Number: 847

Date: 26-Apr-84 12':52':03

Submitter: Sannella.PA

Source: Marshall.wbst

Subject: Garbage Collector hangs when GC hash table overflows during reclaim

Assigned To: 

Attn: Masinter, vanMelle

Status: Open

In/By: 

Problem Type: Bug

Impact: Serious

Difficulty: Moderate

Frequency: Everytime

Priority: Hopefully

System: Language Support

Subsystem: Storage Formats/Mgt

Machine: 

Disk: 

Lisp Version: 

Source Files: 

Microcode Version: 

Memory Size: 

File Server: 

Server Software Version: 

Disposition: [tracked it down far enough to change subject]'
["masinter" "24-Sep-84 17':54':41" Subject': Difficulty':(Hard->Moderate) Disposition':]

Description: '
Date': 25 Apr 84 17':04 EST'
From': Marshall.wbst'
Subject': Lisp': Possible garbage collector bug'
To': LispSupport.pa'
cc': Marshall.wbst'
Lisp-System-Date': 26-Jan-84 01':48':36'
Machine-Type': Dorado'
'
The following short program seems to hang the garbage collector':'
'
DEFINEQ((MAKELIST (N) '
	(PROG (I)'
		(RETURN'
			(for I to N collect'
				(LIST 10000 20000 30000 40000 50000))))))'
'
MAKELIST(100000)'
'
When the history list finally forgets the value of the MAKELIST call a very long garbage collection results. At first, there are many disk reads and writes (as indicated by the cursor) but after a minute the cursor indicates no disk activity and the system is hung. I discovered this when My lisp program attempted to release a huge structure similar to this test case.'
'
--Sidney

Workaround: 

Test Case: 

Edit-By: masinter

Edit-Date: 24-Sep-84 17':54':42