Messages in this thread | | | Date | Mon, 15 Jun 2009 22:21:35 +0300 | From | Avi Kivity <> | Subject | Re: [tip:perfcounters/core] perf_counter: x86: Fix call-chain support to use NMI-safe methods |
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On 06/15/2009 10:10 PM, Peter Zijlstra wrote: >> But one thing is sure: it is certainly going to be faster than the >> INVLPG(s!) we have to do with the GUP solution. >> > > Sure, but we only pay that price when we do the callchain bit, not on > every NMI. >
You can read cr2 on nmi entry and nmi exit, and only write it if it has changed (if it turns out that writing cr2 is expensive; ISTR that it isn't).
-- I have a truly marvellous patch that fixes the bug which this signature is too narrow to contain.
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