Re: [PATCH] this_cpu: Use this_cpu_xx in trace_functions_graph.c

[Christoph Lameter]

On Tue, 13 Oct 2009, Tejun Heo wrote:

> Oh... one question tho.  I used __this_cpu_*() as other conversions
> but I think we should be using the version without the underscores.
> The relationship between get_cpu_var() and __get_cpu_var() is
> different from the one between this_cpu_*() and __this_cpu_*().

For operations like inc/add/dec/sub you need to use the version with __
otherwise the arches that do not support these operations will have to
generate useless expensive code that disables / reenables preempt.

For this_cpu_ptr / __this_cpu_ptr it does not matter. this_cpu_ptr gives
you additional checks.

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