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=-1.0 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 03F29C43387 for ; Thu, 17 Jan 2019 13:54:21 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id C11A920855 for ; Thu, 17 Jan 2019 13:54:20 +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="nZJrXeLq" Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1727279AbfAQNyU (ORCPT ); Thu, 17 Jan 2019 08:54:20 -0500 Received: from mail-pg1-f194.google.com ([209.85.215.194]:44593 "EHLO mail-pg1-f194.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1726805AbfAQNyU (ORCPT ); Thu, 17 Jan 2019 08:54:20 -0500 Received: by mail-pg1-f194.google.com with SMTP id t13so4471187pgr.11 for ; Thu, 17 Jan 2019 05:54:19 -0800 (PST) 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=2pB3Sy1nsN8br99qlgkRZ1OXNL0JnrGQxDKXfgA9KK0=; b=nZJrXeLqGAlsa/Ofbkbns2uDP0VDoBuUNt8uuc7hdmJJhAY2x4XifJLVWZXaHCXfyP RQKRG6ag5E8GaIRG8Du/ZpUpCgZxyyu8eYUuQPYH1xQbAYSLUfa4S9cYcWfkTxTW/BKm 9bEb05lhtuVLXC71fkAizidrDg9GEaAo6PB1noBpGaVA7E+YZHarDSDjbWm2tJn/u3TM zZdFgGMX05+JpDJe8/1yQh9nejkWZEjApfdeHl/yMy5Rnus1JNaqyfDlzf6KasSuvgLS e/qjJNpfm4PDGGJ5TONrH0onWuGtVwH3EX5iU4oCQxIZlhc4cy+oRlC2wKKtj//WO/iy 7e6w== 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=2pB3Sy1nsN8br99qlgkRZ1OXNL0JnrGQxDKXfgA9KK0=; b=ARCkVcPH+YGpd1vMMLgVHhu682IVpTEo4/QcFbliajtPKS/Ca/T9B0/ti7Rad2KVor IWwl0N4M99I+zSoqxQ2JF8Jdf4xvQvvhNiZjTXSwotP5zLZLDP73fPILw8v7HVN5nzC+ pZtbsf8E/LI24xTaSDpjRtsKgLlaoDgjCGaxdxql79edeMvLNj2AiG71oON69TZLScpa p0ggH0VLwJJ1b00K4a7pAbiihZ4ACs1EamWi6fWl1PaxwrHp1+ZjIKUemyo64DI3uUOD lHMpZQwqVbiW0qvKn56t2Nx0d4I1lNrPFzqAc8JlHou/xHoXlNHDZhq1C/AiP7DuKorO LXKw== X-Gm-Message-State: AJcUukeMMZtOXR1k8Q5qZgIK3EG9WwpzkWfr/vVuiJi4xiNjmdscRrYX aP24DY38Gm7kzkNDysJJWsaFEQ== X-Google-Smtp-Source: ALg8bN6SDO82K2p6rgeJ5pBDM9X331XM5qOuvQZti+ymKzNdyTUr9pejlDuvcMKPFhgWQnazDARAUQ== X-Received: by 2002:a63:5723:: with SMTP id l35mr13059633pgb.228.1547733259352; Thu, 17 Jan 2019 05:54:19 -0800 (PST) Received: from [192.168.1.121] (66.29.188.166.static.utbb.net. [66.29.188.166]) by smtp.gmail.com with ESMTPSA id v15sm2438883pfn.94.2019.01.17.05.54.16 (version=TLS1_2 cipher=ECDHE-RSA-AES128-GCM-SHA256 bits=128/128); Thu, 17 Jan 2019 05:54:18 -0800 (PST) Subject: Re: [PATCH 05/15] Add io_uring IO interface To: Roman Penyaev Cc: linux-fsdevel@vger.kernel.org, linux-aio@kvack.org, linux-block@vger.kernel.org, linux-arch@vger.kernel.org, hch@lst.de, jmoyer@redhat.com, avi@scylladb.com, linux-block-owner@vger.kernel.org References: <20190116175003.17880-1-axboe@kernel.dk> <20190116175003.17880-6-axboe@kernel.dk> <362738449bd3f83d18cb1056acc9b875@suse.de> From: Jens Axboe Message-ID: Date: Thu, 17 Jan 2019 06:54:15 -0700 User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:60.0) Gecko/20100101 Thunderbird/60.2.1 MIME-Version: 1.0 In-Reply-To: <362738449bd3f83d18cb1056acc9b875@suse.de> Content-Type: text/plain; charset=utf-8 Content-Language: en-US Content-Transfer-Encoding: 7bit Sender: linux-block-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-block@vger.kernel.org On 1/17/19 5:02 AM, Roman Penyaev wrote: > Hi Jens, > > On 2019-01-16 18:49, Jens Axboe wrote: > > [...] > >> +static void *io_mem_alloc(size_t size) >> +{ >> + gfp_t gfp_flags = GFP_KERNEL | __GFP_ZERO | __GFP_NOWARN | __GFP_COMP >> | >> + __GFP_NORETRY; >> + >> + return (void *) __get_free_pages(gfp_flags, get_order(size)); > > Since these pages are shared between kernel and userspace, do we need > to care about d-cache aliasing on armv6 (or other "strange" archs > which I've never seen) with vivt or vipt cpu caches? > > E.g. vmalloc_user() targets this problem by aligning kernel address > on SHMLBA, so no flush_dcache_page() is required. I'm honestly not sure, it'd be trivial enough to stick a flush_dcache_page() into the few areas we'd need it. The rings are already page (SHMLBA) aligned. -- Jens Axboe