Messages in this thread | | | Date | Tue, 22 Dec 2009 09:54:26 -0600 (CST) | From | Christoph Lameter <> | Subject | Re: [this_cpu_xx V8 11/16] Generic support for this_cpu_cmpxchg |
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On Sat, 19 Dec 2009, Mathieu Desnoyers wrote:
> I am a bit concerned about the "generic" version of this_cpu_cmpxchg. > Given that what LTTng needs is basically an atomic, nmi-safe version of > the primitive (on all architectures that have something close to a NMI), > this means that it could not switch over to your primitives until we add > the equivalent support we currently have with local_t to all > architectures. The transition would be faster if we create an > atomic_cpu_*() variant which would map to local_t operations in the > initial version. > > Or maybe have I missed something in your patchset that address this ?
NMI safeness is not covered by this_cpu operations.
We could add nmi_safe_.... ops?
The atomic_cpu reference make me think that you want full (LOCK) semantics? Then use the regular atomic ops?
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