From patchwork Thu Mar 16 14:31:09 2017 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Arnd Bergmann X-Patchwork-Id: 9628603 Return-Path: Received: from mail.wl.linuxfoundation.org (pdx-wl-mail.web.codeaurora.org [172.30.200.125]) by pdx-korg-patchwork.web.codeaurora.org (Postfix) with ESMTP id 75B3C604AA for ; Thu, 16 Mar 2017 15:11:11 +0000 (UTC) Received: from mail.wl.linuxfoundation.org (localhost [127.0.0.1]) by mail.wl.linuxfoundation.org (Postfix) with ESMTP id 66E6020243 for ; Thu, 16 Mar 2017 15:11:11 +0000 (UTC) Received: by mail.wl.linuxfoundation.org (Postfix, from userid 486) id 59B89285EE; Thu, 16 Mar 2017 15:11:11 +0000 (UTC) X-Spam-Checker-Version: SpamAssassin 3.3.1 (2010-03-16) on pdx-wl-mail.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-6.4 required=2.0 tests=BAYES_00, RCVD_IN_DNSWL_HI, RCVD_IN_SORBS_SPAM autolearn=ham version=3.3.1 Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.wl.linuxfoundation.org (Postfix) with ESMTP id DEE9028537 for ; Thu, 16 Mar 2017 15:11:10 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1753068AbdCPPJO (ORCPT ); Thu, 16 Mar 2017 11:09:14 -0400 Received: from mout.kundenserver.de ([212.227.126.130]:61060 "EHLO mout.kundenserver.de" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751763AbdCPOcq (ORCPT ); Thu, 16 Mar 2017 10:32:46 -0400 Received: from wuerfel.lan ([78.42.17.5]) by mrelayeu.kundenserver.de (mreue001 [212.227.15.129]) with ESMTPA (Nemesis) id 0LbUlf-1cLUDO3R1P-00lC9R; Thu, 16 Mar 2017 15:32:05 +0100 From: Arnd Bergmann To: Masahiro Yamada Cc: Michal Marek , Arnd Bergmann , linux-kbuild@vger.kernel.org, linux-kernel@vger.kernel.org Subject: [PATCH] kbuild: fix compile time regression Date: Thu, 16 Mar 2017 15:31:09 +0100 Message-Id: <20170316143124.1513546-1-arnd@arndb.de> X-Mailer: git-send-email 2.9.0 In-Reply-To: References: X-Provags-ID: V03:K0:nzE4lK/QdXwp+UYU2OejDMBb5NDTd5d3mGjjsukR+JLgJIqZ1uN 0+Mi40pVa6n2181u+EGzUtW1IgaO29qnU04a/R3xKHJL1gIfb+MzDf4tn52tezgBfoXY1zc 4exAnFZICIItE+Nb+3SBHEsDsqXk11EmgoalKSdQYMPvgne+SLaGD+4Nsst010LFsMV6u2d Oz0wAoSGZvL/EC8UTewWg== X-UI-Out-Filterresults: notjunk:1; V01:K0:NUZ/LP37QgA=:ZEmliZKVSIlpuq9lyowjg3 RXF9YV9MRlnZkCKn5JyE+8CzfWSXk6z4QfVozYOcVvVEAqoVJ52Rt4gFBOY/8BoK9dpvPQHJ9 IpzA/KPurlOI8FdtOrh4Y+Bw53GK23q5KhxbRW5CLqz2szwjLHpatQxQfKxRYyxPAhNm5WbuY PzXb2KWyFwV7A5DDxDmi4w8EB+SQaOMlY5sy5vkqXHzy9uZOU0HCBr3aCCwhhiNc0vjQ/DDn8 z6xdtigBCpTqjXeDdZUZn8bzBKS89aEUCf00H1RwYWP7sHE79eMQJIE3AfoInYfx8AZHd7W7f bVvRPtuSB//W5qjeP+qlxADQbEQGIqmPvrTBu8ms2MHmASqa8viTwE9xawlry7m92pYNf6rXZ DB2/7gVkbgjQtyFq9+/Fdo5RStsjQDxybXZ5BHrRVC+RHoQAmtIXvk137wpikAzAIIpGR7S/h ygwdPcHZIT81De8p8E3x2tGeDaT7ioe890p1qAriad9mJ+fHXmHe3TZ+jDow0bqs2YJLDDjMU 5GjKDFaKxE5ep4Dvu2/k29v6uJykmfCeXsiOWdp0YPPmi84G2jkzSIfDYSfMlHB0sESDJWk+B EgZ/JhvULF4PcT3GO2SqdiodAooN0JhvDhXokqnSt7t1dJM/fZHhdCwfj0WS1ONszDEA3pO6E 4g1932xbpdgb0oHUWGNos5kDT3EIhBZFtfmx6a5jn9Efa5OF72CZK5xNVV19TSShSBXw= Sender: linux-kbuild-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kbuild@vger.kernel.org X-Virus-Scanned: ClamAV using ClamSMTP I noticed that a patch I did causes the time for a clean rebuild to go up significantly, from 13 to 18 seconds on ARM defconfig, and in the worst case forcing a rebuild of every file each time. The fix is very simple, using a ':=' assignment instead of '=' to force the cc-disable-warning call to only be evaluated once instead of every time. Signed-off-by: Arnd Bergmann --- Makefile | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) diff --git a/Makefile b/Makefile index 3a964fa3a787..e7d4d20deb4e 100644 --- a/Makefile +++ b/Makefile @@ -381,7 +381,7 @@ LDFLAGS_MODULE = CFLAGS_KERNEL = AFLAGS_KERNEL = LDFLAGS_vmlinux = -CFLAGS_GCOV = -fprofile-arcs -ftest-coverage -fno-tree-loop-im $(call cc-disable-warning,maybe-uninitialized,) +CFLAGS_GCOV := -fprofile-arcs -ftest-coverage -fno-tree-loop-im $(call cc-disable-warning,maybe-uninitialized,) CFLAGS_KCOV := $(call cc-option,-fsanitize-coverage=trace-pc,) ifeq ($(COMPILER),clang)