From mboxrd@z Thu Jan 1 00:00:00 1970 From: Eric Dumazet Subject: Re: [PATCH net-next v3 3/4] net: use skb->priority for overloading skb->dropcount and skb->reserved_tailroom instead of skb->mark Date: Tue, 24 Feb 2015 05:18:35 -0800 Message-ID: <1424783915.5565.74.camel@edumazet-glaptop2.roam.corp.google.com> References: <1424713924-6821-2-git-send-email-eyal.birger@gmail.com> <1424713924-6821-4-git-send-email-eyal.birger@gmail.com> <20150223205633.7fbd08d4@halley> <20150223.164801.842537100812023841.davem@davemloft.net> Mime-Version: 1.0 Content-Type: text/plain; charset="UTF-8" Content-Transfer-Encoding: 7bit Cc: David Miller , Shmulik Ladkani , Eric Dumazet , netdev@vger.kernel.org To: Eyal Birger Return-path: Received: from mail-ie0-f173.google.com ([209.85.223.173]:35983 "EHLO mail-ie0-f173.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752625AbbBXNSi (ORCPT ); Tue, 24 Feb 2015 08:18:38 -0500 Received: by ierx19 with SMTP id x19so31788882ier.3 for ; Tue, 24 Feb 2015 05:18:37 -0800 (PST) In-Reply-To: Sender: netdev-owner@vger.kernel.org List-ID: On Tue, 2015-02-24 at 12:10 +0200, Eyal Birger wrote: > > Well, gave it a shot... it looks like several protocol families > (packet, rxrpc, bluetooth) do not > have room in skb->cb[] for the dropcount - at least on my 64 bit machine. No idea how you took a look ? sizeof(struct packet_skb_cb) == 24 : We have plenty of room ? bluetooth : Whole struct rxrpc_skb_priv is not used when packet is stored in receive queue. We only need bt_cb(skb)->psm & bt_cb(skb)->bdaddr according to l2cap_skb_msg_name() An union will be possible. rxpc is buggy right now anyway, as it reads skb->mark _and_ uses sock_recv_ts_and_drops(), so skb->mark value is pretty much void. Note that resend_at field could probably converted into u32. tcp stack uses same (u32)jiffies trick (tcp_time_stamp) I never said it was going to be easy ;)