From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from eggs.gnu.org ([2001:4830:134:3::10]:53952) by lists.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1an1vL-0006qQ-Bf for qemu-devel@nongnu.org; Mon, 04 Apr 2016 06:40:00 -0400 Received: from Debian-exim by eggs.gnu.org with spam-scanned (Exim 4.71) (envelope-from ) id 1an1vH-0004Ze-81 for qemu-devel@nongnu.org; Mon, 04 Apr 2016 06:39:59 -0400 Received: from mail-lf0-x22f.google.com ([2a00:1450:4010:c07::22f]:32826) by eggs.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1an1vG-0004ZY-Vl for qemu-devel@nongnu.org; Mon, 04 Apr 2016 06:39:55 -0400 Received: by mail-lf0-x22f.google.com with SMTP id p188so136390460lfd.0 for ; Mon, 04 Apr 2016 03:39:54 -0700 (PDT) References: <87y48tu53d.fsf@linaro.org> <57022D7A.1040507@redhat.com> From: Sergey Fedorov Message-ID: <57024478.2080506@gmail.com> Date: Mon, 4 Apr 2016 13:39:52 +0300 MIME-Version: 1.0 In-Reply-To: <57022D7A.1040507@redhat.com> Content-Type: text/plain; charset=utf-8 Content-Transfer-Encoding: 8bit Subject: Re: [Qemu-devel] Should we introduce a TranslationRegion with its own codegen buffer? List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , To: Paolo Bonzini , =?UTF-8?Q?Alex_Benn=c3=a9e?= , QEMU Developers , MTTCG Devel Cc: Peter Maydell , .Cota@braap.org, Richard Henderson On 04/04/16 12:01, Paolo Bonzini wrote: > On 04/04/2016 10:54, Alex Bennée wrote: >> Thoughts, objections? Discuss ;-) > I think we're putting a lot of carts before the horse. > > We have like half a dozen subprojects and none are moving because > there's no clear idea of what to do next and why. The first thing to do > is to focus on fixing and speeding up user-mode MTTCG (Sergey's work on > upstreaming the patches from Fred and me) and on upstreaming Alvise's > work on ll/sc and TLB flushes. > > The second thing to do is to make tb_flush thread safe; here there are > three competing mechanisms (Fred's run_safe_on_cpu, Emilio's mass > invalidation and my idea of using RCU) that we can discuss. Your idea > here is a fourth one. It's not a bad one, not at all. But even if it > has other positive side effects (e.g. easier jump patching), it's a > large project to embark on when there are at least three other > possibilities---two of them with code and the third (mine) being a > subset of yours. > > I would agree with Paolo that this may be a bit ahead of time. But actually, this is an interesting idea we should definitely keep in mind while we're focused on more immediate work and concerning the overall design on MTTCG project. Thanks, Sergey