From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1754674AbYDPSqL (ORCPT ); Wed, 16 Apr 2008 14:46:11 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1751341AbYDPSp6 (ORCPT ); Wed, 16 Apr 2008 14:45:58 -0400 Received: from mx3.mail.elte.hu ([157.181.1.138]:55504 "EHLO mx3.mail.elte.hu" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751320AbYDPSp5 (ORCPT ); Wed, 16 Apr 2008 14:45:57 -0400 Date: Wed, 16 Apr 2008 20:45:43 +0200 From: Ingo Molnar To: Jack Steiner Cc: tglx@linutronix.de, linux-mm@kvack.org, linux-kernel@vger.kernel.org Subject: Re: [PATCH] - Increase MAX_APICS for large configs Message-ID: <20080416184543.GD3722@elte.hu> References: <20080416163936.GA23099@sgi.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20080416163936.GA23099@sgi.com> User-Agent: Mutt/1.5.17 (2007-11-01) X-ELTE-VirusStatus: clean X-ELTE-SpamScore: -1.5 X-ELTE-SpamLevel: X-ELTE-SpamCheck: no X-ELTE-SpamVersion: ELTE 2.0 X-ELTE-SpamCheck-Details: score=-1.5 required=5.9 tests=BAYES_00 autolearn=no SpamAssassin version=3.2.3 -1.5 BAYES_00 BODY: Bayesian spam probability is 0 to 1% [score: 0.0000] Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org * Jack Steiner wrote: > Increase the maximum number of apics when running very large > configurations. This patch has no affect on most systems. > > Signed-off-by: Jack Steiner > > I think this area of the code will be substantially changed when the > full x2apic patch is available. In the meantime, this seems like an > acceptible alternative. The patch has no effect on any 32-bit kernel. > It adds ~4k to the size of 64-bit kernels but only if NR_CPUS > 255. ugly ... but well - applied. What's the static size cost of 64K APICs? Ingo