Re: [PATCH v2 2/2] tools/memory-model: Make ppo a subrelation of po

[Andrea Parri]

> The reason why Wx=1 ->ww-vis Wx=2:
> 
> 	0:Wx=1 ->po-rel 0:Wy=1 and po-rel < fence < ww-post-bounded.
> 
> 	0:Wy=1 ->rfe 1:Ry=1 ->(hb* & int) 1:Rdy=1 and
> 		(rfe ; hb* & int) <= (rfe ; xbstar & int) <= vis.
> 
> 	1:Rdy=1 ->po 1:unlock ->rfe 3:lock ->po 3:Wx=2
> 		so 1:Rdy=1 ->po-unlock-lock-po 3:Wx=2
> 		and po-unlock-lock-po <= mb <= fence <= w-pre-bounded.
> 
> Finally, w-post-bounded ; vis ; w-pre-bounded <= ww-vis.

To clarify, po-unlock-lock-po is not a subrelation of mb; see what
happens without the smp_mb__after_unlock_lock().

  Andrea