From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1756118AbZFWUNK (ORCPT ); Tue, 23 Jun 2009 16:13:10 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1752772AbZFWUM6 (ORCPT ); Tue, 23 Jun 2009 16:12:58 -0400 Received: from smtp1.linux-foundation.org ([140.211.169.13]:60605 "EHLO smtp1.linux-foundation.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752288AbZFWUM6 (ORCPT ); Tue, 23 Jun 2009 16:12:58 -0400 Date: Tue, 23 Jun 2009 13:12:39 -0700 From: Andrew Morton To: Davide Libenzi Cc: linux-kernel@vger.kernel.org, avi@redhat.com, kvm@vger.kernel.org, ghaskins@novell.com, rusty@rustcorp.com.au, bcrl@kvack.org Subject: Re: [patch] eventfd - revised interface and cleanups (2nd rev) Message-Id: <20090623131239.711d9f83.akpm@linux-foundation.org> In-Reply-To: References: X-Mailer: Sylpheed version 2.2.4 (GTK+ 2.8.20; i486-pc-linux-gnu) Mime-Version: 1.0 Content-Type: text/plain; charset=US-ASCII Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Tue, 23 Jun 2009 12:25:36 -0700 (PDT) Davide Libenzi wrote: > Another cleanup this patch does, is making AIO select EVENTFD, instead of > adding a bunch of empty function stubs inside eventfd.h in order to > handle the (AIO && !EVENTFD) case. Given that we're trying to squeak this patch into 2.6.31, it's quite unfortunate to include unrelated changes. Especially ones which involve the always-problematic "select". Although this one looks less than usually deadly due to the simple dependencies of AIO and eventfd. However... Is this a good way of fixing the (AIO && !EVENTFD) case? Surely if the developer selected this combination, he doesn't want to carry the overhead of including eventfd. IOW, if AIO can work acceptably without eventfd being compiled into the kernel then adding the stubs is a superior solution.