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=-2.2 required=3.0 tests=HEADER_FROM_DIFFERENT_DOMAINS, MAILING_LIST_MULTI,SPF_HELO_NONE,SPF_PASS,USER_AGENT_SANE_2 autolearn=no 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 39EAFC5DF62 for ; Tue, 5 Nov 2019 17:26:38 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 1CB1E2190F for ; Tue, 5 Nov 2019 17:26:38 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S2390330AbfKER0h (ORCPT ); Tue, 5 Nov 2019 12:26:37 -0500 Received: from smtprelay0084.hostedemail.com ([216.40.44.84]:56089 "EHLO smtprelay.hostedemail.com" rhost-flags-OK-OK-OK-FAIL) by vger.kernel.org with ESMTP id S2390230AbfKER0h (ORCPT ); Tue, 5 Nov 2019 12:26:37 -0500 Received: from filter.hostedemail.com (clb03-v110.bra.tucows.net [216.40.38.60]) by smtprelay05.hostedemail.com (Postfix) with ESMTP id C627018029583; Tue, 5 Nov 2019 17:26:35 +0000 (UTC) X-Session-Marker: 726F737465647440676F6F646D69732E6F7267 X-HE-Tag: use48_7378f45ee6904 X-Filterd-Recvd-Size: 3241 Received: from grimm.local.home (unknown [146.247.46.6]) (Authenticated sender: rostedt@goodmis.org) by omf01.hostedemail.com (Postfix) with ESMTPA; Tue, 5 Nov 2019 17:26:33 +0000 (UTC) Date: Tue, 5 Nov 2019 12:26:29 -0500 From: Steven Rostedt To: Alexei Starovoitov Cc: Alexei Starovoitov , davem@davemloft.net, daniel@iogearbox.net, peterz@infradead.org, x86@kernel.org, netdev@vger.kernel.org, bpf@vger.kernel.org, kernel-team@fb.com, Thomas Gleixner , Linus Torvalds Subject: Re: [PATCH bpf-next 0/7] Introduce BPF trampoline Message-ID: <20191105122629.29aecc69@grimm.local.home> In-Reply-To: <20191105162801.sffoqe2yedrrplnn@ast-mbp.dhcp.thefacebook.com> References: <20191102220025.2475981-1-ast@kernel.org> <20191105143154.umojkotnvcx4yeuq@ast-mbp.dhcp.thefacebook.com> <20191105104024.4e99a630@grimm.local.home> <20191105154709.utmzm6qvtlux4hww@ast-mbp.dhcp.thefacebook.com> <20191105110028.7775192f@grimm.local.home> <20191105162801.sffoqe2yedrrplnn@ast-mbp.dhcp.thefacebook.com> X-Mailer: Claws Mail 3.17.4git49 (GTK+ 2.24.32; x86_64-pc-linux-gnu) MIME-Version: 1.0 Content-Type: text/plain; charset=US-ASCII Content-Transfer-Encoding: 7bit Sender: netdev-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: netdev@vger.kernel.org On Tue, 5 Nov 2019 08:28:02 -0800 Alexei Starovoitov wrote: > On Tue, Nov 05, 2019 at 11:00:28AM -0500, Steven Rostedt wrote: > > On Tue, 5 Nov 2019 07:47:11 -0800 > > Alexei Starovoitov wrote: > > > > > > If you have to wait you may need to wait. The Linux kernel isn't > > > > something that is suppose to put in temporary hacks, just to satisfy > > > > someone's deadline. > > > > > > Ok. I will switch to text_poke and will make it hack free. > > > ftrace mechanisms are being replaced by text_poke anyway. > > > > I see that Facebook now owns Linux. > > huh? Sorry, I'm a bit grumpy. I've been non stop for over a week (7 days of conferences), and I'm still not done traveling yet. :-p > > > Peter's text poke patches most likely not be ready for the next > > merge window either. Don't you require them? > > nope. > But I strongly support them. ftrace->text_poke + static_call + nop2 > are all great improvements. > I'd really like to see them landing in this merge window. > > > The database of function nops are part of the ftrace mechanisms which > > are not part of text poke, and there's strong accounting associated to > > them which allows the user to see how their kernel is modified. > > I guess the part that wasn't obvious from commit log of bpf trampoline patches > is that they don't care about nops and ftrace recording of nops. bpf trampoline > will work even if there are no nops in front of the function. It will work when > CONFIG_HAVE_FENTRY is off. I'm guessing it will use kprobes (or optimized probes). I haven't had a chance to look at your patches. I still think using the register_ftrace_direct() will be cleaner (as it is built on top of code that's been in the kernel for a decade). Perhaps we can make it work even without the full ftrace code. -- Steve