From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from dpdk.org (dpdk.org [92.243.14.124]) by inbox.dpdk.org (Postfix) with ESMTP id CEFFDA04B3; Fri, 8 Nov 2019 10:40:48 +0100 (CET) Received: from [92.243.14.124] (localhost [127.0.0.1]) by dpdk.org (Postfix) with ESMTP id 493A01BFCD; Fri, 8 Nov 2019 10:40:48 +0100 (CET) Received: from out5-smtp.messagingengine.com (out5-smtp.messagingengine.com [66.111.4.29]) by dpdk.org (Postfix) with ESMTP id 12CFC1BFB5 for ; Fri, 8 Nov 2019 10:40:47 +0100 (CET) Received: from compute1.internal (compute1.nyi.internal [10.202.2.41]) by mailout.nyi.internal (Postfix) with ESMTP id B30F821B8C; Fri, 8 Nov 2019 04:40:43 -0500 (EST) Received: from mailfrontend1 ([10.202.2.162]) by compute1.internal (MEProxy); Fri, 08 Nov 2019 04:40:43 -0500 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=monjalon.net; h= from:to:cc:subject:date:message-id:in-reply-to:references :mime-version:content-transfer-encoding:content-type; s=mesmtp; bh=9762CqPv+z2n0buvi0AMkmqtnAwSC1qDw4HAGz8CygI=; b=O24RmfrBjWXF J9lErYvJZjl+3vokBb1sHYErGBtiyWLdldqD5Uie2OirZQOANJT8gaFs2ZdVUEnB BEsSkhx4PVRwQ29oZdI/bhTyprRjAmhP7qb5JhTqJQrjFZQFWtHZ/kE1I5NshODu NnvncpXVsnJvkJehyvn3fjhAp0ILC2s= DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d= messagingengine.com; h=cc:content-transfer-encoding:content-type :date:from:in-reply-to:message-id:mime-version:references :subject:to:x-me-proxy:x-me-proxy:x-me-sender:x-me-sender :x-sasl-enc; s=fm1; bh=9762CqPv+z2n0buvi0AMkmqtnAwSC1qDw4HAGz8Cy gI=; b=SIyC6ePuA1OZgSvJUapq7j1qVcRDuphQT83lTHv0Gi6EsGkFyqzLa5trv zGckzbf/CSUna3NOA4N/7EGxPLgcslayAw3Q0X68V1NELTyYEirIk0WgypYuvvYd IrpEGkhtgrus+eVonPyKaenjezQcTgqbL1NqBtwi0/HEHG2gLjRS9sFWRFtiCMKd nSX+scj0SwTSEFyVvAQPQ1CtWvJ42xJA1tT2EN5qETsrDQTRrRQydA9+d4iOHa/8 i6tUQMeZj1rPRIR0MQH2AItkvHMyiXpBHN/HIgTn2wsuhnoPiU9y2YxxYDUO9EHE onimR0veGCmRCRoljCzmz+hd3fqlQ== X-ME-Sender: X-ME-Proxy-Cause: gggruggvucftvghtrhhoucdtuddrgedufedruddvuddgtdejucetufdoteggodetrfdotf fvucfrrhhofhhilhgvmecuhfgrshhtofgrihhlpdfqfgfvpdfurfetoffkrfgpnffqhgen uceurghilhhouhhtmecufedttdenucesvcftvggtihhpihgvnhhtshculddquddttddmne cujfgurhephffvufffkfgjfhgggfgtsehtufertddttddvnecuhfhrohhmpefvhhhomhgr shcuofhonhhjrghlohhnuceothhhohhmrghssehmohhnjhgrlhhonhdrnhgvtheqnecukf hppeejjedrudefgedrvddtfedrudekgeenucfrrghrrghmpehmrghilhhfrhhomhepthhh ohhmrghssehmohhnjhgrlhhonhdrnhgvthenucevlhhushhtvghrufhiiigvpedt X-ME-Proxy: Received: from xps.localnet (184.203.134.77.rev.sfr.net [77.134.203.184]) by mail.messagingengine.com (Postfix) with ESMTPA id 8FC6680064; Fri, 8 Nov 2019 04:40:42 -0500 (EST) From: Thomas Monjalon To: Stephen Hemminger Cc: Ferruh Yigit , Andrew Rybchenko , dev@dpdk.org Date: Fri, 08 Nov 2019 10:40:41 +0100 Message-ID: <7184488.knne4pTHYG@xps> In-Reply-To: <20191107194133.7db88620@hermes.lan> References: <20191107221524.23205-1-thomas@monjalon.net> <20191107194133.7db88620@hermes.lan> MIME-Version: 1.0 Content-Transfer-Encoding: 7Bit Content-Type: text/plain; charset="us-ascii" Subject: Re: [dpdk-dev] [PATCH] ethdev: reserve space in main structs for extension X-BeenThere: dev@dpdk.org X-Mailman-Version: 2.1.15 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" 08/11/2019 04:41, Stephen Hemminger: > On Thu, 7 Nov 2019 23:15:24 +0100 > Thomas Monjalon wrote: > > > The struct rte_eth_dev and rte_eth_dev_data are supposed > > to be used internally only, but there is a chance that > > increasing their size would break ABI for some applications. > > In order to allow smooth addition of features without breaking > > ABI compatibility, some space is reserved. > > > > Signed-off-by: Thomas Monjalon > > --- > > @@ -764,6 +767,9 @@ struct rte_eth_dev_data { > > + > > + uint64_t reserved_64s[4]; /**< Reserved for future fields */ > > + void *reserved_ptrs[4]; /**< Reserved for future fields */ > > } __rte_cache_aligned; > > Void * is 32 bits on 32 bit architectures is that helpful or not? That's why I reserved separately uint and pointers. If we need to add a pointer, we decrease the size of the pointer array to keep the same struct size on all archs.