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=-5.2 required=3.0 tests=BAYES_00, 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 F03A3C433FE for ; Thu, 10 Dec 2020 02:32:25 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id B9D4123C81 for ; Thu, 10 Dec 2020 02:32:25 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1728595AbgLJCcV (ORCPT ); Wed, 9 Dec 2020 21:32:21 -0500 Received: from mail.kernel.org ([198.145.29.99]:39936 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1728679AbgLJCcL (ORCPT ); Wed, 9 Dec 2020 21:32:11 -0500 Received: from oasis.local.home (cpe-66-24-58-225.stny.res.rr.com [66.24.58.225]) (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 7EC5E23C43; Thu, 10 Dec 2020 02:31:28 +0000 (UTC) Date: Wed, 9 Dec 2020 21:31:26 -0500 From: Steven Rostedt To: Alexei Starovoitov Cc: Christoph Hellwig , Stanislaw Gruszka , Matthew Wilcox , Michal Kubecek , Justin Forbes , bpf , Alex Shi , Andrew Morton , Souptick Joarder , Linux-MM , LKML , Alexei Starovoitov , Daniel Borkmann , Josef Bacik Subject: Re: [PATCH] mm/filemap: add static for function __add_to_page_cache_locked Message-ID: <20201209213126.79ca1326@oasis.local.home> In-Reply-To: References: <20201207081556.pwxmhgdxayzbofpi@lion.mk-sys.cz> <20201207225351.2liywqaxxtuezzw3@lion.mk-sys.cz> <20201209144628.GA3474@wp.pl> <20201209150826.GP7338@casper.infradead.org> <20201209155148.GA5552@wp.pl> <20201209180552.GA28692@infradead.org> <20201209223206.GA1935@home.goodmis.org> X-Mailer: Claws Mail 3.17.3 (GTK+ 2.24.32; x86_64-pc-linux-gnu) MIME-Version: 1.0 Content-Type: text/plain; charset=US-ASCII Content-Transfer-Encoding: 7bit Precedence: bulk List-ID: X-Mailing-List: bpf@vger.kernel.org On Wed, 9 Dec 2020 17:12:43 -0800 Alexei Starovoitov wrote: > > > > > FWIW, I intend to do some consolidation/renaming in this area. I > > > > > trust that will not be a problem? > > > > > > > > If it does not break anything, it will be not a problem ;-) > > > > > > > > It's possible that __add_to_page_cache_locked() can be a global symbol > > > > with add_to_page_cache_lru() + add_to_page_cache_locked() being just > > > > static/inline wrappers around it. > > > > > > So what happens to BTF if we change this area entirely? Your IDs > > > sound like some kind of ABI to me, which is extremely scary. > > > > Is BTF becoming the new tracepoint? That is, random additions of things like: > > > > BTF_ID(func,__add_to_page_cache_locked) > > > > Like was done in commit 1e6c62a882155 ("bpf: Introduce sleepable BPF > > programs") without any notification to the maintainers of the > > __add_to_page_cache_locked code, will suddenly become an API? > > huh? what api/abi you're talking about? If the function __add_to_page_cache_locked were to be removed due to the code being rewritten, would it break any user space? If not, then there's nothing to worry about. ;-) -- Steve