Re: [PATCH] Add trace event for munmap

Christoph Hellwig
2010-07-08T17:51:57Z

On Thu, Jul 08, 2010 at 07:48:08PM +0200, Peter Zijlstra wrote:
> On Thu, 2010-07-08 at 13:35 -0400, Christoph Hellwig wrote:
>
> > What kind of infrastructure is perf using for recording
> > mmap()/mremap()/brk() information?
>
> A direct hook into mmap_region(), see perf_event_mmap().
>
> We used to only track VM_EXEC regions, but these days we can also track
> data regions (although it wouldn't track mremap and brk I think).
>
> We need the VM_EXEC maps to make sense of the instruction pointer
> samples.
>
> Eric recently added support for !VM_EXEC mmap() in order to interpret
> linear addresses provided by things like the software pagefault events
> and certain powerpc hardware events.

Maybe the user reporting should use trace points everywhere, leaving
the direct hook just for the executable tracking?