Re: [PATCH 1/2] mm: meminit: initialise more memory for inode/dentry hash tables in early boot

[Vlastimil Babka <vbabka@suse.cz>]

On 03/08/2016 04:55 AM, Li Zhang wrote:
> From: Li Zhang <zhlcindy@linux.vnet.ibm.com>
> 
> This patch is based on Mel Gorman's old patch in the mailing list,
> https://lkml.org/lkml/2015/5/5/280 which is discussed but it is
> fixed with a completion to wait for all memory initialised in
> page_alloc_init_late(). It is to fix the OOM problem on X86
> with 24TB memory which allocates memory in late initialisation.
> But for Power platform with 32TB memory, it causes a call trace
> in vfs_caches_init->inode_init() and inode hash table needs more
> memory.
> So this patch allocates 1GB for 0.25TB/node for large system
> as it is mentioned in https://lkml.org/lkml/2015/5/1/627
> 
> This call trace is found on Power with 32TB memory, 1024CPUs, 16nodes.
> Currently, it only allocates 2GB*16=32GB for early initialisation. But
> Dentry cache hash table needes 16GB and Inode cache hash table needs
> 16GB. So the system have no enough memory for it.
> The log from dmesg as the following:
> 
> Dentry cache hash table entries: 2147483648 (order: 18,17179869184 bytes)
> vmalloc: allocation failure, allocated 16021913600 of 17179934720 bytes
> swapper/0: page allocation failure: order:0,mode:0x2080020
> CPU: 0 PID: 0 Comm: swapper/0 Not tainted 4.4.0-0-ppc64
> Call Trace:
> [c0000000012bfa00] [c0000000007c4a50].dump_stack+0xb4/0xb664 (unreliable)
> [c0000000012bfa80] [c0000000001f93d4].warn_alloc_failed+0x114/0x160
> [c0000000012bfb30] [c00000000023c204].__vmalloc_area_node+0x1a4/0x2b0
> [c0000000012bfbf0] [c00000000023c3f4].__vmalloc_node_range+0xe4/0x110
> [c0000000012bfc90] [c00000000023c460].__vmalloc_node+0x40/0x50
> [c0000000012bfd10] [c000000000b67d60].alloc_large_system_hash+0x134/0x2a4
> [c0000000012bfdd0] [c000000000b70924].inode_init+0xa4/0xf0
> [c0000000012bfe60] [c000000000b706a0].vfs_caches_init+0x80/0x144
> [c0000000012bfef0] [c000000000b35208].start_kernel+0x40c/0x4e0
> [c0000000012bff90] [c000000000008cfc]start_here_common+0x20/0x4a4
> Mem-Info:
> 
> Acked-by: Mel Gorman <mgorman@techsingularity.net>
> Signed-off-by: Li Zhang <zhlcindy@linux.vnet.ibm.com>

Acked-by: Vlastimil Babka <vbabka@suse.cz>