[squeak-dev] Fixing Semaphore and SharedQueue

Levente Uzonyi leves at elte.hu
Sun Nov 7 15:47:36 UTC 2010


I uploaded two packages to the Inbox.
Collections-ul.404 is an attempt to fix SharedQueue, so the image can 
survive the following test:

bad := [[Sensor flushNonKbdEvents] repeat] forkAt: Processor userBackgroundPriority.
bad2 := [[Sensor eventQueue peek] repeat] forkAt: Processor userBackgroundPriority.

If the image doesn't freeze in a few seconds, terminate both processes.

The fix seems to be working, but it's incomplete and there are several 
other issues in SharedQueue.

I see three possible solutions:
- fix SharedQueue
- migrate to SharedQueue2 and fix possible issues in Monitor
- migrate to Igor's atomic queue and solve any possible problems

Currently if a process is terminated during a queue operation, the queue 
may break. This also true for SharedQueue2, because it uses Monitor >> 

I also uploaded some fixes to Semaphore which can be found in 
Kernel-ul.514. Most affected methods don't have senders in the image, so 
it's hard to test them. I'd like to ask you to review the code and give 


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