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 AE30FA00C5; Sun, 5 Jul 2020 20:01:49 +0200 (CEST) Received: from [92.243.14.124] (localhost [127.0.0.1]) by dpdk.org (Postfix) with ESMTP id DC4DA1DA2A; Sun, 5 Jul 2020 20:01:48 +0200 (CEST) Received: from out2-smtp.messagingengine.com (out2-smtp.messagingengine.com [66.111.4.26]) by dpdk.org (Postfix) with ESMTP id 7B51E1D8EC for ; Sun, 5 Jul 2020 20:01:47 +0200 (CEST) Received: from compute7.internal (compute7.nyi.internal [10.202.2.47]) by mailout.nyi.internal (Postfix) with ESMTP id 01BFA5C0040; Sun, 5 Jul 2020 14:01:47 -0400 (EDT) Received: from mailfrontend1 ([10.202.2.162]) by compute7.internal (MEProxy); Sun, 05 Jul 2020 14:01:47 -0400 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=fm1; bh= ES83xDiUe33wwApTgpzciST9QWTcwLNsrUTU8V8EdKE=; b=AMMO8mpRZTUAGbRJ i1Cf/NZMprBV6D9T9AiNbuuja09EmEIbl7vnXVr7MA1QCM02ETUrFwEA6kYuRgai hivxx5SeF5Z8KxRPywYbYQNq1bVzI33NA+hIZXvXdDBsSkWECPrGFwBlpdbHg5oJ gt8InlzR65Mo4lXY0gvB31RIbnjsb+ckLzBEeCEcg7c8XrkGOICW40WXhEL4aYG9 B2rgX7CZcxOM/4iThjCV1Z8krgovm2OWyY8RxADF9MV8hNUtu2Ab0uRJj9sgxbXS bBqsoc3ziGCLGymjlZItNnA23nZXC5Z9P9Uqq8u8jq/bEzn/smJmdS3WtAK6mGiJ Ky/zZQ== 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=fm3; bh=ES83xDiUe33wwApTgpzciST9QWTcwLNsrUTU8V8Ed KE=; b=NvgPcgQQGn0HE95itQNH1VLnNzWu6Fag5PwR9/cHn4AkeGAvWZdsNzBIH 3Gfq2T8iFyOhOIM8UlCrt7vjSJydpeOSdU0c9xPBPLfv/o1GixrdopoX9Ofqn1en PAVRzZcqC3NmXsCIMMouPfG+SHpthySiyYQ789jL3WXehCwpEWirGncxHI//9FZq zFBWfvjx2ZfPx2Au+wTxDz7ckClinKo9vQmQiZT0rm5wiz9UNijWAqYVHqK7KP2q TH1WyfhwDSDrEjV0mJeCVFw+3K1hjVqs5wY+VeGWNpfEDu6mW59Rp1RFPtX1gPIq Oe9SuPzXCtl2P/CCN4D3Z1DqdtPJg== X-ME-Sender: X-ME-Proxy-Cause: gggruggvucftvghtrhhoucdtuddrgeduiedruddugdduvddvucetufdoteggodetrfdotf fvucfrrhhofhhilhgvmecuhfgrshhtofgrihhlpdfqfgfvpdfurfetoffkrfgpnffqhgen uceurghilhhouhhtmecufedttdenucesvcftvggtihhpihgvnhhtshculddquddttddmne cujfgurhephffvufffkfgjfhgggfgtsehtufertddttddvnecuhfhrohhmpefvhhhomhgr shcuofhonhhjrghlohhnuceothhhohhmrghssehmohhnjhgrlhhonhdrnhgvtheqnecugg ftrfgrthhtvghrnhepffdvffejueetleefieeludduuefgteejleevfeekjeefieegheet ffdvkeefgedunecuffhomhgrihhnpeguphgukhdrohhrghenucfkphepjeejrddufeegrd dvtdefrddukeegnecuvehluhhsthgvrhfuihiivgeptdenucfrrghrrghmpehmrghilhhf rhhomhepthhhohhmrghssehmohhnjhgrlhhonhdrnhgvth 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 A97D93280059; Sun, 5 Jul 2020 14:01:45 -0400 (EDT) From: Thomas Monjalon To: Bruce Richardson Cc: Stephen Hemminger , dev@dpdk.org, david.marchand@redhat.com, anatoly.burakov@intel.com Date: Sun, 05 Jul 2020 20:01:44 +0200 Message-ID: <3806538.nQ71GYN1Xn@thomas> In-Reply-To: <20200629161538.GE572@bricha3-MOBL.ger.corp.intel.com> References: <20200626145957.722089-1-bruce.richardson@intel.com> <20200629084146.6951685c@hermes.lan> <20200629161538.GE572@bricha3-MOBL.ger.corp.intel.com> MIME-Version: 1.0 Content-Transfer-Encoding: 7Bit Content-Type: text/plain; charset="us-ascii" Subject: Re: [dpdk-dev] [PATCH] eal: don't use default library path for static binaries 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" 29/06/2020 18:15, Bruce Richardson: > On Mon, Jun 29, 2020 at 08:41:46AM -0700, Stephen Hemminger wrote: > > Bruce Richardson wrote: > > > On Mon, Jun 29, 2020 at 10:11:58AM +0100, Bruce Richardson wrote: > > > > On Fri, Jun 26, 2020 at 10:05:42AM -0700, Stephen Hemminger wrote: > > > > > Bruce Richardson wrote: > > > > > > > > > > > When using statically linked DPDK binaries, the EAL checks the default PMD > > > > > > path and tries to load any drivers there, despite the fact that