[devel at bb.net] exclusive locks & fairness

[Vitali Lovich]

Hi,

My impression is that there is no fairness for locks currently & that exclusive locks can starve.  Is that true?

In other words, if I have job A that acquires a counting lock & job B acquires an exclusive lock, job B will correctly wait until A is done.  However, if job C comes in & it in turn also acquires a counting lock,
it will continue since it can acquire the lock thus preventing B from running.

Assuming my analysis is correct, is anyone aware of an easy way to fix this (e.g. via some hook point within buildbot) or where I would even start to look for it?
For example, is there a way to test if anything is waiting to acquire a given exclusive lock?  I had a test that just tried to see if it could get the exclusive lock but I just realized that’s broken since it basically just transforms that lock into an exclusive lock.

Thanks,
Vitali