From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1761475Ab3DDOLg (ORCPT ); Thu, 4 Apr 2013 10:11:36 -0400 Received: from mx1.redhat.com ([209.132.183.28]:28793 "EHLO mx1.redhat.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1761305Ab3DDOLf (ORCPT ); Thu, 4 Apr 2013 10:11:35 -0400 Date: Thu, 4 Apr 2013 10:11:16 -0400 From: Vivek Goyal To: Yinghai Lu Cc: Thomas Gleixner , Ingo Molnar , "H. Peter Anvin" , WANG Chao , "Eric W. Biederman" , linux-kernel@vger.kernel.org Subject: Re: [PATCH v2 1/4] x86, kdump: Set crashkernel_low automatically Message-ID: <20130404141116.GC16459@redhat.com> References: <1365035906-3208-1-git-send-email-yinghai@kernel.org> <1365035906-3208-2-git-send-email-yinghai@kernel.org> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <1365035906-3208-2-git-send-email-yinghai@kernel.org> User-Agent: Mutt/1.5.21 (2010-09-15) Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Wed, Apr 03, 2013 at 05:38:23PM -0700, Yinghai Lu wrote: [..] > + if (ret != 0) { > + /* > + * two parts from lib/swiotlb.c: > + * swiotlb size: user specified with swiotlb= or default. > + * swiotlb overflow buffer: now is hardcoded to 32k, > + * round to 8M to cover more others. > + */ > + low_size = swiotlb_size_or_default() + (8UL<<20); > + auto_set = true; What is the correlation between swiotlb size of first kernel and second kernel. They might be completely different kernel and with different default size for swiotlb buffers. [..] > > + crashkernel_low=size[KMG] > + [KNL, x86_64] range under 4G. When crashkernel= is > + passed, kernel allocate physical memory region > + above 4G, This is not right. "When crashkernel=X;high is passed kernel first tries to allocate memory above 4G". crashkernel=X does not try to allocate memory above 4G. Vivek