From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S969446AbXEIBzr (ORCPT ); Tue, 8 May 2007 21:55:47 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S967846AbXEIBzj (ORCPT ); Tue, 8 May 2007 21:55:39 -0400 Received: from 74-93-104-97-Washington.hfc.comcastbusiness.net ([74.93.104.97]:47053 "EHLO sunset.davemloft.net" rhost-flags-OK-FAIL-OK-OK) by vger.kernel.org with ESMTP id S967364AbXEIBzj (ORCPT ); Tue, 8 May 2007 21:55:39 -0400 Date: Tue, 08 May 2007 18:55:39 -0700 (PDT) Message-Id: <20070508.185539.95059076.davem@davemloft.net> To: clameter@sgi.com Cc: mpm@selenic.com, akpm@linux-foundation.org, linux-kernel@vger.kernel.org Subject: Re: + fix-spellings-of-slab-allocator-section-in-init-kconfig.patch added to -mm tree From: David Miller In-Reply-To: References: <20070508.185141.85412154.davem@davemloft.net> X-Mailer: Mew version 5.1.52 on Emacs 21.4 / Mule 5.0 (SAKAKI) Mime-Version: 1.0 Content-Type: Text/Plain; charset=us-ascii Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org X-Mailing-List: linux-kernel@vger.kernel.org From: Christoph Lameter Date: Tue, 8 May 2007 18:53:28 -0700 (PDT) > On Tue, 8 May 2007, David Miller wrote: > > > SLOB seems to look at the descriptor in the previous blob to figure > > out how big the being-freed blob is. That's actually kind of clever > > :-) > > We were assuming that the objects are actually allocated. How does it > figure out the previous blobs boundaries without metadata? The page is filled entirely with descriptors in the not-in-use regions of the page aparently. So "freed_object - 1" will always give you a descriptor. I'm just reading over the code to figure out what to type to you, you could read the code too it's not very complicated :-)