Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1752519AbaJ2DOQ (ORCPT ); Tue, 28 Oct 2014 23:14:16 -0400 Received: from terminus.zytor.com ([198.137.202.10]:56984 "EHLO mail.zytor.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1750858AbaJ2DOP (ORCPT ); Tue, 28 Oct 2014 23:14:15 -0400 Message-ID: <54505B7A.80502@zytor.com> Date: Tue, 28 Oct 2014 20:14:02 -0700 From: "H. Peter Anvin" User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:31.0) Gecko/20100101 Thunderbird/31.2.0 MIME-Version: 1.0 To: Thomas Gleixner CC: Minfei Huang , mingo@redhat.com, x86@kernel.org, linux-kernel@vger.kernel.org Subject: Re: [PATCH] mm: Avoid overlap the fixmap area on i386 References: <6B680A9E-6CE9-4C96-934B-CB01DCB58278@gmail.com> <544FD138.3030305@zytor.com> In-Reply-To: Content-Type: text/plain; charset=windows-1252 Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On 10/28/2014 10:29 AM, Thomas Gleixner wrote: > On Tue, 28 Oct 2014, H. Peter Anvin wrote: >> On 10/28/2014 04:06 AM, Thomas Gleixner wrote: >>>> >>>> The available address we can use is lower than FIXADDR_BOOT_START. So >>>> We will set the kmap boundary below the FIXADDR_BOOT_START, if configure >>>> the high memory. >>>> >>>> If we configure the high memory, the vmalloc reserve area should end >>>> up to PKMAP_BASE, otherwise should end up to FIXADDR_BOOT_START. >>> >>> Which is not really a problem, because the FIXADDR_BOOT area is only >>> used during boot for early_ioremap() and it's unused when ioremap() is >>> functional. vmalloc becomes available after early boot so the >>> FIXADDR_BOOT area is available for reuse. >>> >> >> Given the very limited address space available on i386, it would be >> extremely undesirable to not reuse address space when possible. > > Fair enough. Then we should do that for the highmem=y case as well. > It is probably even more important for highmem=y... -hpa -- 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/