[hackworks]

NetApp has a very interesting implementation RW spin lock inside the kernel. I tried optimizing to make it more fair for writers by introducing a single variable that would be check in each iteration.

The additional delay it added for checking the state resulted in deadlock timer triggering a dump! Hence, checking a variable is very expensive.

[mareko]

If you're interested in very efficient MCS style reader writer locks, check out this paper:

https://people.csail.mit.edu/mareko/spaa09-scalablerwlocks.p...