Messages in this thread | | | Date | Sun, 11 Mar 2018 00:36:36 +0100 | From | Andrea Parri <> | Subject | Re: Simplifying our RCU models |
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On Sat, Mar 10, 2018 at 02:47:26PM -0800, Paul E. McKenney wrote: > On Sat, Mar 10, 2018 at 05:29:46PM +0100, Andrea Parri wrote: > > On Sat, Mar 10, 2018 at 08:04:09AM -0800, Paul E. McKenney wrote: > > > On Fri, Mar 09, 2018 at 10:55:20AM +0100, Andrea Parri wrote: > > > > On Thu, Mar 08, 2018 at 04:51:45PM -0800, Paul E. McKenney wrote: > > > > > [ Dropping CC ] > > > > > > > > [...] > > > > > > > > > > > Ah, and any thoughts on how best to get feedback from the various people > > > > > > > who would need to reprogram their fingers? Or is everyone already on > > > > > > > board with changing these various names? > > > > > > > > > > > > Experienced should get there in a week (gcc help); newbies would (have to) > > > > > > rely on either on _properly updated_ documentation or weeks/months of code > > > > > > paging; scripts do the renaming. What am I missing? > > > > > > > > > > Linus's reply to my email? ;-) > > > > > > > > > > More seriously, people who use RCU only occasionally would likely > > > > > have more difficulty adjusting. "What the heck is the new name of > > > > > synchronize_rcu()??? Oh forget it, I will just use a lock. My system > > > > > isn't all that large anyway!!!" > > > > > > > > I did miss this group of people. Thanks, > > > > > > I should hasten to add that we have changed the names of RCU-related APIs > > > before, including synchronize_kernel() -> synchronize_sched() back in > > > the day and SLAB_DESTROY_BY_RCU -> SLAB_TYPESAFE_BY_RCU more recently. > > > There was some discussion around this last change, and one of the things > > > we did to help was to add big comments relating the old and new names. > > > That way, someone grepping for the old name can easily find the new name. > > > > > > But it does cause some churn. So name changes can be a good thing, > > > but we don't undertake them lightly. That said, it has been more than > > > a decades since the last name change in the core RCU API, so it is not > > > too early to consider it. As Linus says, however, we won't be changing > > > just for change's sake. ;-) > > > > Absolutely! > > > > And thank you for these remarks (you know, certainly, I was not properly > > "watching" RCU commits a decade ago or so... ;). But maybe other people > > can find these remarks interesting: please feel free to forward to LKML. > > I should probasbly also add that the name change from SLAB_DESTROY_BY_RCU to > SLAB_TYPESAFE_BY_RCU was motivated by several groups misinterpreting the > old name, and thus spending months each chasing weird race conditions...
[ Bringing back CC ]
Thanks, Andrea
> > Thanx, Paul >
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