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=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 C155CC43444 for ; Thu, 17 Jan 2019 20:03:45 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 9B1E520851 for ; Thu, 17 Jan 2019 20:03:45 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1729308AbfAQUDo (ORCPT ); Thu, 17 Jan 2019 15:03:44 -0500 Received: from mx1.redhat.com ([209.132.183.28]:44800 "EHLO mx1.redhat.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1728801AbfAQUDo (ORCPT ); Thu, 17 Jan 2019 15:03:44 -0500 Received: from smtp.corp.redhat.com (int-mx04.intmail.prod.int.phx2.redhat.com [10.5.11.14]) (using TLSv1.2 with cipher AECDH-AES256-SHA (256/256 bits)) (No client certificate requested) by mx1.redhat.com (Postfix) with ESMTPS id A18E58DFFA; Thu, 17 Jan 2019 20:03:43 +0000 (UTC) Received: from segfault.boston.devel.redhat.com (segfault.boston.devel.redhat.com [10.19.60.26]) by smtp.corp.redhat.com (Postfix) with ESMTPS id A0E3D607AD; Thu, 17 Jan 2019 20:03:42 +0000 (UTC) From: Jeff Moyer To: Jens Axboe 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 Subject: Re: [PATCH 05/15] Add io_uring IO interface References: <20190116175003.17880-1-axboe@kernel.dk> <20190116175003.17880-6-axboe@kernel.dk> <718b4d1fbe9f97592d6d7b76d7a4537d@suse.de> X-PGP-KeyID: 1F78E1B4 X-PGP-CertKey: F6FE 280D 8293 F72C 65FD 5A58 1FF8 A7CA 1F78 E1B4 Date: Thu, 17 Jan 2019 15:03:41 -0500 In-Reply-To: (Jens Axboe's message of "Thu, 17 Jan 2019 07:01:07 -0700") Message-ID: User-Agent: Gnus/5.13 (Gnus v5.13) Emacs/26.1 (gnu/linux) MIME-Version: 1.0 Content-Type: text/plain X-Scanned-By: MIMEDefang 2.79 on 10.5.11.14 X-Greylist: Sender IP whitelisted, not delayed by milter-greylist-4.5.16 (mx1.redhat.com [10.5.110.27]); Thu, 17 Jan 2019 20:03:43 +0000 (UTC) Sender: linux-block-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-block@vger.kernel.org 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. -Jeff