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 mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id 1112BC433EF for ; Mon, 25 Oct 2021 13:20:56 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id E78B660F4F for ; Mon, 25 Oct 2021 13:20:55 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S231331AbhJYNXR (ORCPT ); Mon, 25 Oct 2021 09:23:17 -0400 Received: from out30-54.freemail.mail.aliyun.com ([115.124.30.54]:33903 "EHLO out30-54.freemail.mail.aliyun.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S233482AbhJYNXN (ORCPT ); Mon, 25 Oct 2021 09:23:13 -0400 X-Alimail-AntiSpam: AC=PASS;BC=-1|-1;BR=01201311R141e4;CH=green;DM=||false|;DS=||;FP=0|-1|-1|-1|0|-1|-1|-1;HT=e01e04426;MF=yinan@linux.alibaba.com;NM=1;PH=DS;RN=5;SR=0;TI=SMTPD_---0UtePCS2_1635168048; Received: from 30.240.99.57(mailfrom:yinan@linux.alibaba.com fp:SMTPD_---0UtePCS2_1635168048) by smtp.aliyun-inc.com(127.0.0.1); Mon, 25 Oct 2021 21:20:48 +0800 Message-ID: Date: Mon, 25 Oct 2021 21:20:47 +0800 MIME-Version: 1.0 User-Agent: Mozilla/5.0 (Macintosh; Intel Mac OS X 10.15; rv:91.0) Gecko/20100101 Thunderbird/91.2.1 Subject: Re: [PATCH 1/2] scripts: ftrace - move the sort-processing in ftrace_init to compile time From: Yinan Liu To: Steven Rostedt Cc: mark-pk.tsai@mediatek.com, peterz@infradead.org, mingo@redhat.com, linux-kernel@vger.kernel.org References: <20210911135043.16014-1-yinan@linux.alibaba.com> <20210911135043.16014-2-yinan@linux.alibaba.com> <20210911095937.5a298619@rorschach.local.home> <0b783c9e-c129-6907-0637-5c7638158a65@linux.alibaba.com> <20211008194821.3b6a18a4@oasis.local.home> <1d069626-1aed-6244-b932-7853e832eb70@linux.alibaba.com> In-Reply-To: <1d069626-1aed-6244-b932-7853e832eb70@linux.alibaba.com> Content-Type: text/plain; charset=UTF-8; format=flowed Content-Transfer-Encoding: 8bit Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On 2021/10/9 上午10:56, Yinan Liu wrote: >> Probably just keep the sorting algorithm in the kernel and take place >> on module load. >> >> If you still want to sort at compile time, then do the sort for .init >> functions separate from the .text ones, and have a way to extract this >> information (shouldn't be too hard) in the kernel at module load, and >> then just swap the init and text functions if they were added in the >> reverse order that was expect. >> >> The functions in .init will either be before all the functions in .text >> or after. They wont be intermingled. Thus, if they are both sorted, >> then they are placed correctly or the two groups of functions need to >> be switched. No other sorting should be necessary. >> Hi, Steven I try to apply for memory during the relocation phase to separate and adjust the mcount of .init.text and .text. After processing, I found that the mcount redirection in .ko is based on ".text", ".init.text", ".ref.text", ".sched.text", ".spinlock.text", ".irqentry .text", ".softirqentry.text", ".kprobes.text", ".cpuidle.text", ".text.unlikely", which makes the sorting process at compile time cumbersome and inefficient. And .ko is inserted after the kernel start， to a certain extent, the optimization meaning of this part is relatively small. Now I think it makes more sense to optimize mcount during the startup period, because these mcounts based on different section redirects are relatively orderly just like 11, 13, 15, 17, 19, 1, 3, 5, 7, 9, 21, 23, 25, 27, 29 . At present, it seems that the processing of compile-time sorting is only suitable for vmlinux but not suitable for modules. Please review the code of mcount sorting in vmlinux, thank you. > Best regards! > -- Yinan liu