From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1754463AbbFEKaQ (ORCPT ); Fri, 5 Jun 2015 06:30:16 -0400 Received: from 8bytes.org ([81.169.241.247]:57055 "EHLO theia.8bytes.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1750851AbbFEKaG (ORCPT ); Fri, 5 Jun 2015 06:30:06 -0400 From: Joerg Roedel To: Ingo Molnar , Thomas Gleixner , "H. Peter Anvin" , Borislav Petkov Cc: Konrad Rzeszutek Wilk , Vivek Goyal , Dave Young , Baoquan He , x86@kernel.org, kexec@lists.infradead.org, joro@8bytes.org, jroedel@suse.de, linux-kernel@vger.kernel.org Subject: [PATCH 3/3] x86, crash: Allocate enough low-mem when crashkernel=high Date: Fri, 5 Jun 2015 12:30:02 +0200 Message-Id: <1433500202-25531-4-git-send-email-joro@8bytes.org> X-Mailer: git-send-email 1.9.1 In-Reply-To: <1433500202-25531-1-git-send-email-joro@8bytes.org> References: <1433500202-25531-1-git-send-email-joro@8bytes.org> Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org From: Joerg Roedel When the crashkernel is loaded above 4GiB in memory the first kernel only allocates 72MiB of low-memory for the DMA requirements of the second kernel. On systems with many devices this is not enough and causes device driver initialization errors and failed crash dumps. Testing by SUSE and Redhat have shown that 256MiB is a good default value for now and the discussion has agreed on this value as well. So set this default value to 256MiB to make sure there is enough memory available for DMA. Acked-by: Baoquan He Signed-off-by: Joerg Roedel --- arch/x86/kernel/setup.c | 5 ++++- 1 file changed, 4 insertions(+), 1 deletion(-) diff --git a/arch/x86/kernel/setup.c b/arch/x86/kernel/setup.c index d74ac33..a09f368 100644 --- a/arch/x86/kernel/setup.c +++ b/arch/x86/kernel/setup.c @@ -535,8 +535,11 @@ static void __init reserve_crashkernel_low(void) * swiotlb overflow buffer: now is hardcoded to 32k. * We round it to 8M for other buffers that * may need to stay low too. + * Also make sure we allocate enough extra memory + * low memory so that we don't run out of DMA + * buffers for 32bit devices. */ - low_size = swiotlb_size_or_default() + (8UL<<20); + low_size = max(swiotlb_size_or_default() + (8UL<<20), 256UL<<20); auto_set = true; } else { /* passed with crashkernel=0,low ? */ -- 1.9.1