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Bug ID: JDK-7018056 large pages not always enabled by default
JDK-7018056 : large pages not always enabled by default

Details
Type:
Bug
Submit Date:
2011-02-08
Status:
Closed
Updated Date:
2011-04-25
Project Name:
JDK
Resolved Date:
2011-04-25
Component:
hotspot
OS:
solaris,generic,solaris_10,solaris_nevada
Sub-Component:
gc
CPU:
x86,generic
Priority:
P3
Resolution:
Fixed
Affected Versions:
solaris_10u10,solaris_11,hs21,6
Fixed Versions:
hs21 (b05)

Related Reports
Backport:
Backport:
Backport:
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Sub Tasks

Description
Large pages should be enabled by default on Solaris.  When no garbage collector is specified on the command line, large pages are being quietly disabled.

                                    

Comments
EVALUATION

Looks like an unintended consequence of 6888573: class data sharing does not always disable large pages.
                                     
2011-02-08
EVALUATION

http://hg.openjdk.java.net/jdk7/hotspot-gc/hotspot/rev/a2c2eac1ca62
                                     
2011-03-06
EVALUATION

Disable large pages only if class data sharing is possible (i.e., serial gc is in use).

- Move the code that determines whether sharing should be enabled to a new method, set_shared_space_flags().
- Combine the compressed oops checks from check_compressed_oops_compat() into set_shared_space_flags().
   * This is a behavior change: prior to this fix, the vm would exit with an error message if UseCompressedOops and either -Xshare:on or -Xshare:dump was specified on the command line. Now the vm prints a warning and disables UseCompressedOops, which is how other options that conflict with class data sharing are handled (UseParallelGC, UseG1GC, UseLargePages, etc.). The old behavior was also inconsistent between client and server.
- Call set_shared_space_flags() after set_ergonomics_flags() has selected a garbage collector.
- Obsolete the unused var ForceSharedSpaces.
                                     
2011-03-07
EVALUATION

http://hg.openjdk.java.net/jdk7/hotspot-rt/hotspot/rev/a2c2eac1ca62
                                     
2011-03-21
EVALUATION

http://hg.openjdk.java.net/jdk7/hotspot-comp/hotspot/rev/a2c2eac1ca62
                                     
2011-03-25



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