Re: [RFC] perf report: introduce --map-anon-mem for anon-executable-memory symbols parsing

[Hou Pengyang]

On 2015/6/19 18:42, Ingo Molnar wrote:
> * Wangnan (F) <wangnan0@xxxxxxxxxx> wrote:
>
> > On 2015/6/18 22:01, Hou Pengyang wrote:
> > > This patch introduces a --map-anon-mem argument to perf report to deal
> > > with anon-executable-memory symbol parsing.
> >
> > --map-anon-mem is not a good name. The user defined map area list
> > introduced in this patch can be used on not only anon mapping but
> > also file mapping.
>
> Yeah, so quirky options generally suck and only 0.01% of the users will use it.
> It's in a way worse than not having this code, because we'll have to maintain it,
> but it won't be used.
>
> Is there a way to auto-detect 'executable anon mappings' (perhaps by generating an
> MMAP event with some extra bit set, or a new MMAP event?) so that it's all
> seemless?
I think it not difficult to generate such MMAP event, just like :
	
	0 435090424309600 0x3e0 [0x68]: PERF_RECORD_MMAP2 
788/788:[0x7f946c0000(0x4000) @ 0x7f946c0000 00:00 0 0]: ---p //anon

But for symbol parsing, this is not enough. For such mmap area, perf
doesn't know the path of '.so/.o', which is necessarcy for symbol-
parsing. So we need to tell perf the relationship between the .so file 
and the mmap range explicitly.

Thanks,
     Hou

> The user should not be required to know about such details!
>
> Thanks,
>
> 	Ingo
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