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=-0.6 required=3.0 tests=DKIM_INVALID,DKIM_SIGNED, HEADER_FROM_DIFFERENT_DOMAINS,MAILING_LIST_MULTI,SPF_HELO_NONE,SPF_PASS 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 D91CCC2D0FC for ; Wed, 13 May 2020 13:36:23 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id AC3EF22254 for ; Wed, 13 May 2020 13:36:22 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=fail reason="signature verification failed" (2048-bit key) header.d=infradead.org header.i=@infradead.org header.b="QZE+tPjw" Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1728787AbgEMNgX (ORCPT ); Wed, 13 May 2020 09:36:23 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:56392 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1728694AbgEMNgW (ORCPT ); Wed, 13 May 2020 09:36:22 -0400 Received: from bombadil.infradead.org (bombadil.infradead.org [IPv6:2607:7c80:54:e::133]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 701F2C061A0C for ; Wed, 13 May 2020 06:36:22 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; d=infradead.org; s=bombadil.20170209; h=In-Reply-To:Content-Type:MIME-Version :References:Message-ID:Subject:Cc:To:From:Date:Sender:Reply-To: Content-Transfer-Encoding:Content-ID:Content-Description; bh=xSs+CiMh9BR2tUWPtLIWKfYTZt/YCN37Fjwh7L7I57Y=; b=QZE+tPjw5bLjLKdncReNYoVYse efOvAy74RxzcsrWZ/PVPP+KT1AOzMulRr+AvwKAl2mTNFpfa6AzhycN+WulVFmMPakCjCtGACZyg2 fzf3krqfwvrhACxntfH+kGfM1Ki+Sj//qcWku14oH4cVsgXLs5Q1KPovKPJMjz/3NHXuW48K2z9xZ ALdQNYx2vwnqEb9drfxdX3WyIvsqtWFgNVb3DTDDJGLBaKNYFQMDoQVg0w89C8cilWAogWWpd/K1N NwbrBfue+QJ7TyaCtZkcSIPBMjB8O8prUVh0DcglkU8EATaizdskWYivdTFGHU3youDgVipAdbQbb j3n6L6/Q==; Received: from j217100.upc-j.chello.nl ([24.132.217.100] helo=noisy.programming.kicks-ass.net) by bombadil.infradead.org with esmtpsa (Exim 4.92.3 #3 (Red Hat Linux)) id 1jYrYR-0006Hf-GW; Wed, 13 May 2020 13:36:11 +0000 Received: from hirez.programming.kicks-ass.net (hirez.programming.kicks-ass.net [192.168.1.225]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (Client did not present a certificate) by noisy.programming.kicks-ass.net (Postfix) with ESMTPS id 74CD0301A66; Wed, 13 May 2020 15:36:09 +0200 (CEST) Received: by hirez.programming.kicks-ass.net (Postfix, from userid 1000) id 5E84924C0C645; Wed, 13 May 2020 15:36:09 +0200 (CEST) Date: Wed, 13 May 2020 15:36:09 +0200 From: Peter Zijlstra To: David Laight Cc: 'Geert Uytterhoeven' , Greg Kroah-Hartman , Lee Jones , stable , Alexey Brodkin , Alexey Brodkin , Thomas Gleixner , Vineet Gupta , Will Deacon Subject: Re: [PATCH 4.4 03/16] devres: Align data[] to ARCH_KMALLOC_MINALIGN Message-ID: <20200513133609.GO2978@hirez.programming.kicks-ass.net> References: <20200423204014.784944-1-lee.jones@linaro.org> <20200423204014.784944-4-lee.jones@linaro.org> <20200513093536.GB830571@kroah.com> <335fbcc7d9ad4d429ec11e9ac2caf118@AcuMS.aculab.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <335fbcc7d9ad4d429ec11e9ac2caf118@AcuMS.aculab.com> Sender: stable-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: stable@vger.kernel.org On Wed, May 13, 2020 at 10:10:03AM +0000, David Laight wrote: > From: Geert Uytterhoeven > > Sent: 13 May 2020 10:49 > ... > > > I don't want to apply this to older kernels as it could cause extra > > > memory usage for no good reason. I have no idea why a non ARC system > > > would want it :( > > > > I think the reference to ARC is a red herring. > > The real issue is that buffers used for DMA may not have the required > > alignment, which is not limited to ARC systems. > > > > Note that I'm also not super happy with the extra memory usage. > > But devm_*() conveniences come with their penalties... > > Interesting thought. > Could the devm 'header' be put right at the end of the kmalloc() > buffer? https://lkml.kernel.org/r/20191220140655.GN2827@hirez.programming.kicks-ass.net