I inferred this from reading up on the compressed vm project. It can be
higher or lower depending on what devices you have in your system --
however, I've read messages from kernel hackers saying Linux is very
aggressive in reserving memory space for devices because it must be
allocated at boottime.
Josh Berkus wrote:
> William,
>
>
>>The theshold for using PAE is actually far lower than 4GB. 4GB is the
>>total memory address space -- split that in half for 2GB for userspace,
>>2GB for kernel. The OS cache resides in kernel space -- after you take
>>alway the memory allocation for devices, you're left with a window of
>>roughly 900MB.
>
>
> I'm curious, how do you get 1.1GB for memory allocation for devices?
>
