Messages in this thread | | | Date | Mon, 24 Mar 2014 16:00:50 -0400 (EDT) | From | Nicolas Pitre <> | Subject | Re: [PATCH RFC] ARM: extend fixmap mapping region to support 30 CPUs |
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On Mon, 24 Mar 2014, Liu Hua wrote:
> In 32-bit ARM systems, the fixmap mapping region can support > no more than 14 CPUs(total: 896k; one CPU: 64K). And we can > configure NR_CPUS up to 32. So there is a mismatch. > > This patch extends the fixmapping region downwards to boundary > of DMA mapping region(0xffe00000-0xfffe0000). Then the fixmap > mapping region can support up to 30 CPUs.
You failed to update CONSISTENT_END in your patch.
Hmmm? Waitaminute...
Well well...
It looks like the static mapping area for DMA was removed from the code by commit e9da6e9905e6 but the information in Documentation/arm/memory.txt was not updated accordingly.
CONSISTENT_END in arch/arm/include/asm/memory.h has no more users and shoule probably be removed.
This means 0xffc00000 to 0xffefffff is no longer used by anything.
> There seems to be no easy way to support 32 CPUs by simply > changing memory layout on ARM Linux. So I also limit the > maximal CPU number one can configure.
I think the above should help you solve your CPU limit easily.
Nicolas
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