From mboxrd@z Thu Jan 1 00:00:00 1970 From: "Burakov, Anatoly" Subject: Re: [PATCH 0/3] generic channel for multi-process communication Date: Tue, 12 Dec 2017 16:18:15 +0000 Message-ID: <64576b41-8a5c-4949-9fc0-ceb2f2625657@intel.com> References: <1512067450-59203-1-git-send-email-jianfeng.tan@intel.com> <3b6c4096-b68b-d5e3-9dc3-f48fa99dba8e@intel.com> Mime-Version: 1.0 Content-Type: text/plain; charset=utf-8; format=flowed Content-Transfer-Encoding: 7bit Cc: "Richardson, Bruce" , "Ananyev, Konstantin" , "thomas@monjalon.net" To: "Tan, Jianfeng" , "dev@dpdk.org" Return-path: Received: from mga11.intel.com (mga11.intel.com [192.55.52.93]) by dpdk.org (Postfix) with ESMTP id C460D2B99 for ; Tue, 12 Dec 2017 17:18:18 +0100 (CET) In-Reply-To: Content-Language: en-US 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 12-Dec-17 7:34 AM, Tan, Jianfeng wrote: > Hi Anatoly, > >> -----Original Message----- >> From: Burakov, Anatoly >> Sent: Monday, December 11, 2017 6:00 PM >> To: Tan, Jianfeng; dev@dpdk.org >> Cc: Richardson, Bruce; Ananyev, Konstantin; thomas@monjalon.net >> Subject: Re: [PATCH 0/3] generic channel for multi-process communication >> >> On 30-Nov-17 6:44 PM, Jianfeng Tan wrote: >>> This patchset adds a generic channel for multi-process (primary/secondary) >>> communication. >>> >>> Patch 1: addess the purpose and howto; >>> Patch 2: add a syncrhonous way for those messages which need a response >> immediately. >>> Patch 3: Rework vfio to use this generic communication channel. >>> >> >> Hi Jianfeng, >> >> Just a general comment: I am assuming this has the limitation of >> "everything happens through primary process's involvement". This will >> work for VFIO, as secondary always needs to ask the primary before doing >> anything, but it doesn't address other issues that could have been >> addressed with IPC. >> >> For example, if a primary process would've hotplugged a device, it can't >> notify all secondary processes about this; rather, it has to wait until >> secondary processes ask for this info. > > No need to wait the secondary to pull such info. > > It can work like this: > (1) Register a hotplug callback for each process at initialization; > (2) Whenever a process wants to hotplug a device, it will broadcast the info, by broadcast, I mean: > - if plugin happens at the primary, the primary will tell all of the secondary processes; > - if plugin happens at one secondary, it will firstly tell the primary, and the primary will broadcast it to all the secondary process. > >> Neither can it do anything if >> secondary requests a primary to do something, and notify other secondary >> processes about it (i.e. if secondary wants to hotplug a device, but >> there are other secondaries also running). It would be great to have a >> standard way of doing things like this in future revisions of our IPC. > > Please review above thing; If you are OK with that, I'll include this in the next version. > > Thanks, > Jianfeng > >> >> -- >> Thanks, >> Anatoly Yes, that would work, my bad. However i don't think we necessarily need it right now. This can go in a separate patch. I was rather looking at other, future potential use cases, hotplug was just an example. -- Thanks, Anatoly