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 mails.dpdk.org (mails.dpdk.org [217.70.189.124]) by smtp.lore.kernel.org (Postfix) with ESMTP id D8A77106ACC1 for ; Thu, 12 Mar 2026 16:06:24 +0000 (UTC) Received: from mails.dpdk.org (localhost [127.0.0.1]) by mails.dpdk.org (Postfix) with ESMTP id E915440613; Thu, 12 Mar 2026 17:06:23 +0100 (CET) Received: from mail-oa1-f49.google.com (mail-oa1-f49.google.com [209.85.160.49]) by mails.dpdk.org (Postfix) with ESMTP id EE967402AC for ; Thu, 12 Mar 2026 17:06:22 +0100 (CET) Received: by mail-oa1-f49.google.com with SMTP id 586e51a60fabf-4138136f02eso907744fac.2 for ; Thu, 12 Mar 2026 09:06:22 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=networkplumber-org.20230601.gappssmtp.com; s=20230601; t=1773331582; x=1773936382; darn=dpdk.org; h=content-transfer-encoding:mime-version:references:in-reply-to :message-id:subject:cc:to:from:date:from:to:cc:subject:date :message-id:reply-to; bh=UvX4XsQKFVc2F+4/9dxYNNFKNoLaEwRL/RM+QLmILDI=; b=04J+a2unSXlFMwMOOqV5HnnDu9mgoYTFEwX7cNTcmPm7lJlbsimtIBZVJ47YbdywkR SGIpIbTnfZzw5zvFfpe5Xz01/0rKmScRqCqB02KPoTk1Tml/XwreMFLCqH7LGtHlwypm sOYpSgBpMfi9na7D0jsf8cGXhLOAHzkl90vsP+fHGpoFhqIjl2eHoayqTXTyl143cn/W 7eJHAkIU+drzOIV3Dr7dVJ0pw40gdG84So3aPgpcu0gp9PunFQ1ZuYrrHrEYadR1gbld 8FPD2FP0FDUdSfIgR9wKtl3CcDfsUlAnZFZ3UlANq2Ipf4lTuTn4wA+SzZMTBYV2Qh4J gjdQ== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20230601; t=1773331582; x=1773936382; h=content-transfer-encoding:mime-version:references:in-reply-to :message-id:subject:cc:to:from:date:x-gm-gg:x-gm-message-state:from :to:cc:subject:date:message-id:reply-to; bh=UvX4XsQKFVc2F+4/9dxYNNFKNoLaEwRL/RM+QLmILDI=; b=XAHjq/NJ0J1AXb0djaqgkbGmQCfE1kI4pFHqSGtzkWUDNqngmXcgTaOHXdf59dHYuN Py2HeF2pG1y/ib66wOzBoTGyIy9maABFhXQgWXQujI21NV63RfTrcV0+q2vjPfuACCZs Nlu18lNZwLEMZA/TVMNSTroJn5GUFXj+xEsXO2FB1YGvUxxTGMJuss2zcCVtOcim7JQr z6fIy224WcylVjApocZJ9w7m/y9UaUxmPjaZ67CaBTrEAPvf8CXyO1BzgdQNOrvbY+3M O+5x38W1pNmY77D6EsLM5w2abkgig7ctwGuWxqi7uc0xfxxjn7GCLUy4eh+E+OF498DK dMFA== X-Gm-Message-State: AOJu0YxvSHU13Idid1iuYEq1RZyR316uWqCwOusqA0WbYCrvIbiHFoWq mcF4IHvwtOZDeVdSn9h8jq/VMcCeTfNKLp2fs3d4zXa2GdJRemVGb0q/+gB6uYWXTbc= X-Gm-Gg: ATEYQzwEmZzoqosEPg9nsrQBVrMneGUMN9u59TD2/KKcGOfryKflkAnktZkZhTnYN9B GMkbA0euLsvQCPtgcUlYJin7e3dapBjPKA8nqkkXe63HOdyIIAn4ycQETc1zDyP+qT/nck92vg9 cEcZlVtISdT7WCP71WpUFZTfEbZsXxcifOGl+VGGdU7UwLUKFEuM6I9ZpEAeMZODZGoKFYwIKUi peVN9ZIcS8qFLROu1v+G+hOL2w5p7TdEFeRBZEUk3i1CvyEWiDGyD32y3Lw9Z8nhndQ1PVrpSAw bzqIHuNEVwZ+khsNy8G2Jmxt7cWvg/3aW4Ym38nte4U+sr1eDSbl+RFTjYfVVHjHKF8QybZ2oRv inlyA4p+/og0oKf0TtYUAm2eW+Q8nBL8RN6FbT1XvyrM66VPB3j2R8/+Zfj6fsmKm1vB8aklbvZ Dt8B5LX2srrjOY7ngMbwZvDn6zJgh1Di+h5Iw= X-Received: by 2002:a05:6870:b01b:b0:417:69c2:4026 with SMTP id 586e51a60fabf-4177c8c95eemr3302935fac.19.1773331582006; Thu, 12 Mar 2026 09:06:22 -0700 (PDT) Received: from phoenix.local ([104.202.29.139]) by smtp.gmail.com with ESMTPSA id 586e51a60fabf-4177e5e94b4sm5121238fac.11.2026.03.12.09.06.20 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Thu, 12 Mar 2026 09:06:21 -0700 (PDT) Date: Thu, 12 Mar 2026 09:06:18 -0700 From: Stephen Hemminger To: Sriram Yagnaraman Cc: , , Subject: Re: [PATCH v3] net/af_packet: add multi-segment mbuf support for jumbo frames Message-ID: <20260312090618.1d8c081d@phoenix.local> In-Reply-To: <20260312073403.4018157-1-sriram.yagnaraman@ericsson.com> References: <20260312073403.4018157-1-sriram.yagnaraman@ericsson.com> MIME-Version: 1.0 Content-Type: text/plain; charset=US-ASCII Content-Transfer-Encoding: 7bit X-BeenThere: dev@dpdk.org X-Mailman-Version: 2.1.29 Precedence: list List-Id: DPDK patches and discussions List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Errors-To: dev-bounces@dpdk.org On Thu, 12 Mar 2026 08:34:03 +0100 Sriram Yagnaraman wrote: > Enable jumbo frame reception with default mbuf data room size by > chaining multiple mbufs when packet exceeds single mbuf tailroom. > > Scatter Rx is only enabled when RTE_ETH_RX_OFFLOAD_SCATTER is > requested. Packets are dropped if they exceed single mbuf size > and scatter is not enabled, or if mbuf allocation fails during > chaining. Error counter rx_dropped_pkts tracks all drops. > > This allows receiving 9KB jumbo frames using standard 2KB mbufs, > chaining ~5 segments per jumbo packet. > --- Scatter is good, but additional checks are necessary to validate mbuf pool and buffer constraints. See virtio configure for example. bool virtio_rx_check_scatter(uint16_t max_rx_pkt_len, uint16_t rx_buf_size, bool rx_scatter_enabled, const char **error) { if (!rx_scatter_enabled && max_rx_pkt_len > rx_buf_size) { *error = "Rx scatter is disabled and RxQ mbuf pool object size is too small"; return false; } return true; }