On Fri, Jun 28, 2019 at 10:46:08PM +0200, Peter Zijlstra wrote: > On Fri, Jun 28, 2019 at 05:50:03PM +0100, Mark Rutland wrote: > > > + /* > > > + * Wake any perf_event_free_task() waiting for this event to be > > > + * freed. > > > + */ > > > + smp_mb(); /* pairs with wait_var_event() */ > > > + wake_up_var(var); > > > > Huh, so wake_up_var() doesn't imply a RELEASE? > > > > As an aside, doesn't that mean all callers of wake_up_var() have to do > > likewise to ensure it isn't re-ordered with whatever prior stuff they're > > trying to notify waiters about? Several do an smp_store_release() then a > > wake_up_var(), but IIUC the wake_up_var() could get pulled before that > > release... > > Yah,... > > > https://lkml.kernel.org/r/[email protected]
That gets me a 404, so I'll assume that's a speculative store. ;) > I needs to get back to that. Ouch; sorry for reminding you of this mess! Thanks, Mark.
