Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1752764AbaKUUQ7 (ORCPT ); Fri, 21 Nov 2014 15:16:59 -0500 Received: from mail-la0-f53.google.com ([209.85.215.53]:53245 "EHLO mail-la0-f53.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751825AbaKUUQ5 (ORCPT ); Fri, 21 Nov 2014 15:16:57 -0500 MIME-Version: 1.0 In-Reply-To: References: <20141120221122.GA25393@htj.dyndns.org> <20141120230514.GB25393@htj.dyndns.org> <20141120233920.GC25393@htj.dyndns.org> <20141121162742.GB15461@htj.dyndns.org> <20141121170805.GD30603@home.goodmis.org> <20141121142301.564f7eb7@gandalf.local.home> From: Andy Lutomirski Date: Fri, 21 Nov 2014 12:16:34 -0800 Message-ID: Subject: Re: frequent lockups in 3.18rc4 To: Josh Boyer Cc: Linus Torvalds , Steven Rostedt , Tejun Heo , "linux-kernel@vger.kernel.org" , Thomas Gleixner , Peter Zijlstra , Frederic Weisbecker , Don Zickus , Dave Jones , "the arch/x86 maintainers" Content-Type: text/plain; charset=UTF-8 Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Fri, Nov 21, 2014 at 12:14 PM, Josh Boyer wrote: > On Fri, Nov 21, 2014 at 2:52 PM, Andy Lutomirski wrote: >> On Fri, Nov 21, 2014 at 11:46 AM, Linus Torvalds >> wrote: >>> On Fri, Nov 21, 2014 at 11:34 AM, Linus Torvalds >>> wrote: >>>> >>>> So I kind of agree, but it wouldn't be my primary worry. My primary >>>> worry is actually paravirt doing something insane. >>> >>> Btw, on that tangent, does anybody actually care about paravirt any more? >>> >> >> Amazon, for better or for worse. >> >>> I'd love to start moving away from it. It makes a lot of the low-level >>> code completely impossible to follow due to the random indirection >>> through "native" vs "paravirt op table". Not just the page table >>> handling, it's all over. >>> >>> Anybody who seriously does virtualization uses hw virtualization that >>> is much better than it used to be. And the non-serious users aren't >>> that performance-sensitive by definition. >>> >>> I note that the Fedora kernel config seems to include paravirt by >>> default, so you get a lot of the crazy overheads.. >> >> I think that there is a move toward deprecating Xen PV in favor of >> PVH, but we're not there yet. > > A move where? The Xen stuff in Fedora is ... not paid attention to > very much. If there's something we should be looking at turning off > (or on), we're happy to take suggestions. A move in the Xen project. As I understand it, Xen wants to deprecate PV in favor of PVH, but PVH is still experimental. I think that dropping PARAVIRT in Fedora might be a bad idea for several more releases, since that's likely to break the EC2 images. --Andy > > josh -- Andy Lutomirski AMA Capital Management, LLC -- 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/