From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from mail-pj1-f48.google.com (mail-pj1-f48.google.com [209.85.216.48]) (using TLSv1.2 with cipher ECDHE-RSA-AES128-GCM-SHA256 (128/128 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id 55E8B50297 for ; Sun, 5 May 2024 18:11:15 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=209.85.216.48 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1714932676; cv=none; b=SmagLmVgZ3amVm7UTcLIfV+uvU+Hw9lfyAjuRoSF9EDPnpmjf4Ui2cue0ImfZZyKvl6hUBZEbiwybrGbkur25dv5I70bypIzg1bR9rVTdL1GHlXh68BVkNb5u+uGbDTavQJ2n63n0aaoSMvtrzWdO/0yv81G+UEdnKsRLYIX/ak= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1714932676; c=relaxed/simple; bh=k5jNgrzGGbB2SvX2lsGfqjuVDXY9NBn3s5nTft65hiY=; h=Message-ID:Date:MIME-Version:Subject:To:References:From: In-Reply-To:Content-Type; b=LHmqZW6a92911njXRuBHwvG5rZ8GrA1MMPTbSagwrkyGUO3Qn70jPvGNMj77UroK+Vryd8JAtHoVDhgkHjcezY7MvgwzUKeMdPPK0cFt9mPsqEddhE5iJA4VqB8SbNKMxqV9MNBXEj1TOeI52Ms/hqzVhs/16x41udiKuC3thrw= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dmarc=none (p=none dis=none) header.from=kernel.dk; spf=pass smtp.mailfrom=kernel.dk; dkim=pass (2048-bit key) header.d=kernel-dk.20230601.gappssmtp.com header.i=@kernel-dk.20230601.gappssmtp.com header.b=nmzD12c9; arc=none smtp.client-ip=209.85.216.48 Authentication-Results: smtp.subspace.kernel.org; dmarc=none (p=none dis=none) header.from=kernel.dk Authentication-Results: smtp.subspace.kernel.org; spf=pass smtp.mailfrom=kernel.dk Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel-dk.20230601.gappssmtp.com header.i=@kernel-dk.20230601.gappssmtp.com header.b="nmzD12c9" Received: by mail-pj1-f48.google.com with SMTP id 98e67ed59e1d1-2b360096cc4so361496a91.1 for ; Sun, 05 May 2024 11:11:15 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=kernel-dk.20230601.gappssmtp.com; s=20230601; t=1714932674; x=1715537474; darn=vger.kernel.org; h=content-transfer-encoding:in-reply-to:from:content-language :references:to:subject:user-agent:mime-version:date:message-id:from :to:cc:subject:date:message-id:reply-to; bh=tvHkh+5kPDtKzELkpdAuxAbICGRQaj83JbyqcP/eSAU=; b=nmzD12c9Q1P8BZhkvlXv6AHqVQIo4Ok1aSpf1V2yqx2ppIcOcIaMIUyVKFRfkEViut rXMpLkc+fcbaDvECzJYmrG9bLunx2yiEPJwB9sXjGpcwC+DuhiZw1daYeb4QmaM14l1M LBKeNNt2DFjTp3fULGxTvIdJ8DLTyyHgiov0XDRQYg+yBGpljf0OKDoSm4vbfmYtQsaV 3Xzbmv8oreVvhG2YNlgmJKy8pgs6+WKctgSJCtuS+zP4oyij/NJgaETMKVMjg9EKwfxx uFaEOfWEW25sJi++X2tjIdV3Qv6qcBZr35bP5AEe1rUElFfpA9c2aNXl4IjQaenEtKN/ TTWw== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20230601; t=1714932674; x=1715537474; h=content-transfer-encoding:in-reply-to:from:content-language :references:to:subject:user-agent:mime-version:date:message-id :x-gm-message-state:from:to:cc:subject:date:message-id:reply-to; bh=tvHkh+5kPDtKzELkpdAuxAbICGRQaj83JbyqcP/eSAU=; b=hNvQgEdg5OprdJ6v7NKOWVvGQyouT2xVn4e6TxpXHFd0/vlpR2Hf2kfLJ1HyzX2vRb f8lOSRTmODnpNQRkKYExCPpZV+D5Mm5aVjZIsXVmTVsxzEI88FIs+SaYHcOS2qPLssra lTO49tTvwieRyEWDrG6ARR5DLcVEAeDFWtQTTeslOIv0ywl+RCL4wO506679XkRevR9T D7yHFRqlL6gaHRAuqcqzyXxhfOIWTZ43zAjvGkzgX3DBol8qXN1OJi4mz7ROHpD85rE3 WvQO/Ymm91UzEY+HcHT5QHTAxYazm0mzBOHo2CqIzrC2+6DrVYZC21m74O8kpeyoP6Qh 2pHw== X-Forwarded-Encrypted: i=1; AJvYcCW91VPB3isbtQc/68ST5UtF7/VkQGSLQn7fWncNGJVcMCqT/QnNd1kozuqI2yuWbQXVaCLD4phq461WEfa2CNgreS01nfthyhU= X-Gm-Message-State: AOJu0YyHHepFEdlWHp9Jhrsw07jpb/j1qGK1MOsJg76pA5ISjzYEOQ09 PjKDMkMsSkowdWf6wLtXq85qzIuiHRwh/SyOImZFb0cucsHcnsrCyBrD0abJerWwUx199GENQse w X-Google-Smtp-Source: AGHT+IGj6N9fxxnYXC4h6uBDX32Dot6YiT9LutH6nE805dGPLKECQeOiPMh4BlgEE6SvAgJ6nH2eqA== X-Received: by 2002:a17:902:e84e:b0:1e5:1138:e299 with SMTP id t14-20020a170902e84e00b001e51138e299mr10911914plg.1.1714932674659; Sun, 05 May 2024 11:11:14 -0700 (PDT) Received: from [192.168.1.150] ([198.8.77.194]) by smtp.gmail.com with ESMTPSA id e15-20020a17090301cf00b001ec852124f6sm6760889plh.309.2024.05.05.11.11.13 (version=TLS1_3 cipher=TLS_AES_128_GCM_SHA256 bits=128/128); Sun, 05 May 2024 11:11:14 -0700 (PDT) Message-ID: <15ea2df8-f2e3-4cc5-89e0-1abb2279a55b@kernel.dk> Date: Sun, 5 May 2024 12:11:13 -0600 Precedence: bulk X-Mailing-List: io-uring@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 User-Agent: Mozilla Thunderbird Subject: Re: Submitting IO events with IORING_FEAT_NODROP and overflown CQ ring To: Alexander Babayants , io-uring@vger.kernel.org References: Content-Language: en-US From: Jens Axboe In-Reply-To: Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 7bit On 5/3/24 5:21 PM, Alexander Babayants wrote: > Hi! > > Per io_uring_setup(2): > >> IORING_FEAT_NODROP > ... >> If this overflow condition is entered, >> attempting to submit more IO will fail with the -EBUSY >> error value, if it can't flush the overflown events to the >> CQ ring. If this happens, the application must reap events >> from the CQ ring and attempt the submit again. > > But I'm not getting -EBUSY on a 6.2 kernel when submitting to the ring > with a full CQ ring and an overflow flag set. I'm not an expert in > uring code, but it seems the error was removed in commit > 1b346e4aa8e79227391ffd6b7c6ee5acf0fa8bfc. Could you please check if > I'm right and if that change was intentional? This is correct and intentional. The man page should get updated with a note on the current behavior. -- Jens Axboe