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 32893C43387 for ; Thu, 17 Jan 2019 20:14:14 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id F26E620859 for ; Thu, 17 Jan 2019 20:14:13 +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="fjRezZAh" Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1729529AbfAQUOM (ORCPT ); Thu, 17 Jan 2019 15:14:12 -0500 Received: from mail-it1-f196.google.com ([209.85.166.196]:53291 "EHLO mail-it1-f196.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1729313AbfAQUOM (ORCPT ); Thu, 17 Jan 2019 15:14:12 -0500 Received: by mail-it1-f196.google.com with SMTP id g85so3445620ita.3 for ; Thu, 17 Jan 2019 12:14:11 -0800 (PST) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=kernel-dk.20150623.gappssmtp.com; s=20150623; h=subject:from:to:cc:references:message-id:date:user-agent :mime-version:in-reply-to:content-language:content-transfer-encoding; bh=XyRrDI3BH5M0SQKfmOW5KmC4HdgD8pjALNOmbTA6qAM=; b=fjRezZAhlht5g3vpPbBL94ihrpsSDmU+UkqOod54zIRfnRVmyaSCmlqWnB/3f1fOqs OQ2tZlFaWri8N4NtUBUeWd3OIiixTtEzzRu+eOrgjoQBjfkKwYIkE5JAI+inMw93vvOi pEJUHzCtuO2ss/iy9bGSn0fbOkgOibfv/cZRV+LnBi95sEV3Tr0tyx2lfM2gEAoR+YMp 6HMbJJYpMIm/cROCyqkX6a7IPnseTi+IEsfvkDQVEWjadJDJ5acK+ineqxjdgHaKayyq 4c9QA+XmzeAo/y+aQOCINt3AswNrOLjglrqsCBCF+SGRyFKdprLwuTKaUV/rsLaLLGVR iYEw== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20161025; h=x-gm-message-state:subject:from:to:cc:references:message-id:date :user-agent:mime-version:in-reply-to:content-language :content-transfer-encoding; bh=XyRrDI3BH5M0SQKfmOW5KmC4HdgD8pjALNOmbTA6qAM=; b=lPiigc7BQDMMYRoGoNUHjJFxbO1wYpFappumIAes+ldBr9zCv7ktMbWm7OcNpEkE7C n+oIId0SsnY43olgqtBpTlNPF+a/pa4IsoTgInNByfMswvTOLTDo86WBljmNR4dDkkZ1 LC+WO5eABure31Mj4qaHyP92Ql950kiU4hHrcJO3hBRx31AvDGx6edJlBlLt7Fh062+6 IzQN256VQiEX2IfpQtSfXWNxoN0noYV+9SNPc84XStmnMUdCs/Xu8y4JTDfT58NS/VC6 KMKW9Cyvlz2FoYtE5BAsQpqxTlWfR8BuOJQs6nuFo3ljKA5eUZxdH94TYATcWLPH7yQc hjAg== X-Gm-Message-State: AJcUukcfcRj/pnn9xPbUWGQgWlpOXtQFnby6oX/T5X9pF2dbn0kbLIev //F/0rln1Zp56FCUchkcAgAVXw== X-Google-Smtp-Source: ALg8bN7o783jjdmJouM/SIB9WNij+RjQ6S4T56Pjc/qBzSPkM/CJxbLe3eBaVsGM2rmsqa5eyWoyuQ== X-Received: by 2002:a02:b424:: with SMTP id i33mr9690951jaj.37.1547756051483; Thu, 17 Jan 2019 12:14:11 -0800 (PST) Received: from [192.168.1.56] ([216.160.245.98]) by smtp.gmail.com with ESMTPSA id v19sm1144935itb.0.2019.01.17.12.14.09 (version=TLS1_2 cipher=ECDHE-RSA-AES128-GCM-SHA256 bits=128/128); Thu, 17 Jan 2019 12:14:10 -0800 (PST) Subject: Re: [PATCH 05/15] Add io_uring IO interface From: Jens Axboe To: Jeff Moyer Cc: Roman Penyaev , linux-fsdevel@vger.kernel.org, linux-aio@kvack.org, linux-block@vger.kernel.org, linux-arch@vger.kernel.org, hch@lst.de, avi@scylladb.com, linux-block-owner@vger.kernel.org References: <20190116175003.17880-1-axboe@kernel.dk> <20190116175003.17880-6-axboe@kernel.dk> <718b4d1fbe9f97592d6d7b76d7a4537d@suse.de> Message-ID: <02568485-cd10-182d-98e3-619077cf9bdc@kernel.dk> Date: Thu, 17 Jan 2019 13:14:09 -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 1/17/19 1:09 PM, Jens Axboe wrote: > On 1/17/19 1:03 PM, Jeff Moyer wrote: >> Jens Axboe writes: >> >>> On 1/17/19 5:48 AM, Roman Penyaev wrote: >>>> On 2019-01-16 18:49, Jens Axboe wrote: >>>> >>>> [...] >>>> >>>>> +static int io_allocate_scq_urings(struct io_ring_ctx *ctx, >>>>> + struct io_uring_params *p) >>>>> +{ >>>>> + struct io_sq_ring *sq_ring; >>>>> + struct io_cq_ring *cq_ring; >>>>> + size_t size; >>>>> + int ret; >>>>> + >>>>> + sq_ring = io_mem_alloc(struct_size(sq_ring, array, p->sq_entries)); >>>> >>>> It seems that sq_entries, cq_entries are not limited at all. Can nasty >>>> app consume a lot of kernel pages calling io_setup_uring() from a loop >>>> passing random entries number? (or even better: decreasing entries >>>> number, >>>> in order to consume all pages orders with min number of loops). >>> >>> Yes, that's an oversight, we should have a limit in place. I'll add that. >> >> Can we charge the ring memory to the RLIMIT_MEMLOCK as well? I'd prefer >> not to repeat the mistake of fs.aio-max-nr. > > Sure, we can do that. With the ring limited in size (it's now 4k entries > at most), the amount of memory gobbled up by that is much smaller than > the fixed buffers. A max sized ring is about 256k of memory. One concern here is that, at least looking at my boxes, the default setting for RLIMIT_MEMLOCK is really low. I'd hate for everyone to run into issues using io_uring just because it seems to require root, because the memlock limit is so low. That's much less of a concern with the fixed buffers, since it's a more esoteric part of it. But everyone should be able to setup a few io_uring queues and use them without having to worry about failing due to an absurdly low RLIMIT_MEMLOCK. Comments? -- Jens Axboe