David Miller wrote:
> From: John Heffner <jheffner@psc.edu>
> Date: Wed, 14 Mar 2007 17:25:22 -0400
> 
>> The current tcp_mem initialization gives values that are really too 
>> small for systems with ~256-768 MB of memory, and also for systems with 
>> larger page sizes (ia64).  This patch gives an alternate method of 
>> initialization that doesn't depend on the cache allocation functions, 
>> but I think should still provide a nice curve that gives a smaller 
>> fraction of total memory with small-memory systems, while maintaining 
>> the same upper bound (pressure at 1/2, max as 3/4) on larger memory systems.
> 
> Indeed, it's really dumb for any of these calculations to be
> dependant upon the page size.
> 
> Your patch looks good, and I'll review it further tomorrow and
> push upstream unless I find some issues with it.
> 
> Thanks John.


The way it's coded is somewhat opaque since it has to be done with 
32-bit integer arithmetic.  These plots might help make the motivation 
behind the code a little clearer.

Thanks,
   -John