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=-3.9 required=3.0 tests=BAYES_00,DKIM_SIGNED, DKIM_VALID,DKIM_VALID_AU,HEADER_FROM_DIFFERENT_DOMAINS,MAILING_LIST_MULTI, SPF_HELO_NONE,SPF_PASS 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 E803BC388F2 for ; Tue, 3 Nov 2020 19:00:27 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 9363E22226 for ; Tue, 3 Nov 2020 19:00:27 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (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" Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1729293AbgKCTAX (ORCPT ); Tue, 3 Nov 2020 14:00:23 -0500 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:33556 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1727706AbgKCTAX (ORCPT ); Tue, 3 Nov 2020 14:00:23 -0500 Received: from galois.linutronix.de (Galois.linutronix.de [IPv6:2a0a:51c0:0:12e:550::1]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 2F8B3C0613D1; Tue, 3 Nov 2020 11:00:23 -0800 (PST) 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 Cc: LKML , Peter Zijlstra , Paul McKenney , Christoph Hellwig , Sebastian Andrzej Siewior , Andrew Morton , Linux-MM , Alexander Viro , Benjamin LaHaise , linux-fsdevel , linux-aio@kvack.org, Chris Mason , Josef Bacik , David Sterba , linux-btrfs , the arch/x86 maintainers , Vineet Gupta , "open list\:SYNOPSYS ARC ARCHITECTURE" , Russell King , Arnd Bergmann , Linux ARM , linux-csky@vger.kernel.org, Michal Simek , Thomas Bogendoerfer , linux-mips@vger.kernel.org, Nick Hu , Greentime Hu , Vincent Chen , Michael Ellerman , Benjamin Herrenschmidt , Paul Mackerras , linuxppc-dev , "David S. Miller" , linux-sparc , Chris Zankel , Max Filippov , linux-xtensa@linux-xtensa.org, Ingo Molnar , Juri Lelli , Vincent Guittot , Dietmar Eggemann , Steven Rostedt , Ben Segall , Mel Gorman , Daniel Bristot de Oliveira , Christian Koenig , Huang Rui , David Airlie , Daniel Vetter , dri-devel , VMware Graphics , Roland Scheidegger , Dave Airlie , Gerd Hoffmann , virtualization@lists.linux-foundation.org, spice-devel@lists.freedesktop.org, Ben Skeggs , nouveau@lists.freedesktop.org, Jani Nikula , Joonas Lahtinen , Rodrigo Vivi , intel-gfx 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 Content-Type: text/plain Precedence: bulk List-ID: X-Mailing-List: linux-btrfs@vger.kernel.org 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 From mboxrd@z Thu Jan 1 00:00:00 1970 From: Thomas Gleixner Date: Tue, 03 Nov 2020 19:00:20 +0000 Subject: Re: [patch V3 22/37] highmem: High implementation details and document API Message-Id: <87y2ji1d17.fsf@nanos.tec.linutronix.de> List-Id: References: <20201103092712.714480842@linutronix.de> <20201103095858.827582066@linutronix.de> In-Reply-To: MIME-Version: 1.0 Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit To: Linus Torvalds 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 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 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=-3.9 required=3.0 tests=BAYES_00,DKIM_SIGNED, DKIM_VALID,DKIM_VALID_AU,HEADER_FROM_DIFFERENT_DOMAINS,MAILING_LIST_MULTI, SPF_HELO_NONE,SPF_PASS 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 48F83C388F9 for ; Tue, 3 Nov 2020 19:00:27 +0000 (UTC) Received: from kanga.kvack.org (kanga.kvack.org [205.233.56.17]) by mail.kernel.org (Postfix) with ESMTP id C503220870 for ; Tue, 3 Nov 2020 19:00:26 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (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 C503220870 Authentication-Results: mail.kernel.org; dmarc=fail (p=none dis=none) header.from=linutronix.de Authentication-Results: mail.kernel.org; spf=pass smtp.mailfrom=owner-linux-mm@kvack.org Received: by kanga.kvack.org (Postfix) id 41B1D6B0036; Tue, 3 Nov 2020 14:00:26 -0500 (EST) Received: by kanga.kvack.org (Postfix, from userid 40) id 3CA1C6B005D; Tue, 3 Nov 2020 14:00:26 -0500 (EST) X-Delivered-To: int-list-linux-mm@kvack.org