Re: [tip:tracing/ftrace] ftrace: remove struct list_head from structdyn_ftrace

[Lai Jiangshan]

Frederic Weisbecker wrote:
> 
> 
> May be I'm wrong. May be I misunderstood this patch.
> But I don't understand how flags can be used at the same time as a pointer
> and as a flag value.
> 

When a new dyn_ftrace is added to ftrace_new_addrs list, the flag is 0,
it's always 0 until this dyn_ftrace is removed from the list, so we can
reuse the flag field. As Steven's suggest, using an union is better.

ftrace_convert_nops()
  ftrace_record_ip() // allocate dyn_ftrace, and add it
                     // to ftrace_new_addrs list
  ftrace_update_code() // remove it from ftrace_new_addrs.

Lai.

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