Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1751183AbaLCEBs (ORCPT ); Tue, 2 Dec 2014 23:01:48 -0500 Received: from mx1.redhat.com ([209.132.183.28]:45981 "EHLO mx1.redhat.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1750798AbaLCEBr (ORCPT ); Tue, 2 Dec 2014 23:01:47 -0500 Date: Wed, 3 Dec 2014 12:01:23 +0800 From: WANG Chao To: Joerg Roedel Cc: Ingo Molnar , Thomas Gleixner , "H. Peter Anvin" , Konrad Rzeszutek Wilk , x86@kernel.org, linux-kernel@vger.kernel.org, Joerg Roedel , Joerg Roedel , WANG Chao Subject: Re: [PATCH 0/3] Fix kdump failures with crashkernel=high Message-ID: <20141203040123.GB23163@dhcp-17-37.nay.redhat.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <1417174149-31210-1-git-send-email-joro@8bytes.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 > Hi, > > here is a patch-set to fix failed kdump kernel boots when > the systems was booted with crashkernel=X,high. On those > systems the kernel allocates only 72MiB of low-memory for > DMA buffers, which showed to be too low on some systems. >From your experience It seems like swiotlb isn't working well with crashkernel=X,high alone. What about using crashkernel=X,low with crashkernel=X,high? Is there any reason you have to use crashkernel=X,high alone? > > The problem is that 64MiB of the low-memory is allocated by > swiotlb, leaving 8MB for the page-allocator. But swiotlb > tries to allocate DMA memory from the page-allocator first, > which fails pretty fast in the boot sequence, causing > warnings. This patch-set removes these warnings. > > But even the 64MiB for swiotlb are eaten up on some systems, > so that the default of low-memory allocated for the > crash-kernel is increase from 72MB to 256MB (only changing > the defaults, can still be overwritten by crashkernel=X,low). crashkernel=X,high shouldn't automatically reserve 72M low at the first place. Now it's going insane if you increase it to 256M by default. Thanks WANG Chao > This number comes from experiments on the affected systems, > 128MiB low-memory was still not enough there, thus I set the > value to 256MiB to fix the issues. > > Any feedback appreciated. > > Thanks, > > Joerg > > Joerg Roedel (3): > swiotlb: Warn on allocation failure in swiotlb_alloc_coherent > x86, swiotlb: Try coherent allocations with __GFP_NOWARN > x86, crash: Allocate enough low-mem when crashkernel=high > > arch/x86/kernel/pci-swiotlb.c | 8 ++++++++ > arch/x86/kernel/setup.c | 5 ++++- > lib/swiotlb.c | 11 +++++++++-- > 3 files changed, 21 insertions(+), 3 deletions(-) > > -- > 1.9.1 > > -- > 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/ > > -- 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/