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Bug ID: JDK-7029458 G1: Add newly-reclaimed regions to the beginning of the region free list, not the end
JDK-7029458 : G1: Add newly-reclaimed regions to the beginning of the region free list, not the end

Details
Type:
Enhancement
Submit Date:
2011-03-21
Status:
Closed
Updated Date:
2011-04-24
Project Name:
JDK
Resolved Date:
2011-04-24
Component:
hotspot
OS:
generic
Sub-Component:
gc
CPU:
generic
Priority:
P3
Resolution:
Fixed
Affected Versions:
hs21
Fixed Versions:
hs21 (b08)

Related Reports
Backport:

Sub Tasks

Description
Currently, when we reclaim one or more regions we always add them to the end of the free list. Based on testing our performance team did, this seems to be pathological for applications that grow the heap very slowly given that regions that have just been reclaimed will be the last to be re-allocated, which causes us to "churn" unnecessarily through the free regions and touching the entire address space of the G1 heap even though we don't have to.

                                    

Comments
SUGGESTED FIX

When we add reclaimed regions to the free list, they should have added to the front of the free list, not the end.
                                     
2011-03-21
EVALUATION

See Description.
                                     
2011-03-21
EVALUATION

http://hg.openjdk.java.net/jdk7/hotspot-gc/hotspot/rev/455328d90876
                                     
2011-03-30



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