Status: Accepted
Owner:
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CC:
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New issue 5167 by
[hidden email]: Fix weak finalization thrashing
http://code.google.com/p/pharo/issues/detail?id=5167==================== Summary ====================
Name: Collections-dtl.469
Author: dtl
Time: 30 December 2011, 12:57:50.064 am
UUID: f8d7d7a5-e127-4108-95ae-6ef48ac43d86
Ancestors: Collections-cmm.468
Fix weak finalization thrashing, root cause of user interrupt issues.
Perform the check for VM support of new finalization once at image startUp
time. This prevents the weak finalization process from creating new weak
references that result in thrashing between VM and image as the VM signals
the the image to clean up weak references, and the finalization process
produces additional weak to be removed.
With this change the finalization process is much less active, and user
interrupt handling works as intended such that any of the following can
interrupted in the expected way:
"[true] whileTrue"
"[[true] whileTrue] forkAt: Processor userSchedulingPriority + 1"
"Smalltalk createStackOverflow"
"[Smalltalk createStackOverflow] forkAt: Processor userSchedulingPriority
+ 1"
=============== Diff against Collections-cmm.468 ===============
Item was changed:
----- Method: WeakArray class>>finalizationProcess (in category 'private')
-----
finalizationProcess
+ | initialized |
+ initialized := false.
+ [FinalizationSemaphore wait.
+ initialized ifFalse: ["check VM capability once at image startup
time"
+ WeakFinalizationList initTestPair.
+ Smalltalk garbageCollect.
- [ WeakFinalizationList initTestPair.
- FinalizationSemaphore wait.
- FinalizationLock critical:
- [
WeakFinalizationList checkTestPair.
+ initialized := true].
+ FinalizationLock critical:
+ [FinalizationDependents do:
+ [ :weakDependent |
- FinalizationDependents do:
- [:weakDependent |
weakDependent ifNotNil:
[weakDependent finalizeValues]]]
ifError:
+ [:msg :rcvr | rcvr error: msg]] repeat!
- [:msg :rcvr | rcvr error: msg] ] repeat!
well, i have doubts that it causing a problem. But yes, a single check
at startup is enough,
except that forcing full GC makes startup slower.
So, making it lazy will be better.
On Jan 10, 2012, at 1:22 PM, Igor Stasenko wrote:
hmm.. but where the startup code?
do they use #restartFinalizationProcess in some startup method?
On 7 January 2012 22:01, Stéphane Ducasse <
[hidden email]> wrote:
[hidden email] via lists.squeakfoundation.org
12/30/11 (8 days ago)
to squeak-dev, packages
David T. Lewis uploaded a new version of Collections to project The Trunk:
http://source.squeak.org/trunk/Collections-dtl.469.mcz==================== Summary ====================
Name: Collections-dtl.469
Author: dtl
Time: 30 December 2011, 12:57:50.064 am
UUID: f8d7d7a5-e127-4108-95ae-6ef48ac43d86
Ancestors: Collections-cmm.468
Fix weak finalization thrashing, root cause of user interrupt issues.
Perform the check for VM support of new finalization once at image startUp
time. This prevents the weak finalization process from creating new weak
references that result in thrashing between VM and image as the VM signals
the the image to clean up weak references, and the finalization process
produces additional weak to be removed.
With this change the finalization process is much less active, and user
interrupt handling works as intended such that any of the following can
interrupted in the expected way:
"[true] whileTrue"
"[[true] whileTrue] forkAt: Processor userSchedulingPriority + 1"
"Smalltalk createStackOverflow"
"[Smalltalk createStackOverflow] forkAt: Processor userSchedulingPriority
+ 1"
=============== Diff against Collections-cmm.468 ===============
Item was changed:
----- Method: WeakArray class>>finalizationProcess (in category 'private')
-----
finalizationProcess
+ | initialized |
+ initialized := false.
+ [FinalizationSemaphore wait.
+ initialized ifFalse: ["check VM capability once at image startup
time"
+ WeakFinalizationList initTestPair.
+ Smalltalk garbageCollect.
- [ WeakFinalizationList initTestPair.
- FinalizationSemaphore wait.
- FinalizationLock critical:
- [
WeakFinalizationList checkTestPair.
+ initialized := true].
+ FinalizationLock critical:
+ [FinalizationDependents do:
+ [ :weakDependent |
- FinalizationDependents do:
- [:weakDependent |
weakDependent ifNotNil:
[weakDependent finalizeValues]]]
ifError:
+ [:msg :rcvr | rcvr error: msg]] repeat!
- [:msg :rcvr | rcvr error: msg] ] repeat!
--
Best regards,
Igor Stasenko.
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