Fadump kernel reserves large chunks of memory even before the pages are initialised. This could mean memory that corresponds to several nodes might fall in memblock reserved regions. Kernels compiled with CONFIG_DEFERRED_STRUCT_PAGE_INIT will initialise only certain size memory per node. The certain size takes into account the dentry and inode cache sizes. However such a kernel when booting a secondary 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 This can be solved by two approaches. 1. Disable deferred struct page initialisation on fadump. 2. Detect reserved nodes and allocate accordingly. - Detecting nodes whose memblocks are mostly reserved. - Allocating extra memory in other nodes in lieu of the nodes whose memory is reserved. This patchset takes the first approach. Srikar Dronamraju (2): mm: Allow disabling deferred struct page initialisation fadump: Disable deferred page struct initialisation arch/powerpc/kernel/fadump.c | 1 + include/linux/mmzone.h | 2 +- mm/page_alloc.c | 20 ++++++++++++++++++++ 3 files changed, 22 insertions(+), 1 deletion(-) -- 1.8.5.6 -- To unsubscribe, send a message with 'unsubscribe linux-mm' in the body to majordomo@xxxxxxxxx. For more info on Linux MM, see: http://www.linux-mm.org/ . Don't email: <a href=mailto:"dont@xxxxxxxxx";> email@xxxxxxxxx </a>