Messages in this thread Patch in this message | | | Subject | [PATCH 04/12] x86_64: reserve dma32 early for gart | Date | Wed, 19 Mar 2008 14:03:54 -0700 | From | Yinghai Lu <> |
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[PATCH] x86_64: reserve dma32 early for gart
one system with 256g when numa is disabled said:
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>
Index: linux-2.6/arch/x86/kernel/pci-dma_64.c =================================================================== --- linux-2.6.orig/arch/x86/kernel/pci-dma_64.c +++ linux-2.6/arch/x86/kernel/pci-dma_64.c @@ -8,6 +8,8 @@ #include <linux/pci.h> #include <linux/module.h> #include <linux/dmar.h> +#include <linux/bootmem.h> +#include <asm/proto.h> #include <asm/io.h> #include <asm/gart.h> #include <asm/calgary.h> @@ -286,8 +288,53 @@ static __init int iommu_setup(char *p) } early_param("iommu", iommu_setup); +static __initdata void *dma32_bootmem_ptr; +static unsigned long dma32_bootmem_size __initdata = (128ULL<<20); + +static int __init parse_dma32_size_opt(char *p) +{ + if (!p) + return -EINVAL; + dma32_bootmem_size = memparse(p, &p); + return 0; +} +early_param("dma32_size", parse_dma32_size_opt); + +void __init dma32_reserve_bootmem(void) +{ + unsigned long size, align; + if (end_pfn <= MAX_DMA32_PFN) + return; + + align = 64ULL<<20; + size = round_up(dma32_bootmem_size, align); + dma32_bootmem_ptr = __alloc_bootmem_nopanic(size, align, + __pa(MAX_DMA_ADDRESS)); + if (dma32_bootmem_ptr) + dma32_bootmem_size = size; + else + dma32_bootmem_size = 0; +} +static void __init dma32_free_bootmem(void) +{ + int node; + + if (end_pfn <= MAX_DMA32_PFN) + return; + + if (!dma32_bootmem_ptr) + return; + + free_bootmem(__pa(dma32_bootmem_ptr), dma32_bootmem_size); + + dma32_bootmem_ptr = NULL; + dma32_bootmem_size = 0; +} + void __init pci_iommu_alloc(void) { + /* free the range so iommu could get some range less than 4G */ + dma32_free_bootmem(); /* * The order of these functions is important for * fall-back/fail-over reasons Index: linux-2.6/arch/x86/kernel/setup_64.c =================================================================== --- linux-2.6.orig/arch/x86/kernel/setup_64.c +++ linux-2.6/arch/x86/kernel/setup_64.c @@ -397,6 +397,8 @@ void __init setup_arch(char **cmdline_p) early_res_to_bootmem(); + dma32_reserve_bootmem(); + #ifdef CONFIG_ACPI_SLEEP /* * Reserve low memory region for sleep support. Index: linux-2.6/include/asm-x86/pci_64.h =================================================================== --- linux-2.6.orig/include/asm-x86/pci_64.h +++ linux-2.6/include/asm-x86/pci_64.h @@ -25,6 +25,7 @@ extern int (*pci_config_write)(int seg, +extern void dma32_reserve_bootmem(void); extern void pci_iommu_alloc(void); /* The PCI address space does equal the physical memory
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