Messages in this thread | | | Date | Fri, 26 Sep 2008 20:18:14 -0400 (EDT) | From | Steven Rostedt <> | Subject | Re: [PATCH v6] Unified trace buffer |
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On Fri, 26 Sep 2008, Mike Travis wrote: > Steven Rostedt wrote: > >> The other thing to consider is using a percpu variable. > > > > This structure is allocated on request. > > > > -- Steve > > > Ahh, then it would need the yet to be added cpu_alloc() from Christoph.
We can always change this later.
> > Your best bet then is to allocate based on nr_cpu_ids.
Actually in this case I chose num_possible_cpus(). Reason being is that later I may add an interface to allow the user to select which CPUs they want to trace, and this will only allocate a subset of CPU buffers. (not going to implement that in the first release).
But to lay the ground work, I set a buffers->cpumask to be that of all the cpus with buffers allocated. For now that mask is set to cpu_possible_map. Since num_possible_cpus() is defined as cpus_weight_nr(cpu_possible_map) I figured that was the better choice.
-- Steve
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