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 Received: from bombadil.infradead.org (bombadil.infradead.org [198.137.202.133]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.lore.kernel.org (Postfix) with ESMTPS id EA6E3EB64DC for ; Mon, 3 Jul 2023 14:45:57 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; d=lists.infradead.org; s=bombadil.20210309; h=Sender:List-Subscribe:List-Help :List-Post:List-Archive:List-Unsubscribe:List-Id:Content-Transfer-Encoding: Content-Type:In-Reply-To:From:References:Cc:To:Subject:MIME-Version:Date: Message-ID:Reply-To:Content-ID:Content-Description:Resent-Date:Resent-From: Resent-Sender:Resent-To:Resent-Cc:Resent-Message-ID:List-Owner; bh=hqL5DFLipdvYOiivsQ5q7CYvlHpJO0eTtqUGDIDRZ7w=; b=SmrhW79x4EHKiR2LW0ww1DBVg1 FctumB+Cy7FV8fRYfzlTHePajMWVKuF6/Y/JdQx/gTDmQ+fqt6lru9bo7xNm61P+JDUmRWn4gaWOz Q0ZhIUaP03p6a4RY/B+RkhoxSIK7g6S/7CQoe8Sfbum/nbj7/eILqCUfB+sBUd0YGWhC5lH9WVx8A 0bb3gy4FG9nAaCWoXFimXOiwntbp78c8CFSMM2MyPaJH13ET5EHDNhPo5cmo7NKeTQ9tvUNHgp0Jg gBNo08MsmPB55LMNdWSdaowONtbMAKGHx09dsryy1aEgqp0/rL22uM5H+GGAoEmhGU5Yt7o2zEHg1 sJvZCmsw==; Received: from localhost ([::1] helo=bombadil.infradead.org) by bombadil.infradead.org with esmtp (Exim 4.96 #2 (Red Hat Linux)) id 1qGKoC-00AmQU-1e; Mon, 03 Jul 2023 14:45:44 +0000 Received: from dfw.source.kernel.org ([139.178.84.217]) by bombadil.infradead.org with esmtps (Exim 4.96 #2 (Red Hat Linux)) id 1qGKo9-00AmPL-1v; Mon, 03 Jul 2023 14:45:43 +0000 Received: from smtp.kernel.org (relay.kernel.org [52.25.139.140]) (using TLSv1.3 with cipher TLS_AES_256_GCM_SHA384 (256/256 bits) key-exchange X25519 server-signature RSA-PSS (2048 bits)) (No client certificate requested) by dfw.source.kernel.org (Postfix) with ESMTPS id ED5D660F6F; Mon, 3 Jul 2023 14:45:40 +0000 (UTC) Received: by smtp.kernel.org (Postfix) with ESMTPSA id 09284C433C7; Mon, 3 Jul 2023 14:45:38 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1688395540; bh=D01JRZ6YxzSYbxJrhvbB7jt0pV/WAPNqrzz0yrSDBY4=; h=Date:Subject:To:Cc:References:From:In-Reply-To:From; b=nid7zAbx5g66G0jxhPwIuRrSe6clrHM+diWwYK36r5HLou+d21CdoXV1kKd99ae/k plsXDrsHdZPBWAb505ac6PTNUSyXrill8bz0q5G+5qeEfdCw0pjQhF7gNOgaQQHQmq RlLHGRGE7Oiy0wHSzLOPlIBjthQiVu3ej+HM05RRuoZ/ajSb5XDRfiEaDU40VbB4x/ R64zJ4uiFke89Lf2kCIDMclGvXOekCa2yqceZlcS0XIKZocuOQXafgltwj7hJzwFmf JY1acKGcAF68LxFF1ydiGLW4Mf4ujSSY+ctIwaxY1AP3pgtrMbCbwaDLAoF5ssPPs8 Zv/3fbrJMvFnw== Message-ID: <47b79e77-461b-8fe9-41fb-b69a6b205ef2@kernel.org> Date: Mon, 3 Jul 2023 08:45:38 -0600 MIME-Version: 1.0 User-Agent: Mozilla/5.0 (Macintosh; Intel Mac OS X 10.15; rv:102.0) Gecko/20100101 Thunderbird/102.12.0 Subject: Re: Memory providers multiplexing (Was: [PATCH net-next v4 4/5] page_pool: remove PP_FLAG_PAGE_FRAG flag) Content-Language: en-US To: Mina Almasry Cc: Jakub Kicinski , Jesper Dangaard Brouer , brouer@redhat.com, Alexander Duyck , Yunsheng Lin , davem@davemloft.net, pabeni@redhat.com, netdev@vger.kernel.org, linux-kernel@vger.kernel.org, Lorenzo Bianconi , Yisen Zhuang , Salil Mehta , Eric Dumazet , Sunil Goutham , Geetha sowjanya , Subbaraya Sundeep , hariprasad , Saeed Mahameed , Leon Romanovsky , Felix Fietkau , Ryder Lee , Shayne Chen , Sean Wang , Kalle Valo , Matthias Brugger , AngeloGioacchino Del Regno , Jesper Dangaard Brouer , Ilias Apalodimas , linux-rdma@vger.kernel.org, linux-wireless@vger.kernel.org, linux-arm-kernel@lists.infradead.org, linux-mediatek@lists.infradead.org, Jonathan Lemon References: <20230612130256.4572-1-linyunsheng@huawei.com> <20230612130256.4572-5-linyunsheng@huawei.com> <20230614101954.30112d6e@kernel.org> <8c544cd9-00a3-2f17-bd04-13ca99136750@huawei.com> <20230615095100.35c5eb10@kernel.org> <908b8b17-f942-f909-61e6-276df52a5ad5@huawei.com> <72ccf224-7b45-76c5-5ca9-83e25112c9c6@redhat.com> <20230616122140.6e889357@kernel.org> <20230619110705.106ec599@kernel.org> <5e0ac5bb-2cfa-3b58-9503-1e161f3c9bd5@kernel.org> From: David Ahern In-Reply-To: Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 7bit X-CRM114-Version: 20100106-BlameMichelson ( TRE 0.8.0 (BSD) ) MR-646709E3 X-CRM114-CacheID: sfid-20230703_074541_726844_622E8F1A X-CRM114-Status: GOOD ( 11.45 ) X-BeenThere: linux-mediatek@lists.infradead.org X-Mailman-Version: 2.1.34 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Sender: "Linux-mediatek" Errors-To: linux-mediatek-bounces+linux-mediatek=archiver.kernel.org@lists.infradead.org On 7/3/23 12:22 AM, Mina Almasry wrote: > tcpdump is able to access the header of these skbs which is in host > memory, but not the payload in device memory. Here is an example > session with my netcat-like test for device memory TCP: > https://pastebin.com/raw/FRjKf0kv > > tcpdump seems to work, and the length of the packets above is correct. > tcpdump -A however isn't able to print the payload of the packets: > https://pastebin.com/raw/2PcNxaZV That is my expectation. The tcpdump is just an easy example of accessing the skb page frags. skb_copy_and_csum_bits used by icmp is another example that can walk frags wanting access to device memory. You did not cause a panic or trip a WARN_ON for example with the tcpdump? Thanks for checking.