Subject: Re: "const int" in conf/param.c?
To: Jonathan Stone <jonathan@DSG.Stanford.EDU>
From: Eduardo E. Horvath <eeh@one-o.com>
List: tech-kern
Date: 04/26/1999 10:17:48
On Sun, 25 Apr 1999, Jonathan Stone wrote:

> In message <199904251255.WAA14243@balrog.supp.cpr.itg.telecom.com.au>,
> Simon Burg e writes:
> 
> > + Why does the alpha want 256 byte mbufs?  If the 64 bit architecture
> >   is really an issue, should sparc64 also have 256 byte mbufs?
> 
> Header overhead. There's just not much left out of 128 bytes after
> subtracting out the 64-bit pointers and ints and what-have-you, and
> then aligning the remainder to a 64-bit boundary, etc.

sparc64 currently runs in either 32-bit or 64-bit mode, so the mbuf size
should vary depending on the kernel.  What we really need is some cpp
define that reports pointer size so we can check that rather than:

#if defined(alpha) || (defined(sparc64) && defined(__arch64__)) || \
	(defined(mips) && ...) || (defined(powerpc) ....

=========================================================================
Eduardo Horvath				eeh@one-o.com
	"I need to find a pithy new quote." -- me