Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1758550Ab3EGM4U (ORCPT ); Tue, 7 May 2013 08:56:20 -0400 Received: from smtp.eu.citrix.com ([46.33.159.39]:42298 "EHLO SMTP.EU.CITRIX.COM" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1757131Ab3EGM4T (ORCPT ); Tue, 7 May 2013 08:56:19 -0400 X-IronPort-AV: E=Sophos;i="4.87,552,1363132800"; d="scan'208";a="4300408" Message-ID: <1367931376.26321.117.camel@zakaz.uk.xensource.com> Subject: Re: [Xen-devel] [PATCH RFC v2 2/4] arm: introduce CONFIG_PARAVIRT and pv_time_ops From: Ian Campbell To: Stefano Stabellini CC: "xen-devel@lists.xensource.com" , "linux@arm.linux.org.uk" , "arnd@arndb.de" , "marc.zyngier@arm.com" , "konrad.wilk@oracle.com" , "will.deacon@arm.com" , "linux-kernel@vger.kernel.org" , "nico@linaro.org" , "olof@lixom.net" , "linux-arm-kernel@lists.infradead.org" , "cov@codeaurora.org" Date: Tue, 7 May 2013 13:56:16 +0100 In-Reply-To: References: <1367851878-21629-2-git-send-email-stefano.stabellini@eu.citrix.com> <1367918609.26321.43.camel@zakaz.uk.xensource.com> Organization: Citrix Systems, Inc. Content-Type: text/plain; charset="UTF-8" X-Mailer: Evolution 3.4.4-1 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: 1505 Lines: 37 On Tue, 2013-05-07 at 13:15 +0100, Stefano Stabellini wrote: > On Tue, 7 May 2013, Ian Campbell wrote: > > On Mon, 2013-05-06 at 15:51 +0100, Stefano Stabellini wrote: > > > Introduce CONFIG_PARAVIRT on ARM. > > > > What about PARAVIRT_TIME_ACCOUNTING? I'm not sure what it is but it > > looks like a more lightweight version of pv stolen time? > > PARAVIRT_TIME_ACCOUNTING selects PARAVIRT on x86 :-) Ah, that's maybe what confused me. TBH its not at all clear to me what distinction the core code is trying to make with those two options, but do we not also want/need PARAVIRT_TIME_ACCOUNTING? Having reread the help text it seems to be some sort of "more accurate" accounting? > > I think it would be a worthwhile change to refactor the stolen time > > handling out from under the rather wide reaching umbrella of the x86 > > PARAVIRT option. (assuming PARAVIRT_TIME_ACCOUNTING isn't already that) > > Actually PARAVIRT doesn't mean much in common code, the only thing it > covers is stolen time. > What I mean to say is that just because we are introducing something > called "PARAVIRT" on ARM, it doesn't mean that it has to come with all > sort of baggage. I was more concerned with perceived baggage than actual trunks full of skeletons. Ian. -- 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/