From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mail.kernel.org ([198.145.29.99]:43902 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1727358AbgBFHEp (ORCPT ); Thu, 6 Feb 2020 02:04:45 -0500 Date: Thu, 6 Feb 2020 07:04:41 +0000 From: Greg Kroah-Hartman Subject: Re: [PATCH] Revert kheaders feature Message-ID: <20200206070441.GB3265390@kroah.com> References: <20200205154629.GA1257054@kroah.com> <20200205160250.GG142103@google.com> <20200205171353.GI142103@google.com> <20200205213354.GB1465126@kroah.com> <20200205214841.GB1468203@kroah.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: Sender: linux-kbuild-owner@vger.kernel.org List-ID: To: Joel Fernandes Cc: Olof Johansson , Alexei Starovoitov , Masahiro Yamada , Michal Marek , Jonathan Corbet , Thomas Gleixner , Tejun Heo , Mauro Carvalho Chehab , David Howells , Patrick Bellasi , Krzysztof Kozlowski , linux-kbuild@vger.kernel.org, "open list:DOCUMENTATION" , Linux Kernel Mailing List On Wed, Feb 05, 2020 at 01:53:15PM -0800, Joel Fernandes wrote: > On Wed, Feb 5, 2020 at 1:48 PM Greg Kroah-Hartman > wrote: > > > > On Wed, Feb 05, 2020 at 01:35:56PM -0800, Joel Fernandes wrote: > > > On Wed, Feb 5, 2020 at 1:33 PM Greg Kroah-Hartman > > > wrote: > > > [snip] > > > > > > like the BTF approach is significantly better and said users are > > > > > > hopefully moving forward to it quickly, and if they can't move > > > > > > forward, then they're likely also not going to move forward to newer > > > > > > kernels either? > > > > > > > > > > I think BCC runs on a lot of upstream machines. I think the migration > > > > > strategy is a matter of opinion, one way is to take it out and cause some > > > > > pain in the hope that users/tools will migrate soon (while probably carrying > > > > > the reverted patches out of tree). Another is to migrate the tools first and > > > > > then take it out (which has its own disadvantages such as introducing even > > > > > more users of it while it is still upstream). > > > > > > > > Do we "know" what tools today require this, and what needs to be done to > > > > "fix" them? If we don't know that, then there's no way to drop this, > > > > pretty much ever :( > > > > > > Is there a real reason to drop it or a problem dropping this solves though? > > > > Olof had some reasons, but as we were drinking at the time when it came > > up last night, I can't really remember them specifically. Hopefully he > > does :) > > But that didn't answer my question of "who is still using this"? I was > > hoping we actually knew this given it was created for specific users. > > I think I mentioned this in a previous thread of this email. Several > BCC tools are using it - see for example the criticalstat BCC tool > which includes linux/sched.h : > https://github.com/iovisor/bcc/blob/master/tools/criticalstat.py#L73 > , or filetop BCC tool which uses struct dentry : > https://github.com/iovisor/bcc/blob/master/tools/filetop.py#L101 > > These would break without kernel headers either on the host or via > CONFIG_IKHEADERS. Ah, ok, then this can't work just yet. If those get fixed up, then we can do this. thanks for the info, nevermind about this patch :( greg k-h