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 0xfffe0000 - 0xffffffff(2M). And part > is used by vector table. So I move this region down to 0xffc00000 > - 0xffdffff. > > > 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 [email protected] More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
