From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from eggs.gnu.org ([2001:4830:134:3::10]:38624) by lists.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1an0OP-0006ER-TG for qemu-devel@nongnu.org; Mon, 04 Apr 2016 05:01:54 -0400 Received: from Debian-exim by eggs.gnu.org with spam-scanned (Exim 4.71) (envelope-from ) id 1an0OM-0002B8-NU for qemu-devel@nongnu.org; Mon, 04 Apr 2016 05:01:53 -0400 Received: from mx1.redhat.com ([209.132.183.28]:40211) by eggs.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1an0OM-0002B4-Hu for qemu-devel@nongnu.org; Mon, 04 Apr 2016 05:01:50 -0400 References: <87y48tu53d.fsf@linaro.org> From: Paolo Bonzini Message-ID: <57022D7A.1040507@redhat.com> Date: Mon, 4 Apr 2016 11:01:46 +0200 MIME-Version: 1.0 In-Reply-To: <87y48tu53d.fsf@linaro.org> Content-Type: text/plain; charset=utf-8 Content-Transfer-Encoding: quoted-printable 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: =?UTF-8?Q?Alex_Benn=c3=a9e?= , QEMU Developers , MTTCG Devel Cc: Peter Maydell , Sergey Fedorov , .Cota@braap.org, Richard Henderson On 04/04/2016 10:54, Alex Benn=C3=A9e 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. Paolo