On Mon, 11 Sep 2023 16:10:31 -0700 Ankur Arora <ankur.a.arora@xxxxxxxxxx> wrote: > An even crazier version of that idea would be to have > preempt_disable/enable() demarcate regions, and the compiler putting all > of the preemption disabled region out-of-line to a special section. > Seems to me, that then we could do away to preempt_enable/disable()? > (Ignoring the preempt_count used in hardirq etc.) > I thought about this too, but wasn't sure if it would be easier or harder to implement. This would still require the duplicate functions (which I guess would be the most difficult part). > This would allow preemption always, unless executing in the > preemption-disabled section. > > Though I don't have any intuition for how much extra call overhead this > would add. I don't think this version would have as high of an overhead. You would get a direct jump (which isn't bad as all speculation knows exactly where to look), and it would improve the look up. No table, just a simple range check. -- Steve
