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 vger.kernel.org (vger.kernel.org [23.128.96.18]) by smtp.lore.kernel.org (Postfix) with ESMTP id 5431CC433EF for ; Wed, 13 Jul 2022 23:38:36 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S231428AbiGMXid (ORCPT ); Wed, 13 Jul 2022 19:38:33 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:48664 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S229624AbiGMXia (ORCPT ); Wed, 13 Jul 2022 19:38:30 -0400 Received: from ams.source.kernel.org (ams.source.kernel.org [IPv6:2604:1380:4601:e00::1]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 0EF024C62C; Wed, 13 Jul 2022 16:38:29 -0700 (PDT) Received: from smtp.kernel.org (relay.kernel.org [52.25.139.140]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by ams.source.kernel.org (Postfix) with ESMTPS id A20FCB8220B; Wed, 13 Jul 2022 23:38:27 +0000 (UTC) Received: by smtp.kernel.org (Postfix) with ESMTPSA id A83A3C3411E; Wed, 13 Jul 2022 23:38:25 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1657755506; bh=sGMnc7ZlfnsYBnaBql7SMpnhQXnrXLXhnd3x7TOfCGw=; h=Date:Subject:To:Cc:References:From:In-Reply-To:From; b=tybh7T9F/yucZzbqEG/YK8RSvc9LnMRr+IQ1Mh3ANPfvogKy0tr5uRabcvI7NTv9G ftk7gMBC3jdyZ5ENbP5J26o7EADL7EF3S0v7ctx3brNpX4KzjolpEApeuEoFdIExAk M04xHoaR7g5MyzIMQ40SJoI3O8JxgNefjUuFstt/SyGZBqYnomhtIe/ozI3u6H8lgg 6tLFTfdzxAfhO0QEnxwIu6lfZfVkiHBB3kbtV4fYeuJzvb3drS1dSTwANWYnI2ddo+ JY+f8QrzTle5y57cJkPQpkna0fMFL5vsZhTi05UkvLhVLyhfHTQXrtukOoGGMHjYge Njr2PX88kfGwQ== Message-ID: Date: Wed, 13 Jul 2022 16:38:24 -0700 MIME-Version: 1.0 User-Agent: Mozilla/5.0 (Macintosh; Intel Mac OS X 10.15; rv:91.0) Gecko/20100101 Thunderbird/91.11.0 Subject: Re: [PATCH net-next v4 11/27] tcp: support externally provided ubufs Content-Language: en-US To: Pavel Begunkov , io-uring@vger.kernel.org, netdev@vger.kernel.org, linux-kernel@vger.kernel.org Cc: "David S . Miller" , Jakub Kicinski , Jonathan Lemon , Willem de Bruijn , Jens Axboe , kernel-team@fb.com References: <7ee05f644e3b3626b693973738364bcb23cf905d.1657194434.git.asml.silence@gmail.com> <62e1daba-fb20-bf20-5c4d-c31770e5420e@kernel.org> <45cd36ee-ef99-fb67-df8d-218603facfd7@gmail.com> From: David Ahern In-Reply-To: <45cd36ee-ef99-fb67-df8d-218603facfd7@gmail.com> Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On 7/8/22 7:03 AM, Pavel Begunkov wrote: >>> @@ -1356,9 +1362,11 @@ int tcp_sendmsg_locked(struct sock *sk, struct >>> msghdr *msg, size_t size) >>>                 copy = min_t(int, copy, pfrag->size - pfrag->offset); >>>   -            if (tcp_downgrade_zcopy_pure(sk, skb)) >>> -                goto wait_for_space; >>> - >>> +            if (unlikely(skb_zcopy_pure(skb) || >>> skb_zcopy_managed(skb))) { >>> +                if (tcp_downgrade_zcopy_pure(sk, skb)) >>> +                    goto wait_for_space; >>> +                skb_zcopy_downgrade_managed(skb); >>> +            } >>>               copy = tcp_wmem_schedule(sk, copy); >>>               if (!copy) >>>                   goto wait_for_space; >> >> You dropped the msg->msg_ubuf checks on jump labels. Removing the one >> you had at 'out_nopush' I agree with based on my tests (i.e, it is not >> needed). > > It was an optimisation, which I dropped for simplicity. Will be sending it > and couple more afterwards. > > >> The one at 'out_err' seems like it is needed - but it has been a few >> weeks since I debugged that case. I believe the error path I was hitting >> was sk_stream_wait_memory with MSG_DONTWAIT flag set meaning timeout is >> 0 and it jumps there with EPIPE. > > Currently, it's consistent with MSG_ZEROCOPY ubuf_info, we grab a ubuf_info > reference at the beginning (msg_zerocopy_realloc() for MSG_ZEROCOPY and > net_zcopy_get() for msg_ubuf), and then release it at the end > with net_zcopy_put() or net_zcopy_put_abort(). > my fault; I somehow dropped a line in the port to the 5.13 kernel.