From patchwork Thu Apr 4 18:44:11 2019 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Miroslav Benes X-Patchwork-Id: 10886087 Return-Path: Received: from mail.wl.linuxfoundation.org (pdx-wl-mail.web.codeaurora.org [172.30.200.125]) by pdx-korg-patchwork-2.web.codeaurora.org (Postfix) with ESMTP id 6AB251708 for ; Thu, 4 Apr 2019 18:44:30 +0000 (UTC) Received: from mail.wl.linuxfoundation.org (localhost [127.0.0.1]) by mail.wl.linuxfoundation.org (Postfix) with ESMTP id 5469328AD2 for ; Thu, 4 Apr 2019 18:44:30 +0000 (UTC) Received: by mail.wl.linuxfoundation.org (Postfix, from userid 486) id 52AE128AF2; Thu, 4 Apr 2019 18:44:30 +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=-7.9 required=2.0 tests=BAYES_00,MAILING_LIST_MULTI, RCVD_IN_DNSWL_HI 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 CD7E928AFA for ; Thu, 4 Apr 2019 18:44:29 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1729456AbfDDSo3 (ORCPT ); Thu, 4 Apr 2019 14:44:29 -0400 Received: from mx2.suse.de ([195.135.220.15]:51958 "EHLO mx1.suse.de" rhost-flags-OK-OK-OK-FAIL) by vger.kernel.org with ESMTP id S1728934AbfDDSo3 (ORCPT ); Thu, 4 Apr 2019 14:44:29 -0400 X-Virus-Scanned: by amavisd-new at test-mx.suse.de Received: from relay2.suse.de (unknown [195.135.220.254]) by mx1.suse.de (Postfix) with ESMTP id 8B69BAF19; Thu, 4 Apr 2019 18:44:27 +0000 (UTC) From: Miroslav Benes To: yamada.masahiro@socionext.com, michal.lkml@markovi.net, jpoimboe@redhat.com, pmladek@suse.com, jikos@kernel.org Cc: joe.lawrence@redhat.com, ggherdovich@suse.cz, linux-kbuild@vger.kernel.org, live-patching@vger.kernel.org, linux-kernel@vger.kernel.org, Miroslav Benes Subject: [PATCH v2] kbuild: use -flive-patching when CONFIG_LIVEPATCH is enabled Date: Thu, 4 Apr 2019 20:44:11 +0200 Message-Id: <20190404184411.1392-1-mbenes@suse.cz> X-Mailer: git-send-email 2.21.0 MIME-Version: 1.0 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 GCC 9 introduces a new option, -flive-patching. It disables certain optimizations which could make a compilation unsafe for later live patching of the running kernel. The option is used only if CONFIG_LIVEPATCH is enabled and $(CC) supports it. Performance impact of the option was measured on three different Intel machines - two bigger NUMA boxes and one smaller UMA box. Kernel intensive (IO, scheduling, networking) benchmarks were selected, plus a set of HPC workloads from NAS Parallel Benchmark. The tests were done on upstream kernel 5.0-rc8 with openSUSE Leap 15.0 userspace. The majority of the tests is unaffected. The only significant exception is the scheduler section which suffers 1-3% degradation. Evaluated-by: Giovanni Gherdovich Signed-off-by: Miroslav Benes Acked-by: Josh Poimboeuf --- The patch is based on master branch of the livepatching tree on git.kernel.org. Many thanks to Giovanni who ran the whole testing campaign and analyzed the results. I archived the dashboard and detailed data. If anyone is interested, we could probably set up a public website somewhere. Makefile | 4 ++++ 1 file changed, 4 insertions(+) diff --git a/Makefile b/Makefile index f070e0d65186..464a693a22e9 100644 --- a/Makefile +++ b/Makefile @@ -789,6 +789,10 @@ KBUILD_CFLAGS_KERNEL += -ffunction-sections -fdata-sections LDFLAGS_vmlinux += --gc-sections endif +ifdef CONFIG_LIVEPATCH +KBUILD_CFLAGS += $(call cc-option, -flive-patching=inline-clone) +endif + # arch Makefile may override CC so keep this after arch Makefile is included NOSTDINC_FLAGS += -nostdinc -isystem $(shell $(CC) -print-file-name=include)