Messages in this thread | | | Date | Wed, 9 Oct 2013 11:54:23 +0200 | From | Ingo Molnar <> | Subject | Re: [RFC] perf: mmap2 not covering VM_CLONE regions |
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* David Ahern <dsahern@gmail.com> wrote:
> On 10/8/13 1:54 PM, Stephane Eranian wrote: > >>>If the current MMAP2 is not a complete solution for what you (Google) > >>>need, should support be reverted before 3.12 is released? No sense in > >>>making this part of the forever API if more work is needed on it. > >> > >>Instead of a full revert we could just turn off the ABI portion minimally > >>and not recognize it for now. Assuming a more complete solution is in the > >>works for v3.13. > >> > >That's a possibility. They are also pieces in the perf tool itself. > >We could certainly make the attr->mmap2 bit disappear. > > > >I think it boils down to how can we uniquely identify virtual > >mapping to the same physical data either via shmat(), files, VM_CLONE. > >We had all covered but the last case with the ino approach. We don't have > >a solution for VM_CLONE yet. > > > > I was mainly thinking the 2 parts that generate MMAP2 events: kernel > side it's the mmap2 attribute and perf_event_mmap_output; userspace side > it's perf_event__synthesize_mmap_event. Certainly the rest of the > plumbing can be left in place until the solution is refined as needed.
Could some of you please send a patch ASAP?
Thanks,
Ingo
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