Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1751271AbWELNMk (ORCPT ); Fri, 12 May 2006 09:12:40 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1751277AbWELNMk (ORCPT ); Fri, 12 May 2006 09:12:40 -0400 Received: from ecfrec.frec.bull.fr ([129.183.4.8]:49846 "EHLO ecfrec.frec.bull.fr") by vger.kernel.org with ESMTP id S1751271AbWELNMj convert rfc822-to-8bit (ORCPT ); Fri, 12 May 2006 09:12:39 -0400 Subject: Re: [RFC][PATCH RT 1/2] futex_requeue-optimize From: =?ISO-8859-1?Q?S=E9bastien_Dugu=E9?= To: Ingo Molnar Cc: Andrew Morton , linux-kernel@vger.kernel.org, tglx@linutronix.de In-Reply-To: <20060512111256.GA27481@elte.hu> References: <20060510112701.7ea3a749@frecb000686> <20060511091541.05160b2c.akpm@osdl.org> <20060512063220.GA630@elte.hu> <1147421427.3969.60.camel@frecb000686> <1147432419.3969.70.camel@frecb000686> <20060512111256.GA27481@elte.hu> Date: Fri, 12 May 2006 15:16:56 +0200 Message-Id: <1147439816.3969.81.camel@frecb000686> Mime-Version: 1.0 X-Mailer: Evolution 2.4.2.1 X-MIMETrack: Itemize by SMTP Server on ECN002/FR/BULL(Release 5.0.12 |February 13, 2003) at 12/05/2006 15:15:37, Serialize by Router on ECN002/FR/BULL(Release 5.0.12 |February 13, 2003) at 12/05/2006 15:15:39, Serialize complete at 12/05/2006 15:15:39 Content-Transfer-Encoding: 8BIT Content-Type: text/plain; charset=ISO-8859-15 Sender: linux-kernel-owner@vger.kernel.org X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 1316 Lines: 37 On Fri, 2006-05-12 at 13:12 +0200, Ingo Molnar wrote: > * S?bastien Dugu? wrote: > > > On Fri, 2006-05-12 at 10:10 +0200, S?bastien Dugu? wrote: > > > On Fri, 2006-05-12 at 08:32 +0200, Ingo Molnar wrote: > > > > * Andrew Morton wrote: > > > > > > > > > Should the futex code be using hlist_heads for that hashtable? > > > > > > > > yeah. That would save 1K of .data on 32-bit platforms, 2K on 64-bit > > > > platforms. > > > > > > I'll try to look into this. > > > > > > > Well, moving the hash bucket list to an hlist may save a few bytes > > on .data, but all the insertions are done at the tail on this list > > which would not be easily done using hlists. > > > > Any thoughts? > > just queue to the head. This is a hash-list, ordering has only > performance effects. > Queuing to the head would mean that tasks are woken up in LIFO order (i.e. the last task put to sleep will be the first to be woken up). I'm not sure that's what people would expect, or am I missing something here? S?bastien. - 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/