On Tue, 22 Aug 2006, Luck, Tony wrote: > > Could we set these limits consitently to the largest IA64 configuration to > > make sure that a generic IA64 kernel is able to run on all machines? > > We could ... but Horms has a good point that we might not > want to do this if the cost is high. Can you estimate how > much memory will be allocated in these NR_CPUS and MAX_NUMNODES > sized arrays. If it is only[1] a couple of hundred Kbytes, then > it might be worth it (even little IA-64 systems have 1GB, so > 100K is 0.01%). Worst case is probably the slab allocator. The kmem_cache struct has pointer arrays per node and per cpu. If a corresponding cpu / node is not up then no further structures will be allocated. pointers to per cpu caches array cache = NR_CPUS * sizeof(void *) = 8k. up from 64* sizeof(void *) = 512 byte. pointers to per node l3 array = MAX_NUMNODES * sizeof(void *) = 8k. again up from currently 2k. So additional overhead per slab is around 13k. About 40 slabs. That results in ~520k additional overhead. - To unsubscribe from this list: send the line "unsubscribe linux-ia64" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
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