From mboxrd@z Thu Jan 1 00:00:00 1970 From: Anthony Liguori Subject: Re: [PATCH 05/24] compatfd is included before, and it is compiled unconditionally Date: Thu, 01 Oct 2009 09:24:27 -0500 Message-ID: <4AC4BB9B.9090907@codemonkey.ws> References: <6e46fe952ba8d1896e3cab5b24232828d3f827a9.1253272938.git.quintela@redhat.com> <20090922131901.GA22109@infradead.org> <20090922133438.GA12443@infradead.org> <20091001120508.GA2459@infradead.org> Mime-Version: 1.0 Content-Type: text/plain; charset=ISO-8859-1; format=flowed Content-Transfer-Encoding: 7bit Cc: Juan Quintela , kvm@vger.kernel.org To: Christoph Hellwig Return-path: Received: from mail-px0-f179.google.com ([209.85.216.179]:45549 "EHLO mail-px0-f179.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S932529AbZJAOY1 (ORCPT ); Thu, 1 Oct 2009 10:24:27 -0400 Received: by pxi9 with SMTP id 9so190030pxi.4 for ; Thu, 01 Oct 2009 07:24:31 -0700 (PDT) In-Reply-To: <20091001120508.GA2459@infradead.org> Sender: kvm-owner@vger.kernel.org List-ID: Christoph Hellwig wrote: > 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. > That's what I'd suggest. The use of eventfd in qemu-kvm is wrong because the compat function is not implemented correctly. Regards, Anthony Liguori