all drivers > > > > > > are normally linked into the binary. This behaviour can cause issues if > > > > > > the PMD path and lib dir is configured to a non-standard location which is > > > > > > not in the ld.so.conf paths, e.g. a build with prefix set to a home > > > > > > directory location. In a case such as this, EAL will try and > > > > > > (unnecessarily) load the .so driver files but that load will fail as their > > > > > > dependent libraries, such as ethdev, for example, will not be found. > > > > > > > > > > > > Because of this, it is better if statically linked DPDK apps do not load > > > > > > drivers from the standard paths automatically. The user can always have > > > > > > this behaviour by explicitly specifying the path using -d flag, if so > > > > > > desired. > > > > > > > > > > > > Not loading the libraries automatically can also prevent potential issues > > > > > > with a user building and running a statically-linked DPDK binary based off > > > > > > a private copy of DPDK, while there exists on the same machine a > > > > > > system-wide installation of DPDK in the default locations. Without this > > > > > > change, the system-installed drivers will be loaded to the binary alongside > > > > > > the statically-linked drivers, which is not what the user would have > > > > > > intended. > > > > > > > > > > > > To detect whether we are in a statically or dynamically linked binary, we > > > > > > can have EAL try to get a dlopen handle to its own shared library, by > > > > > > calling dlopen with the RTLD_NOLOAD flag. This will return NULL if there is > > > > > > no such shared lib loaded i.e. the code is executing from a static library, > > > > > > or a handle to the lib if it is loaded. > > > > > > > > > > > > Signed-off-by: Bruce Richardson > > > > > > > > > > But what if the majority of the DPDK is statically linked but the > > > > > application wants also load a dynamically linked driver? > > > > > > > > > They use the -d flag as now. The only change here is that we don't > > > > *automatically* (and silently) attempt to load all drivers from a system > > > > location when you have a static binary. > > > > > > I'd also make a couple of additional points: > > > 1. If you have a static app and you have extra drivers in your EAL_PMD_PATH > > > directory you have no way of preventing the loading of them. > > > > > > 2. Since all DPDK apps try to load all files in that directory, all one has > > > to do is put a non-loadable file into the DPDK PMD directory and suddenly > > > all DPDK apps on the system will fail to run. [Patchset > > > http://patches.dpdk.org/project/dpdk/list/?series=10553 will also help > > > here] > > > > > > 3. Since this is a behaviour change, perhaps it needs to be deferred to > > > 20.11? Ideally I think we should fix this now, because I think the current > > > behaviour doesn't make sense and causes more problems than it solves, but > > > if it needs to be deferred, so be it. > > > > > > Thanks, just trying to poke the corners of this change. > > Please make sure the documentation and web site match the behavior. > > > > Acked-by: Stephen Hemminger > > This appears to be a gap, since I looked through the docs and couldn't find > any reference to this behaviour at all. However, I may well have missed > something so please flag if so. Yes we are lacking some doc around the basics of EAL (and also ethdev). This is a behaviour change, but I prefer applying it in 20.08, so we can get some user feedback before the LTS release. Applied, thanks