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([2600:380:4562:fb25:b980:6664:b71f:35b5]) by smtp.gmail.com with ESMTPSA id k44sm3731287pjb.20.2020.01.23.11.13.58 (version=TLS1_3 cipher=TLS_AES_128_GCM_SHA256 bits=128/128); Thu, 23 Jan 2020 11:13:59 -0800 (PST) Subject: Re: [PATCH] io_uring: wakeup threads waiting for EPOLLOUT events To: Stefano Garzarella Cc: Alexander Viro , io-uring@vger.kernel.org, linux-kernel@vger.kernel.org, linux-fsdevel@vger.kernel.org References: <20200116134946.184711-1-sgarzare@redhat.com> <2d2dda92-3c50-ee62-5ffe-0589d4c8fc0d@kernel.dk> <20200116155557.mwjc7vu33xespiag@steredhat> <5723453a-9326-e954-978e-910b8b495b38@kernel.dk> <20200116162630.6r3xc55kdyyq5tvz@steredhat> <20200116170342.4jvkhbbw4x6z3txn@steredhat> From: Jens Axboe Message-ID: <2d3d4932-8894-6969-4006-25141ca1286e@kernel.dk> Date: Thu, 23 Jan 2020 12:13:57 -0700 User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:68.0) Gecko/20100101 Thunderbird/68.4.1 MIME-Version: 1.0 In-Reply-To: <20200116170342.4jvkhbbw4x6z3txn@steredhat> Content-Type: text/plain; charset=utf-8 Content-Language: en-US Content-Transfer-Encoding: 7bit Sender: io-uring-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: io-uring@vger.kernel.org On 1/16/20 10:03 AM, Stefano Garzarella wrote: > On Thu, Jan 16, 2020 at 09:30:12AM -0700, Jens Axboe wrote: >> On 1/16/20 9:26 AM, Stefano Garzarella wrote: >>>> Since the use case is mostly single submitter, unless you're doing >>>> something funky or unusual, you're not going to be needing POLLOUT ever. >>> >>> The case that I had in mind was with kernel side polling enabled and >>> a single submitter that can use epoll() to wait free slots in the SQ >>> ring. (I don't have a test, maybe I can write one...) >> >> Right, I think that's the only use case where it makes sense, because >> you have someone else draining the sq side for you. A test case would >> indeed be nice, liburing has a good arsenal of test cases and this would >> be a good addition! > > Sure, I'll send a test to liburing for this case! Gentle ping on the test case :-) -- Jens Axboe