Messages in this thread | | | Date | Sun, 6 Jun 2004 05:16:57 -0700 | From | Paul Jackson <> | Subject | Re: [PATCH] cpumask 5/10 rewrite cpumask.h - single bitmap based implementation |
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Rusty wrote: > Yes, NR_CPUS needs to get to userspace somehow sanely if we want to fix > this in general.
Are you saying that NR_CPUS is needed, or just the number of longs in a cpumask (sizeof (cpumask_t), essentially)?
I can see where the size is needed, in order to make the system calls to set and get masks of arbitrary size. Since these sizes are a multiple of sizeof(long), at a minimum this means user code needs to know the number of longs in a mask. Though the number of bytes, as in sizeof(cpumask_t), rather than of longs, is perhaps a less surprising interface.
I can't see where the user code cares whether NR_CPUS is 47 or 48?
Am I missing something?
I am a firm believer in passing the minimum essential information across major boundaries. Passing too much creates maintaince problems, and encourages misuse of information, resulting in bogus user code.
-- I won't rest till it's the best ... Programmer, Linux Scalability Paul Jackson <pj@sgi.com> 1.650.933.1373 - To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
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