Re: interesting commit about llvm introducing barrier_data()

[Stephan Mueller]

Am Dienstag, 23. Februar 2016, 14:32:43 schrieb Mathieu Desnoyers:

Hi Mathieu,

> ----- On Feb 23, 2016, at 9:23 AM, Paul E. McKenney 
paulmck@xxxxxxxxxxxxxxxxxx wrote:
> > On Tue, Feb 23, 2016 at 02:02:26PM +0000, Mathieu Desnoyers wrote:
> >> commit 7829fb09a2b4268b30dd9bc782fa5ebee278b137
> >> Author: Daniel Borkmann <daniel@xxxxxxxxxxxxx>
> >> Date:   Thu Apr 30 04:13:52 2015 +0200
> >> 
> >>     lib: make memzero_explicit more robust against dead store elimination
> >> 
> >> ^ interesting commit. Any idea on the impact of this on kernel RCU
> >> implementation and liburcu cmm_barrier() ?
> > 
> > First I knew of it!  But I bet that more like this are needed.  ;-)
> 
> I recommend you check my IRC discussion with peterz on the matter of
> this new "barrier_data()".
> 
The key idea of the memzero_explicit is about forcing the compiler to do a 
memset.

See the trivial test attached.

Ciao
Stephan

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