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=-2.4 required=3.0 tests=DKIM_SIGNED,DKIM_VALID, DKIM_VALID_AU,HEADER_FROM_DIFFERENT_DOMAINS,MAILING_LIST_MULTI,SPF_HELO_NONE, SPF_PASS,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 ED0F6C2BA18 for ; Fri, 3 Apr 2020 10:19:35 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id B4D4A20787 for ; Fri, 3 Apr 2020 10:19:35 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (1024-bit key) header.d=alien8.de header.i=@alien8.de header.b="ebAvHLEm" Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S2390591AbgDCKTe (ORCPT ); Fri, 3 Apr 2020 06:19:34 -0400 Received: from mail.skyhub.de ([5.9.137.197]:53496 "EHLO mail.skyhub.de" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1727835AbgDCKTd (ORCPT ); Fri, 3 Apr 2020 06:19:33 -0400 Received: from zn.tnic (p200300EC2F0D8900185F9BE223BA1C94.dip0.t-ipconnect.de [IPv6:2003:ec:2f0d:8900:185f:9be2:23ba:1c94]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by mail.skyhub.de (SuperMail on ZX Spectrum 128k) with ESMTPSA id 5AE661EC0C84; Fri, 3 Apr 2020 12:19:32 +0200 (CEST) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=alien8.de; s=dkim; t=1585909172; h=from:from:reply-to:subject:subject:date:date:message-id:message-id: to:to:cc:cc:mime-version:mime-version:content-type:content-type: content-transfer-encoding:content-transfer-encoding: in-reply-to:in-reply-to:references:references; bh=4gTxr2tMtcHZvA+vMMjjeuIyzVHlsntBq8xEiI0nftM=; b=ebAvHLEmjItjXy3diROes48QoOr+3V7Mabl957HF8ZUmg01Zs+dudqR+068+JvUD5k6JfG mAMsGMxxsOyOnlEUMSoOI3VUWUJh9XwaHmNnfmGRpzLIltI0GM5Iz+85gp9RHAFFd2Bhai /pKE+LLfkN8Fla9geFNQbWuL9S8uYj8= Date: Fri, 3 Apr 2020 12:19:29 +0200 From: Borislav Petkov To: Nick Terrell Cc: Nick Terrell , "linux-kernel@vger.kernel.org" , Chris Mason , "linux-kbuild@vger.kernel.org" , "x86@kernel.org" , "gregkh@linuxfoundation.org" , Petr Malat , Kees Cook , Kernel Team , Adam Borowski , Patrick Williams , Michael van der Westhuizen , "mingo@kernel.org" , Patrick Williams , Sedat Dilek Subject: Re: [PATCH v4 6/8] x86: bump ZO_z_extra_bytes margin for zstd Message-ID: <20200403101929.GC20218@zn.tnic> References: <20200401053913.216783-1-nickrterrell@gmail.com> <20200401053913.216783-7-nickrterrell@gmail.com> <20200401093310.GA13748@zn.tnic> <20200402155810.GD9352@zn.tnic> <2370741E-FE5A-44C1-8BF3-24A03E321F4E@fb.com> MIME-Version: 1.0 Content-Type: text/plain; charset=utf-8 Content-Disposition: inline Content-Transfer-Encoding: 8bit In-Reply-To: <2370741E-FE5A-44C1-8BF3-24A03E321F4E@fb.com> 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, Apr 02, 2020 at 08:25:49PM +0000, Nick Terrell wrote: > So it is possible that there is a use case for kernel compression that > I’m not aware of where RAM is extremely tight and within 64 KB of > the current limits. That's exactly my concern, albeit a very minor one. > It seems to me that adding 64KB to the memory requirement for kernel > decompression is not going to break anyone. If it did the kernel image > is taking up nearly all available RAM, which doesn’t seem likely. > But, I don’t know all use cases. If it does break someone, we can > put up a separate patch that switches all the compression methods over > a per-method ZO_z_extra_bytes. Ok. Thx. -- Regards/Gruss, Boris. https://people.kernel.org/tglx/notes-about-netiquette