From f62f1fc9ef94f74fda2b456d935ba2da69fa0a40 Mon Sep 17 00:00:00 2001 From: Yinghai Lu Date: Fri, 7 Mar 2008 15:02:50 -0800 Subject: x86: reserve dma32 early for gart 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: [] panic+0xb2/0x190 [] ? release_console_sem+0x7c/0x250 [] ? __alloc_bootmem_nopanic+0x48/0x90 [] ? free_bootmem+0x29/0x50 [] gart_iommu_hole_init+0x5e7/0x680 [] ? alloc_large_system_hash+0x16b/0x310 [] ? _etext+0x0/0x1 [] pci_iommu_alloc+0x1c/0x40 [] mem_init+0x45/0x1a0 [] start_kernel+0x295/0x380 [] _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 Signed-off-by: Ingo Molnar Signed-off-by: Thomas Gleixner --- include/asm-x86/pci_64.h | 1 + 1 file changed, 1 insertion(+) (limited to 'include/asm-x86/pci_64.h') diff --git a/include/asm-x86/pci_64.h b/include/asm-x86/pci_64.h index 374690314539..da8266a08005 100644 --- a/include/asm-x86/pci_64.h +++ b/include/asm-x86/pci_64.h @@ -25,6 +25,7 @@ extern int (*pci_config_write)(int seg, int bus, int dev, int fn, int reg, int l +extern void dma32_reserve_bootmem(void); extern void pci_iommu_alloc(void); /* The PCI address space does equal the physical memory -- cgit v1.2.3