Re: [PATCH v4 0/13] Uprobes v4

[Srikar Dronamraju]

> * Srikar Dronamraju (srikar@xxxxxxxxxxxxxxxxxx) wrote:
> > Uprobes Patches
> > 
> > Changelog from v3:
> >   - Reverted to background page replacement as suggested by Peter Zijlstra.
> 
> Why ?
> 
> I'm not sure we reached any concensus about the need for a background page
> replacement.
> 
> Thanks,
> 
> Mathieu
> 

I was tested with access_process_vm(previous patchset) and the current
(background page replacement) and the results are the same. 

However Peter Zijlstra's contention still stands that we might be
relying on a undocumented feature in the hardware and the flipping the
pages isnt that hard or expensive.

Even Linus, (http://lkml.org/lkml/2010/1/27/87) had shown inclination
towards background page replacement. 

Also when uprobes implements global tracing support (i.e probing a
particular symbol in a dso across processes), it has to rely on
background page replacement. 

Hence I based this patchset on background page replacement rather than
on access_process_vm. Later On, if there is a consensus on using
access_process_vm, we can make the corresponding changes.

--
Thanks and Regards
Srikar
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