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I've upgraded my PC by adding another 512Mb Kingston DDR RAM module. The bios recognises the new ram correctly (1Gb), and also does WinXP, but when it comes to linux... I see more than 100Mb dissapeared.
I've checked RAM memory with "cat /proc/meminfo | grep MemTotal" and the output is 906140 kB, so where's the rest of the RAM??
Originally posted by foo_bar_foo you have to enable highmem in the kernel to get that extra little bit
Should you enable CONFIG_HIGHMEM for your 1 GB RAM system?
It is advised to not enable CONFIG_HIGHMEM in the kernel to utilize
the extra 128 MB you get for your 1 GB RAM system. I/O Devices cannot
directly address high memory from PCI space, so bounce buffers have to
be used. Plus the virtual memory management and paging costs come with
extra mappings. For details on bounce buffers, refer to Mel Gorman's
documentation (link below).
Originally posted by SlackerLX Should you enable CONFIG_HIGHMEM for your 1 GB RAM system?
It is advised to not enable CONFIG_HIGHMEM in the kernel to utilize
the extra 128 MB you get for your 1 GB RAM system. I/O Devices cannot
directly address high memory from PCI space, so bounce buffers have to
be used. Plus the virtual memory management and paging costs come with
extra mappings. For details on bounce buffers, refer to Mel Gorman's
documentation (link below).
O.o wow....please, explain the same like if I was 4.... (AKA too complicated for me to understand). Although, I really appretiate your info, at least I know is not Linux's fault I don't see those 128Mb
I'm sorry about being unclear
You need to recompile kernel for highmem usage. However, performance may be affected as you see from document I linked to..
Sorry again...
Originally posted by SlackerLX Should you enable CONFIG_HIGHMEM for your 1 GB RAM system?
It is advised to not enable CONFIG_HIGHMEM in the kernel to utilize
the extra 128 MB you get for your 1 GB RAM system. I/O Devices cannot
directly address high memory from PCI space, so bounce buffers have to
be used. Plus the virtual memory management and paging costs come with
extra mappings. For details on bounce buffers, refer to Mel Gorman's
documentation (link below).
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