JDK-4851412 : Hotspot JVM should not require a contiguous heap
  • Type: Enhancement
  • Component: hotspot
  • Sub-Component: gc
  • Affected Version: 1.4.0
  • Priority: P5
  • Status: Closed
  • Resolution: Duplicate
  • OS: windows_xp
  • CPU: x86
  • Submitted: 2003-04-21
  • Updated: 2003-09-11
  • Resolved: 2003-09-11
Related Reports
Duplicate :  
Description

Name: jl125535			Date: 04/21/2003


FULL PRODUCT VERSION :
java version "1.4.0_01"
Java(TM) 2 Runtime Environment, Standard Edition (build 1.4.0_01-b03) Java
HotSpot(TM) Client VM (build 1.4.0_01-b03, mixed mode)


FULL OPERATING SYSTEM VERSION :
Microsoft Windows 2000 [Version 5.00.2195]

ADDITIONAL OPERATING SYSTEMS :
Microsoft Windows XP [Version 5.1.2600]


A DESCRIPTION OF THE PROBLEM :
The JVM requires a contiguous chunk of the process's
virtual memory address space.  This is an unreasonable
limitation.

JUSTIFCATION:
There exists an application that we "plugin" to that
makes it impossible to specify a larger heap size to the
JVM (i.e. -Xmx and -XX:MaxPermSize options).  Our attempts
to load/create a JVM in this environment fail because the
virtual address space of the process is fragmented.  Even
though there is over 1.8G of free memory in the process,
the largest contiguous chunk of free memory is
considerably smaller (< 500M).  Neither we, nor the
application can control how virtual memory space is used
(i.e. many third-party plugins) and therefore we have no
control over how much fragmentation occurs.

We need a JVM that can fully utilize ALL the free memory
available to the process (within normal OS constraints ..
i.e. given enough physical memory and/or swap space).

(Review ID: 181087) 
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Comments
EVALUATION re-assigning to GC team for further eval. ###@###.### 2003-04-21 ---------------------------------------------------------------- I think the solution here is "chunked" heaps. As such, I'm closing this as a duplicate of 4408373. ###@###.### 2003-09-11 ----------------------------------------------------------------
11-09-2003