From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-7.0 required=3.0 tests=BAYES_00,DKIMWL_WL_HIGH, DKIM_SIGNED,DKIM_VALID,MAILING_LIST_MULTI,SPF_HELO_NONE,SPF_PASS, USER_AGENT_SANE_1 autolearn=no autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id 46DF6C12002 for ; Wed, 21 Jul 2021 16:36:00 +0000 (UTC) Received: from bombadil.infradead.org (bombadil.infradead.org [198.137.202.133]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by mail.kernel.org (Postfix) with ESMTPS id 0DE4660FF3 for ; Wed, 21 Jul 2021 16:36:00 +0000 (UTC) DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org 0DE4660FF3 Authentication-Results: mail.kernel.org; dmarc=fail (p=none dis=none) header.from=kernel.org Authentication-Results: mail.kernel.org; spf=none smtp.mailfrom=linux-arm-kernel-bounces+linux-arm-kernel=archiver.kernel.org@lists.infradead.org DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; d=lists.infradead.org; s=bombadil.20210309; h=Sender:Content-Type: List-Subscribe:List-Help:List-Post:List-Archive:List-Unsubscribe:List-Id: In-Reply-To:MIME-Version:References:Message-ID:Subject:Cc:To:From:Date: Reply-To:Content-Transfer-Encoding:Content-ID:Content-Description:Resent-Date :Resent-From:Resent-Sender:Resent-To:Resent-Cc:Resent-Message-ID:List-Owner; bh=OSNN9N+D0kQq5ePz4cv3yq2lNlkZtHfFfuaWoWCxQig=; b=iyTZULdcpvE0g0tNYshTlcCgLe XsfkMn9X9jPCs3snXIj+7N47hsrrgK4qHzyHXY6x491TxuiLnYKykO3hniQ4zQSpWvGzY95DXeRYU LFgNrGfrYkJaMKQxPwIDJBNcsHvN5vKMo3uwbS55s+wZC5DXxOcbDlt4IYMuRnYj2w081iUROw7Q8 1kcTV81Vv1I6GhUqrXoUllF8Ree+Y0k3zNbRGM71iw5WPwl/3jAdq90i4HnIuZjscserFbAY8Krye txHO7k6jv+VaDLFCMXjzWSYlYqYP0khG9ijdTrg3+8AGifzTxVWY3Pg4JRi+YLJNc4vYGEv6HZKf0 pkpyCI1w==; Received: from localhost ([::1] helo=bombadil.infradead.org) by bombadil.infradead.org with esmtp (Exim 4.94.2 #2 (Red Hat Linux)) id 1m6FBA-00GbAS-8Y; Wed, 21 Jul 2021 16:34:40 +0000 Received: from mail.kernel.org ([198.145.29.99]) by bombadil.infradead.org with esmtps (Exim 4.94.2 #2 (Red Hat Linux)) id 1m6FB5-00Gb9e-NW for linux-arm-kernel@lists.infradead.org; Wed, 21 Jul 2021 16:34:36 +0000 Received: by mail.kernel.org (Postfix) with ESMTPSA id C8FDF61242; Wed, 21 Jul 2021 16:34:34 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1626885275; bh=IVG1+yxPP4XDbVZmLLtNJrLaOWArv/cCybM1fchzMrU=; h=Date:From:To:Cc:Subject:References:In-Reply-To:From; b=gMd1GbUeiVRXwxGCJ9aeIbakRp5lOFmEOdSPHJNEvdb1+rsTo5735gOi3Sm2BVZdg 7reGq6QWZ1xaCZzil5E/meqrWdyuiI9CMlQkQnY3kLTomL1kvT2PfBKvsxP6EuE1gA zooKIPK+xHi16Afk8b4+jLILtji5mPQXx9agklNq8BLxKGK/tdQFLDLgItOoZ07/Xz YeJpmyUiDWRj6Dam2kG2TOWd9AnWiZTp9dtPCpMUzsuXTqhyKbMlKOqKpASTLw35ny SctJxxUeCcaHIstK382cPz4AjXRbyUyM2HwOGHWIhA2/ku3OG4NELhO3x7AZpTORdy +wgxn9SqtApvg== Date: Wed, 21 Jul 2021 17:34:29 +0100 From: Mark Brown To: Dave Martin Cc: Catalin Marinas , Will Deacon , Julien Grall , Zhang Lei , Daniel Kiss , Julien Grall , linux-arm-kernel@lists.infradead.org Subject: Re: [PATCH v7 0/3] arm64/sve: Improve performance when handling SVE access traps Message-ID: <20210721163429.GF4259@sirena.org.uk> References: <20210303201117.24777-1-broonie@kernel.org> <20210721143350.GX4187@arm.com> MIME-Version: 