From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mail-pl0-f67.google.com ([209.85.160.67]:41753 "EHLO mail-pl0-f67.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S932078AbeCGCxc (ORCPT ); Tue, 6 Mar 2018 21:53:32 -0500 Received: by mail-pl0-f67.google.com with SMTP id d9-v6so522580plo.8 for ; Tue, 06 Mar 2018 18:53:32 -0800 (PST) Message-ID: <1520391209.109662.33.camel@gmail.com> Subject: Re: [RFC v3 net-next 08/18] net: SO_TXTIME: Add clockid and drop_if_late params From: Eric Dumazet To: Jesus Sanchez-Palencia , netdev@vger.kernel.org Cc: jhs@mojatatu.com, xiyou.wangcong@gmail.com, jiri@resnulli.us, vinicius.gomes@intel.com, richardcochran@gmail.com, intel-wired-lan@lists.osuosl.org, anna-maria@linutronix.de, henrik@austad.us, tglx@linutronix.de, john.stultz@linaro.org, levi.pearson@harman.com, edumazet@google.com, willemb@google.com, mlichvar@redhat.com Date: Tue, 06 Mar 2018 18:53:29 -0800 In-Reply-To: <20180307011230.24001-9-jesus.sanchez-palencia@intel.com> References: <20180307011230.24001-1-jesus.sanchez-palencia@intel.com> <20180307011230.24001-9-jesus.sanchez-palencia@intel.com> Content-Type: text/plain; charset="UTF-8" Mime-Version: 1.0 Content-Transfer-Encoding: 8bit Sender: netdev-owner@vger.kernel.org List-ID: On Tue, 2018-03-06 at 17:12 -0800, Jesus Sanchez-Palencia wrote: > Extend SO_TXTIME APIs with new per-packet parameters: a clockid_t and > a drop_if_late flag. With this commit the API becomes: > > * diff --git a/include/linux/skbuff.h b/include/linux/skbuff.h * index d8340e6e8814..951969ceaf65 100644 * --- a/include/linux/skbuff.h * +++ b/include/linux/skbuff.h * @@ -788,6 +788,9 @@ struct sk_buff { *   __u8 tc_redirected:1; *   __u8 tc_from_ingress:1; *  #endif * + __u8 tc_drop_if_late:1; * + * + clockid_t txtime_clockid; *   *  #ifdef CONFIG_NET_SCHED *   __u16 tc_index; /* traffic control index */ This is adding 32+1 bits to sk_buff, and possibly holes in this very very hot (and already too fat) structure. Do we really need 32 bits for a clockid_t ?