From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1755587AbZCOFer (ORCPT ); Sun, 15 Mar 2009 01:34:47 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1751976AbZCOFej (ORCPT ); Sun, 15 Mar 2009 01:34:39 -0400 Received: from hera.kernel.org ([140.211.167.34]:39659 "EHLO hera.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751838AbZCOFej (ORCPT ); Sun, 15 Mar 2009 01:34:39 -0400 Message-ID: <49BC933F.3090507@kernel.org> Date: Sat, 14 Mar 2009 22:33:51 -0700 From: Yinghai Lu User-Agent: Thunderbird 2.0.0.19 (X11/20081227) MIME-Version: 1.0 To: "H. Peter Anvin" CC: Jeremy Fitzhardinge , Linux Kernel Mailing List Subject: Re: Latest brk patchset References: <49BC413B.5020104@zytor.com> <49BC4CAC.202@goop.org> <49BC5BCF.1070602@zytor.com> <49BC878D.5090402@kernel.org> <49BC8955.5070009@zytor.com> In-Reply-To: <49BC8955.5070009@zytor.com> Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org H. Peter Anvin wrote: > Yinghai Lu wrote: >> H. Peter Anvin wrote: >>> On this subject, what is the point of the 64 K "slop space", and if it >>> is necessary, why not just put it as a RESERVE_BRK() somewhere (*with* a >>> significant comment as to its necessity) instead of putting it as a >>> hack in the linker script? >>> >> >> 32bit already have that >> >> +INIT_MAP_SIZE = (PAGE_TABLE_SIZE + ALLOCATOR_SLOP) * PAGE_SIZE_asm >> +RESERVE_BRK(pagetables, INIT_MAP_SIZE) >> >> in head_32.S >> >> so need to update vmlinux_32.lds.S >> > > What about 64 bits? Also, do we really need the "allocator slop", or > can we push that into the user location, which is where it really > belongs? What does use this? 64 bit does not has this problem. 32 bit we already removed bootmem there, that is not needed. ALLOCATOR_SLOP is needed... + * (KERNEL_IMAGE_SIZE/4096) / 1024 pages (worst case, non PAE) + * (KERNEL_IMAGE_SIZE/4096) / 512 + 4 pages (worst case for PAE) YH