From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from smtp.kernel.org (aws-us-west-2-korg-mail-1.web.codeaurora.org [10.30.226.201]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id 1FE8E26B2AE; Tue, 24 Jun 2025 23:31:16 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=10.30.226.201 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1750807876; cv=none; b=Vk8pkIVxP4tDNcOT7gyj8kK3+pPCYXMjN9HDTWqU/wCz/J5CwTSbPYo6eAK2qKmoyw7AUqJ/j9gDzIw8LQczJ96C6bOFTuEvMRe42OcnX3Ot8ERAxfckmXaqthWSwjTFfvgmHijzyHNZnUVb3/0MHHlUDcHRsWbzXy1IwAUOr54= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1750807876; c=relaxed/simple; bh=VlBs7o7mBF7VcdvN1sBvor007d7BqlY6Pz6in6IqgJ4=; h=Date:From:To:Cc:Subject:Message-ID:In-Reply-To:References: MIME-Version:Content-Type; b=LQ//qzWWXz59ElMAzfsnLEZIMdW9KVjWWrtgES5/xon7IED3hIAAHXRb24P6M/MITS6EqxdmrDk4mpkd3VrHa1CD1Ae+3Wy+d17GGh8AxfSLTrTNhOJvjSjmFXs0ehJv8DAWWsq0yRt/1UVP8gLoBXcQXEJHhi4slHwMfSIdeOU= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b=NWDqrtPJ; arc=none smtp.client-ip=10.30.226.201 Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b="NWDqrtPJ" Received: by smtp.kernel.org (Postfix) with ESMTPSA id 33706C4CEE3; Tue, 24 Jun 2025 23:31:15 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1750807876; bh=VlBs7o7mBF7VcdvN1sBvor007d7BqlY6Pz6in6IqgJ4=; h=Date:From:To:Cc:Subject:In-Reply-To:References:From; b=NWDqrtPJn0fgSFxbSHTURM8GuH2RixHQydw6tnz9DE5zJIpk+qzoGzWdzl7zKf4En N0VIO02dYWHHh89/ekgv3PQiwiS1+ALgSeVg+sgSOpieFJBugrOQU2BDZTSLBafQsy LUu8+vRGLS5qAOXDqet5/RBYswb8EM1sKZX2eClEwFZdYvF0Uw1GCDhVfhlyIimnRV pGkQAXfQxPMuMgzWECcwMNCg62JHb0MFZFwKn+eId6C+7+LqLnzWQGH4fQSdjeoV1J 3WFB4bQ7ucdZItdoeIrjCzM41vwYQ1Bg4PvP90PXBXbwYRy8TheHb57kmX85XPy6WJ /YUH4eU/gAFKw== Date: Tue, 24 Jun 2025 16:31:14 -0700 From: Jakub Kicinski To: Jason Xing Cc: davem@davemloft.net, edumazet@google.com, pabeni@redhat.com, bjorn@kernel.org, magnus.karlsson@intel.com, maciej.fijalkowski@intel.com, jonathan.lemon@gmail.com, sdf@fomichev.me, ast@kernel.org, daniel@iogearbox.net, hawk@kernel.org, john.fastabend@gmail.com, joe@dama.to, willemdebruijn.kernel@gmail.com, bpf@vger.kernel.org, netdev@vger.kernel.org, Jason Xing Subject: Re: [PATCH net-next v4] net: xsk: introduce XDP_MAX_TX_BUDGET setsockopt Message-ID: <20250624163114.712a9c43@kernel.org> In-Reply-To: <20250623021345.69211-1-kerneljasonxing@gmail.com> References: <20250623021345.69211-1-kerneljasonxing@gmail.com> Precedence: bulk X-Mailing-List: netdev@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Type: text/plain; charset=US-ASCII Content-Transfer-Encoding: 7bit On Mon, 23 Jun 2025 10:13:45 +0800 Jason Xing wrote: > @@ -424,7 +421,9 @@ bool xsk_tx_peek_desc(struct xsk_buff_pool *pool, struct xdp_desc *desc) > rcu_read_lock(); > again: > list_for_each_entry_rcu(xs, &pool->xsk_tx_list, tx_list) { > - if (xs->tx_budget_spent >= MAX_PER_SOCKET_BUDGET) { > + int max_budget = READ_ONCE(xs->max_tx_budget); > + > + if (xs->tx_budget_spent >= max_budget) { > budget_exhausted = true; > continue; > } I still think you're mixing two very different things. In the generic xmit path the value you're changing is a budget. But xsk_tx_peek_desc() *does not* exit after the "per socket budget" gets spent. The per socket budget only controls how many frames we pick from a single sock before we move to the next. But if we run out of budget on all sockets we give every socket a full budget again and start from the first one again. For the ZC case the true budget is set by the driver's NAPI loop. -- pw-bot: cr