From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S965970AbXCFROG (ORCPT ); Tue, 6 Mar 2007 12:14:06 -0500 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S965953AbXCFROF (ORCPT ); Tue, 6 Mar 2007 12:14:05 -0500 Received: from smtp.osdl.org ([65.172.181.24]:47998 "EHLO smtp.osdl.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S965971AbXCFROE (ORCPT ); Tue, 6 Mar 2007 12:14:04 -0500 Date: Tue, 6 Mar 2007 09:13:48 -0800 (PST) From: Linus Torvalds To: Benjamin Herrenschmidt , David Howells cc: Linux Kernel Mailing List , Andrew Morton Subject: Re: get_order() broken ! In-Reply-To: <1173200555.9349.2.camel@localhost.localdomain> Message-ID: References: <1173200555.9349.2.camel@localhost.localdomain> MIME-Version: 1.0 Content-Type: TEXT/PLAIN; charset=US-ASCII Sender: linux-kernel-owner@vger.kernel.org X-Mailing-List: linux-kernel@vger.kernel.org On Tue, 6 Mar 2007, Benjamin Herrenschmidt wrote: > > Ok, maybe I have lots of shit in my eyes.... but it looks like get_order > in asm-generic/page.h is broken. > > AFAIK, get_order() should round up (and we have code here or there > assuming such). > > However, it seems to assume that ilog2 rounds up, which it doesn't. It > rounds down. At least the generic implementation seems to do so and the > powerpc optimized one too. Yeah, I think the recent get_order() changes to change it to use ilog2() are just crap. I actually looked at it when it went in, but I assumed that it had been tested. I don't think it has. Let's just revert that entirely. David, quick comments before I undo commit 39d61db0? Linus