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=-4.1 required=3.0 tests=BAYES_00,DKIMWL_WL_HIGH, DKIM_SIGNED,DKIM_VALID,DKIM_VALID_AU,HEADER_FROM_DIFFERENT_DOMAINS, MAILING_LIST_MULTI,SPF_HELO_NONE,SPF_PASS autolearn=no 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 D94E7C433E1 for ; Thu, 13 Aug 2020 20:49:13 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id A782620675 for ; Thu, 13 Aug 2020 20:49:13 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (1024-bit key) header.d=redhat.com header.i=@redhat.com header.b="KW+C77a/" Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1726384AbgHMUtN (ORCPT ); Thu, 13 Aug 2020 16:49:13 -0400 Received: from us-smtp-2.mimecast.com ([205.139.110.61]:29381 "EHLO us-smtp-delivery-1.mimecast.com" rhost-flags-OK-OK-OK-FAIL) by vger.kernel.org with ESMTP id S1726192AbgHMUtN (ORCPT ); Thu, 13 Aug 2020 16:49:13 -0400 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=redhat.com; s=mimecast20190719; t=1597351751; h=from:from:reply-to:subject:subject:date:date:message-id:message-id: to:to:cc:cc:mime-version:mime-version:content-type:content-type: in-reply-to:in-reply-to:references:references; bh=ffn4p6zbGDq2jZcq23ay+hgurYer5FQwJQjcpNrhDM8=; b=KW+C77a/W/v8+qYZfd72B2wTzPVS+b33AQO3M7+I1Lx6FCtkqwXEHsKt9+vkYZqehQyUNZ /sTg4weTSUJVjqVMLoaZ/x6wUsn7AA9ZxlzGRE96TkOr6MtLRcLLROKvUazH7q60vFmnsF H5b9Bpsr5fTt9s+zEQA3ly3zO2zvb5c= Received: from mimecast-mx01.redhat.com (mimecast-mx01.redhat.com [209.132.183.4]) (Using TLS) by relay.mimecast.com with ESMTP id us-mta-328-dZ5c0GxXPg-ZEsbNZFeN7w-1; Thu, 13 Aug 2020 16:49:09 -0400 X-MC-Unique: dZ5c0GxXPg-ZEsbNZFeN7w-1 Received: from smtp.corp.redhat.com (int-mx06.intmail.prod.int.phx2.redhat.com [10.5.11.16]) (using TLSv1.2 with cipher AECDH-AES256-SHA (256/256 bits)) (No client certificate requested) by mimecast-mx01.redhat.com (Postfix) with ESMTPS id A2C2C1005504; Thu, 13 Aug 2020 20:49:08 +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 421AD5C1C2; Thu, 13 Aug 2020 20:49:08 +0000 (UTC) From: Jeff Moyer To: Jens Axboe Cc: io-uring@vger.kernel.org, david@fromorbit.com Subject: Re: [PATCHSET 0/2] io_uring: handle short reads internally References: <20200813175605.993571-1-axboe@kernel.dk> <99c39782-6523-ae04-3d48-230f40bc5d05@kernel.dk> <9f050b83-a64a-c112-fc26-309342076c71@kernel.dk> X-PGP-KeyID: 1F78E1B4 X-PGP-CertKey: F6FE 280D 8293 F72C 65FD 5A58 1FF8 A7CA 1F78 E1B4 Date: Thu, 13 Aug 2020 16:49:07 -0400 In-Reply-To: (Jens Axboe's message of "Thu, 13 Aug 2020 14:41:36 -0600") 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 10.5.11.16 Sender: io-uring-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: io-uring@vger.kernel.org Jens Axboe writes: > On 8/13/20 2:37 PM, Jens Axboe wrote: >> On 8/13/20 2:33 PM, Jens Axboe wrote: >>> On 8/13/20 2:25 PM, Jeff Moyer wrote: >>>> Jens Axboe writes: >>>> >>>>> Since we've had a few cases of applications not dealing with this >>>>> appopriately, I believe the safest course of action is to ensure that >>>>> we don't return short reads when we really don't have to. >>>>> >>>>> The first patch is just a prep patch that retains iov_iter state over >>>>> retries, while the second one actually enables just doing retries if >>>>> we get a short read back. >>>> >>>> Have you run this through the liburing regression tests? >>>> >>>> Tests failed >>>> >>>> I'll take a look at the failures, but wanted to bring it to your >>>> attention sooner rather than later. I was using your io_uring-5.9 >>>> branch. >>> >>> The eed8b54e0df-test failure is known with this one, pretty sure it >>> was always racy, but I'm looking into it. >>> >>> The timeout-overflow test needs fixing, it's just an ordering thing >>> with the batched completions done through submit. Not new with these >>> patches. OK. >>> The read-write one I'm interested in, what did you run it on? And >>> what was the failure? >> >> BTW, what git sha did you run? > > I do see a failure with dm on that, I'll take a look. I ran it on a file system atop nvme with 8 poll queues. liburing head: 9e1d69e078ee51f253a829ff421b17cfc996d158 linux-block head: ff1353802d86a9d8e40ef1377efb12a1d3000a20 The error I saw was: Running test read-write: Non-vectored IO not supported, skipping cqe res -22, wanted 2048 test_buf_select_short vec failed Test read-write failed with ret 1 But I don't think it was due to these two commits. Thanks, Jeff