From patchwork Thu Sep 8 13:09:30 2022 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: "Leizhen (ThunderTown)" X-Patchwork-Id: 12970054 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 5FCFBC38145 for ; Thu, 8 Sep 2022 13:10:48 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S232199AbiIHNKr (ORCPT ); Thu, 8 Sep 2022 09:10:47 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:35130 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S232203AbiIHNKd (ORCPT ); Thu, 8 Sep 2022 09:10:33 -0400 Received: from szxga08-in.huawei.com (szxga08-in.huawei.com [45.249.212.255]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 7BDAFBF61; Thu, 8 Sep 2022 06:10:12 -0700 (PDT) Received: from dggpemm500020.china.huawei.com (unknown [172.30.72.53]) by szxga08-in.huawei.com (SkyGuard) with ESMTP id 4MNfWw45tNz14QMJ; Thu, 8 Sep 2022 21:06:20 +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 15.1.2375.24; Thu, 8 Sep 2022 21:10:10 +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 15.1.2375.24; Thu, 8 Sep 2022 21:10:09 +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 1/7] scripts/kallsyms: don't compress symbol type when CONFIG_KALLSYMS_ALL=y Date: Thu, 8 Sep 2022 21:09:30 +0800 Message-ID: <20220908130936.674-2-thunder.leizhen@huawei.com> X-Mailer: git-send-email 2.26.0.windows.1 In-Reply-To: <20220908130936.674-1-thunder.leizhen@huawei.com> References: <20220908130936.674-1-thunder.leizhen@huawei.com> MIME-Version: 1.0 X-Originating-IP: [10.174.178.55] X-ClientProxiedBy: dggems706-chm.china.huawei.com (10.3.19.183) To dggpemm500006.china.huawei.com (7.185.36.236) X-CFilter-Loop: Reflected Precedence: bulk List-ID: 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 increases the size of 'kallsyms_names'. About 48KiB, 2.67%, on x86 with defconfig. Before: kallsyms_num_syms=131392, sizeof(kallsyms_names)=1823659 After : kallsyms_num_syms=131392, sizeof(kallsyms_names)=1872418 However, if CONFIG_KALLSYMS_ALL is not set, the size of 'kallsyms_names' does not change. Signed-off-by: Zhen Lei --- scripts/kallsyms.c | 15 ++++++++++++--- 1 file changed, 12 insertions(+), 3 deletions(-) diff --git a/scripts/kallsyms.c b/scripts/kallsyms.c index f18e6dfc68c5839..ab6fe7cd014efd1 100644 --- a/scripts/kallsyms.c +++ b/scripts/kallsyms.c @@ -60,6 +60,7 @@ static unsigned int table_size, table_cnt; static int all_symbols; static int absolute_percpu; static int base_relative; +static int sym_start_idx; static int token_profit[0x10000]; @@ -511,7 +512,7 @@ static void learn_symbol(const unsigned char *symbol, int len) { int i; - for (i = 0; i < len - 1; i++) + for (i = sym_start_idx; i < len - 1; i++) token_profit[ symbol[i] + (symbol[i + 1] << 8) ]++; } @@ -520,7 +521,7 @@ static void forget_symbol(const unsigned char *symbol, int len) { int i; - for (i = 0; i < len - 1; i++) + for (i = sym_start_idx; i < len - 1; i++) token_profit[ symbol[i] + (symbol[i + 1] << 8) ]--; } @@ -538,7 +539,7 @@ static unsigned char *find_token(unsigned char *str, int len, { int i; - for (i = 0; i < len - 1; i++) { + for (i = sym_start_idx; i < len - 1; i++) { if (str[i] == token[0] && str[i+1] == token[1]) return &str[i]; } @@ -780,6 +781,14 @@ int main(int argc, char **argv) } else if (argc != 1) usage(); + /* + * Skip the symbol type, do not compress it to optimize the performance + * of finding or traversing symbols in kernel, this is good for modules + * such as livepatch. + */ + if (all_symbols) + sym_start_idx = 1; + read_map(stdin); shrink_table(); if (absolute_percpu)