From patchwork Thu Sep 1 09:32:58 2022 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Dylan Yudaken X-Patchwork-Id: 12962157 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by smtp.lore.kernel.org (Postfix) with ESMTP id 66AFDECAAD1 for ; Thu, 1 Sep 2022 09:33:28 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S230101AbiIAJd1 (ORCPT ); Thu, 1 Sep 2022 05:33:27 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:42780 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S233076AbiIAJd0 (ORCPT ); Thu, 1 Sep 2022 05:33:26 -0400 Received: from mx0b-00082601.pphosted.com (mx0b-00082601.pphosted.com [67.231.153.30]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id BC4B01314DE for ; Thu, 1 Sep 2022 02:33:24 -0700 (PDT) Received: from pps.filterd (m0109332.ppops.net [127.0.0.1]) by mx0a-00082601.pphosted.com (8.17.1.5/8.17.1.5) with ESMTP id 2819Wfd1002750 for ; Thu, 1 Sep 2022 02:33:24 -0700 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=fb.com; h=from : to : cc : subject : date : message-id : in-reply-to : references : mime-version : content-transfer-encoding : content-type; s=facebook; bh=EK9NhxtaoyAmN4a9SiaR96Y291lR6GH5HqekGq5np2o=; b=D9WgXD4tDVZWePMlhM1CpIsbCBe0grlwYP2cDeNc44E0fM8wbYZc9q/L054aHcpdGxIz PTjqUvIDnrJ9Ba9rMQ2sBJTGSk+n4k1VchhSu/q1IhRWfgPOX0YCc1LBG+CgcaWwoYiI 4E1RJ73POndUEWTS2B/BEq6d5XQbuFzNQjg= Received: from maileast.thefacebook.com ([163.114.130.16]) by mx0a-00082601.pphosted.com (PPS) with ESMTPS id 3jat6s0040-1 (version=TLSv1.2 cipher=ECDHE-RSA-AES128-GCM-SHA256 bits=128 verify=NOT) for ; Thu, 01 Sep 2022 02:33:23 -0700 Received: from twshared0646.06.ash9.facebook.com (2620:10d:c0a8:1b::d) by mail.thefacebook.com (2620:10d:c0a8:83::4) with Microsoft SMTP Server (version=TLS1_2, cipher=TLS_ECDHE_RSA_WITH_AES_128_GCM_SHA256) id 15.1.2375.31; Thu, 1 Sep 2022 02:33:22 -0700 Received: by devbig038.lla2.facebook.com (Postfix, from userid 572232) id C0DCE57693FC; Thu, 1 Sep 2022 02:33:06 -0700 (PDT) From: Dylan Yudaken To: Jens Axboe , Pavel Begunkov , CC: , Dylan Yudaken Subject: [PATCH liburing v2 07/12] update io_uring_enter.2 docs for IORING_FEAT_NODROP Date: Thu, 1 Sep 2022 02:32:58 -0700 Message-ID: <20220901093303.1974274-8-dylany@fb.com> X-Mailer: git-send-email 2.30.2 In-Reply-To: <20220901093303.1974274-1-dylany@fb.com> References: <20220901093303.1974274-1-dylany@fb.com> MIME-Version: 1.0 X-FB-Internal: Safe X-Proofpoint-GUID: PvN-Nl86LZdMquk6qwvXLow3P0LnZ_B2 X-Proofpoint-ORIG-GUID: PvN-Nl86LZdMquk6qwvXLow3P0LnZ_B2 X-Proofpoint-Virus-Version: vendor=baseguard engine=ICAP:2.0.205,Aquarius:18.0.895,Hydra:6.0.517,FMLib:17.11.122.1 definitions=2022-09-01_06,2022-08-31_03,2022-06-22_01 Precedence: bulk List-ID: X-Mailing-List: io-uring@vger.kernel.org The EBUSY docs are out of date, so update them for the IORING_FEAT_NODROP feature flag Signed-off-by: Dylan Yudaken --- man/io_uring_enter.2 | 13 ++++++++++++- 1 file changed, 12 insertions(+), 1 deletion(-) diff --git a/man/io_uring_enter.2 b/man/io_uring_enter.2 index 1a9311e20357..4d8d488b5c1f 100644 --- a/man/io_uring_enter.2 +++ b/man/io_uring_enter.2 @@ -1330,7 +1330,18 @@ is a valid file descriptor, but the io_uring ring is not in the right state for details on how to enable the ring. .TP .B EBUSY -The application is attempting to overcommit the number of requests it can have +If the +.B IORING_FEAT_NODROP +feature flag is set, then +.B EBUSY +will be returned if there were overflow entries, +.B IORING_ENTER_GETEVENTS +flag is set and not all of the overflow entries were able to be flushed to +the CQ ring. + +Without +.B IORING_FEAT_NODROP +the application is attempting to overcommit the number of requests it can have pending. The application should wait for some completions and try again. May occur if the application tries to queue more requests than we have room for in the CQ ring, or if the application attempts to wait for more events without