From mboxrd@z Thu Jan 1 00:00:00 1970 From: Daniel Borkmann Subject: Re: [RFC PATCH net-next 1/2] bpf: Save original ebpf instructions Date: Fri, 03 Feb 2017 22:09:46 +0100 Message-ID: <5894F19A.60305@iogearbox.net> References: <1486154303-32278-1-git-send-email-dsa@cumulusnetworks.com> <1486154303-32278-2-git-send-email-dsa@cumulusnetworks.com> Mime-Version: 1.0 Content-Type: text/plain; charset=windows-1252; format=flowed Content-Transfer-Encoding: 7bit Cc: roopa@cumulusnetworks.com To: David Ahern , netdev@vger.kernel.org, alexei.starovoitov@gmail.com Return-path: Received: from www62.your-server.de ([213.133.104.62]:37832 "EHLO www62.your-server.de" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752530AbdBCVJ7 (ORCPT ); Fri, 3 Feb 2017 16:09:59 -0500 In-Reply-To: <1486154303-32278-2-git-send-email-dsa@cumulusnetworks.com> Sender: netdev-owner@vger.kernel.org List-ID: On 02/03/2017 09:38 PM, David Ahern wrote: > Similar to classic bpf, support saving original ebpf instructions > > Signed-off-by: David Ahern Not convinced that this is in the right direction, this not only *significantly* increases mem footprint for each and every program, but also when you dump this, then map references from relocs inside the insns are meaningless (f.e. what about prog arrays used in tail calls?), so things like criu also won't be able to use this kind of interface for dump and restore. If it's just for debugging, then why not extend the existing tracing infrastructure around bpf that was started with intention to gain more visibility. Thanks, Daniel