Re: [PATCH 1/6] perf_counter: move the event overflow output bitsto record_type

[Peter Zijlstra]

On Thu, 2009-04-02 at 16:27 -0700, Corey Ashford wrote:
> Whoops, nevermind.
> 
> My misunderstanding on this one.  This enum is used for event type, not 
> the record_type, and as such is makes sense for there to be exclusive 
> mmap and munmap event records.
> 
> Thinking about this a bit, I'm guessing that the idea is to track the 
> loading and unloading of shared objects which uses mmap and munmap, so 
> that that the ip can be related to a particular object that was mapped 
> in at the time of the counter overflow interrupt.  Is that right?

Indeed, whenever a mmap/munmap happens of a PROT_EXEC range we record
that information so that we can relate the userspace IPs to some file
and hence the actual userspace code.



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