Received: by kanga.kvack.org (Postfix, from userid 63042) id 2E0126B0068; Tue, 3 Nov 2020 14:00:26 -0500 (EST) X-Delivered-To: linux-mm@kvack.org Received: from forelay.hostedemail.com (smtprelay0144.hostedemail.com [216.40.44.144]) by kanga.kvack.org (Postfix) with ESMTP id F0E036B005D for ; Tue, 3 Nov 2020 14:00:25 -0500 (EST) Received: from smtpin08.hostedemail.com (10.5.19.251.rfc1918.com [10.5.19.251]) by forelay01.hostedemail.com (Postfix) with ESMTP id 819E5180AD801 for ; Tue, 3 Nov 2020 19:00:25 +0000 (UTC) X-FDA: 77444022810.08.show65_4f07f60272bb Received: from filter.hostedemail.com (10.5.16.251.rfc1918.com [10.5.16.251]) by smtpin08.hostedemail.com (Postfix) with ESMTP id 4AA4A1819E76F; Tue, 3 Nov 2020 19:00:25 +0000 (UTC) X-HE-Tag: show65_4f07f60272bb X-Filterd-Recvd-Size: 5615 Received: from galois.linutronix.de (Galois.linutronix.de [193.142.43.55]) by imf17.hostedemail.com (Postfix) with ESMTP; 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 Cc: LKML , Peter Zijlstra , Paul McKenney , Christoph Hellwig , Sebastian Andrzej Siewior , Andrew Morton , Linux-MM , Alexander Viro , Benjamin LaHaise , linux-fsdevel , linux-aio@kvack.org, Chris Mason , Josef Bacik , David Sterba , linux-btrfs , the arch/x86 maintainers , Vineet Gupta , "open list\:SYNOPSYS ARC ARCHITECTURE" , Russell King , Arnd Bergmann , Linux ARM , linux-csky@vger.kernel.org, Michal Simek , Thomas Bogendoerfer , linux-mips@vger.kernel.org, Nick Hu , Greentime Hu , Vincent Chen , Michael Ellerman , Benjamin Herrenschmidt , Paul Mackerras , linuxppc-dev , "David S. Miller" , linux-sparc , Chris Zankel , Max Filippov , linux-xtensa@linux-xtensa.org, Ingo Molnar , Juri Lelli , Vincent Guittot , Dietmar Eggemann , Steven Rostedt , Ben Segall , Mel Gorman , Daniel Bristot de Oliveira , Christian Koenig , Huang Rui , David Airlie , Daniel Vetter , dri-devel , VMware Graphics , Roland Scheidegger , Dave Airlie , Gerd Hoffmann , virtualization@lists.linux-foundation.org, spice-devel@lists.freedesktop.org, Ben Skeggs , nouveau@lists.freedesktop.org, Jani Nikula , Joonas Lahtinen , Rodrigo Vivi , intel-gfx 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 Content-Type: text/plain X-Bogosity: Ham, tests=bogofilter, spamicity=0.000000, version=1.2.4 Sender: owner-linux-mm@kvack.org Precedence: bulk X-Loop: owner-majordomo@kvack.org List-ID: 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 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 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 00F00C4742C for ; Tue, 3 Nov 2020 21:02:29 +0000 (UTC) Received: from lists.ozlabs.org (lists.ozlabs.org [203.11.71.2]) (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 26B4F205ED for ; Tue, 3 Nov 2020 21:02:27 +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 26B4F205ED Authentication-Results: mail.kernel.org; dmarc=fail (p=none dis=none) header.from=linutronix.de Authentication-Results: mail.kernel.org; spf=pass smtp.mailfrom=linuxppc-dev-bounces+linuxppc-dev=archiver.kernel.org@lists.ozlabs.org Received: from bilbo.ozlabs.org (lists.ozlabs.org [IPv6:2401:3900:2:1::3]) by lists.ozlabs.org (Postfix) with ESMTP id 4CQj0J27PszDqsR for ; Wed, 4 Nov 2020 08:02:24 +1100 (AEDT) Authentication-Results: lists.ozlabs.org; spf=pass (sender SPF authorized) smtp.mailfrom=linutronix.de (client-ip=193.142.43.55; helo=galois.linutronix.de; envelope-from=tglx@linutronix.de; receiver=) Authentication-Results: lists.ozlabs.org; dmarc=pass (p=none dis=none) header.from=linutronix.de Authentication-Results: lists.ozlabs.org; dkim=pass (2048-bit key; secure) header.d=linutronix.de header.i=@linutronix.de header.a=rsa-sha256 header.s=2020 header.b=Wh43mnWM; dkim=pass header.d=linutronix.de header.i=@linutronix.de header.a=ed25519-sha256 header.s=2020e header.b=STcwQ6Ra; dkim-atps=neutral Received: from galois.linutronix.de (Galois.linutronix.de [193.142.43.55]) (using