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=-3.8 required=3.0 tests=DKIM_SIGNED,DKIM_VALID, HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_PATCH,MAILING_LIST_MULTI,SPF_HELO_NONE, SPF_PASS,URIBL_BLOCKED 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 8107FC433FF for ; Wed, 31 Jul 2019 08:55:25 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 554A620693 for ; Wed, 31 Jul 2019 08:55:25 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (2048-bit key) header.d=nifty.com header.i=@nifty.com header.b="pgdq/SN9" Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1727962AbfGaIzY (ORCPT ); Wed, 31 Jul 2019 04:55:24 -0400 Received: from conssluserg-03.nifty.com ([210.131.2.82]:64931 "EHLO conssluserg-03.nifty.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1726410AbfGaIzX (ORCPT ); Wed, 31 Jul 2019 04:55:23 -0400 Received: from mail-vs1-f42.google.com (mail-vs1-f42.google.com [209.85.217.42]) (authenticated) by conssluserg-03.nifty.com with ESMTP id x6V8svpa012390; Wed, 31 Jul 2019 17:54:59 +0900 DKIM-Filter: OpenDKIM Filter v2.10.3 conssluserg-03.nifty.com x6V8svpa012390 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=nifty.com; s=dec2015msa; t=1564563299; bh=+6VnkpjvIjwaRHB0EeFGcKCol1oBBgahP6+w4Ilp5Ew=; h=References:In-Reply-To:From:Date:Subject:To:Cc:From; b=pgdq/SN9RbWGSQz3b8aGMAR8L2MbVAlrkSAAgdgTJa3jfQWnkDJwSrrLJYF8zpSCs EmdSBg6XovFX19J8SuDfbc/mXjJ9DTPsw+qXzf2QNpvLishtsNZC3aUgfac9JrBo6b uuV32vyCE0jJ0Ikqu95O/e1C4U8A06iPML4Z8Y7sMY8R3Pmv4CCTB523c9ZjmH043Y Z+yVaEgpIHFoAPMVSlEOenQMhVmXpRhbvlA3zcZDWIiq1sDVlzWO1jgvhqU9XrrMIp 6e703X87sTezCQuKtNOOm7M1U3fmnNQg/B+WoZdwb3oE3WQfaxa2z1GYd30Egr2O+M DaRYXo/+xHZ5A== X-Nifty-SrcIP: [209.85.217.42] Received: by mail-vs1-f42.google.com with SMTP id v129so45633200vsb.11; Wed, 31 Jul 2019 01:54:59 -0700 (PDT) X-Gm-Message-State: APjAAAUPliwwn6t0H1+Ugi0v1r0I0DBQA8jNx4zueVbn7PZe42XXN1mX 2gmot+pqpZRDjPmvPxoUm/3PLfq5r8jRfVXjWco= X-Google-Smtp-Source: APXvYqzNOUYxH3dkGmr5NVvz1LQM4uZuveEacwZhA0iB2msRv4KMUeu7A2oJHRpRDrWs9bSGwiKRG4QieuuK5VNqiPo= X-Received: by 2002:a67:fc45:: with SMTP id p5mr14825701vsq.179.1564563296511; Wed, 31 Jul 2019 01:54:56 -0700 (PDT) MIME-Version: 1.0 References: <20190714152817.24693-1-efremov@linux.com> <20190730181146.6507-1-efremov@linux.com> In-Reply-To: <20190730181146.6507-1-efremov@linux.com> From: Masahiro Yamada Date: Wed, 31 Jul 2019 17:54:19 +0900 X-Gmail-Original-Message-ID: Message-ID: Subject: Re: [PATCH v4] modpost: check for static EXPORT_SYMBOL* functions To: Denis Efremov Cc: Michal Marek , Emil Velikov , Stephen Rothwell , Linux Kbuild mailing list , Linux Kernel Mailing List Content-Type: text/plain; charset="UTF-8" Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Hi. On Wed, Jul 31, 2019 at 3:12 AM Denis Efremov wrote: > > This patch adds a check to warn about static EXPORT_SYMBOL* functions > during the modpost. In most of the cases, a static symbol marked for > exporting is an odd combination that should be fixed either by deleting > the exporting mark or by removing the static attribute and adding the > appropriate declaration to headers. > > This check could help to detect the following problems: > 1. 550113d4e9f5 ("i2c: add newly exported functions to the header, too") > 2. 54638c6eaf44 ("net: phy: make exported variables non-static") > 3. 98ef2046f28b ("mm: remove the exporting of totalram_pages") > 4. 73df167c819e ("s390/zcrypt: remove the exporting of ap_query_configuration") > 5. a57caf8c527f ("sunrpc/cache: remove the exporting of cache_seq_next") > 6. e4e4730698c9 ("crypto: skcipher - remove the exporting of skcipher_walk_next") > 7. 14b4c48bb1ce ("gve: Remove the exporting of gve_probe") > 8. 9b79ee9773a8 ("scsi: libsas: remove the exporting of sas_wait_eh") > 9. ... > > Build time impact, allmodconfig, Dell XPS 15 9570 (measurements 3x): > $ make mrproper; make allmodconfig; time make -j12; \ > git checkout HEAD~1; \ > make mrproper; make allmodconfig; time make -j12 > 1. > (with patch) 17635,94s user 1895,54s system 1085% cpu 29:59,22 total > (w/o patch) 17275,42s user 1803,87s system 1112% cpu 28:35,66 total > 2. > (with patch) 17369,51s user 1763,28s system 1111% cpu 28:41,47 total > (w/o patch) 16880,50s user 1670,93s system 1113% cpu 27:46,56 total > 3. > (with patch) 17937,88s user 1842,53s system 1109% cpu 29:42,26 total > (w/o patch) 17267,55s user 1725,09s system 1111% cpu 28:28,17 total > > The check adds less than a minute to a usual build. I am not convinced with this analysis. Since commit b7dca6dd1e591ad19, scripts/mod/modpost is only invoked from scripts/Makefile.modpost. So, it is much easier to to measure the elapsed time of modpost directly. I applied your patch on top next-20190731, and the following: diff --git a/scripts/Makefile.modpost b/scripts/Makefile.modpost index 92ed02d7cd5e..e0db1a626e50 100644 --- a/scripts/Makefile.modpost +++ b/scripts/Makefile.modpost @@ -98,7 +98,7 @@ MODPOST += $(subst -i,-n,$(filter -i,$(MAKEFLAGS))) -s -T - $(wildcard vmlinux) # We can go over command line length here, so be careful. quiet_cmd_modpost = MODPOST $(words $(modules)) modules - cmd_modpost = sed 's/ko$$/o/' $(modorder) | $(MODPOST) + cmd_modpost = sed 's/ko$$/o/' $(modorder) | time -o modpost-time.txt $(MODPOST) PHONY += modules-modpost modules-modpost: The difference is less than 1 sec (not 1 min!) even for allmodconfig. So, the performance regression is almost unnoticeable level. -- Best Regards Masahiro Yamada