From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1752892AbYKXMLl (ORCPT ); Mon, 24 Nov 2008 07:11:41 -0500 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1750892AbYKXMLd (ORCPT ); Mon, 24 Nov 2008 07:11:33 -0500 Received: from fgwmail7.fujitsu.co.jp ([192.51.44.37]:55296 "EHLO fgwmail7.fujitsu.co.jp" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751191AbYKXMLc (ORCPT ); Mon, 24 Nov 2008 07:11:32 -0500 From: KOSAKI Motohiro To: Mathieu Desnoyers Subject: Re: [ltt-dev] [RFC PATCH] Poll : add poll_wait_set_exclusive (fixing thundering herd problem in LTTng) Cc: kosaki.motohiro@jp.fujitsu.com, ltt-dev@lists.casi.polymtl.ca, Ingo Molnar , linux-kernel@vger.kernel.org, William Lee Irwin III In-Reply-To: <20081124115134.GA17972@Krystal> References: <20081124203932.26BE.KOSAKI.MOTOHIRO@jp.fujitsu.com> <20081124115134.GA17972@Krystal> Message-Id: <20081124205512.26C1.KOSAKI.MOTOHIRO@jp.fujitsu.com> MIME-Version: 1.0 Content-Type: text/plain; charset="US-ASCII" Content-Transfer-Encoding: 7bit X-Mailer: Becky! ver. 2.42 [ja] Date: Mon, 24 Nov 2008 21:11:28 +0900 (JST) Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org > > I fully agreed this feature is needed. > > Actually, I've made similar patch at one years ago. > > > > http://marc.info/?l=linux-kernel&m=120257050719087&w=2 > > > > > > but, I have one question. > > My version have epoll support, but yours donesn't have. > > Is it intensionally? > > > > this is just dumb question, it doesn't mean any objection. > > Hrm, actually, your patch seems cleaner than mine, but it adds a branch > in the standard hotpath, which mine does not do (but I am not sure it is > such an important optimization...). Why do you think poll_wait() is hotpath? I think sysm_poll() isn't hotpath because it often cause task sleeping. > Is there any reason why your patch > did not get merged ? my patch was developed for a part of mem_notify patch series. but the mem_notify was naked by akpm. therefore it lost merging motivation ;-) Ingo, I'll rebase and post my patch for -tip tommorow. Could you please review it? > The only reason I did not make a epoll version is simply because LTTng > currently does not support it. :) thanks. I understand your original intension.