Re: [PATCH] CONFIG_NR_CPUS, redux

[William Lee Irwin III <wli@holomorphy.com>]

On Wed, Jun 12, 2002 at 08:06:58AM -0700, Martin J. Bligh wrote:
> Indeed. And before that gets changed, it would be necessary
> to change the bootstrap procedure not to crash if you have
> more than NR_CPUS cpus (as Andrew reported it did), but instead 
> to just not configure them ... much less troublesome.
> M.

There are also fun deadlocks on i386 with "too many cpu's" as it
appears the kernel attempts to use logical APIC mode to get beyond
the eigth cpu and seems unaware that it can't IPI them that way unless
it's configured to always use the clustered hierarchical destination
format, though that's perhaps a little beyond just NR_CPUS. Perhaps
some kind of sanity checking is needed at the arch level for issues
like this as well, not just the absolute maximum number of cpu's?


Cheers,
Bill