Re: [PATCH 4/5] kmemtrace: SLUB hooks.

Mathieu Desnoyers
2008-08-11T18:29:39Z

* Christoph Lameter (cl@linux-foundation.org) wrote:
> Steven Rostedt wrote:
>
> > The kmemtrace_mark_alloc_node itself is an inline function, which calls
> > another inline function "trace_mark" which is designed to test a
> > read_mostly variable, and will do an "unlikely" jmp if the variable is
> > set (which it is when tracing is enabled), to the actual function call.
> >
> > There should be no extra function calls when this is configured on but
> > tracing disabled. We try very hard to keep the speed of the tracer as
> > close to a non tracing kernel as possible when tracing is disabled.
>
> Makes sense. But then we have even more code bloat because of the tests that
> are inserted in all call sites of kmalloc.
>

The long-term goal is to turn the tests into NOPs, but only once we get
gcc support.

Mathieu

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Mathieu Desnoyers
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