Just to make sure I understand it correctly... Assuming I have allocated per CPU data (numa control, etc.) pointed at by: void *per_cpu[MAXCPUS]; Assuming a per CPU variable has got an "offset" in each per CPU data area. Accessing this variable can be done as follows: err = vgetcpu(&my_cpu, ...); if (err) goto .... pointer = (typeof pointer) (per_cpu[my_cpu] + offset); // use "pointer"... It is hundred times more long than "__get_per_cpu(var)++". As we do not know when we can be moved to another CPU, "vgetcpu()" has to be called again after a "reasonable short" time. My idea is to map the current task structure at an arch. dependent virtual address into the user space (obviously in RO). #define current ((struct task_struct *) 0x...) No more need to for "vgetcpu()" at all. The example above becomes: pointer = (typeof pointer) (per_cpu[current->thread_info.cpu] + offset); // use "pointer"... As obtaining "pointer" does not cost much, it can be re-calculated at each usage => no problem to know when to recheck it, there is less chance for using the data of a neighbor. Regards, Zoltan Menyhart - : 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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