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=-2.4 required=3.0 tests=DKIM_SIGNED,DKIM_VALID, DKIM_VALID_AU,HEADER_FROM_DIFFERENT_DOMAINS,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 ED094C432C3 for ; Fri, 15 Nov 2019 07:17:09 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id C217620733 for ; Fri, 15 Nov 2019 07:17:09 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (2048-bit key) header.d=linaro.org header.i=@linaro.org header.b="tw7VLLub" Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1727163AbfKOHRI (ORCPT ); Fri, 15 Nov 2019 02:17:08 -0500 Received: from mail-wm1-f67.google.com ([209.85.128.67]:39562 "EHLO mail-wm1-f67.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1727002AbfKOHRI (ORCPT ); Fri, 15 Nov 2019 02:17:08 -0500 Received: by mail-wm1-f67.google.com with SMTP id t26so9162429wmi.4 for ; Thu, 14 Nov 2019 23:17:07 -0800 (PST) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=linaro.org; s=google; h=date:from:to:cc:subject:message-id:references:mime-version :content-disposition:in-reply-to:user-agent; bh=3rWXfoENBk01hvOSkg8kCt1Ez88OrYUmZuEToQ/hW7Y=; b=tw7VLLubU1v0LrWgVXyiOXB5Can5hWCnbuo68UCr0doGqLMjERKMAszkWW8jAQoAyB 8vhVMbfP2ayvLx0jjPiWn19Trhn+0ZYC3GO2QaWOHiex1r5jT/2OCw2Ow8hhTP9hdmj9 B8UDMK8D1rwfrZNx6P/81mmx7JO6xltRwipr77TMNfF9MNx16N7Jfx+omnaPGcdP5Ca4 WWwrOuaGGOh2yuWf15ltJTPg+O6mSD6n02l3GYTcd8l2zRIc21tphXW4dcR71EBwp+Nj DtvDdCuj3oP77jCBdtn+MDbqsSrC65maAjUz/pego/Mi0TvAYgXJC/+xN0G/EjqCDVAF 2/PA== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20161025; h=x-gm-message-state:date:from:to:cc:subject:message-id:references :mime-version:content-disposition:in-reply-to:user-agent; bh=3rWXfoENBk01hvOSkg8kCt1Ez88OrYUmZuEToQ/hW7Y=; b=mFcBm//LGuZ46XfZehdF4bVOeDueCkqmw6jQnnyfmE0omb0q/MfoYBUtzw1TofT/rR Rs+tnatqkzyPv2PkGZqqCeHEs/RMqv8c5P7efCafXg0DmlszareW7fmB/oxTColXX3sV L4Y6RSMHzeb7pAMNrJ9jYs6ASDtPPiorjVgLYX9Z9SqErQO3x+2VfK/CDVqpd/2kz4TU 8Xn834WWvK+zn71iCnrtK9ED54PLa2hTOQETvwNb3wFGDcIMcEnoWpMUSd4zUwtCFbVR /5qjmt16BwSodkPJvCK93t7GwIVUPDrKBptvyxuoHZxx+ABfoeaUXQvnhPUGIXp8bX4w 5FQQ== X-Gm-Message-State: APjAAAW29fuNegU1nq57AOLEohJ9KZvIGkZjWD0wccRUzx+VN3uVgFJ1 Noq/BPWUZ6HRGzhc74+0Ro9gbA== X-Google-Smtp-Source: APXvYqzReM+bpsihfuf0ohonI8fOMspQ/bGrJUagOi+uNBkqXaZck0XDCo/VT8LBq/xKgnCJ8c80Rg== X-Received: by 2002:a05:600c:506:: with SMTP id i6mr13435203wmc.153.1573802226201; Thu, 14 Nov 2019 23:17:06 -0800 (PST) Received: from apalos.home (athedsl-4484009.home.otenet.gr. [94.71.55.177]) by smtp.gmail.com with ESMTPSA id w11sm12262094wra.83.2019.11.14.23.17.04 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Thu, 14 Nov 2019 23:17:05 -0800 (PST) Date: Fri, 15 Nov 2019 09:17:03 +0200 From: Ilias Apalodimas To: Jonathan Lemon Cc: Lorenzo Bianconi , netdev@vger.kernel.org, lorenzo.bianconi@redhat.com, davem@davemloft.net, thomas.petazzoni@bootlin.com, brouer@redhat.com, matteo.croce@redhat.com Subject: Re: [PATCH net-next 2/3] net: page_pool: add the possibility to sync DMA memory for non-coherent devices Message-ID: <20191115071703.GB99458@apalos.home> References: <68229f90060d01c1457ac945b2f6524e2aa27d05.1573383212.git.lorenzo@kernel.org> <6BF4C165-2AA2-49CC-B452-756CD0830129@gmail.com> <20191114185326.GA43048@PC192.168.49.172> <3648E256-C048-4F74-90FB-94D184B26499@gmail.com> <20191114204227.GA43707@PC192.168.49.172> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: User-Agent: Mutt/1.12.2 (2019-09-21) Sender: netdev-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: netdev@vger.kernel.org Hi Jonathan, > [...] > > For the skb reserved queues, this depends on the 'anything'. If the rest > > of the > > layers touch (or rather write) into that area, then we'll again gave to > > sync. > > If we know that the data has not been altered though, we can hand them > > back to > > the device skipping that sync right? > > Sure, but this is also true for eBPF programs. How would the driver know > that > the data has not been altered / compacted by the upper layers? I haven't looked that up in detail. I was just explaining the reasoning behind picking a u8 instead of a flag. As Jesper pointed we can get the same result by using len = 0, so i am fine with the proposed change. Thanks /Ilias > -- > Jonathan