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 patchset solves this problem by accounting the size of reserved memory when calculating the size of large system hashes. While this patchset applies on v4.8-rc3, it cannot be tested on v4.8-rc3 because of http://lkml.kernel.org/r/20160829093844.GA2592@xxxxxxxxxxxxxxxxxx However it has been tested on v4.7/v4.6 and v4.4 v2: http://lkml.kernel.org/r/1470330729-6273-1-git-send-email-srikar@xxxxxxxxxxxxxxxxxx Cc: linux-mm@xxxxxxxxx Cc: Mel Gorman <mgorman@xxxxxxxxxxxxxxxxxxx> Cc: Vlastimil Babka <vbabka@xxxxxxx> Cc: Michal Hocko <mhocko@xxxxxxxxxx> Cc: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx> Cc: Michael Ellerman <mpe@xxxxxxxxxxxxxx> Cc: linuxppc-dev@xxxxxxxxxxxxxxxx Cc: Mahesh Salgaonkar <mahesh@xxxxxxxxxxxxxxxxxx> Cc: Hari Bathini <hbathini@xxxxxxxxxxxxxxxxxx> Cc: Dave Hansen <dave.hansen@xxxxxxxxx> Cc: Balbir Singh <bsingharora@xxxxxxxxx> Cc: Srikar Dronamraju <srikar@xxxxxxxxxxxxxxxxxx> Srikar Dronamraju (3): mm: Introduce arch_reserved_kernel_pages() mm/memblock: Expose total reserved memory powerpc: Implement arch_reserved_kernel_pages arch/powerpc/include/asm/mmzone.h | 3 +++ arch/powerpc/kernel/fadump.c | 5 +++++ include/linux/memblock.h | 1 + include/linux/mm.h | 3 +++ mm/memblock.c | 5 +++++ mm/page_alloc.c | 12 ++++++++++++ 6 files changed, 29 insertions(+) -- 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>