Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1753955Ab0D1NWJ (ORCPT ); Wed, 28 Apr 2010 09:22:09 -0400 Received: from mx1.redhat.com ([209.132.183.28]:17007 "EHLO mx1.redhat.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1753397Ab0D1NWH (ORCPT ); Wed, 28 Apr 2010 09:22:07 -0400 Organization: Red Hat UK Ltd. Registered Address: Red Hat UK Ltd, Amberley Place, 107-111 Peascod Street, Windsor, Berkshire, SI4 1TE, United Kingdom. Registered in England and Wales under Company Registration No. 3798903 From: David Howells In-Reply-To: References: <1272430986-20436-1-git-send-email-xiaosuo@gmail.com> <20100428081545.GA19027@windriver.com> <8482.1272446987@redhat.com> To: Changli Gao Cc: dhowells@redhat.com, Yong Zhang , Xiaotian Feng , Ingo Molnar , Alexander Viro , Andrew Morton , "Eric W. Biederman" , Davide Libenzi , Roland Dreier , Stefan Richter , Peter Zijlstra , "David S. Miller" , Eric Dumazet , Christoph Lameter , Andreas Herrmann , Thomas Gleixner , Takashi Iwai , linux-fsdevel@vger.kernel.org, linux-kernel@vger.kernel.org Subject: Re: [RFC] sched: implement the exclusive wait queue as a LIFO queue Date: Wed, 28 Apr 2010 14:21:02 +0100 Message-ID: <12671.1272460862@redhat.com> Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 695 Lines: 19 Changli Gao wrote: > You are right. I made the wrong assumption. But we indeed need some > primitive to add wait_queue at the head of the wait_queue_head, and I > know epoll needs it, at least. > > fs/eventpoll.c: 1443. > wait.flags |= WQ_FLAG_EXCLUSIVE; > __add_wait_queue(&ep->wq, &wait); You can add at either end of the wait queue with __add_wait_queue() and __add_wait_queue_tail(). David -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/