Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1764774AbXESWNZ (ORCPT ); Sat, 19 May 2007 18:13:25 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1760457AbXESWNR (ORCPT ); Sat, 19 May 2007 18:13:17 -0400 Received: from smtp2.linux-foundation.org ([207.189.120.14]:37285 "EHLO smtp2.linux-foundation.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1756853AbXESWNQ (ORCPT ); Sat, 19 May 2007 18:13:16 -0400 Date: Sat, 19 May 2007 15:09:34 -0700 From: Andrew Morton To: William Lee Irwin III Cc: Nick Piggin , Christoph Lameter , Linux Kernel Mailing List , Linux Memory Management List , linux-arch@vger.kernel.org Subject: Re: [rfc] increase struct page size?! Message-Id: <20070519150934.bdabc9b5.akpm@linux-foundation.org> In-Reply-To: <20070519181501.GC19966@holomorphy.com> References: <20070518040854.GA15654@wotan.suse.de> <20070519012530.GB15569@wotan.suse.de> <20070519181501.GC19966@holomorphy.com> X-Mailer: Sylpheed 2.4.1 (GTK+ 2.8.17; x86_64-unknown-linux-gnu) 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 Content-Length: 697 Lines: 15 On Sat, 19 May 2007 11:15:01 -0700 William Lee Irwin III wrote: > Much the same holds for the atomic_t's; 32 + PAGE_SHIFT is > 44 bits or more, about as much as is possible, and one reference per > page per page is not even feasible. Full-length atomic_t's are just > not necessary. You can overflow a page's refcount by mapping it 4G times. That requires 32GB of pagetable memory. It's quite feasible with remap_file_pages(). - 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/