* Davidlohr Bueso <d...@stgolabs.net> wrote: > On Fri, 05 Feb 2016, Ingo Molnar wrote: > > >So I too didn't understand that sentence at first, because the capitalization > >really throws off quick parsing of that comment, as 'MB' ususally denotes > >megabytes. > > Sure, fair enough. > > > > >So please change it to "mb(); (A)" or so - and I think all of these comments > >should be changed to use a standard API name for the barrier they imply, as > >the > >head of futex.c does: > > > >* waiters++; (a) > >* mb(); (A) <-- paired with -. > >* | > >* lock(hash_bucket(futex)); | > >* | > >* uval = *futex; | > >* | *futex = newval; > >* | sys_futex(WAKE, futex); > >* | futex_wake(futex); > >* | > >* `-------> mb(); (B) > > > >Btw., pedantic: shouldn't that be smp_mb()? Futexes don't operate on IO > >spaces, so > >on UP they only need compiler barriers. > > Right, but we do in fact use smp barriers in this cases in the real code, > that > mb() is just in the comments, I guess it would be desirable to change it to > smp_mb nonetheless. > > However, could these changes be in a followup? Mainly because the barrier B > references will be updated across all futex.c... unless there are still > concerns > about this particular patch, of course.
How about doing it first in a preparatory patch? So that reviews of patches actually making substantial changes don't get derailed by hard to read comments and so. Thanks, Ingo