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=-3.5 required=3.0 tests=BAYES_00,DKIM_INVALID, DKIM_SIGNED,HEADER_FROM_DIFFERENT_DOMAINS,MAILING_LIST_MULTI,SPF_HELO_NONE, SPF_PASS,URIBL_BLOCKED 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 C9F30C55178 for ; Wed, 4 Nov 2020 08:24:09 +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 67FD620781 for ; Wed, 4 Nov 2020 08:24:09 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=fail reason="signature verification failed" (2048-bit key) header.d=linutronix.de header.i=@linutronix.de header.b="Wh43mnWM"; dkim=permerror (0-bit key) header.d=linutronix.de header.i=@linutronix.de header.b="STcwQ6Ra" DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org 67FD620781 Authentication-Results: mail.kernel.org; dmarc=fail (p=none dis=none) header.from=linutronix.de 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 3734E6F3D8; Wed, 4 Nov 2020 08:22:57 +0000 (UTC) Received: from galois.linutronix.de (Galois.linutronix.de [193.142.43.55]) by gabe.freedesktop.org (Postfix) with ESMTPS id A29486ECE0; Tue, 3 Nov 2020 19:00:23 +0000 (UTC) From: Thomas Gleixner DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=linutronix.de; s=2020; t=1604430021; h=from:from:reply-to:subject:subject:date:date:message-id:message-id: to:to:cc:cc:mime-version:mime-version:content-type:content-type: in-reply-to:in-reply-to:references:references; bh=p7vA0Pp8Yw32NcCmeGMglrNZNTsusNNmUR0JbokXn0s=; b=Wh43mnWM8kdYti+K6Ejg70IQfa+GmZ8DCSo20FQE/hkLNmxVT4iphQnlk6m40FPrmWktQO 8ayXKz0ztE1cqx/iEhmcbhojQh9yCHEkFANOGr1w8fGEwrPOcrWAWxi/OenSb5evTEILWa oclhRZDu2W0eltn+sc+1j25HCEzKjNSXz+4io/CbYUyMFuxTbNnNJEiCm1jMBn8PGej5s3 E3JpbZR0aFWpI6lV+SZv22HUNUyPWbXG8oMYz+BmJikgi+ivLhTWpXqqgXf53DcJR+Ltrn dCfpJUdQQNPCTgPlSMPzbs0whzNCaCVS/fZbTm34UVovthqkFff3qyFpeY0sbA== DKIM-Signature: v=1; a=ed25519-sha256; c=relaxed/relaxed; d=linutronix.de; s=2020e; t=1604430021; h=from:from:reply-to:subject:subject:date:date:message-id:message-id: to:to:cc:cc:mime-version:mime-version:content-type:content-type: in-reply-to:in-reply-to:references:references; bh=p7vA0Pp8Yw32NcCmeGMglrNZNTsusNNmUR0JbokXn0s=; b=STcwQ6RaI64DeextSGHfCvrA9zLqnmZlfhd6kn3GgHfcpWRfVbJIkhHpoM7lA8B8jXR4lp QBLUYE/euA+zomCg== To: Linus Torvalds Subject: Re: [patch V3 22/37] highmem: High implementation details and document API In-Reply-To: References: <20201103092712.714480842@linutronix.de> <20201103095858.827582066@linutronix.de> Date: Tue, 03 Nov 2020 20:00:20 +0100 Message-ID: <87y2ji1d17.fsf@nanos.tec.linutronix.de> MIME-Version: 1.0 X-Mailman-Approved-At: Wed, 04 Nov 2020 08:22:13 +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 , linux-aio@kvack.org, Peter Zijlstra , Sebastian Andrzej Siewior , dri-devel , linux-mips@vger.kernel.org, Ben Segall , Chris Mason , Huang Rui , Paul Mackerras , Gerd Hoffmann , Daniel Bristot de Oliveira , linux-sparc , Vincent Chen , Christoph Hellwig , Vincent Guittot , Paul McKenney , Max Filippov , Michael Ellerman , the arch/x86 maintainers , Russell King , linux-csky@vger.kernel.org, Ingo Molnar , David Airlie , VMware Graphics , Mel Gorman , nouveau@lists.freedesktop.org, Dave Airlie , "open list:SYNOPSYS ARC ARCHITECTURE" , Ben Skeggs , linux-xtensa@linux-xtensa.org, Arnd Bergmann , intel-gfx , Roland Scheidegger , Josef Bacik , Steven Rostedt , Rodrigo Vivi , Alexander Viro , spice-devel@lists.freedesktop.org, David Sterba , virtualization@lists.linux-foundation.org, Dietmar Eggemann , Linux ARM , Chris Zankel , Michal Simek , Thomas Bogendoerfer , Nick Hu , Linux-MM , Vineet Gupta , LKML , Christian Koenig , Benjamin LaHaise , linux-fsdevel , Andrew Morton , linuxppc-dev , "David S. Miller" , linux-btrfs , Greentime Hu Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit Errors-To: dri-devel-bounces@lists.freedesktop.org Sender: "dri-devel" On Tue, Nov 03 2020 at 09:48, Linus Torvalds wrote: > I have no complaints about the patch, but it strikes me that if people > want to actually have much better debug coverage, this is where it > should be (I like the "every other address" thing too, don't get me > wrong). > > In particular, instead of these PageHighMem(page) tests, I think > something like this would be better: > > #ifdef CONFIG_DEBUG_HIGHMEM > #define page_use_kmap(page) ((page),1) > #else > #define page_use_kmap(page) PageHighMem(page) > #endif > > adn then replace those "if (!PageHighMem(page))" tests with "if > (!page_use_kmap())" instead. > > IOW, in debug mode, it would _always_ remap the page, whether it's > highmem or not. That would really stress the highmem code and find any > fragilities. Yes, that makes a lot of sense. We just have to avoid that for the architectures with aliasing issues. > Anyway, this is all sepatrate from the series, which still looks fine > to me. Just a reaction to seeing the patch, and Thomas' earlier > mention that the highmem debugging doesn't actually do much. Right, forcing it for both kmap and kmap_local is straight forward. I'll cook a patch on top for that. Thanks, tglx _______________________________________________ dri-devel mailing list dri-devel@lists.freedesktop.org https://lists.freedesktop.org/mailman/listinfo/dri-devel