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=-15.9 required=3.0 tests=BAYES_00, HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_CR_TRAILER,INCLUDES_PATCH, MAILING_LIST_MULTI,NICE_REPLY_A,SPF_HELO_NONE,SPF_PASS,URIBL_BLOCKED, USER_AGENT_SANE_1 autolearn=ham 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 BA92EC4708F for ; Wed, 2 Jun 2021 17:26:28 +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 66C2161D1A for ; Wed, 2 Jun 2021 17:26:28 +0000 (UTC) DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org 66C2161D1A Authentication-Results: mail.kernel.org; dmarc=fail (p=none dis=none) header.from=linux.intel.com 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 C363B6EDFE; Wed, 2 Jun 2021 17:26:27 +0000 (UTC) Received: from mga01.intel.com (mga01.intel.com [192.55.52.88]) by gabe.freedesktop.org (Postfix) with ESMTPS id AA0316EDFE; Wed, 2 Jun 2021 17:26:26 +0000 (UTC) IronPort-SDR: LBD+9/qIzTTH2G/IJj2piDU1/1Bn4nwLbcZ9ZWeS9aiQmICqTiXAnnFNh2xFFWhXy3FAERyVQ5 tAWLwMyUsKtw== X-IronPort-AV: E=McAfee;i="6200,9189,10003"; a="225137803" X-IronPort-AV: E=Sophos;i="5.83,242,1616482800"; d="scan'208";a="225137803" Received: from orsmga003.jf.intel.com ([10.7.209.27]) by fmsmga101.fm.intel.com with ESMTP/TLS/ECDHE-RSA-AES256-GCM-SHA384; 02 Jun 2021 10:26:19 -0700 IronPort-SDR: KUFRNQXDD1R05k4vmLhCKg1eragC0zRUVZD2rxPeTkQgQWHfpMSNQcxX9YSHNSxjaYMaczbqbw 1RJnC2gRHjXQ== X-IronPort-AV: E=Sophos;i="5.83,242,1616482800"; d="scan'208";a="399811505" Received: from ibanaga-mobl.ger.corp.intel.com (HELO [10.249.254.50]) ([10.249.254.50]) by orsmga003-auth.jf.intel.com with ESMTP/TLS/ECDHE-RSA-AES256-GCM-SHA384; 02 Jun 2021 10:26:18 -0700 Subject: Re: [PATCH v9 07/15] drm: Add a prefetching memcpy_from_wc To: Jani Nikula , intel-gfx@lists.freedesktop.org, dri-devel@lists.freedesktop.org References: <20210601074654.3103-1-thomas.hellstrom@linux.intel.com> <20210601074654.3103-8-thomas.hellstrom@linux.intel.com> <87im2xrcqu.fsf@intel.com> From: =?UTF-8?Q?Thomas_Hellstr=c3=b6m?= Message-ID: <1aa312f7-2c02-c92b-7a71-335a6baea796@linux.intel.com> Date: Wed, 2 Jun 2021 19:26:15 +0200 User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:78.0) Gecko/20100101 Thunderbird/78.10.1 MIME-Version: 1.0 In-Reply-To: <87im2xrcqu.fsf@intel.com> Content-Type: text/plain; charset=utf-8; format=flowed Content-Transfer-Encoding: 8bit Content-Language: en-US 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: , Errors-To: dri-devel-bounces@lists.freedesktop.org Sender: "dri-devel" On 6/1/21 2:27 PM, Jani Nikula wrote: > On Tue, 01 Jun 2021, Thomas Hellström wrote: >> Reading out of write-combining mapped memory is typically very slow >> since the CPU doesn't prefetch. However some archs have special >> instructions to do this. >> >> So add a best-effort memcpy_from_wc taking dma-buf-map pointer >> arguments that attempts to use a fast prefetching memcpy and >> otherwise falls back to ordinary memcopies, taking the iomem tagging >> into account. >> >> The code is largely copied from i915_memcpy_from_wc. >> >> Cc: Daniel Vetter >> Cc: Christian König >> Suggested-by: Daniel Vetter >> Signed-off-by: Thomas Hellström >> Acked-by: Christian König >> Acked-by: Daniel Vetter >> --- >> v7: >> - Perform a memcpy even if warning with in_interrupt(). Suggested by >> Christian König. >> - Fix compilation failure on !X86 (Reported by kernel test robot >> lkp@intel.com) >> v8: >> - Skip kerneldoc for drm_memcpy_init_early() >> - Export drm_memcpy_from_wc() also for non-x86. >> --- >> Documentation/gpu/drm-mm.rst | 2 +- >> drivers/gpu/drm/drm_cache.c | 148 +++++++++++++++++++++++++++++++++++ >> drivers/gpu/drm/drm_drv.c | 2 + >> include/drm/drm_cache.h | 7 ++ >> 4 files changed, 158 insertions(+), 1 deletion(-) >> >> diff --git a/Documentation/gpu/drm-mm.rst b/Documentation/gpu/drm-mm.rst >> index 21be6deadc12..c66058c5bce7 100644 >> --- a/Documentation/gpu/drm-mm.rst >> +++ b/Documentation/gpu/drm-mm.rst >> @@ -469,7 +469,7 @@ DRM MM Range Allocator Function References >> .. kernel-doc:: drivers/gpu/drm/drm_mm.c >> :export: >> >> -DRM Cache Handling >> +DRM Cache Handling and Fast WC memcpy() >> ================== > The title underline needs to be as long as the title. > > BR, > Jani. Thanks, Jani. I think Daniel was trying to point this out to me as well with limited success. It's fixed now. /Thomas