From mboxrd@z Thu Jan 1 00:00:00 1970 From: Christoph Hellwig Subject: Re: [PATCH 05/24] compatfd is included before, and it is compiled unconditionally Date: Thu, 1 Oct 2009 08:05:08 -0400 Message-ID: <20091001120508.GA2459@infradead.org> References: <6e46fe952ba8d1896e3cab5b24232828d3f827a9.1253272938.git.quintela@redhat.com> <20090922131901.GA22109@infradead.org> <20090922133438.GA12443@infradead.org> Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii Cc: Christoph Hellwig , kvm@vger.kernel.org To: Juan Quintela Return-path: Received: from bombadil.infradead.org ([18.85.46.34]:50762 "EHLO bombadil.infradead.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1756514AbZJAMFF (ORCPT ); Thu, 1 Oct 2009 08:05:05 -0400 Content-Disposition: inline In-Reply-To: Sender: kvm-owner@vger.kernel.org List-ID: On Thu, Oct 01, 2009 at 01:58:10PM +0200, Juan Quintela wrote: > Discused with Anthony about it. signalfd is complicated for qemu > upstream (too difficult to use properly), and eventfd ... The current > eventfd emulation is worse than the pipe code that it substitutes. > > His suggestion here was to create a new abstraction with an API like: > > push_notify() > > pop_notify() > > and then you can implement it with eventfd() pipes/whatever. > > What was missing for you of compatfd: qemu_eventfd/qemu_signalfd? > Do a push_notify()/pop_notify() work for you? I don't desperately want to use it myself anyway. I just want to get rid of the highly annoyind spurious differences in the AIO code due to use of compatfd. I would be perfectly fine with just killing this use of eventfd in qemu-kvm.