From mboxrd@z Thu Jan 1 00:00:00 1970 Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.remote-ip=100.103.45.18 ARC-Seal: i=1; d=subspace.kernel.org; s=arc20261015; a=rsa-sha256; cv=none; t=1794496224; b=snOZgEZSfH67YC3QbQJaqI6QaqQshkzrSwZOYAnixq4IbX+FQCQEC0RAaMHSuJLMZEX9 kyV0aEXUiWKEyY/jfFlfSaGcuRifEGxKPP177ILqFMqZm3dkRCQFJXtkWFiK+9gxk1h8z f1btavPRMhxhiqW6Dp+t9bCEsK+vSshgX3SIfWtcefqulvAc7KW/j9Ck/ypK2Akc3Z3Df 1JAIuHNYwpykwsAHyinONBkD/R1cbdyC3scodUQlnRa9qNJp79HntbxtWyVvrqexghbfy WEql4Z6w6+mWYOktv1i0g/UqWa8s8ZT8XqGsD9Zz7H9jaWCDHW8Y2xfTjaU8kTQQdLw== ARC-Message-Signature: i=1; d=subspace.kernel.org; s=arc20261015; a=rsa-sha256; c=relaxed/relaxed; t=1794496224; h=Received:DKIM-Signature:From:To:Cc:Subject:In-Reply-To:References: Date:Message-ID:MIME-Version:Content-Type:Content-Transfer-Encoding; bh=eCnP3f/5sYjDgXu5gjLcJGqvVbM8pnJiTnh+Y99hcQc=; b=BjjtmEFPke+RJ9ALOm57CbBnucRcKJffAwfUBk8HBZfCfV+xe/ixYuPs52BlN17Os+nl NiFehmKb9RV020nj44tWe9Y/p+y8saUyZRAE2Oi6sG2wsYBVkrwBhVm3OlpG25PSFrezD bF7FKk0bK8gkEqSCPMVTAx+g6bOAF2D3j2Fas78XdVIEUxy/LK2mtMHkylpk46TPrKnol e7HwZFfmCKD/pOZ+8aNl+Wq73nVErMVrAmce9qIsHbTZKg4R5E09v/4Wc5qn27H7heW8N JBrTbK5Tl5W4eb9/3/a9BZG2cYNLihSxzSqrXDWC8nWt56Dcinrh+CI15yTcpvQqD8Q== ARC-Authentication-Results: i=1; smtp.subspace.kernel.org; dkim=pass header.d=kernel.org header.i=@kernel.org header.a=rsa-sha256 header.s=k20260515 header.b=FO5t0psT; arc=none smtp.remote-ip=100.103.45.18 Received: from smtp.kernel.org (quasi.space.kernel.org [100.103.45.18]) (using TLSv1.3 with cipher TLS_AES_256_GCM_SHA384 (256/256 bits) key-exchange X25519 server-signature ECDSA (prime256v1)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id 6569E606A321; Thu, 12 Nov 2026 15:10:24 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.a=rsa-sha256 header.s=k20260515 header.b=FO5t0psT Received: by smtp.kernel.org (Postfix) with ESMTPSA id 34B841F00A05; Thu, 12 Nov 2026 15:10:23 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=kernel.org; s=k20260515; t=1794496223; bh=eCnP3f/5sYjDgXu5gjLcJGqvVbM8pnJiTnh+Y99hcQc=; h=From:To:Cc:Subject:In-Reply-To:References:Date; b=FO5t0psTMMZWTQWrqQmrvKX36gkiFfAvWR4ZiJcJQPFqWVcWeZ6he0Lnaz9j6IYXe OEhcfG3tlmlZ/fATPT5sFcQSt7MVxQJvfaGiDGWXbrugT/e9zrsByvjQuURudjIKql gtAG65W3qOmSeFUxExq7PhBgy3xrfs6MpgPQ2jKTx248VgzHeub57/eF3bpAJsts6c OGSCZc/p5egFjnMBgPqeFROyK9o1O2FzrbS6UGt8xstf9stnD3hpsFKzx85K9HsqhR kF8f7qvoEkDB6/QcIXpKjVxAjj4hT5qouLyrG2HDncrZTR16M4thCL4WmT+Fa9EI/F beW8/QL8AEP5Q== From: =?utf-8?B?QmrDtnJuIFTDtnBlbA==?= To: Stanislav Fomichev Cc: Magnus Karlsson , Maciej Fijalkowski , Stanislav Fomichev , "David S. Miller" , Eric Dumazet , Jakub Kicinski , Paolo Abeni , Simon Horman , Jonathan Corbet , Shuah Khan , Randy Dunlap , Alexander Duyck , kernel-team@meta.com, Andrew Lunn , Jesper Dangaard Brouer , Ilias Apalodimas , Alexei Starovoitov , Daniel Borkmann , John Fastabend , Pavel Begunkov , Jens Axboe , Andrii Nakryiko , Eduard Zingerman , Kumar Kartikeya Dwivedi , Martin KaFai Lau , Song Liu , Yonghong Song , Jiri Olsa , Emil Tsalapatis , Ihor Solodrai , netdev@vger.kernel.org, bpf@vger.kernel.org, io-uring@vger.kernel.org, Mina Almasry , "Mike Marciniszyn (Meta)" , Weiming Shi , Nikolay Aleksandrov , David Wei , Alexander Lobakin , linux-doc@vger.kernel.org, linux-kernel@vger.kernel.org, Stuart Clark Subject: Re: [PATCH net-next v1 07/11] xsk: Deliver provider chunks without copying In-Reply-To: References: <20261110102039.1002605-1-bjorn@kernel.org> <20261110102039.1002605-8-bjorn@kernel.org> Date: Thu, 12 Nov 2026 16:10:21 +0100 Message-ID: <87qzgqqe5e.fsf@all.your.base.are.belong.to.us> X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Post: List-Help: List-Subscribe: List-Unsubscribe: List-Owner: Precedence: list MIME-Version: 1.0 Content-Type: text/plain; charset=utf-8 Content-Transfer-Encoding: quoted-printable Stanislav Fomichev writes: > On 11/10, Bj=C3=B6rn T=C3=B6pel wrote: >> diff --git a/net/xdp/xsk.c b/net/xdp/xsk.c >> index 113b0b08356d..b419c673e3f1 100644 >> --- a/net/xdp/xsk.c >> +++ b/net/xdp/xsk.c >> @@ -453,8 +501,14 @@ static int xsk_rcv_check(struct xdp_sock *xs, struc= t xdp_buff *xdp, u32 len) >>=20=20 >> static void xsk_flush(struct xdp_sock *xs) >> { >> + struct xsk_pp *pp =3D xs->pool->pp; >> + >> + if (pp) >> + xsk_pp_flush(pp); >> xskq_prod_submit(xs->rx); >> - __xskq_cons_release(xs->pool->fq); >> + /* A provider releases FILL entries under its lock. */ >> + if (!pp) >> + __xskq_cons_release(xs->pool->fq); >> sock_def_readable(&xs->sk); > > optional nit: > > if (pp) { > pp_flush > prod_submit > } else { > prod_submit > cons_release > } > > sock_def_readable > > (hard to follow these scattered if(pp) checks :-( ) Sure, will do! > >> } >>=20=20 >> @@ -464,6 +518,11 @@ int xsk_generic_rcv(struct xdp_sock *xs, struct xdp= _buff *xdp) >> int err; >>=20=20 >> err =3D xsk_rcv_check(xs, xdp, len); >> + /* Only the NAPI of the queue feeds a memory provider socket. */ >> + if (!err && xs->pool->pp) { >> + xs->rx_dropped++; >> + err =3D -EOPNOTSUPP; >> + } > > This is confusing? Why even call xsk_rcv_check for pp case? Hmm! I think you're right here... this was a (is it bound) check. I might have been wrong in my reply to Maciej as well. I'll drop this. >> if (!err) { >> spin_lock_bh(&xs->pool->rx_lock); >> err =3D __xsk_rcv(xs, xdp, len); >> @@ -488,7 +547,26 @@ static int xsk_rcv(struct xdp_sock *xs, struct xdp_= buff *xdp) >> return xsk_rcv_zc(xs, xdp, len); >> } >>=20=20 >> - err =3D __xsk_rcv(xs, xdp, len); >> + if (!xs->pool->pp) { >> + err =3D __xsk_rcv(xs, xdp, len); >> + } else { > > [..] > >> + /* A CPUMAP program runs XDP on another CPU, not in NAPI. */ >> + if (unlikely(!xdp_rxq_info_is_reg(xdp->rxq))) { >> + xs->rx_dropped++; >> + return -EINVAL; >> + } >> + >> + err =3D xsk_pp_rcv_zc(xs->pool->pp, xs, xdp); >> + if (err !=3D -EXDEV) >> + return err; >> + >> + /* Copy only packets of the queue, from its NAPI */ >> + if (unlikely(!xsk_pp_queue_buf(xs->pool->pp, xdp))) { >> + xs->rx_dropped++; >> + return -EINVAL; >> + } >> + err =3D xsk_pp_rcv_copy(xs, xdp, len); > > Move this into __xsk_rcv_pp ? Yes. Bj=C3=B6rn