On Mon, 6 Oct 2025 16:51:38 +0200 Morten Brørup <[email protected]> wrote:
> > From: Bruce Richardson [mailto:[email protected]] > > 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/[email protected]/ > 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 Brørup <[email protected]> Date: Wed Jul 30 14:04:51 2025 +0000 net/null: add fast mbuf release Tx offload Added fast mbuf release, reusing the existing mbuf pool pointer in the queue structure. Signed-off-by: Morten Brørup <[email protected]>
