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 X-Spam-Level: X-Spam-Status: No, score=-2.0 required=3.0 tests=DKIM_INVALID,DKIM_SIGNED, HEADER_FROM_DIFFERENT_DOMAINS,MAILING_LIST_MULTI,SPF_HELO_NONE,SPF_PASS, URIBL_BLOCKED,USER_AGENT_SANE_1 autolearn=no autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id 809FCFA373A for ; Thu, 17 Oct 2019 12:50:41 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 560DE20854 for ; Thu, 17 Oct 2019 12:50:41 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=fail reason="signature verification failed" (2048-bit key) header.d=armlinux.org.uk header.i=@armlinux.org.uk header.b="UAxwMGPH" Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S2502634AbfJQMsc (ORCPT ); Thu, 17 Oct 2019 08:48:32 -0400 Received: from pandora.armlinux.org.uk ([78.32.30.218]:46136 "EHLO pandora.armlinux.org.uk" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S2502595AbfJQMs0 (ORCPT ); Thu, 17 Oct 2019 08:48:26 -0400 DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; d=armlinux.org.uk; s=pandora-2019; h=Sender:In-Reply-To:Content-Type: MIME-Version:References:Message-ID:Subject:Cc:To:From:Date:Reply-To: Content-Transfer-Encoding:Content-ID:Content-Description:Resent-Date: Resent-From:Resent-Sender:Resent-To:Resent-Cc:Resent-Message-ID:List-Id: List-Help:List-Unsubscribe:List-Subscribe:List-Post:List-Owner:List-Archive; bh=BSKcCWiRviL7yuVf7QVZQ1HezXwIp2YHkhMLls+eGWI=; b=UAxwMGPH0baHzDDrCvBpoyp5t 20cOK9b6vMF3TqTdgjFsEJDQ15gptizcZXRwf8aEbt5KiUP7h0rHplnsHP5ZiH0VBIDv8Ts7tglRU /jD90DoI6nTfe+SbL0fYwnKH0OEVkkWLlgLoTpO5wIDwZi0iJESyrotG2ocJXU+12CAzlX2Tk8v9O y76ilUCx9ImCodYn8PKctQS0dQXe8rTBd5I2YFcOcC7115UjAwjLojW5CjVcaGDts3fIJVRJLj0pa Ts0YiQmU3LoFu5buxbkFHpODMkokds8HhDilIcNOdgykS+00D/kXqAd6S4G9tnUwCvCIkjS3WxNfm 6yWxmSHLQ==; Received: from shell.armlinux.org.uk ([fd8f:7570:feb6:1:5054:ff:fe00:4ec]:55528) by pandora.armlinux.org.uk with esmtpsa (TLSv1.2:ECDHE-RSA-AES256-GCM-SHA384:256) (Exim 4.90_1) (envelope-from ) id 1iL5CS-0000pi-VL; Thu, 17 Oct 2019 13:48:17 +0100 Received: from linux by shell.armlinux.org.uk with local (Exim 4.92) (envelope-from ) id 1iL5CR-0008DC-7e; Thu, 17 Oct 2019 13:48:15 +0100 Date: Thu, 17 Oct 2019 13:48:15 +0100 From: Russell King - ARM Linux admin To: Rasmus Villemoes Cc: Masahiro Yamada , Andrew Morton , Gao Xiang , kernel@pengutronix.de, Linus Walleij , linux-kernel@vger.kernel.org, linux-arm-kernel@lists.infradead.org Subject: Re: [RFC PATCH 0/3] watchdog servicing during decompression Message-ID: <20191017124815.GE25745@shell.armlinux.org.uk> References: <20191017114906.30302-1-linux@rasmusvillemoes.dk> <20191017120310.GD25745@shell.armlinux.org.uk> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: User-Agent: Mutt/1.10.1 (2018-07-13) Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Thu, Oct 17, 2019 at 02:34:52PM +0200, Rasmus Villemoes wrote: > On 17/10/2019 14.03, Russell King - ARM Linux admin wrote: > > We used to have this on ARM - it was called from the decompressor > > code via an arch_decomp_wdog() hook. > > > > That code got removed because it is entirely unsuitable for a multi- > > platform kernel. This looks like it takes an address for the watchdog > > from the Kconfig, and builds that into the decompressor, making the > > decompressor specific to that board or platform. > > > > I'm not sure distros are going to like that given where we are with > > multiplatform kernels. > > This is definitely not for multiplatform kernels or general distros, > it's for kernels that are built as part of a BSP for a specific board - > hence the "Say N unless you know you need this.". > > I didn't know it used to exist. But I do know that something like this > is carried out-of-tree for lots of boards, so I thought I'd try to get > upstream support. Sorry, it does still exist, just been moved around a bit. See lib/inflate.c: STATIC int INIT inflate(void) { ... #ifdef ARCH_HAS_DECOMP_WDOG arch_decomp_wdog(); #endif Given that it still exists, maybe this hook name should be used for this same issue in the LZ4 code? > The first two patches, or something like them, would be nice on their > own, as that would minimize the conflicts when forward-porting the > board-specific patch. But such a half-implemented feature that requires > out-of-tree patches to actually do anything useful of course won't fly. > > I'm not really a big fan of the third patch, even though it does work > for all the cases I've encountered so far - I'm sure there would be > boards where a much more complicated solution would be needed. Another > method I thought of was to just supply a __weak no-op > decompress_keepalive(), and then have a config option to point at an > extra object file to link into the compressed/vmlinux (similar to the > initramfs_source option that also points to some external resource). > > But if the mainline kernel doesn't want anything like this > re-introduced, that's also fine, that just means a bit of job security. Well, we'll see whether the arm-soc people have anything to add... -- RMK's Patch system: https://www.armlinux.org.uk/developer/patches/ FTTC broadband for 0.8mile line in suburbia: sync at 12.1Mbps down 622kbps up According to speedtest.net: 11.9Mbps down 500kbps up