Jason R Thorpe wrote:
>  > I believe the right thing here is to allocate the necessary memory
>  > space in pipe(2) and later only reallocate if needed for bigpipes
>  > (if possible to do so).  Note the memory is not wired, so no physical
>  > memory is wasted, "just" kernel virtual memory space.  Typically,
> 
> Wasting "just" KVA space isn't a very nice thing, either.  Some CPUs
> don't have a lot to spare.

An option here is to change back to unidirectional pipes and only allocate
the buffer for the "real" write end. 
I admit every possible solution is not quite ideal :-/

Jaromir
-- 
Jaromir Dolecek <jdolecek@NetBSD.org>      http://www.ics.muni.cz/~dolecek/
NetBSD - just plain best OS! -=<>=- Got spare MCA cards or docs? Hand me them!