From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from eggs.gnu.org ([2001:4830:134:3::10]:44697) by lists.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1gSYIM-0008Ts-9H for qemu-devel@nongnu.org; Thu, 29 Nov 2018 21:12:43 -0500 Received: from Debian-exim by eggs.gnu.org with spam-scanned (Exim 4.71) (envelope-from ) id 1gSYIH-0001n9-8I for qemu-devel@nongnu.org; Thu, 29 Nov 2018 21:12:42 -0500 Received: from gate.crashing.org ([63.228.1.57]:42607) by eggs.gnu.org with esmtps (TLS1.0:DHE_RSA_AES_256_CBC_SHA1:32) (Exim 4.71) (envelope-from ) id 1gSYIG-0001kx-3k for qemu-devel@nongnu.org; Thu, 29 Nov 2018 21:12:37 -0500 Message-ID: From: Benjamin Herrenschmidt Date: Fri, 30 Nov 2018 13:12:08 +1100 In-Reply-To: References: <408ef3b1c0bab7d26cffeb366a5ee87bb8448fa4.camel@kernel.crashing.org> Content-Type: text/plain; charset="UTF-8" Mime-Version: 1.0 Content-Transfer-Encoding: 7bit Subject: Re: [Qemu-devel] [RFC/PATCH] i386: Atomically update PTEs with mttcg List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , To: Richard Henderson , qemu-devel@nongnu.org Cc: Paolo Bonzini On Thu, 2018-11-29 at 16:12 -0800, Richard Henderson wrote: > > You mean translating once for the load and for the udpate ? Do you > > expect that translation to have such a significant cost considering > > that all it needs should be in L1 at that point ? > > I guess if the update is rare-ish, the re-translating isn't a big deal. And I > suppose we'd have to retain the RCU lock to hold on to the translation, which > probably isn't the best idea. Yeay I toyed with this a bit but it ended up very messy real quick. Cheers, Ben.