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=-0.8 required=3.0 tests=DKIMWL_WL_MED,DKIM_SIGNED, DKIM_VALID,HEADER_FROM_DIFFERENT_DOMAINS,MAILING_LIST_MULTI,SPF_PASS autolearn=ham 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 D5216ECE560 for ; Mon, 24 Sep 2018 18:09:48 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 90660214D5 for ; Mon, 24 Sep 2018 18:09:48 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (2048-bit key) header.d=kernel-dk.20150623.gappssmtp.com header.i=@kernel-dk.20150623.gappssmtp.com header.b="Eihb7jRH" DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org 90660214D5 Authentication-Results: mail.kernel.org; dmarc=none (p=none dis=none) header.from=kernel.dk Authentication-Results: mail.kernel.org; spf=none smtp.mailfrom=linux-kernel-owner@vger.kernel.org Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S2387412AbeIYAND (ORCPT ); Mon, 24 Sep 2018 20:13:03 -0400 Received: from mail-it1-f170.google.com ([209.85.166.170]:51993 "EHLO mail-it1-f170.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1731633AbeIYAND (ORCPT ); Mon, 24 Sep 2018 20:13:03 -0400 Received: by mail-it1-f170.google.com with SMTP id e14-v6so11859025itf.1 for ; Mon, 24 Sep 2018 11:09:40 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=kernel-dk.20150623.gappssmtp.com; s=20150623; h=subject:to:cc:references:from:message-id:date:user-agent :mime-version:in-reply-to:content-language:content-transfer-encoding; bh=UHCeYyqZzNK6+M3bf4mg3QpUQh57EyXFgjsqKKsrGCg=; b=Eihb7jRHsFUSBQ7rNZLWVsmUrDeA1VbPk29jqAXyvL7i32hh/aEFfy50fW9Z/Ax6vL wvHcjGSl6FnZbgNGMdhR+r4KtHC1VAU6MH3zHVB/sFTuRjKC1UbUp3vi7298zIGXlIs3 dLSXeChXM0oEXn/4ssG5PntyoCKbbw9cmdygg45QOoxR83GRaxc9hJre6vhbriAqygY0 yz8/vEbU77LfdanfpZW7+AZZsJZQbekag9taXDkxTBHAJRTJ5m7fzDANi2EazFXPl7HS QQPgkJqEXf2xjE95ix72sbg09bLQnztTdvx6Y+e32SUjXLcRwmuS1jH44EA5V+0UIF/9 qyQQ== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20161025; h=x-gm-message-state:subject:to:cc:references:from:message-id:date :user-agent:mime-version:in-reply-to:content-language :content-transfer-encoding; bh=UHCeYyqZzNK6+M3bf4mg3QpUQh57EyXFgjsqKKsrGCg=; b=b4WzeZspAlk7O1Ygv4ZkmiQwH+VqHbRLAuYl7ZJwFapDirWLlLJJK6GCW3tSbj3c8t Nkn8aizTqygT+/E2Ds2Sbp7X383ZuLTIFNdUMUOJILehaYZBg/K/o1VdhxcLlfgjXCdn 7H+6dZ5Jxpybd5KYWlvCwmDZ1rRi5wWSvDn5UAsZ1FamAgpULPgZuLBHk7hLoU7Ygpb9 JaGN0ayb2d2zEnIQ2oFVJ40tGA53fnWyJoMS8/q3vV1MlQAJ7gpbkkA5Dxy/e+bvrJNx s7+t3YpmH4Itfcr+5oFL/3tkyMmDTTmDXDB9wSBCG3263nWIH/cAkgalzAc/XbyY5wYF Q6qQ== X-Gm-Message-State: ABuFfoiWCwVDZDdyuD2wZmzmbtcPTRXhBwi+lTKeomKnwog8AAxnIof/ C4KKXb5gdw7DT17tNTiHxBa4+w== X-Google-Smtp-Source: ACcGV6354j3hOuH/c3H+IleEzd1hDuPCpe4UWhyHKugMjfk5b6uVOs7jBTdAd00cjLv+Saw8J+yPYA== X-Received: by 2002:a02:898d:: with SMTP id p13-v6mr31670jaj.74.1537812579878; Mon, 24 Sep 2018 11:09:39 -0700 (PDT) Received: from [192.168.1.56] ([216.160.245.98]) by smtp.gmail.com with ESMTPSA id t134-v6sm6846988itb.41.2018.09.24.11.09.37 (version=TLS1_2 cipher=ECDHE-RSA-AES128-GCM-SHA256 bits=128/128); Mon, 24 Sep 2018 11:09:38 -0700 (PDT) Subject: Re: block: DMA alignment of IO buffer allocated from slab To: Christopher Lameter Cc: Christoph Hellwig , Vitaly Kuznetsov , Ming Lei , linux-block , linux-mm , Linux FS Devel , "open list:XFS FILESYSTEM" , Dave Chinner , Linux Kernel Mailing List , Ming Lei References: <20180920063129.GB12913@lst.de> <87h8ij0zot.fsf@vitty.brq.redhat.com> <20180921130504.GA22551@lst.de> <010001660c54fb65-b9d3a770-6678-40d0-8088-4db20af32280-000000@email.amazonses.com> <1f88f59a-2cac-e899-4c2e-402e919b1034@kernel.dk> <010001660cbd51ea-56e96208-564d-4f5d-a5fb-119a938762a9-000000@email.amazonses.com> From: Jens Axboe Message-ID: <1a5b255f-682e-783a-7f99-9d02e39c4af2@kernel.dk> Date: Mon, 24 Sep 2018 12:09:37 -0600 User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:60.0) Gecko/20100101 Thunderbird/60.0 MIME-Version: 1.0 In-Reply-To: <010001660cbd51ea-56e96208-564d-4f5d-a5fb-119a938762a9-000000@email.amazonses.com> Content-Type: text/plain; charset=utf-8 Content-Language: en-US Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On 9/24/18 12:00 PM, Christopher Lameter wrote: > On Mon, 24 Sep 2018, Jens Axboe wrote: > >> The situation is making me a little uncomfortable, though. If we export >> such a setting, we really should be honoring it... > > Various subsystems create custom slab arrays with their particular > alignment requirement for these allocations. Oh yeah, I think the solution is basic enough for XFS, for instance. They just have to error on the side of being cautious, by going full sector alignment for memory... -- Jens Axboe