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=-5.2 required=3.0 tests=BAYES_00, HEADER_FROM_DIFFERENT_DOMAINS,MAILING_LIST_MULTI,SPF_HELO_NONE,SPF_PASS, URIBL_BLOCKED,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 88E1EC2D0E0 for ; Tue, 15 Sep 2020 07:07:53 +0000 (UTC) Received: from gabe.freedesktop.org (gabe.freedesktop.org [131.252.210.177]) (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 D12E1206C9 for ; Tue, 15 Sep 2020 07:07:52 +0000 (UTC) DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org D12E1206C9 Authentication-Results: mail.kernel.org; dmarc=none (p=none dis=none) header.from=gondor.apana.org.au Authentication-Results: mail.kernel.org; spf=none smtp.mailfrom=dri-devel-bounces@lists.freedesktop.org Received: from gabe.freedesktop.org (localhost [127.0.0.1]) by gabe.freedesktop.org (Postfix) with ESMTP id CC80D6E84F; Tue, 15 Sep 2020 07:07:21 +0000 (UTC) Received: from fornost.hmeau.com (helcar.hmeau.com [216.24.177.18]) by gabe.freedesktop.org (Postfix) with ESMTPS id CECBA6E088; Tue, 15 Sep 2020 06:24:25 +0000 (UTC) Received: from gwarestrin.arnor.me.apana.org.au ([192.168.0.7]) by fornost.hmeau.com with smtp (Exim 4.92 #5 (Debian)) id 1kI4Mf-0007aN-HK; Tue, 15 Sep 2020 16:22:54 +1000 Received: by gwarestrin.arnor.me.apana.org.au (sSMTP sendmail emulation); Tue, 15 Sep 2020 16:22:53 +1000 Date: Tue, 15 Sep 2020 16:22:53 +1000 From: Herbert Xu To: Ard Biesheuvel Subject: Re: [patch 00/13] preempt: Make preempt count unconditional Message-ID: <20200915062253.GA26275@gondor.apana.org.au> References: <20200914204209.256266093@linutronix.de> <871rj4owfn.fsf@nanos.tec.linutronix.de> MIME-Version: 1.0 Content-Disposition: inline In-Reply-To: User-Agent: Mutt/1.10.1 (2018-07-13) X-Mailman-Approved-At: Tue, 15 Sep 2020 07:07:18 +0000 X-BeenThere: dri-devel@lists.freedesktop.org X-Mailman-Version: 2.1.29 Precedence: list List-Id: Direct Rendering Infrastructure - Development List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Cc: Juri Lelli , Peter Zijlstra , Sebastian Andrzej Siewior , Lai Jiangshan , dri-devel , Ben Segall , Linux-MM , linux-hexagon@vger.kernel.org, Will Deacon , Ingo Molnar , Anton Ivanov , linux-arch , Vincent Guittot , Brian Cain , Richard Weinberger , Russell King , "open list:KERNEL SELFTEST FRAMEWORK" , David Airlie , Ingo Molnar , Geert Uytterhoeven , Mel Gorman , intel-gfx , Matt Turner , Valentin Schneider , linux-xtensa@linux-xtensa.org, Shuah Khan , "Paul E. McKenney" , Jeff Dike , linux-um , Josh Triplett , Steven Rostedt , rcu@vger.kernel.org, linux-m68k , Ivan Kokshaysky , Rodrigo Vivi , Thomas Gleixner , Dietmar Eggemann , Linux ARM , Richard Henderson , Chris Zankel , Max Filippov , Daniel Bristot de Oliveira , LKML , alpha , Mathieu Desnoyers , Andrew Morton , Linus Torvalds Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit Errors-To: dri-devel-bounces@lists.freedesktop.org Sender: "dri-devel" On Tue, Sep 15, 2020 at 09:20:59AM +0300, Ard Biesheuvel wrote: > > The documentation of kmap_atomic() states the following: > > * The use of kmap_atomic/kunmap_atomic is discouraged - kmap/kunmap > * gives a more generic (and caching) interface. But kmap_atomic can > * be used in IRQ contexts, so in some (very limited) cases we need > * it. > > so if this is no longer accurate, perhaps we should fix it? This hasn't been accurate for at least ten years :) > But another reason I tried to avoid kmap_atomic() is that it disables > preemption unconditionally, even on 64-bit architectures where HIGHMEM > is irrelevant. So using kmap_atomic() here means that the bulk of > WireGuard packet encryption runs with preemption disabled, essentially > for legacy reasons. Agreed. We should definitely fix that. Thanks, -- Email: Herbert Xu Home Page: http://gondor.apana.org.au/~herbert/ PGP Key: http://gondor.apana.org.au/~herbert/pubkey.txt _______________________________________________ dri-devel mailing list dri-devel@lists.freedesktop.org https://lists.freedesktop.org/mailman/listinfo/dri-devel