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[142.68.25.194]) by smtp.gmail.com with ESMTPSA id q185-20020a632ac2000000b0055fedbf1938sm278952pgq.31.2023.07.17.15.12.17 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Mon, 17 Jul 2023 15:12:18 -0700 (PDT) Received: from jgg by wakko with local (Exim 4.95) (envelope-from ) id 1qLWS0-002PFZ-GX; Mon, 17 Jul 2023 19:12:16 -0300 Date: Mon, 17 Jul 2023 19:12:16 -0300 From: Jason Gunthorpe To: Alex Williamson Cc: Grzegorz Jaszczyk , Christian Brauner , linux-fsdevel@vger.kernel.org, linux-aio@kvack.org, linux-usb@vger.kernel.org, Matthew Rosato , Paul Durrant , Tom Rix , Jason Wang , dri-devel@lists.freedesktop.org, Michal Hocko , linux-mm@kvack.org, Kirti Wankhede , Paolo Bonzini , Jens Axboe , Vineeth Vijayan , Diana Craciun , Alexander Gordeev , Xuan Zhuo , Shakeel Butt , Vasily Gorbik , Leon Romanovsky , Harald Freudenberger , Fei Li , x86@kernel.org, Roman Gushchin , Halil Pasic , Ingo Molnar , intel-gfx@lists.freedesktop.org, Christian Borntraeger , linux-fpga@vger.kernel.org, Zhi Wang , Wu Hao , Jason Herne , Eric Farman , Dave Hansen , Andrew Donnellan , Arnd Bergmann , linux-s390@vger.kernel.org, Heiko Carstens , Johannes Weiner , linuxppc-dev@lists.ozlabs.org, Eric Auger , Borislav Petkov , kvm@vger.kernel.org, Rodrigo Vivi , cgroups@vger.kernel.org, Thomas Gleixner , virtualization@lists.linux-foundation.org, intel-gvt-dev@lists.freedesktop.org, io-uring@vger.kernel.org, netdev@vger.kernel.org, Tony Krowiak , Tvrtko Ursulin , Pavel Begunkov , Sean Christopherson , Oded Gabbay , Muchun Song , Peter Oberparleiter , linux-kernel@vger.kernel.org, linux-rdma@vger.kernel.org, Benjamin LaHaise , "Michael S. Tsirkin" , Sven Schnelle , Greg Kroah-Hartman , Frederic Barrat , Moritz Fischer , Vitaly Kuznetsov , David Woodhouse , Xu Yilun , Dominik Behr , Marcin Wojtas Subject: Re: [PATCH 0/2] eventfd: simplify signal helpers Message-ID: References: <20230630155936.3015595-1-jaz@semihalf.com> <20230714-gauner-unsolidarisch-fc51f96c61e8@brauner> <20230717130831.0f18381a.alex.williamson@redhat.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20230717130831.0f18381a.alex.williamson@redhat.com> X-Rspamd-Queue-Id: D9A49A0010 X-Rspam-User: X-Rspamd-Server: rspam02 X-Stat-Signature: bskyek767h6j91fiomqd43azdsnjkr9s X-HE-Tag: 1689631940-42666 X-HE-Meta: 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 KflIO809 6rh2Cyzh+dNB5t+OOzX26aYFLGDUICOYtsij9EW0pw0W03wJlhPwLbLofKj3LxoY02OgdxFo9XzTeQTbhw5BOVED4XgIXvKRmw/mYUDDF/8ffNk66ZSUAAqYzhx/qsULmEBkc+3rn3I3D/wwvfNAVvJ2bwlDAuDIPowJb0IIi0cLMPxT1HN4o4kYu1UNzyBw4wgPZTXdHg94ruwTbxNysegvC/bl7jXU3kJOHEHsTMpmAg1IulrwuuYzI8iURxo5T/KBLfrKKjor3eFlDl9GPH73PfPp1580PilJFoz0zTxIZqB4KB1L4ZdFwXFWl96hXhlbb/N4rAXV4oSe4DYFov5F+PoekrV1GQ4GTfcYQijT/JHM2CasP2Y/yMzz4I48E5cVOhqMlEiqHtYU= X-Bogosity: Ham, tests=bogofilter, spamicity=0.000000, version=1.2.4 Sender: owner-linux-mm@kvack.org Precedence: bulk X-Loop: owner-majordomo@kvack.org List-ID: On Mon, Jul 17, 2023 at 01:08:31PM -0600, Alex Williamson wrote: > What would that mechanism be? We've been iterating on getting the > serialization and buffering correct, but I don't know of another means > that combines the notification with a value, so we'd likely end up with > an eventfd only for notification and a separate ring buffer for > notification values. All FDs do this. You just have to make a FD with custom file_operations that does what this wants. The uAPI shouldn't be able to tell if the FD is backing it with an eventfd or otherwise. Have the kernel return the FD instead of accepting it. Follow the basic design of eg mlx5vf_save_fops Jason