U Area Removal

[Bruce M Simpson]

Hey there,

On Wed, Nov 10, 2004 at 10:00:35PM -0500, David Schultz wrote:
> Over the years, the amount of data we have stored in each process' U
> area has eroded to the point where all we have left are the following:
> 
>   - A struct kinfo_proc that is only used for a.out core dumps.
>     This can be reconstructed at the time of the core dump, so
>     it doesn't need to be there.

Aren't we 100% ELF these days? Surely aout is no longer relevant?

>   - The struct pstats for the process, which takes a mere 216 bytes
>     on i386.

That's pretty small. I don't see the rusage or timeval structs growing
much for 64-bit platforms.

> I propose to remove the ability to swap the U area, allocating p_stats
> from malloced memory instead.

I think this is a good idea.

> 	http://www.freebsd.org/~das/patches/upages.diff

I've briefly looked over this and am happy to see it simplifies MD code
somewhat.

BMS