TLSv1.3 with cipher TLS_AES_256_GCM_SHA384 (256/256 bits) key-exchange X25519 server-signature RSA-PSS (2048 bits) server-digest SHA256) (No client certificate requested) by lists.ozlabs.org (Postfix) with ESMTPS id 4CQfHd6xHbzDqcH for ; Wed, 4 Nov 2020 06:00:29 +1100 (AEDT) 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 Content-Type: text/plain X-Mailman-Approved-At: Wed, 04 Nov 2020 07:56:20 +1100 X-BeenThere: linuxppc-dev@lists.ozlabs.org X-Mailman-Version: 2.1.29 Precedence: list List-Id: Linux on PowerPC Developers Mail List List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Cc: Juri Lelli , linux-aio@kvack.org, Peter Zijlstra , Sebastian Andrzej Siewior , Joonas Lahtinen , 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 , 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 , Jani Nikula , Chris Zankel , Michal Simek , Thomas Bogendoerfer , Nick Hu , Linux-MM , Vineet Gupta , LKML , Christian Koenig , Benjamin LaHaise , Daniel Vetter , linux-fsdevel , Andrew Morton , linuxppc-dev , "David S. Miller" , linux-btrfs , Greentime Hu Errors-To: linuxppc-dev-bounces+linuxppc-dev=archiver.kernel.org@lists.ozlabs.org Sender: "Linuxppc-dev" 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 From mboxrd@z Thu Jan 1 00:00:00 1970 From: Thomas Gleixner Subject: Re: [patch V3 22/37] highmem: High implementation details and document API Date: Tue, 03 Nov 2020 20:00:20 +0100 Message-ID: <87y2ji1d17.fsf@nanos.tec.linutronix.de> References: <20201103092712.714480842@linutronix.de> <20201103095858.827582066@linutronix.de> Mime-Version: 1.0 Content-Type: text/plain Return-path: In-Reply-To: To: Linus Torvalds Cc: LKML , Peter Zijlstra , Paul McKenney , Christoph Hellwig , Sebastian Andrzej Siewior , Andrew Morton , Linux-MM , Alexander Viro , Benjamin LaHaise , linux-fsdevel , linux-aio@kvack.org, Chris Mason , Josef Bacik , David Sterba , linux-btrfs , the arch/x86 maintainers , Vineet Gupta , "open list:SYNOPSYS ARC ARCHITECTURE" , Russell King List-Id: nouveau.vger.kernel.org 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 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=-3.8 required=3.0 tests=BAYES_00,DKIMWL_WL_HIGH, DKIM_SIGNED,DKIM_VALID,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 01243C388F2 for ; Tue, 3 Nov 2020 19:00:32 +0000 (UTC) Received: from merlin.infradead.org (merlin.infradead.org [205.233.59.134]) (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 2083A20786 for ; Tue, 3 Nov 2020 19:00:31 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (2048-bit key) header.d=lists.infradead.org header.i=@lists.infradead.org header.b="tWf0igaA"; 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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-CRM114-Version: 20100106-BlameMichelson ( TRE 0.8.0 (BSD) ) MR-646709E3 X-CRM114-CacheID: sfid-20201103_140026_073524_911005C1 X-CRM114-Status: GOOD ( 18.98 ) X-BeenThere: linux-snps-arc@lists.infradead.org X-Mailman-Version: 2.1.29 Precedence: list List-Id: Linux on Synopsys ARC Processors List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Cc: Juri Lelli , linux-aio@kvack.org, Peter Zijlstra , Benjamin Herrenschmidt , Sebastian Andrzej Siewior , Joonas Lahtinen , 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 , Jani Nikula , Chris Zankel , Michal Simek , Thomas Bogendoerfer , Nick Hu , Linux-MM , Vineet Gupta , LKML , Christian Koenig , Benjamin LaHaise , Daniel Vetter , linux-fsdevel , Andrew Morton , linuxppc-dev , "David S. Miller" , linux-btrfs , Greentime Hu Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit Sender: "linux-snps-arc" Errors-To: linux-snps-arc-bounces+linux-snps-arc=archiver.kernel.org@lists.infradead.org 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 _______________________________________________ linux-snps-arc mailing list linux-snps-arc@lists.infradead.org http://lists.infradead.org/mailman/listinfo/linux-snps-arc 