From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mails.dpdk.org (mails.dpdk.org [217.70.189.124]) by inbox.dpdk.org (Postfix) with ESMTP id 97DCBA0C4D; Tue, 24 Aug 2021 17:10:57 +0200 (CEST) Received: from [217.70.189.124] (localhost [127.0.0.1]) by mails.dpdk.org (Postfix) with ESMTP id 5E7CE40DDE; Tue, 24 Aug 2021 17:10:57 +0200 (CEST) Received: from mail-pj1-f54.google.com (mail-pj1-f54.google.com [209.85.216.54]) by mails.dpdk.org (Postfix) with ESMTP id 63052406A3 for ; Tue, 24 Aug 2021 17:10:56 +0200 (CEST) Received: by mail-pj1-f54.google.com with SMTP id oa17so14471889pjb.1 for ; Tue, 24 Aug 2021 08:10:56 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=networkplumber-org.20150623.gappssmtp.com; s=20150623; h=date:from:to:cc:subject:message-id:in-reply-to:references :mime-version:content-transfer-encoding; bh=gwSGBrUX0yr4Ok6R8oQL1Euys563NhifrQY/Mu297BI=; b=Zvh73Qr1JuSxghpjpSpcpyuYrHkgc9JsVjtOTZwyp199zie61/3Rmqu6t/U1WZZzSl VjSJ7EQW3biX7pAVTSHaJHsRkKJE63ARabt4QZtF7Id0LKjbalQ2iaJrENBbTVTJOXB5 KipDR+gOGhW/8+F5DnhHJ6aY6Y7uI10lXOglSu+0a2xLPG1j6/We/E3+jy/RrA9kVX02 Wk37IQIkZP312qsICnSgXRbzRBOj4HEwzbIsvJM1nKnq0j+NO97gcLa0h9ULY2CBCAKX x8UX+bUZ7RLCOR2Pr1owSmfJDW80Sl12h57nOu8kNFoDowIazNBIT7yKDW4/0Wvi2yzn qoCg== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20161025; h=x-gm-message-state:date:from:to:cc:subject:message-id:in-reply-to :references:mime-version:content-transfer-encoding; bh=gwSGBrUX0yr4Ok6R8oQL1Euys563NhifrQY/Mu297BI=; b=PB+1Q1yUhyyDWETBAppyt0XhR0a5tOw2FJ2Pdgijwm90z9G9uR3TZ6IPWR7uJH5sTF NfoizijcBWrlZ7JMNt6SidUIATdBg97sN3TLTKHN72Dvqty7rVCnbLYquirrAysahgUV afMvEYoaKN8yayZNs+mpTec6dDTBOT8brZ0Iy3UD2evof/60gm+16GCj1K0YzTrYdMdm uXm9fD38H99Z8kkhgGDjKUSYjv9MKmC4x5zliofPPpD6Zhu+pjPt9ROu/QfQqQN0tJcj pqtG1FQC1P0A2P9tJHVMd+Tw96XRQOTTECQqCDxiCc/4Mw/ht06kCMVxQGpXBCtajHFj UFgQ== X-Gm-Message-State: AOAM531stvp/wT5uvyZQG7Ytx2PLi7ezV5lM/ssQtvQOlnCyWVqhj5pI nvHD6ba8aqL66PJ0zxOo+N+EMA== X-Google-Smtp-Source: ABdhPJxgaadF4a3JWhkDjk90gkX/jj8UzvV7mao4YYibMAYRjXzh6qmANcppY5KrPKUXcrfpHJbmYQ== X-Received: by 2002:a17:902:d2c5:b0:135:2fca:57b2 with SMTP id n5-20020a170902d2c500b001352fca57b2mr7311390plc.54.1629817855540; Tue, 24 Aug 2021 08:10:55 -0700 (PDT) Received: from hermes.local (204-195-33-123.wavecable.com. [204.195.33.123]) by smtp.gmail.com with ESMTPSA id q1sm3421344pfj.132.2021.08.24.08.10.54 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Tue, 24 Aug 2021 08:10:55 -0700 (PDT) Date: Tue, 24 Aug 2021 08:10:52 -0700 From: Stephen Hemminger To: Cc: , Erik Gabriel Carrillo , , Message-ID: <20210824081052.3c357945@hermes.local> In-Reply-To: <20210823194020.1229-11-pbhagavatula@marvell.com> References: <20210823194020.1229-1-pbhagavatula@marvell.com> <20210823194020.1229-11-pbhagavatula@marvell.com> MIME-Version: 1.0 Content-Type: text/plain; charset=US-ASCII Content-Transfer-Encoding: 7bit Subject: Re: [dpdk-dev] [RFC 11/15] eventdev: reserve fields in timer object X-BeenThere: dev@dpdk.org X-Mailman-Version: 2.1.29 Precedence: list List-Id: DPDK patches and discussions List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Errors-To: dev-bounces@dpdk.org Sender: "dev" On Tue, 24 Aug 2021 01:10:15 +0530 wrote: > From: Pavan Nikhilesh > > Reserve fields in rte_event_timer data structure to address future > use cases. > Also, remove volatile from rte_event_timer. > > Signed-off-by: Pavan Nikhilesh Reserve fields are not a good idea. They don't solve future API/ABI problems. The issue is that you need to zero them and check they are zero otherwise they can't safely be used later. This happened with the Linux kernel system calls where in several cases a flag field was added for future. The problem is that old programs would work with any garbage in the flag field, and therefore the flag could not be extended. A better way to make structures internal opaque objects that can be resized. Why is rte_event_timer_adapter exposed in API?