On 07-Nov 14:16, Peter Zijlstra wrote: > On Mon, Oct 29, 2018 at 06:32:57PM +0000, Patrick Bellasi wrote: > > > +static void uclamp_group_put(unsigned int clamp_id, unsigned int group_id) > > { > > + union uclamp_map *uc_maps = &uclamp_maps[clamp_id][0]; > > + union uclamp_map uc_map_old, uc_map_new; > > + long res; > > + > > +retry: > > + > > + uc_map_old.data = atomic_long_read(&uc_maps[group_id].adata); > > + uc_map_new = uc_map_old; > > + uc_map_new.se_count -= 1; > > + res = atomic_long_cmpxchg(&uc_maps[group_id].adata, > > + uc_map_old.data, uc_map_new.data); > > + if (res != uc_map_old.data) > > + goto retry; > > +} > > Please write cmpxchg loops in the form: > > atomic_long_t *ptr = &uclamp_maps[clamp_id][group_id].adata; > union uclamp_map old, new; > > old.data = atomic_long_read(ptr); > do { > new.data = old.data; > new.se_cound--; > } while (!atomic_long_try_cmpxchg(ptr, &old.data, new.data)); > > > (same for all the others of course)
Ok, I did that to save some indentation, but actually it's most commonly used in a while loop... will update in v6. Out of curiosity, apart from code consistency, is that required also specifically for any possible compiler related (mis)behavior ? -- #include <best/regards.h> Patrick Bellasi