From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mail-pa0-f69.google.com (mail-pa0-f69.google.com [209.85.220.69]) by kanga.kvack.org (Postfix) with ESMTP id C1FD96B0005 for ; Thu, 4 Aug 2016 17:01:35 -0400 (EDT) Received: by mail-pa0-f69.google.com with SMTP id ez1so425042993pab.1 for ; Thu, 04 Aug 2016 14:01:35 -0700 (PDT) Received: from mail.linuxfoundation.org (mail.linuxfoundation.org. [140.211.169.12]) by mx.google.com with ESMTPS id q72si16327032pfj.148.2016.08.04.14.01.34 for (version=TLS1_2 cipher=ECDHE-RSA-AES128-GCM-SHA256 bits=128/128); Thu, 04 Aug 2016 14:01:35 -0700 (PDT) Date: Thu, 4 Aug 2016 14:01:33 -0700 From: Andrew Morton Subject: Re: [PATCH V2 2/2] fadump: Register the memory reserved by fadump Message-Id: <20160804140133.edf295b8263845e50c185fc2@linux-foundation.org> In-Reply-To: <1470330729-6273-2-git-send-email-srikar@linux.vnet.ibm.com> References: <1470330729-6273-1-git-send-email-srikar@linux.vnet.ibm.com> <1470330729-6273-2-git-send-email-srikar@linux.vnet.ibm.com> Mime-Version: 1.0 Content-Type: text/plain; charset=US-ASCII Content-Transfer-Encoding: 7bit Sender: owner-linux-mm@kvack.org List-ID: To: Srikar Dronamraju Cc: linux-mm@kvack.org, Mel Gorman , Vlastimil Babka , Michal Hocko , Michael Ellerman , linuxppc-dev@lists.ozlabs.org, Mahesh Salgaonkar , Hari Bathini , Dave Hansen , Balbir Singh On Thu, 4 Aug 2016 22:42:09 +0530 Srikar Dronamraju wrote: > Fadump kernel reserves large chunks of memory even before the pages are > initialized. This could mean memory that corresponds to several nodes might > fall in memblock reserved regions. > > Kernels compiled with CONFIG_DEFERRED_STRUCT_PAGE_INIT will initialize > only certain size memory per node. The certain size takes into account > the dentry and inode cache sizes. Currently the cache sizes are > calculated based on the total system memory including the reserved > memory. However such a kernel when booting the same kernel as fadump > kernel will not be able to allocate the required amount of memory to > suffice for the dentry and inode caches. This results in crashes like > the below on large systems such as 32 TB systems. > > Dentry cache hash table entries: 536870912 (order: 16, 4294967296 bytes) > vmalloc: allocation failure, allocated 4097114112 of 17179934720 bytes > swapper/0: page allocation failure: order:0, mode:0x2080020(GFP_ATOMIC) > CPU: 0 PID: 0 Comm: swapper/0 Not tainted 4.6-master+ #3 > Call Trace: > [c00000000108fb10] [c0000000007fac88] dump_stack+0xb0/0xf0 (unreliable) > [c00000000108fb50] [c000000000235264] warn_alloc_failed+0x114/0x160 > [c00000000108fbf0] [c000000000281484] __vmalloc_node_range+0x304/0x340 > [c00000000108fca0] [c00000000028152c] __vmalloc+0x6c/0x90 > [c00000000108fd40] [c000000000aecfb0] > alloc_large_system_hash+0x1b8/0x2c0 > [c00000000108fe00] [c000000000af7240] inode_init+0x94/0xe4 > [c00000000108fe80] [c000000000af6fec] vfs_caches_init+0x8c/0x13c > [c00000000108ff00] [c000000000ac4014] start_kernel+0x50c/0x578 > [c00000000108ff90] [c000000000008c6c] start_here_common+0x20/0xa8 > > Register the memory reserved by fadump, so that the cache sizes are > calculated based on the free memory (i.e Total memory - reserved > memory). Looks harmless enough to me. I'll schedule the patches for 4.8. But it sounds like they should be backported into older kernels? -- 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