[PATCH] Add MAXCPU as a kernel config option and quality discussion on this

[Peter Wemm]

On Fri, Jul 8, 2011 at 10:14 AM, John Baldwin <jhb at freebsd.org> wrote:
> On Friday, July 08, 2011 12:48:44 pm Kostik Belousov wrote:
>> On Fri, Jul 08, 2011 at 05:37:17PM +0200, Attilio Rao wrote:
>> > I've made this patch for making MAXCPU a kernel config option:
>> > http://www.freebsd.org/~attilio/maxcpu_kernel_opt.diff
>> >
>> > Besides if this is a good idea or not (which I think it is) I want to
>> > discuss this implementation and similar related problems.
>> > In this case I've been forced to include opt_maxcpu.h in all the MD
>> > param.h implementations. A similar case, KSTACK_PAGES, includes the
>> > opt_kstack_pages.h only in the consumers. While this is possible for
>> > KSTACK_PAGES, because there are very little consumers, it would be
>> > impratical for MAXCPU. Besides, this is a very dangerous practice
>> > IMHO: if a consumer fails to add opt_kstack_pages it may end up with a
>> > faulty value, introducing a breakage that would go unnoticed.
>> >
>> > In my case, I think that including opt_maxcpu is a viable panacea, but
>> > in general, after discussing with peter@, probabilly the better idea
>> > would be having a centralized script that does pre-processing before
>> > to start compiling and set with the right values all those constants
>> > (something like genassym.c, but of course with a different purpose).
>> >
>> > What are your ideas on that? Do you think that including opt_maxcpu.h
>> > would be acceptable for the time being?
>>
>> I vote for putting MAXCPU in opt_global.h.
>> Why did you choosed separate opt header ?
>
> I agree this should just go into opt_global.h.

I disagree. That makes it even harder to track down KLD's that depend
on the correct value of MAXCPU.

-- 
Peter Wemm - peter at wemm.org; peter at FreeBSD.org; peter at yahoo-inc.com; KI6FJV
"All of this is for nothing if we don't go to the stars" - JMS/B5
"If Java had true garbage collection, most programs would delete
themselves upon execution." -- Robert Sewell