On Mon, Dec 14, 2015, at 07:48 PM, Greg Parker wrote: > > > On Dec 14, 2015, at 7:39 PM, Kevin Ballard <ke...@sb.org> wrote: > > > >> On Mon, Dec 14, 2015, at 07:34 PM, Greg Parker wrote: > >> > >>> On Dec 14, 2015, at 7:26 PM, Kevin Ballard via swift-dev > >>> <swift-dev@swift.org> wrote: > >>> > >>>> On Mon, Dec 14, 2015, at 12:19 PM, Greg Parker via swift-dev wrote: > >>>> > >>>>> On Dec 14, 2015, at 9:47 AM, John McCall via swift-dev > >>>>> <swift-dev@swift.org> wrote: > >>>>> > >>>>>> On Dec 12, 2015, at 7:04 PM, Chris Lattner <clatt...@apple.com> wrote: > >>>>>> #3 sounds like a great approach to me. I agree with Kevin that if we > >>>>>> keep the object husk approach that any use of a weak pointer that > >>>>>> returns nil should drop any reference to a husk. > >>>>> > >>>>> Spin locks are, unfortunately, illegal on iOS, which does not guarantee > >>>>> progress in the face of priority inversion. > >>>> > >>>> There is a spinlock algorithm that does work (in practice if not in > >>>> theory), but it requires a full word of storage instead of a single bit. > >>> > >>> Is that what OSSpinLock uses? > >> > >> It does not. OSSpinLock is unsafe unless you can guarantee that all users > >> have the same priority. > > > > Hmm, that's pretty unfortunate to hear. I've written code with spinlocks on > > iOS, and I imagine I'm not the only one. Does the system provide an > > implementation of this "safe in practice" spinlock that's visible to > > third-party devs? > > Not that I know of. You should file a bug report.
Filed as rdar://problem/23896366. -Kevin Ballard _______________________________________________ swift-dev mailing list swift-dev@swift.org https://lists.swift.org/mailman/listinfo/swift-dev
