slacker (sla@c.ker) on 5/13/07 wrote:
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>Your virtual address space needs to be a multiple of the maximum resident set
>size of your applications. If you have a single application which is working
>with 1GB of physical memory, then you will need > 1GB (and likely > 4GB) of virtual memory.
>
>If you are the average desktop user who has ten tiny applications open, each using
>100MB of RAM, then a 32 bit virtual address space is fine.

No it is NOT. I have no idea where you got this impression. The requirements are (as Linus already explained):

Virtual address space >= user address space + kernel address space
Kernel address space >= physical memory size + memory-mapped I/O size + kernel virtual mappings

Assuming you want to allow a user virtual address space
on the order of physical memory size, virtual memory size should be at least 2x physical memory.

The resident set size has NOTHING do do with it. The user (virtual) address space contains all mapped addresses, both resident and non-resident. You need space for all of that.