From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-5.8 required=3.0 tests=DKIMWL_WL_HIGH,DKIM_SIGNED, DKIM_VALID,HEADER_FROM_DIFFERENT_DOMAINS,MAILING_LIST_MULTI, MENTIONS_GIT_HOSTING,SPF_HELO_NONE,SPF_PASS,URIBL_BLOCKED autolearn=ham autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id 27233C2D0B1 for ; Thu, 6 Feb 2020 07:04:47 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id EAEF7214AF for ; Thu, 6 Feb 2020 07:04:46 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1580972687; bh=4ysceoC63lI7xZahrtI8MfuoiltYgZmmut3aPCCS7QM=; h=Date:From:To:Cc:Subject:References:In-Reply-To:List-ID:From; b=F1xb9C59DGk7A0CmSK/jRAC2ZI1xOLELgPmg84fBNHbt0vARz+iujVBywLBZwWTEA dZLP+qTK5AjqXF4VexRqxRV+nQ49zRmNpuMGOeEf+XbAnpk4OMmtMluch0Dot4c4gW smzG+xgy2Pvk+nsjiz97W2hkN+/2WGhV58lQKZTY= Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1727860AbgBFHEq (ORCPT ); Thu, 6 Feb 2020 02:04:46 -0500 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 Received: from localhost (unknown [213.123.58.114]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by mail.kernel.org (Postfix) with ESMTPSA id BBF4D206CC; Thu, 6 Feb 2020 07:04:43 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1580972684; bh=4ysceoC63lI7xZahrtI8MfuoiltYgZmmut3aPCCS7QM=; h=Date:From:To:Cc:Subject:References:In-Reply-To:From; b=UGLqbwHFmGySWcxx4pWEb8R7MFA16FMLf3OizEgIAo77WwycU9zgScTRvIn3RyZh6 s8jfUnt+nBAZ2HDLP1MJeEDzyhwl6LZv07NdamLUT6SOWAy58tBxzn+IUqc8saCYJZ BYydv0KBEYtSF6UoQDZ7VA38WQ/pHoksW2yWkohc= Date: Thu, 6 Feb 2020 07:04:41 +0000 From: Greg Kroah-Hartman 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 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-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org 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