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, URIBL_BLOCKED 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 A8A14C04EB8 for ; Fri, 30 Nov 2018 22:12:03 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 6CFD12082F for ; Fri, 30 Nov 2018 22:12:03 +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="kZL2O/lE" DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org 6CFD12082F 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-block-owner@vger.kernel.org Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1726139AbeLAJWr (ORCPT ); Sat, 1 Dec 2018 04:22:47 -0500 Received: from mail-it1-f196.google.com ([209.85.166.196]:34010 "EHLO mail-it1-f196.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1726111AbeLAJWr (ORCPT ); Sat, 1 Dec 2018 04:22:47 -0500 Received: by mail-it1-f196.google.com with SMTP id x124so3027501itd.1 for ; Fri, 30 Nov 2018 14:12:01 -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=/p0yTGibIrupKYU42dPBLFonRWhw4F3SMz4uxrjj8KE=; b=kZL2O/lEPo6+eUS6j+BpAjWoEkm69l8u8j1yCtNDlnAWcW+NNnslCQxVGYBXB1QPZS XHQIl3YH3apEixYKMi5C3rZNbFQsmgTVWCGG5GFBQZ1WJLi2qr90pdOYSrPYjhQ1wWg5 v4NykgdaWD54kpzbA/SejHxpKOGTESXpDx5Q+487XfAMUP+4QBbvKhfxVpPn9JfWRHPC Y7iB1lPFT1FlSNjTSbYnzq9+bP/nA5tuivGm3s+7Cz4Fn6x+0s0jiExkZYMwoKTtS0Xg H5fuJmnGwhUVJxjSCCQ4rzXGHUcHeuKsaimyOGxVq4WcpX5m5EsOzN52IFshJ7lamLVC BU1w== 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=/p0yTGibIrupKYU42dPBLFonRWhw4F3SMz4uxrjj8KE=; b=dhym4eSKfCGWq//JWC8FC+huzAa0HPOpgDlHAo27dYgHbctVuqTjR568rDshwNfT73 td/65bYMPc6ETIiY67Gy/95ug46FDCfEMCP9g5W6sHjBZTp0VNncwIlo67es00tDRkhU 3ymobkQRUEr5yd47/F4qTALl0Cb01goJCoE22dDC8dQ96izxdEZk4vr3wJEoNshjjMcy AMG5I/9XjWmLZKoLfqGdPC9GemXupHeHkbQmP6iImG/Qken7kp/KTeOa9Tfh92+U3bls vEIgx7AoTwU0WL2xJI4CjloD1N4ay/qXxkFFD782dVomjQKHPX/H/g1v4odRrwvGlPPH 38xA== X-Gm-Message-State: AA+aEWbSx3xPxOhJezNrdScijYhnWUDVh0oU3FM/N3/JBNtP4ws+GrF9 Ok9sm1L0G6+Li6gAEdQVAvZzqQ== X-Google-Smtp-Source: AFSGD/XaLabHs9+1lPwqYSqKR5OIR5wlX33qiridV0BSn9rwMgLewrGXsmVV35JVyW0ykLtbbGE3Gg== X-Received: by 2002:a24:3842:: with SMTP id b63mr587692ita.19.1543615921123; Fri, 30 Nov 2018 14:12:01 -0800 (PST) Received: from [192.168.1.56] ([216.160.245.98]) by smtp.gmail.com with ESMTPSA id d3sm208957itc.40.2018.11.30.14.11.59 (version=TLS1_2 cipher=ECDHE-RSA-AES128-GCM-SHA256 bits=128/128); Fri, 30 Nov 2018 14:12:00 -0800 (PST) Subject: Re: [PATCH 27/27] aio: add support for pre-mapped user IO buffers To: Jeff Moyer Cc: linux-block@vger.kernel.org, linux-fsdevel@vger.kernel.org, linux-aio@kvack.org, hch@lst.de References: <20181130165646.27341-1-axboe@kernel.dk> <20181130165646.27341-28-axboe@kernel.dk> <8dc2ea1d-b6a4-728b-7550-87d32240989c@kernel.dk> From: Jens Axboe Message-ID: Date: Fri, 30 Nov 2018 15:11:59 -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: 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 11/30/18 3:04 PM, Jeff Moyer wrote: > Jens Axboe writes: > >>>> A limit of 4M is imposed as the largest buffer we currently support. >>>> There's nothing preventing us from going larger, but we need some cap, >>>> and 4M seemed like it would definitely be big enough. >>> >>> Doesn't this mean that a user can pin a bunch of memory? Something like >>> 4MB * aio_max_nr? >>> >>> $ sysctl fs.aio-max-nr >>> fs.aio-max-nr = 1048576 >>> >>> If so, it may be a good idea to account the memory under RLIMIT_MEMLOCK. >> >> Yes, it'll need some kind of limiting, right now the limit would indeed >> be aio-max-nr * 4MB. 4G isn't terrible, but... > > Unless my math's wrong, that's 4TiB on my system. ;-) I guess that's a little more terrible ;-) >> RLIMIT_MEMLOCK isn't a bad idea. >> >>> I'm not sure how close you are to proposing this patch set for realz. >>> If it's soon (now?), then CC-ing linux-api and writing man pages would >>> be a good idea. I can help out with the libaio bits if you'd like. I >>> haven't yet had time to take this stuff for a spin, sorry. I'll try to >>> get to that soonish. >> >> I am proposing it for real, not sure how long it'll take to get it >> reviewed and moved forward. Unless I get lucky. 4.22 seems like a more >> viable version than 4.21. >> >> I'll take any help I can get on the API/man page parts. And/or testing! > > OK, I'll add libaio support (including unit tests), write the man page, > and I'll definitely do some testing. I'll start on all that probably in > the latter half of next week. Awesome, that's much appreciated! -- Jens Axboe