From patchwork Tue Sep 20 07:13:09 2022 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Zhen Lei X-Patchwork-Id: 12981456 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by smtp.lore.kernel.org (Postfix) with ESMTP id A77CEC54EE9 for ; Tue, 20 Sep 2022 07:14:22 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S229812AbiITHOV (ORCPT ); Tue, 20 Sep 2022 03:14:21 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:39528 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S229667AbiITHOU (ORCPT ); Tue, 20 Sep 2022 03:14:20 -0400 Received: from szxga03-in.huawei.com (szxga03-in.huawei.com [45.249.212.189]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id C00D35C357; Tue, 20 Sep 2022 00:14:18 -0700 (PDT) Received: from dggpemm500020.china.huawei.com (unknown [172.30.72.54]) by szxga03-in.huawei.com (SkyGuard) with ESMTP id 4MWt5h3pjlzHp0v; Tue, 20 Sep 2022 15:12:08 +0800 (CST) Received: from dggpemm500006.china.huawei.com (7.185.36.236) by dggpemm500020.china.huawei.com (7.185.36.49) with Microsoft SMTP Server (version=TLS1_2, cipher=TLS_ECDHE_RSA_WITH_AES_128_GCM_SHA256) id 15.1.2375.31; Tue, 20 Sep 2022 15:14:16 +0800 Received: from thunder-town.china.huawei.com (10.174.178.55) by dggpemm500006.china.huawei.com (7.185.36.236) with Microsoft SMTP Server (version=TLS1_2, cipher=TLS_ECDHE_RSA_WITH_AES_128_GCM_SHA256) id 15.1.2375.31; Tue, 20 Sep 2022 15:14:16 +0800 From: Zhen Lei To: Josh Poimboeuf , Jiri Kosina , Miroslav Benes , Petr Mladek , Joe Lawrence , , , Masahiro Yamada , Alexei Starovoitov , Jiri Olsa , Kees Cook , Andrew Morton , "Luis Chamberlain" , CC: Zhen Lei Subject: [PATCH v4 0/8] kallsyms: Optimizes the performance of lookup symbols Date: Tue, 20 Sep 2022 15:13:09 +0800 Message-ID: <20220920071317.1787-1-thunder.leizhen@huawei.com> X-Mailer: git-send-email 2.26.0.windows.1 MIME-Version: 1.0 X-Originating-IP: [10.174.178.55] X-ClientProxiedBy: dggems705-chm.china.huawei.com (10.3.19.182) To dggpemm500006.china.huawei.com (7.185.36.236) X-CFilter-Loop: Reflected Precedence: bulk List-ID: v3 --> v4: 1. Move the declaration of function kallsyms_sym_address() to linux/kallsyms.h, fix a build warning. v2 --> v3: 1. Improve test cases, perform complete functional tests on functions kallsyms_lookup_name(), kallsyms_on_each_symbol() and kallsyms_on_each_match_symbol(). 2. Add patch [PATCH v3 2/8] scripts/kallsyms: ensure that all possible combinations are compressed. 3. The symbol type is not compressed regardless of whether CONFIG_KALLSYMS_ALL is set or not. The memory overhead is increased by less than 20KiB if CONFIG_KALLSYMS_ALL=n. 4. Discard [PATCH v2 3/8] kallsyms: Adjust the types of some local variables v1 --> v2: Add self-test facility v1: Currently, to search for a symbol, we need to expand the symbols in 'kallsyms_names' one by one, and then use the expanded string for comparison. This is very slow. In fact, we can first compress the name being looked up and then use it for comparison when traversing 'kallsyms_names'. This patch series optimizes the performance of function kallsyms_lookup_name(), and function klp_find_object_symbol() in the livepatch module. Based on the test results, the performance overhead is reduced to 5%. That is, the performance of these functions is improved by 20 times. To avoid increasing the kernel size in non-debug mode, the optimization is only for the case CONFIG_KALLSYMS_ALL=y. Zhen Lei (8): scripts/kallsyms: rename build_initial_tok_table() scripts/kallsyms: ensure that all possible combinations are compressed scripts/kallsyms: don't compress symbol types kallsyms: Improve the performance of kallsyms_lookup_name() kallsyms: Add helper kallsyms_on_each_match_symbol() livepatch: Use kallsyms_on_each_match_symbol() to improve performance livepatch: Improve the search performance of module_kallsyms_on_each_symbol() kallsyms: Add self-test facility include/linux/kallsyms.h | 9 + init/Kconfig | 13 ++ kernel/Makefile | 1 + kernel/kallsyms.c | 106 +++++++++- kernel/kallsyms_selftest.c | 423 +++++++++++++++++++++++++++++++++++++ kernel/livepatch/core.c | 25 ++- kernel/module/kallsyms.c | 13 +- scripts/kallsyms.c | 24 ++- 8 files changed, 598 insertions(+), 16 deletions(-) create mode 100644 kernel/kallsyms_selftest.c