From mboxrd@z Thu Jan 1 00:00:00 1970 Date: Thu, 23 Aug 2007 14:21:33 -0700 From: Andrew Morton Subject: Re: [BUG] 2.6.23-rc3-mm1 Kernel panic - not syncing: DMA: Memory would be corrupted Message-Id: <20070823142133.9359a1ce.akpm@linux-foundation.org> In-Reply-To: <617E1C2C70743745A92448908E030B2A023EB020@scsmsx411.amr.corp.intel.com> References: <617E1C2C70743745A92448908E030B2A023B2FD5@scsmsx411.amr.corp.intel.com> <20070823091556.GA18456@skynet.ie> <20070823221005.0D76.Y-GOTO@jp.fujitsu.com> <617E1C2C70743745A92448908E030B2A023EB020@scsmsx411.amr.corp.intel.com> Mime-Version: 1.0 Content-Type: text/plain; charset=US-ASCII Content-Transfer-Encoding: 7bit Sender: owner-linux-mm@kvack.org Return-Path: To: "Luck, Tony" Cc: Yasunori Goto , Mel Gorman , Jeremy Higdon , Kamalesh Babulal , Andi Kleen , linux-kernel@vger.kernel.org, Balbir Singh , linux-ia64@vger.kernel.org, Christoph Lameter , linux-mm@kvack.org List-ID: On Thu, 23 Aug 2007 10:22:26 -0700 "Luck, Tony" wrote: > > __get_free_pages() of swiotlb_alloc_coherent() fails in rc3-mm1. > > But, it doesn't fail on rc2-mm2, and kernel can boot up. > > That looks to be part of the problem here ... failing an order=3 > allocation during boot on a system that just a few lines earlier > in the boot log reported "Memory: 37474000k/37680640k available" > looks bad ... but perhaps having *more* memory is part of your problem. > You may have run low on GFP_DMA memory because some allocation > scaled by memory size has chewed up a lot of your memory. To check > this try booting with a "mem=4G" parameter and see if that helps > you. > > But it is also bad that the swiotlb() code failed to handle this. > Can you check whether the problem is related to the size of the > allocation being just over 256K (a magic number for swiotlb since > IO_TLB_SEGSIZE is 128 times a slab size of 2k). Try changing > lib/swiotlb.c to set IO_TLB_SEGSIZE to 256 instead. > Others are reporting machines which fail int he memory allcoator much earlier, and which claim to have four CPUs and 16 nodes. So something is very wonky in the rc3-mm1 page allocator. I guess suspicion has to be directed at the memoryless-nodes patches, but until that's cleared up I don't think there's much to be gained from chasing this iommu problem, now that you've worked out that it's a bogus memory allocation failure (thanks). -- To unsubscribe, send a message with 'unsubscribe linux-mm' in the body to majordomo@kvack.org. For more info on Linux MM, see: http://www.linux-mm.org/ . Don't email: email@kvack.org