Re: [PATCH v2 0/2] change ARM linux memory layout to support 32 CPUs
On Fri, 11 Apr 2014, Liu Hua wrote: > Hi Nicolas or Russell, > > This patch series change fixmap mapping region to suppport 32 CPUs. > Because the "top_pmd" covers 0xfffe - 0x(2M). And part > is used by vector table. So I move this region down to 0xffc0 > - 0xffd. > > > I have tested the patches on arma9(2 CPUs) and arma15(16 CPUs) platforms > > BTW, As we know we can configure NR_CPUS up to 32. So we need 2048K > at most. But for ARM systems with less cpus, there is a waste > of virtual address. So should we change its size according to > NR_CPUS, as what MIPS linux does ? It is probably not worth the bother. We lived with this area reserved for static DMA mapping while there was no longer any DMA mapped there for quite a while. > > Changes from v1: > --- > - changed documentation for ARM linux memory layout. > - moved fixmap mapping region, not just extended. > > Liu Hua (2): > ARM : DMA : remove useless information about DMA > ARM : extend fixmap mapping region to support 32 CPUs > > Documentation/arm/memory.txt | 8 ++-- > arch/arm/include/asm/fixmap.h | 4 ++-- > arch/arm/include/asm/highmem.h | 1 + > arch/arm/include/asm/memory.h | 2 -- > arch/arm/mm/highmem.c | 10 +- > arch/arm/mm/mm.h | 7 +++ > arch/arm/mm/mmu.c | 4 > mm/highmem.c | 1 + > 8 files changed, 22 insertions(+), 15 deletions(-) > > -- > 1.9.0 > -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majord...@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
[PATCH v2 0/2] change ARM linux memory layout to support 32 CPUs
Hi Nicolas or Russell, This patch series change fixmap mapping region to suppport 32 CPUs. Because the "top_pmd" covers 0xfffe - 0x(2M). And part is used by vector table. So I move this region down to 0xffc0 - 0xffd. I have tested the patches on arma9(2 CPUs) and arma15(16 CPUs) platforms BTW, As we know we can configure NR_CPUS up to 32. So we need 2048K at most. But for ARM systems with less cpus, there is a waste of virtual address. So should we change its size according to NR_CPUS, as what MIPS linux does ? Changes from v1: --- - changed documentation for ARM linux memory layout. - moved fixmap mapping region, not just extended. Liu Hua (2): ARM : DMA : remove useless information about DMA ARM : extend fixmap mapping region to support 32 CPUs Documentation/arm/memory.txt | 8 ++-- arch/arm/include/asm/fixmap.h | 4 ++-- arch/arm/include/asm/highmem.h | 1 + arch/arm/include/asm/memory.h | 2 -- arch/arm/mm/highmem.c | 10 +- arch/arm/mm/mm.h | 7 +++ arch/arm/mm/mmu.c | 4 mm/highmem.c | 1 + 8 files changed, 22 insertions(+), 15 deletions(-) -- 1.9.0 -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majord...@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
[PATCH v2 0/2] change ARM linux memory layout to support 32 CPUs
Hi Nicolas or Russell, This patch series change fixmap mapping region to suppport 32 CPUs. Because the top_pmd covers 0xfffe - 0x(2M). And part is used by vector table. So I move this region down to 0xffc0 - 0xffd. I have tested the patches on arma9(2 CPUs) and arma15(16 CPUs) platforms BTW, As we know we can configure NR_CPUS up to 32. So we need 2048K at most. But for ARM systems with less cpus, there is a waste of virtual address. So should we change its size according to NR_CPUS, as what MIPS linux does ? Changes from v1: --- - changed documentation for ARM linux memory layout. - moved fixmap mapping region, not just extended. Liu Hua (2): ARM : DMA : remove useless information about DMA ARM : extend fixmap mapping region to support 32 CPUs Documentation/arm/memory.txt | 8 ++-- arch/arm/include/asm/fixmap.h | 4 ++-- arch/arm/include/asm/highmem.h | 1 + arch/arm/include/asm/memory.h | 2 -- arch/arm/mm/highmem.c | 10 +- arch/arm/mm/mm.h | 7 +++ arch/arm/mm/mmu.c | 4 mm/highmem.c | 1 + 8 files changed, 22 insertions(+), 15 deletions(-) -- 1.9.0 -- To unsubscribe from this list: send the line unsubscribe linux-kernel in the body of a message to majord...@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
Re: [PATCH v2 0/2] change ARM linux memory layout to support 32 CPUs
On Fri, 11 Apr 2014, Liu Hua wrote: Hi Nicolas or Russell, This patch series change fixmap mapping region to suppport 32 CPUs. Because the top_pmd covers 0xfffe - 0x(2M). And part is used by vector table. So I move this region down to 0xffc0 - 0xffd. I have tested the patches on arma9(2 CPUs) and arma15(16 CPUs) platforms BTW, As we know we can configure NR_CPUS up to 32. So we need 2048K at most. But for ARM systems with less cpus, there is a waste of virtual address. So should we change its size according to NR_CPUS, as what MIPS linux does ? It is probably not worth the bother. We lived with this area reserved for static DMA mapping while there was no longer any DMA mapped there for quite a while. Changes from v1: --- - changed documentation for ARM linux memory layout. - moved fixmap mapping region, not just extended. Liu Hua (2): ARM : DMA : remove useless information about DMA ARM : extend fixmap mapping region to support 32 CPUs Documentation/arm/memory.txt | 8 ++-- arch/arm/include/asm/fixmap.h | 4 ++-- arch/arm/include/asm/highmem.h | 1 + arch/arm/include/asm/memory.h | 2 -- arch/arm/mm/highmem.c | 10 +- arch/arm/mm/mm.h | 7 +++ arch/arm/mm/mmu.c | 4 mm/highmem.c | 1 + 8 files changed, 22 insertions(+), 15 deletions(-) -- 1.9.0 -- To unsubscribe from this list: send the line unsubscribe linux-kernel in the body of a message to majord...@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
