On Mon, 19 Apr 2021 at 11:41, Hillf Danton <hdanton@xxxxxxxx> wrote: > > On Mon, 19 Apr 2021 10:50:25 Marco Elver wrote: > > + > > + WRITE_ONCE(kfence_timer_waiting, true); > > + smp_mb(); /* See comment in __kfence_alloc(). */ > > This is not needed given task state change in wait_event(). Yes it is. We want to avoid the unconditional irq_work in __kfence_alloc(). When the system is under load doing frequent allocations, at least in my tests this avoids the irq_work almost always. Without the irq_work you'd be correct of course. > > + wait_event_timeout(allocation_wait, atomic_read(&kfence_allocation_gate), HZ); > > + smp_store_release(&kfence_timer_waiting, false); /* Order after wait_event(). */ > > +