1.0 In-Reply-To: <20210721143350.GX4187@arm.com> X-Cookie: Many pages make a thick book. User-Agent: Mutt/1.10.1 (2018-07-13) X-CRM114-Version: 20100106-BlameMichelson ( TRE 0.8.0 (BSD) ) MR-646709E3 X-CRM114-CacheID: sfid-20210721_093435_829276_2C0C2F94 X-CRM114-Status: GOOD ( 18.33 ) X-BeenThere: linux-arm-kernel@lists.infradead.org X-Mailman-Version: 2.1.34 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Content-Type: multipart/mixed; boundary="===============4403808897501957909==" Sender: "linux-arm-kernel" Errors-To: linux-arm-kernel-bounces+linux-arm-kernel=archiver.kernel.org@lists.infradead.org --===============4403808897501957909== Content-Type: multipart/signed; micalg=pgp-sha512; protocol="application/pgp-signature"; boundary="vA66WO2vHvL/CRSR" Content-Disposition: inline --vA66WO2vHvL/CRSR Content-Type: text/plain; charset=us-ascii Content-Disposition: inline On Wed, Jul 21, 2021 at 03:33:54PM +0100, Dave Martin wrote: > While I think this was a worthwhile experiment, my concern here is that > while the approach taken in this series is reasonable, it doesn't seem > to reduce the amount of code or result in a net simplification. From my > side I think it's probably best to stick with what we have, until > someone comes up with something that's clearly easier to understand. I did find it was making it easier to understand some of what was going on TBH - I forget which specific bits but I found the whole model of specifying the goal state at a higher level clarified things for me. It's definitely not saving much in the way of code though and the code that was already merged to do the zeroing in place gives us most of the win with dramatically less code, it just doesn't help if we do context switch. > So, I'd still favour the version based on Julien's code, which is more > of an incremental change to what we already had (and I think was most of > the way there in your post recent version of it). I prefer Julien's approach too, the requirement to trigger the slow path on return to userspace doesn't really work with the newer approach AFAICT. If this gets resurrected I'll go back to the last _NO_FLUSH version. --vA66WO2vHvL/CRSR Content-Type: application/pgp-signature; name="signature.asc" -----BEGIN PGP SIGNATURE----- iQEzBAABCgAdFiEEreZoqmdXGLWf4p/qJNaLcl1Uh9AFAmD4TJUACgkQJNaLcl1U h9BaxQf/RmgzWb5tuJQcZRn7nXz7FlQBxMKrEAUIL5PCCu520GsGY8/xFp52D83V EXCHLnvugeyLGVX5Hd5tXhmaR+q4UEK7U/yBd0LB/NtJbPqEvPhjpGcXLXBZ6GxG oKK+WTwCINhxXyruHNeYr/jQn06JbfHGsSHImJ/gc51iBIf9h6XMxorj5Vt6wNnt NXwtptl+y8yGOMWeoR7o/xsqwu2Na+ZOnmUcYieEf7wF1I7A0tyAIM6cDV8IDevz 5bDg3omgh3hokXVtLB7zJnKugLHK0fw3vtysjDEIk9iF8FivFsC5rCl9/x0WwNPe kNy6Nhv016pVmDCKMlWifyJ050fRTg== =hFVf -----END PGP SIGNATURE----- --vA66WO2vHvL/CRSR-- --===============4403808897501957909== Content-Type: text/plain; charset="us-ascii" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit Content-Disposition: inline _______________________________________________ linux-arm-kernel mailing list linux-arm-kernel@lists.infradead.org http://lists.infradead.org/mailman/listinfo/linux-arm-kernel --===============4403808897501957909==--