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 BFF0CCCF9EB for ; Wed, 29 Oct 2025 20:32:12 +0000 (UTC) Received: from mails.dpdk.org (localhost [127.0.0.1]) by mails.dpdk.org (Postfix) with ESMTP id 77924402AE; Wed, 29 Oct 2025 21:32:11 +0100 (CET) Received: from mail-pj1-f43.google.com (mail-pj1-f43.google.com [209.85.216.43]) by mails.dpdk.org (Postfix) with ESMTP id 89E894025E for ; Wed, 29 Oct 2025 21:32:09 +0100 (CET) Received: by mail-pj1-f43.google.com with SMTP id 98e67ed59e1d1-33ff5149ae8so292669a91.3 for ; Wed, 29 Oct 2025 13:32:09 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=networkplumber-org.20230601.gappssmtp.com; s=20230601; t=1761769928; x=1762374728; 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=v2NidpLVknbTF4NN+wOlz/MYNHahkxnuA1q/oi1QnZI=; b=oBhI1k70mKQ3RLM+eEBeV/ILyabchEovzu+YUhi1bGeIotFv9f6DUC62U6byZNUNZe iFdEJeVIZm7mDWMY/OBfhNVcmoSqgOz26B2BIqXob0QbmXybj81xSvefWGqkjldAa7cD /czSRERrOdgCjd1XzSHfT+N3M9j92+0EvOjBxe7v7bX3F9NZ3j20QT6g8Vgd3hbXH200 kl3MB0C/27NI3HNmI4KnLq7HpVZ5ZTXWC/AXnO06yWXtD/JLZdkDFPEm8vRTqQ3Sos5b sxeaK9opegBEko5AxW44/lFlgdi07cZ22e2OfYoOpUWL4I3/zlr/7fLPfFPZDTtlDKgh sOyQ== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20230601; t=1761769928; x=1762374728; h=content-transfer-encoding:mime-version:references:in-reply-to :message-id:subject:cc:to:from:date:x-gm-message-state:from:to:cc :subject:date:message-id:reply-to; bh=v2NidpLVknbTF4NN+wOlz/MYNHahkxnuA1q/oi1QnZI=; b=WsyRQae6OIj19L8H1ypce5GQLb6TzOvMhRzxWGAtSzdRxr7Mz4/MIU+rthkrDdrQEH s3DNFakUpoCNt61AG4VxtwOkrXWBsExIXdetGMBYXSITJ1Abq5X+3agbf97hqwvLaUg6 5OumnwkFAyKgA9hGGLGWdeX9n/viokdXP4ZRDvW5VpRpVNht453EQTfd/G6Xgfnw/1u5 s1dlwuUeJZVMt7pMa55zlAxWyzidgLUerDzJ6FYsojaTBbTdIcbDw9RFcEz+gmKg+bpI Ucm1u2MbLpaSsItPaT0IEj6bEsi+dHagIMd7h1W60yfEFxUni9FewKL/VY8nivslO9if FAWQ== X-Gm-Message-State: AOJu0YzOY21us33Gg2Y+QoNq0oGeKEMAK3M+pmZf5yvVHbKo4qEMGFBi I0Ow4NNefEL2xxo1TfwESUdx6xT3RmbO1QF0Pwswim8V1jxYJXm7lKxl6OYows+AibA= X-Gm-Gg: ASbGncvHS3FQXA7T5BYGnQzmDQa1CvizQOLZFg4DxnFaqbKT7fjlWdRsGQCPom3qi5C mg70felGMDDTvt9DiDozGoQXop6mIe8/RGWB/L8ZW+XwiGEO7pUb791hWyMW7bJbusL3ZXe2mx6 /FMrfKufnxTmFspbL4FyH3tNBp7MntpAJYFbiUOVeHurDDwxAR+4CKBRGiJC7h/4Ho04tdx3H3I 9sRwPR1HR4CbfZmXRAtnKvUX2YGimt8nHZ1RNIEl+t4YBLhbSFeTj4QS5Kpl1I7CSOBfrRrXblo yLkncDRgJXpnvnWmCbM3NpAm96lCEG21BkS8BAZymzaMlLtMW+NZPPjqfW4mccQo4ay1DIvzap8 Fm0E0Cur49NIGICTU0XOcRyMehdYvPpi4zd+5T2+WWQLHjGZtDvZpDgFZxMSV7gQlrf8nWnFv1S NvWXBsWInDLc0qgjD4/EeWdl6BJdmg3ACtJA== X-Google-Smtp-Source: AGHT+IFgKf0S3BFcYgCud1Qmbq2K9wbeXdWF1oq7SiFJ10IqVbFzyx8CKM4sV3kSqUoZ6Sx0aEwDbQ== X-Received: by 2002:a17:90b:164f:b0:32e:d599:1f66 with SMTP id 98e67ed59e1d1-3404c46747bmr722621a91.30.1761769928195; Wed, 29 Oct 2025 13:32:08 -0700 (PDT) Received: from phoenix (204-195-96-226.wavecable.com. [204.195.96.226]) by smtp.gmail.com with ESMTPSA id 98e67ed59e1d1-3404df3ec94sm132459a91.1.2025.10.29.13.32.07 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Wed, 29 Oct 2025 13:32:07 -0700 (PDT) Date: Wed, 29 Oct 2025 13:32:06 -0700 From: Stephen Hemminger To: Morten =?UTF-8?B?QnLDuHJ1cA==?