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=-11.7 required=3.0 tests=HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_PATCH,MAILING_LIST_MULTI, MENTIONS_GIT_HOSTING,SIGNED_OFF_BY,SPF_HELO_NONE,SPF_PASS,URIBL_BLOCKED autolearn=ham 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 232D9C43331 for ; Thu, 26 Mar 2020 10:09:04 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 032B520775 for ; Thu, 26 Mar 2020 10:09:03 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1727977AbgCZKIp (ORCPT ); Thu, 26 Mar 2020 06:08:45 -0400 Received: from Galois.linutronix.de ([193.142.43.55]:50200 "EHLO Galois.linutronix.de" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1726270AbgCZKIn (ORCPT ); Thu, 26 Mar 2020 06:08:43 -0400 Received: from [5.158.153.53] (helo=tip-bot2.lab.linutronix.de) by Galois.linutronix.de with esmtpsa (TLS1.2:DHE_RSA_AES_256_CBC_SHA256:256) (Exim 4.80) (envelope-from ) id 1jHPRE-00047r-Pu; Thu, 26 Mar 2020 11:08:36 +0100 Received: from [127.0.1.1] (localhost [IPv6:::1]) by tip-bot2.lab.linutronix.de (Postfix) with ESMTP id 5707A1C0440; Thu, 26 Mar 2020 11:08:36 +0100 (CET) Date: Thu, 26 Mar 2020 10:08:35 -0000 From: "tip-bot2 for Peter Zijlstra" Reply-to: linux-kernel@vger.kernel.org To: linux-tip-commits@vger.kernel.org Subject: [tip: core/objtool] objtool: Optimize find_section_by_index() Cc: "Peter Zijlstra (Intel)" , Miroslav Benes , Josh Poimboeuf , x86 , LKML In-Reply-To: <20200324160924.381249993@infradead.org> References: <20200324160924.381249993@infradead.org> MIME-Version: 1.0 Message-ID: <158521731598.28353.8097168736160020060.tip-bot2@tip-bot2> X-Mailer: tip-git-log-daemon Robot-ID: Robot-Unsubscribe: Contact to get blacklisted from these emails Content-Type: text/plain; charset="utf-8" Content-Transfer-Encoding: 7bit X-Linutronix-Spam-Score: -1.0 X-Linutronix-Spam-Level: - X-Linutronix-Spam-Status: No , -1.0 points, 5.0 required, ALL_TRUSTED=-1,SHORTCIRCUIT=-0.0001 Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org The following commit has been merged into the core/objtool branch of tip: Commit-ID: 530389968739883a61192767e1c215653ba4ba2b Gitweb: https://git.kernel.org/tip/530389968739883a61192767e1c215653ba4ba2b Author: Peter Zijlstra AuthorDate: Tue, 10 Mar 2020 18:43:35 +01:00 Committer: Peter Zijlstra CommitterDate: Wed, 25 Mar 2020 18:28:28 +01:00 objtool: Optimize find_section_by_index() In order to avoid a linear search (over 20k entries), add an section_hash to the elf object. This reduces objtool on vmlinux.o from a few minutes to around 45 seconds. Signed-off-by: Peter Zijlstra (Intel) Reviewed-by: Miroslav Benes Acked-by: Josh Poimboeuf Link: https://lkml.kernel.org/r/20200324160924.381249993@infradead.org --- tools/objtool/elf.c | 13 ++++++++----- tools/objtool/elf.h | 2 ++ 2 files changed, 10 insertions(+), 5 deletions(-) diff --git a/tools/objtool/elf.c b/tools/objtool/elf.c index ff29306..9007713 100644 --- a/tools/objtool/elf.c +++ b/tools/objtool/elf.c @@ -38,7 +38,7 @@ static struct section *find_section_by_index(struct elf *elf, { struct section *sec; - list_for_each_entry(sec, &elf->sections, list) + hash_for_each_possible(elf->section_hash, sec, hash, idx) if (sec->idx == idx) return sec; @@ -166,8 +166,6 @@ static int read_sections(struct elf *elf) INIT_LIST_HEAD(&sec->rela_list); hash_init(sec->rela_hash); - list_add_tail(&sec->list, &elf->sections); - s = elf_getscn(elf->elf, i); if (!s) { WARN_ELF("elf_getscn"); @@ -201,6 +199,9 @@ static int read_sections(struct elf *elf) } } sec->len = sec->sh.sh_size; + + list_add_tail(&sec->list, &elf->sections); + hash_add(elf->section_hash, &sec->hash, sec->idx); } if (stats) @@ -439,6 +440,7 @@ struct elf *elf_read(const char *name, int flags) memset(elf, 0, sizeof(*elf)); hash_init(elf->symbol_hash); + hash_init(elf->section_hash); INIT_LIST_HEAD(&elf->sections); elf->fd = open(name, flags); @@ -501,8 +503,6 @@ struct section *elf_create_section(struct elf *elf, const char *name, INIT_LIST_HEAD(&sec->rela_list); hash_init(sec->rela_hash); - list_add_tail(&sec->list, &elf->sections); - s = elf_newscn(elf->elf); if (!s) { WARN_ELF("elf_newscn"); @@ -579,6 +579,9 @@ struct section *elf_create_section(struct elf *elf, const char *name, shstrtab->len += strlen(name) + 1; shstrtab->changed = true; + list_add_tail(&sec->list, &elf->sections); + hash_add(elf->section_hash, &sec->hash, sec->idx); + return sec; } diff --git a/tools/objtool/elf.h b/tools/objtool/elf.h index 1222980..8c272eb 100644 --- a/tools/objtool/elf.h +++ b/tools/objtool/elf.h @@ -25,6 +25,7 @@ struct section { struct list_head list; + struct hlist_node hash; GElf_Shdr sh; struct list_head symbol_list; struct list_head rela_list; @@ -71,6 +72,7 @@ struct elf { char *name; struct list_head sections; DECLARE_HASHTABLE(symbol_hash, 20); + DECLARE_HASHTABLE(section_hash, 16); };