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 3B011C388F7 for ; Tue, 3 Nov 2020 19:00:32 +0000 (UTC) Received: from silver.osuosl.org (smtp3.osuosl.org [140.211.166.136]) (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 7E47720870 for ; Tue, 3 Nov 2020 19:00:31 +0000 (UTC) Authentication-Results: mail.kernel.org; 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Tue, 3 Nov 2020 19:00:29 +0000 (UTC) Received: from whitealder.osuosl.org (smtp1.osuosl.org [140.211.166.138]) by lists.linuxfoundation.org (Postfix) with ESMTP id CD8F1C0051 for ; Tue, 3 Nov 2020 19:00:27 +0000 (UTC) Received: from localhost (localhost [127.0.0.1]) by whitealder.osuosl.org (Postfix) with ESMTP id B2D1F86CEC for ; Tue, 3 Nov 2020 19:00:27 +0000 (UTC) X-Virus-Scanned: amavisd-new at osuosl.org Received: from whitealder.osuosl.org ([127.0.0.1]) by localhost (.osuosl.org [127.0.0.1]) (amavisd-new, port 10024) with ESMTP id O+zk5AlQntUK for ; Tue, 3 Nov 2020 19:00:24 +0000 (UTC) X-Greylist: domain auto-whitelisted by SQLgrey-1.7.6 Received: from galois.linutronix.de (Galois.linutronix.de [193.142.43.55]) by whitealder.osuosl.org (Postfix) with ESMTPS id A3F4086CA1 for ; Tue, 3 Nov 2020 19:00:24 +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 Cc: Juri Lelli , linux-aio@kvack.org, Peter Zijlstra , Benjamin Herrenschmidt , Sebastian Andrzej Siewior , Joonas Lahtinen , dri-devel , linux-mips@vger.kernel.org, Ben Segall , Chris Mason , Huang Rui , Paul Mackerras , 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 , Jani Nikula , Chris Zankel , Michal Simek , Thomas Bogendoerfer , Nick Hu , Linux-MM , Vineet Gupta , LKML , Christian Koenig , Benjamin LaHaise , Daniel Vetter , linux-fsdevel , Andrew Morton , linuxppc-dev , "David S. Miller" , linux-btrfs , Greentime Hu X-BeenThere: virtualization@lists.linux-foundation.org X-Mailman-Version: 2.1.15 Precedence: list List-Id: Linux virtualization List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit Errors-To: virtualization-bounces@lists.linux-foundation.org Sender: "Virtualization" 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 _______________________________________________ Virtualization mailing list Virtualization@lists.linux-foundation.org https://lists.linuxfoundation.org/mailman/listinfo/virtualization 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 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 A14CBC388F7 for ; Tue, 3 Nov 2020 19:00:25 +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 102CA20870 for ; Tue, 3 Nov 2020 19:00:24 +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 102CA20870 Authentication-Results: mail.kernel.org; dmarc=fail (p=none dis=none) header.from=linutronix.de Authentication-Results: mail.kernel.org; spf=none smtp.mailfrom=intel-gfx-bounces@lists.freedesktop.org Received: from gabe.freedesktop.org (localhost [127.0.0.1]) by gabe.freedesktop.org (Postfix) with ESMTP id 468886ECE0; Tue, 3 Nov 2020 19:00:24 +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 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 Subject: Re: [Intel-gfx] [patch V3 22/37] highmem: High implementation details and document API X-BeenThere: intel-gfx@lists.freedesktop.org X-Mailman-Version: 2.1.29 Precedence: list List-Id: Intel graphics driver community testing & development List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Cc: Juri Lelli , linux-aio@kvack.org, Peter Zijlstra , Benjamin Herrenschmidt , 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 , 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 , 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: intel-gfx-bounces@lists.freedesktop.org Sender: "Intel-gfx" 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 _______________________________________________ Intel-gfx mailing list Intel-gfx@lists.freedesktop.org https://lists.freedesktop.org/mailman/listinfo/intel-gfx