a system with 256 GB of RAM, when NUMA is disabled crashes the
following way:
Your BIOS doesn't leave a aperture memory hole
Please enable the IOMMU option in the BIOS setup
This costs you 64 MB of RAM
Cannot allocate aperture memory hole (ffff8101c0000000,65536K)
Kernel panic - not syncing: Not enough memory for aperture
Pid: 0, comm: swapper Not tainted 2.6.25-rc4-x86-latest.git #33
Call Trace:
[<ffffffff84037c62>] panic+0xb2/0x190
[<ffffffff840381fc>] ? release_console_sem+0x7c/0x250
[<ffffffff847b1628>] ? __alloc_bootmem_nopanic+0x48/0x90
[<ffffffff847b0ac9>] ? free_bootmem+0x29/0x50
[<ffffffff847ac1f7>] gart_iommu_hole_init+0x5e7/0x680
[<ffffffff847b255b>] ? alloc_large_system_hash+0x16b/0x310
[<ffffffff84506a2f>] ? _etext+0x0/0x1
[<ffffffff847a2e8c>] pci_iommu_alloc+0x1c/0x40
[<ffffffff847ac795>] mem_init+0x45/0x1a0
[<ffffffff8479ff35>] start_kernel+0x295/0x380
[<ffffffff8479f1c2>] _sinittext+0x1c2/0x230
the root cause is : memmap PMD is too big,
[ffffe200e0600000-ffffe200e07fffff] PMD ->ffff81383c000000 on node 0
almost near 4G..., and vmemmap_alloc_block will use up the ram under 4G.
solution will be:
1. make memmap allocation get memory above 4G...
2. reserve some dma32 range early before we try to set up memmap for all.
and release that before pci_iommu_alloc, so gart or swiotlb could get some
range under 4g limit for sure.
the patch is using method 2.
because method1 may need more code to handle SPARSEMEM and SPASEMEM_VMEMMAP
will get
Your BIOS doesn't leave a aperture memory hole
Please enable the IOMMU option in the BIOS setup
This costs you 64 MB of RAM
Mapping aperture over 65536 KB of RAM @ 4000000
Memory: 264245736k/268959744k available (8484k kernel code, 4187464k reserved, 4004k data, 724k init)
Signed-off-by: Yinghai Lu <yhlu.kernel@gmail.com>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
f62f1fc9ef