Messages in this thread | | | Date | Tue, 25 Feb 2014 11:49:24 +0100 | From | Peter Zijlstra <> | Subject | Re: sched: hang in migrate_swap |
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On Tue, Feb 25, 2014 at 12:47:01PM +0800, Michael wang wrote: > On 02/24/2014 09:10 PM, Peter Zijlstra wrote: > > On Mon, Feb 24, 2014 at 01:12:18PM +0100, Peter Zijlstra wrote: > >> + if (p) { > >> + if (unlikely(p == RETRY_TASK)) > >> + goto again; > > > > We could even make that: unlikely(p & 1), I think most CPUs can encode > > that far better than the full pointer immediate. > > Agree, unless odd-align stuff appeared...
That shouldn't happen; we rely on u32 alignment all over the place. So for general objects we should have at least the lower two bits free to play with.
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