Excerpts from Waiman Long's message of July 24, 2020 12:29 am: > On 7/23/20 9:30 AM, Nicholas Piggin wrote: >>> I would prefer to extract out the pending bit handling code out into a >>> separate helper function which can be overridden by the arch code >>> instead of breaking the slowpath into 2 pieces. >> You mean have the arch provide a queued_spin_lock_slowpath_pending >> function that the slow path calls? >> >> I would actually prefer the pending handling can be made inline in >> the queued_spin_lock function, especially with out-of-line locks it >> makes sense to put it there. >> >> We could ifdef out queued_spin_lock_slowpath_queue if it's not used, >> then __queued_spin_lock_slowpath_queue would be inlined into the >> caller so there would be no split? > > The pending code is an optimization for lightly contended locks. That is > why I think it is appropriate to extract it into a helper function and > mark it as such. > > You can certainly put the code in the arch's spin_lock code, you just > has to override the generic pending code by a null function. I see what you mean. I guess that would work fine. Thanks, Nick
