From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mails.dpdk.org (mails.dpdk.org [217.70.189.124]) by inbox.dpdk.org (Postfix) with ESMTP id 8D9B8488C8; Mon, 6 Oct 2025 16:51:41 +0200 (CEST) Received: from mails.dpdk.org (localhost [127.0.0.1]) by mails.dpdk.org (Postfix) with ESMTP id 74C4E402E2; Mon, 6 Oct 2025 16:51:41 +0200 (CEST) Received: from dkmailrelay1.smartsharesystems.com (smartserver.smartsharesystems.com [77.243.40.215]) by mails.dpdk.org (Postfix) with ESMTP id 0347C402AF; Mon, 6 Oct 2025 16:51:40 +0200 (CEST) Received: from smartserver.smartsharesystems.com (smartserver.smartsharesys.local [192.168.4.10]) by dkmailrelay1.smartsharesystems.com (Postfix) with ESMTP id CF80B202CC; Mon, 6 Oct 2025 16:51:39 +0200 (CEST) Content-class: urn:content-classes:message MIME-Version: 1.0 Content-Type: text/plain; charset="iso-8859-1" Content-Transfer-Encoding: quoted-printable Subject: Use of TX offload flags MBUF_FAST_FREE and MULTI_SEGS Date: Mon, 6 Oct 2025 16:51:38 +0200 Message-ID: <98CBD80474FA8B44BF855DF32C47DC35F654A3@smartserver.smartshare.dk> In-Reply-To: X-MimeOLE: Produced By Microsoft Exchange V6.5 X-MS-Has-Attach: X-MS-TNEF-Correlator: Thread-Topic: Use of TX offload flags MBUF_FAST_FREE and MULTI_SEGS Thread-Index: Adw0Rp0aNcBqsJnpSuinX2U7NfkFnAChp3KQ References: From: =?iso-8859-1?Q?Morten_Br=F8rup?= To: , , , "Thomas Monjalon" , "Andrew Rybchenko" Cc: "Patrick Robb" 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 > From: Bruce Richardson [mailto:bruce.richardson@intel.com] > Sent: Friday, 3 October 2025 11.18 > Subject: Minutes of techboard meeting, 2025-10-01 > * 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. IMO, the patch [1] making MBUF_FAST_FREE and MULTI_SEGS explicitly = incompatible 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 = offloads) will not need fixing. [1]: = https://patchwork.dpdk.org/project/dpdk/patch/20250803194218.683318-3-mb@= smartsharesystems.com/