Re: [PATCH] rudimentary tracing for Classic RCU

From: Andi Kleen
Date: Thu Oct 09 2008 - 02:49:24 EST


> In this case, why not define it as:
> static char buf[20*NR_CPUS + 100];

Actually you should near never use NR_CPUS now but always num_possible_cpus()
(or even num_online_cpus()) Using NR_CPUS can lead to extreme waste
of memory on kernels which are compiled for 4096 CPUs for example.

And with num_possible_cpus() kmalloc is needed.

-Andi
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