Re: [PATCH] ppc64 ftrace: mark data_access callees "notrace" (pt.1)

[Jiri Kosina]

yOn Sat, 16 May 2015, Torsten Duwe wrote:

> > > There's got to be a better solution than this.
> >
> > Can you think of a better approach?
> 
> Maybe a per thread variable to lock out a recursion into tracing?
> Thanks for your doubt.

ftrace already handles recursion protection by itself (depending on the 
per-ftrace-ops FTRACE_OPS_FL_RECURSION_SAFE flag).

It's however not really well-defined what to do when recursion would 
happen. Therefore __notrace__ annotation, that just completely avoid such 
situation by making tracing impossible, looks like saner general solution 
to me.

-- 
Jiri Kosina
SUSE Labs

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