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 Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by smtp.lore.kernel.org (Postfix) with ESMTP id D2BC7C3A5A7 for ; Wed, 7 Dec 2022 01:42:07 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S229845AbiLGBmH (ORCPT ); Tue, 6 Dec 2022 20:42:07 -0500 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:54386 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S229940AbiLGBlu (ORCPT ); Tue, 6 Dec 2022 20:41:50 -0500 Received: from szxga02-in.huawei.com (szxga02-in.huawei.com [45.249.212.188]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id E7283326CE; Tue, 6 Dec 2022 17:41:49 -0800 (PST) Received: from dggpemm500006.china.huawei.com (unknown [172.30.72.54]) by szxga02-in.huawei.com (SkyGuard) with ESMTP id 4NRg3Z5wQgzJqGv; Wed, 7 Dec 2022 09:40:58 +0800 (CST) Received: from [10.174.178.55] (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; Wed, 7 Dec 2022 09:30:43 +0800 Subject: Re: [PATCH v8 6/9] livepatch: Use kallsyms_on_each_match_symbol() to improve performance To: Luis Chamberlain CC: Petr Mladek , Josh Poimboeuf , Jiri Kosina , Miroslav Benes , Joe Lawrence , , , Masahiro Yamada , Alexei Starovoitov , Jiri Olsa , Kees Cook , Andrew Morton , , Steven Rostedt , Ingo Molnar , David Laight References: <20221102084921.1615-1-thunder.leizhen@huawei.com> <20221102084921.1615-7-thunder.leizhen@huawei.com> <45a28bcf-c6e1-8d39-613a-d30bd7b685f0@huawei.com> From: "Leizhen (ThunderTown)" Message-ID: Date: Wed, 7 Dec 2022 09:30:31 +0800 User-Agent: Mozilla/5.0 (Windows NT 10.0; WOW64; rv:60.0) Gecko/20100101 Thunderbird/60.7.0 MIME-Version: 1.0 In-Reply-To: Content-Type: text/plain; charset="utf-8" Content-Language: en-US Content-Transfer-Encoding: 7bit X-Originating-IP: [10.174.178.55] X-ClientProxiedBy: dggems701-chm.china.huawei.com (10.3.19.178) To dggpemm500006.china.huawei.com (7.185.36.236) X-CFilter-Loop: Reflected Precedence: bulk List-ID: X-Mailing-List: live-patching@vger.kernel.org On 2022/12/7 6:08, Luis Chamberlain wrote: > On Thu, Nov 24, 2022 at 10:36:23AM +0800, Leizhen (ThunderTown) wrote: >> >> >> On 2022/11/23 21:28, Petr Mladek wrote: >>> Hi, >>> >>> I am sorry for the late review. I have been snowed under another >>> tasks. >>> >>> On Wed 2022-11-02 16:49:18, Zhen Lei wrote: >>>> Based on the test results of kallsyms_on_each_match_symbol() and >>>> kallsyms_on_each_symbol(), the average performance can be improved by >>>> more than 1500 times. >>> >>> Sounds great. >>> >>>> --- 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; >>> >>> This duplicates most of the klp_find_callback(). Please, call this >>> new function in klp_find_callback() instead of the duplicated code. >>> I mean to do: >>> >>> static int klp_find_callback(void *data, const char *name, unsigned long addr) >>> { >>> struct klp_find_arg *args = data; >>> >>> if (strcmp(args->name, name)) >>> return 0; >>> >>> return klp_match_callback(data, addr); >>> } >> >> Good idea. But these patches have been merged into linux-next, how about I post >> a new cleanup patch after v6.2-rc1? > > You can send the cleanup now. The code doesn't change drastically, just > base it on modules-next. OK > > Luis > . > -- Regards, Zhen Lei