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([2605:e000:100e:8c61:adf1:7e34:eff4:95bb]) by smtp.gmail.com with ESMTPSA id w126sm2516181pfb.117.2020.05.15.11.17.41 (version=TLS1_3 cipher=TLS_AES_128_GCM_SHA256 bits=128/128); Fri, 15 May 2020 11:17:42 -0700 (PDT) Subject: Re: [PATCH v2 0/2] io_uring: add a CQ ring flag to enable/disable eventfd notification To: Stefano Garzarella Cc: linux-kernel@vger.kernel.org, Alexander Viro , io-uring@vger.kernel.org, linux-fsdevel@vger.kernel.org References: <20200515163805.235098-1-sgarzare@redhat.com> From: Jens Axboe Message-ID: <5795fd28-ee65-e610-5472-d1493902f2cd@kernel.dk> Date: Fri, 15 May 2020 12:17:40 -0600 User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:68.0) Gecko/20100101 Thunderbird/68.7.0 MIME-Version: 1.0 In-Reply-To: <20200515163805.235098-1-sgarzare@redhat.com> 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 5/15/20 10:38 AM, Stefano Garzarella wrote: > v1 -> v2: > - changed the flag name and behaviour from IORING_CQ_NEED_EVENT to > IORING_CQ_EVENTFD_DISABLED [Jens] > > The first patch adds the new 'cq_flags' field for the CQ ring. It > should be written by the application and read by the kernel. > > The second patch adds a new IORING_CQ_EVENTFD_DISABLED flag that can be > used by the application to disable/enable eventfd notifications. > > This feature can be useful if the application are using eventfd to be > notified when requests are completed, but they don't want a notification > for every request. > Of course the application can already remove the eventfd from the event > loop, but as soon as it adds the eventfd again, it will be notified, > even if it has already handled all the completed requests. > > The most important use case is when the registered eventfd is used to > notify a KVM guest through irqfd and we want a mechanism to > enable/disable interrupts. Thanks, applied. -- Jens Axboe