= Cc: , , "Thomas Monjalon" , "Andrew Rybchenko" , "Patrick Robb" Subject: Re: Use of TX offload flags MBUF_FAST_FREE and MULTI_SEGS Message-ID: <20251029133206.254d61ef@phoenix> In-Reply-To: <98CBD80474FA8B44BF855DF32C47DC35F654A3@smartserver.smartshare.dk> References: <98CBD80474FA8B44BF855DF32C47DC35F654A3@smartserver.smartshare.dk> MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: quoted-printable 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 Mon, 6 Oct 2025 16:51:38 +0200 Morten Br=C3=B8rup wrote: > > From: Bruce Richardson [mailto:bruce.richardson@intel.com] > > Sent: Friday, 3 October 2025 11.18 > > Subject: Minutes of techboard meeting, 2025-10-01 =20 >=20 > > * Use of FAST_FREE and multi-buffer/scattered mbuf flags > > - The flags for enabling fast-free and supporting multi-mbuf packets > > are > > now documented incompatible > > - Previously they were not defined as incompatible, but that seems to > > have been assumed for some usages. > > - Techboard discussed how best to resolve this incompatibility with > > regards to: > > - ensuring correctness > > - avoiding major churn to DPDK code > > - avoiding churn to end-user code > > - Options discussed: > > 1 change definition back to not have the settings incompatible: > > this > > necessitates checking drivers for correctness > > 2 keep as explicitly incompatible and report error if both > > specified: > > this could break end-user apps, and requires changes to example > > apps > > 3 drop the fast-free flag if multi-segment mbufs are also > > specified: > > "hides" the issue, but probably minimises changes. Would need to > > decide whether the dropping of flag done in drivers vs ethdev > > level. > > Pros and cons to both options. Needs clear documenting. > > - No firm decision reached, will discuss more over email. =20 >=20 > IMO, the patch [1] making MBUF_FAST_FREE and MULTI_SEGS explicitly incomp= atible should be reverted, at least for RC1. > That will take the project back to the state it was in before we started = this discussion. > And all the examples broken by the patch (because they use both TX offloa= ds) will not need fixing. >=20 > [1]: https://patchwork.dpdk.org/project/dpdk/patch/20250803194218.683318-= 3-mb@smartsharesystems.com/ >=20 There is still code NULL PMD which checks for FAST_FREE with MULTI_SEGS. I think this commit needs to be reverted as well. commit 675ddc233d68d90b3858cdb6267dd407c4e85984 Author: Morten Br=C3=B8rup Date: Wed Jul 30 14:04:51 2025 +0000 net/null: add fast mbuf release Tx offload =20 Added fast mbuf release, reusing the existing mbuf pool pointer in the queue structure. =20 Signed-off-by: Morten Br=C3=B8rup