Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1752284Ab2EROhu (ORCPT ); Fri, 18 May 2012 10:37:50 -0400 Received: from casper.infradead.org ([85.118.1.10]:58363 "EHLO casper.infradead.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751054Ab2EROhr convert rfc822-to-8bit (ORCPT ); Fri, 18 May 2012 10:37:47 -0400 Message-ID: <1337351857.573.47.camel@twins> Subject: Re: [PATCH 1/2] perf: Add persistent event facilities From: Peter Zijlstra To: Borislav Petkov Cc: Ingo Molnar , Frederic Weisbecker , Ingo Molnar , Steven Rostedt , LKML , Borislav Petkov Date: Fri, 18 May 2012 16:37:37 +0200 In-Reply-To: <20120518142131.GO20215@aftab.osrc.amd.com> References: <1332340496-21658-1-git-send-email-bp@amd64.org> <1332340496-21658-2-git-send-email-bp@amd64.org> <1337336040.573.12.camel@twins> <20120518110357.GH20215@aftab.osrc.amd.com> <1337340263.573.31.camel@twins> <20120518115957.GB19785@gmail.com> <20120518125505.GK20215@aftab.osrc.amd.com> <1337348267.573.37.camel@twins> <20120518140945.GN20215@aftab.osrc.amd.com> <1337350462.573.39.camel@twins> <20120518142131.GO20215@aftab.osrc.amd.com> Content-Type: text/plain; charset=US-ASCII Content-Transfer-Encoding: 7BIT X-Mailer: Evolution 3.2.2- Mime-Version: 1.0 Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 1161 Lines: 26 On Fri, 2012-05-18 at 16:21 +0200, Borislav Petkov wrote: > On Fri, May 18, 2012 at 04:14:22PM +0200, Peter Zijlstra wrote: > > On Fri, 2012-05-18 at 16:09 +0200, Borislav Petkov wrote: > > > What happens here if a second user wants to enable a second set of > > > persistent events, allocate a second set of per-CPU buffers? > > > > I'm not seeing the relation to VM_SHARED here. > > Well, in the sense that if mmap fails in the !VM_SHARED case, I can't > enable any persistent events except the ones which are enabled and so > I need to allocate another set of resources for that second persistent > events user. Right, well, you could actually allow operations on the fd, just not a second mapping :-) Anyway.. I'd push that error back to the user. If they need a second set, let them create it. Do you really need multiple consumers for your MCE stuff? If so, what would be the problem of using VM_SHARED? -- 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/