On Thu, 02/05 09:37, Paolo Bonzini wrote: > > > On 05/02/2015 07:23, Fam Zheng wrote: > >> > @@ -1381,14 +1397,16 @@ static ram_addr_t ram_block_add(RAMBlock > >> > *new_block, Error **errp) > >> > QTAILQ_INSERT_TAIL(&ram_list.blocks, new_block, next); > >> > } > >> > ram_list.mru_block = NULL; > >> > + atomic_rcu_set(&ram_list.version, ram_list.version + 1); > >> > > >> > - ram_list.version++; > > Why is this not atomic_inc > > Because writes are protected by the ramlist lock. atomic_inc is more > expensive.
OK! > > > (or why is atomic_rcu_set necessary here)? > > I probably should move it to patch 9; it is needed to update the list > before ram_list.version. > > If you prefer I can change it to > > smp_wmb(); > atomic_set(&ram_list.version, ram_list.version + 1); > > ? > Yes, this looks more obvious :) Fam
