.infradead.org/rpr.html Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 884 Lines: 18 On Wed, Jul 23, 2008 at 01:08:41PM +0300, Avi Kivity wrote: > trace_mark() is implement kvmtrace, which is propagated to userspace. > So while trace_mark() itself is not a userspace interface, one of its > users is. > > It's an unstable interface. But so is dmesg; that's the nature of tracing. Trace_mark is as stable as any other kernel interface, and the data you pass through it is as stable as you want it to. In most cases like kvmtrace or my spu scheduler tracing code the trace data is directly forwarded through a userspace interface, and that is as stable as any freeform interface, e.g. as like printk mentioned above. -- 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/