> 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. -- Greg Parker gpar...@apple.com Runtime Wrangler _______________________________________________ swift-dev mailing list swift-dev@swift.org https://lists.swift.org/mailman/listinfo/swift-dev
