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 5D3DFE7D243 for ; Tue, 26 Sep 2023 07:14:41 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S232093AbjIZHOp (ORCPT ); Tue, 26 Sep 2023 03:14:45 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:49670 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S232166AbjIZHOm (ORCPT ); Tue, 26 Sep 2023 03:14:42 -0400 Received: from wout1-smtp.messagingengine.com (wout1-smtp.messagingengine.com [64.147.123.24]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id CA37A10A; Tue, 26 Sep 2023 00:14:35 -0700 (PDT) Received: from compute6.internal (compute6.nyi.internal [10.202.2.47]) by mailout.west.internal (Postfix) with ESMTP id 309D8320094D; Tue, 26 Sep 2023 03:14:34 -0400 (EDT) Received: from imap51 ([10.202.2.101]) by compute6.internal (MEProxy); Tue, 26 Sep 2023 03:14:35 -0400 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=arndb.de; h=cc :cc:content-type:content-type:date:date:from:from:in-reply-to :in-reply-to:message-id:mime-version:references:reply-to:sender :subject:subject:to:to; s=fm1; t=1695712473; x=1695798873; bh=VF VeVZmTfs9bsTzTBLiILy5KA2+NCbWVhaZijAd/VUg=; b=RD/znBmfPhrGsAnVAY +irDC1f47jwc/OcjLoXLDdVUlj1zpwTv0GWS7Dpasxt0ve/H43ktE5AlC/mqEMKR ep1xWhoEEkI7ZY/OjixKQdAP+3ziGChjqiRAlm4Y+PfzFTLDsLcBVJ7i/fRn6Jb3 HMmFKjpCbGGxb18L0YIasG8OAIVmisiROiqoPRzDAQBpTbuzDbTGrhYdOqTqnkmR N6RZGRkOQdmMabpuuUZ3eYqMW78/NM6NWplH74ZkFcrhvmMcsLf6mGsLOok/aVo4 Aj3f+SVK1GyM/VBdy7NtsjSm8LNIcS61Hlam+uhlqr+ObXhHuTP9CDlKYVO/PN1r byKw== DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d= messagingengine.com; h=cc:cc:content-type:content-type:date:date :feedback-id:feedback-id:from:from:in-reply-to:in-reply-to :message-id:mime-version:references:reply-to:sender:subject :subject:to:to:x-me-proxy:x-me-proxy:x-me-sender:x-me-sender :x-sasl-enc; s=fm2; t=1695712473; x=1695798873; bh=VFVeVZmTfs9bs TzTBLiILy5KA2+NCbWVhaZijAd/VUg=; b=Ahh6tOszfUEWLcNcTiHI95DQ4R64V qFSrCmckpTae9k4He4XOTDs3KBomVkkso3mw+ynZIFoMiSqGV/G4ckBtZA1MJ4mm 7gdY8wtbyMMrjIQafA+JBk15LR/NeELV4B3EspPY8plBzzY08TeD3bt9gJ8PYm92 v8iw6vN92eHlDqC/lyVIiSGsbfaNzwLBQXpcfSCRnfaeuXkxXsmTBRN1Seua6n3O 0yAm+1GcweN6o8OLGuFTXtymeLacVGJ4O/u0WVRlUMBK4s/bxPXrT7gQ9+HzEvCj ITlpEN2QCGDN9Ghljw4CeoFvJE3c1Z5sTDe+zHYWSAeHaW3hXvL/lx1Gg== X-ME-Sender: X-ME-Proxy-Cause: gggruggvucftvghtrhhoucdtuddrgedviedrudelhedgudduiecutefuodetggdotefrod ftvfcurfhrohhfihhlvgemucfhrghsthforghilhdpqfgfvfdpuffrtefokffrpgfnqfgh necuuegrihhlohhuthemuceftddtnecusecvtfgvtghiphhivghnthhsucdlqddutddtmd enucfjughrpefofgggkfgjfhffhffvvefutgesthdtredtreertdenucfhrhhomhepfdet rhhnugcuuegvrhhgmhgrnhhnfdcuoegrrhhnugesrghrnhgusgdruggvqeenucggtffrrg htthgvrhhnpeffheeugeetiefhgeethfejgfdtuefggeejleehjeeutefhfeeggefhkedt keetffenucevlhhushhtvghrufhiiigvpedtnecurfgrrhgrmhepmhgrihhlfhhrohhmpe grrhhnugesrghrnhgusgdruggv X-ME-Proxy: Feedback-ID: i56a14606:Fastmail Received: by mailuser.nyi.internal (Postfix, from userid 501) id 7A2D7B60089; Tue, 26 Sep 2023 03:14:32 -0400 (EDT) X-Mailer: MessagingEngine.com Webmail Interface User-Agent: Cyrus-JMAP/3.9.0-alpha0-957-ga1ccdb4cff-fm-20230919.001-ga1ccdb4c MIME-Version: 1.0 Message-Id: In-Reply-To: References: Date: Tue, 26 Sep 2023 09:14:11 +0200 From: "Arnd Bergmann" To: "Zhangjin Wu" , linux-kernel@vger.kernel.org, linux-mips@vger.kernel.org, linux-riscv@lists.infradead.org Cc: "Palmer Dabbelt" , "Paul Walmsley" , paulburton@kernel.org, "Paul E. McKenney" , "Thomas Bogendoerfer" , "Willy Tarreau" , =?UTF-8?Q?Thomas_Wei=C3=9Fschuh?= , "Tim Bird" , "Geert Uytterhoeven" , "Nicolas Pitre" Subject: Re: [PATCH v1 0/7] DCE/DSE: Add Dead Syscalls Elimination support, part1 Content-Type: text/plain Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Tue, Sep 26, 2023, at 00:33, Zhangjin Wu wrote: > > This series aims to add DCE based DSE support, here is the first > revision of the RFC patchset [1], the whole series includes three parts, > here is the Part1. > > This Part1 adds basic DCE based DSE support. > > Part2 will further eliminate the unused syscalls forcely kept by the > exception tables. > > Part3 will add DSE test support with nolibc-test.c. I missed the RFC version, but I think this is a useful thing to have overall, though it will probably need to go through a couple of revisions and rewrites, mostly to ensure we are not adding complexity that gets in the way of other improvements I would like to see to the syscall entry handling. It would be nice to include some size numbers here for at least one practical use case. If you have a defconfig for a shipping product with a small kernel, what is the 'size -B' output you see comparing with and without DCE and, and with DCE+DSE? There is generally not much work going into micro-optimizing the size of the kernel image any more, for a number of reasons, but if you are able to show that this is a noticeable improvement, we should be able to find a way to do it. Geert is doing statistics about size bloat over time, and anything that undoes a couple of years worth of bloat would clearly be significant here. Another alternative would be to resume the work done by Nicolas Pitre, who added Kconfig symbols for controlling groups of system calls. Since we already have a number of those compile time options, adding more of them should generally be less controversial and more consistent, while bringing most of the same benefits. Arnd