On 05/27/16 02:17 PM, Mateusz Guzik wrote: > Hello there, > > quite some time ago I posted a trivial patch to locking primitives. What > they do is the inline part tries an atomic op and if that fails the > actual function is called, which immediately tries the same op. > > The obvious optimisation checks for the availability of the lock first. > > There concerns about the way it was done previously by relying on > volatile behaving in a specific way. > > Later a simplified version was posted which should not have the concern, > but the thread died. > > I refer you to https://lists.freebsd.org/pipermail/freebsd-current/2015-November/058100.html > for simple benchmark results. > > I would like to get the patch in before 11 freeze. This makes sense to me, and the patch looks good. Please consider adding a comment to each location that explains why the extra condition is tested before the atomic op. Without such a comment, I am concerned that your changes will be garbage collected later, because the extra condition would seem superfluous to someone less familiar with the code. EricReceived on Fri May 27 2016 - 18:34:28 UTC
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