From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from out30-57.freemail.mail.aliyun.com ([115.124.30.57]:50419 "EHLO out30-57.freemail.mail.aliyun.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1726404AbgF2COH (ORCPT ); Sun, 28 Jun 2020 22:14:07 -0400 Content-Type: text/plain; charset=us-ascii Mime-Version: 1.0 (Mac OS X Mail 12.4 \(3445.104.11\)) Subject: Re: [PATCH v3 0/3] Build ORC fast lookup table in scripts/sorttable tool From: changhuaixin In-Reply-To: <20200603143945.64248-1-changhuaixin@linux.alibaba.com> Date: Mon, 29 Jun 2020 10:14:01 +0800 Content-Transfer-Encoding: 8BIT Message-Id: <217C22B3-D08F-4CB9-BC8D-3645C8389F5D@linux.alibaba.com> References: <20200601173840.3f36m6l4fsu5bill@treble> <20200603143945.64248-1-changhuaixin@linux.alibaba.com> Sender: linux-kbuild-owner@vger.kernel.org List-ID: To: jpoimboe@redhat.com Cc: changhuaixin , bp@alien8.de, hpa@zytor.com, linux-kbuild@vger.kernel.org, linux-kernel@vger.kernel.org, luto@amacapital.net, michal.lkml@markovi.net, mingo@redhat.com, Peter Zijlstra , tglx@linutronix.de, x86@kernel.org, yamada.masahiro@socionext.com Hi Josh, will you please have a look at this patchset? There might be another way to set SHT_PROGBITS of section .orc_lookup by writing section headers when orc_unwind and orc_unwind_ip tables are writen. It might be as follows: diff --git a/tools/objtool/orc_gen.c b/tools/objtool/orc_gen.c index 3f98dcfbc177..860d4dcec8e6 100644 --- a/tools/objtool/orc_gen.c +++ b/tools/objtool/orc_gen.c @@ -183,6 +183,10 @@ int create_orc_sections(struct objtool_file *file) u_sec = elf_create_section(file->elf, ".orc_unwind", sizeof(struct orc_entry), idx); + /* make flags of section orc_lookup right */ + if (!elf_create_section(file->elf, ".orc_lookup", sizeof(int), 0)) + return -1; + What do you think about this way of setting SHT_PROGBITS? > On Jun 3, 2020, at 10:39 PM, Huaixin Chang wrote: > > Move building of fast lookup table from boot to sorttable tool. This saves us > 6380us boot time on Intel(R) Xeon(R) CPU E5-2682 v4 @ 2.50GHz with cores. It > adds a little more than 7ms to boot time when testing on the same CPU. > > Changelog v3: > 1. Modify annotation of unwind_init(). > > Changelog v2: > 1. Type of section orc_lookup needs to be SHT_PROGBITS. > 2. unwind_init() cannot be removed totally as setting lookup_num_blocks is needed. > > Huaixin Chang (3): > scripts/sorttable: Change section type of orc_lookup to SHT_PROGBITS > scripts/sorttable: Build orc fast lookup table via sorttable tool > x86/unwind/orc: Simplify unwind_init() for x86 boot > > arch/x86/kernel/unwind_orc.c | 41 +--------------- > include/asm-generic/vmlinux.lds.h | 2 + > scripts/sorttable.h | 99 ++++++++++++++++++++++++++++++++++++--- > 3 files changed, 96 insertions(+), 46 deletions(-) > > -- > 2.14.4.44.g2045bb6