From mboxrd@z Thu Jan 1 00:00:00 1970 From: Mathieu Desnoyers Subject: Re: [RFC v2] epoll: avoid spinlock contention with wfcqueue Date: Tue, 7 May 2013 16:09:48 -0400 Message-ID: <20130507200948.GC8879@Krystal> References: <20130314044215.GA27312@dcvr.yhbt.net> <20130318110722.GA8798@dcvr.yhbt.net> <20130318130649.GA15947@Krystal> <20130318173237.GB8798@dcvr.yhbt.net> Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii Cc: linux-kernel@vger.kernel.org, Davide Libenzi , Al Viro , Andrew Morton , linux-fsdevel@vger.kernel.org To: Eric Wong Return-path: Received: from mail.openrapids.net ([64.15.138.104]:47027 "EHLO blackscsi.openrapids.net" rhost-flags-OK-OK-OK-FAIL) by vger.kernel.org with ESMTP id S1752070Ab3EGUJw (ORCPT ); Tue, 7 May 2013 16:09:52 -0400 Content-Disposition: inline In-Reply-To: <20130318173237.GB8798@dcvr.yhbt.net> Sender: linux-fsdevel-owner@vger.kernel.org List-ID: * Eric Wong (normalperson@yhbt.net) wrote: > Mathieu Desnoyers wrote: [...] > > I'm also not entirely sure why you need to add enum epoll_item_state > > along with expensive atomic ops to compute the state. Wouldn't it be > > enough to know in which queue the nodes are located ? If need be, you > > could add new queues, e.g. one per state. So instead of marking states, > > you would simply re-enqueue the nodes into per-state queues. This would > > simplify zombie management and save a couple of brains in the process. ;-) > > Is there a quick way to know which queue the node is located? Unfortunately, no. We don't do such "tagging", so you'd have to iterate on all list items to find this info in the worse case. Thanks, Mathieu -- Mathieu Desnoyers EfficiOS Inc. http://www.efficios.com