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In Linux the RAM is divided in three Zones DMA Zone, Normal Zone, and HiGHMEM Zone. So when user space process requests for memory which zone is used when and why?

user2542088
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1 Answers1

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User space processes only access the HighMem zone. The Normal and DMA zones (low mem) are privileged and directly accessed only by the kernel.

The memory regions themselves may be laid out differently depending on if you're running a 32-bit or 64-bit machine, how much physical memory is installed, and your kernel options.

spudone
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