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Mon, 22 Jan 2024 13:16:19 -0800 (PST) Received: from fastly.com ([208.184.224.238]) by smtp.gmail.com with ESMTPSA id u4-20020a170902b28400b001d720c7ed48sm5693728plr.286.2024.01.22.13.16.18 (version=TLS1_2 cipher=ECDHE-RSA-AES128-GCM-SHA256 bits=128/128); Mon, 22 Jan 2024 13:16:19 -0800 (PST) Date: Mon, 22 Jan 2024 13:16:16 -0800 From: Joe Damato To: Christian Brauner Cc: netdev@vger.kernel.org, linux-kernel@vger.kernel.org, chuck.lever@oracle.com, jlayton@kernel.org, linux-api@vger.kernel.org, edumazet@google.com, davem@davemloft.net, alexander.duyck@gmail.com, sridhar.samudrala@intel.com, kuba@kernel.org Subject: Re: [RFC 1/1] eventpoll: support busy poll per epoll instance Message-ID: <20240122211616.GA1244@fastly.com> References: <20240120004247.42036-1-jdamato@fastly.com> <20240120004247.42036-2-jdamato@fastly.com> <20240122-erwidern-erleichtern-8a04080a4db3@brauner> Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20240122-erwidern-erleichtern-8a04080a4db3@brauner> User-Agent: Mutt/1.5.24 (2015-08-30) On Mon, Jan 22, 2024 at 04:25:01PM +0100, Christian Brauner wrote: > On Sat, Jan 20, 2024 at 12:42:47AM +0000, Joe Damato wrote: > > Add F_EPOLL_{S,G}ET_BUSY_POLL_USECS to allow setting a busy poll timeout > > per epoll instance so that individual applications can enable (or > > disable) epoll based busy poll as needed. > > > > Prior to this change, epoll-based busy poll could only be enabled > > system-wide, which limits the usefulness of busy poll. > > > > Signed-off-by: Joe Damato > > --- > > This should be an ioctl on the epoll fd, not a fcntl(). fcntl()s > should aim to be generic which this isn't. We've recently rejected a > memfd addition as a fcntl() as well for the same reason. OK, thanks for the review. An ioctl makes more sense, I agree. I'll rewrite it as you've suggested and send another RFC.