From patchwork Fri Sep 9 13:00:14 2022 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: "Leizhen (ThunderTown)" X-Patchwork-Id: 12971756 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 30179C6FA8B for ; Fri, 9 Sep 2022 13:03:27 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S231371AbiIINDZ (ORCPT ); Fri, 9 Sep 2022 09:03:25 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:37126 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S229601AbiIINDT (ORCPT ); Fri, 9 Sep 2022 09:03:19 -0400 Received: from szxga01-in.huawei.com (szxga01-in.huawei.com [45.249.212.187]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id CDB08F341A; Fri, 9 Sep 2022 06:03:18 -0700 (PDT) Received: from dggpemm500023.china.huawei.com (unknown [172.30.72.57]) by szxga01-in.huawei.com (SkyGuard) with ESMTP id 4MPGKT0qDyzlVq6; Fri, 9 Sep 2022 20:59:25 +0800 (CST) Received: from dggpemm500006.china.huawei.com (7.185.36.236) by dggpemm500023.china.huawei.com (7.185.36.83) with Microsoft SMTP Server (version=TLS1_2, cipher=TLS_ECDHE_RSA_WITH_AES_128_GCM_SHA256) id 15.1.2375.24; Fri, 9 Sep 2022 21:03:16 +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 15.1.2375.24; Fri, 9 Sep 2022 21:03:15 +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 v2 6/8] livepatch: Use kallsyms_on_each_match_symbol() to improve performance Date: Fri, 9 Sep 2022 21:00:14 +0800 Message-ID: <20220909130016.727-7-thunder.leizhen@huawei.com> X-Mailer: git-send-email 2.26.0.windows.1 In-Reply-To: <20220909130016.727-1-thunder.leizhen@huawei.com> References: <20220909130016.727-1-thunder.leizhen@huawei.com> MIME-Version: 1.0 X-Originating-IP: [10.174.178.55] X-ClientProxiedBy: dggems704-chm.china.huawei.com (10.3.19.181) To dggpemm500006.china.huawei.com (7.185.36.236) X-CFilter-Loop: Reflected Precedence: bulk List-ID: Based on the test results of kallsyms_on_each_match_symbol() and kallsyms_on_each_symbol(), this can reduce the performance overhead by approximately 95%, if CONFIG_KALLSYMS_ALL=y. Signed-off-by: Zhen Lei --- kernel/livepatch/core.c | 20 +++++++++++++++++++- 1 file changed, 19 insertions(+), 1 deletion(-) diff --git a/kernel/livepatch/core.c b/kernel/livepatch/core.c index 42f7e716d56bf72..31b57ccf908017e 100644 --- a/kernel/livepatch/core.c +++ b/kernel/livepatch/core.c @@ -153,6 +153,24 @@ static int klp_find_callback(void *data, const char *name, return 0; } +static int klp_match_callback(void *data, unsigned long addr) +{ + struct klp_find_arg *args = data; + + args->addr = addr; + args->count++; + + /* + * Finish the search when the symbol is found for the desired position + * or the position is not defined for a non-unique symbol. + */ + if ((args->pos && (args->count == args->pos)) || + (!args->pos && (args->count > 1))) + return 1; + + return 0; +} + static int klp_find_object_symbol(const char *objname, const char *name, unsigned long sympos, unsigned long *addr) { @@ -167,7 +185,7 @@ static int klp_find_object_symbol(const char *objname, const char *name, if (objname) module_kallsyms_on_each_symbol(klp_find_callback, &args); else - kallsyms_on_each_symbol(klp_find_callback, &args); + kallsyms_on_each_match_symbol(klp_match_callback, name, &args); /* * Ensure an address was found. If sympos is 0, ensure symbol is unique;