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Bug ID: JDK-8026887 Make issues due to failed large pages allocations easier to debug
JDK-8026887 : Make issues due to failed large pages allocations easier to debug

Details
Type:
Bug
Submit Date:
2013-10-18
Status:
Closed
Updated Date:
2014-04-18
Project Name:
JDK
Resolved Date:
2013-11-06
Component:
hotspot
OS:
Sub-Component:
gc
CPU:
Priority:
P3
Resolution:
Fixed
Affected Versions:
7u40
Fixed Versions:
7u51 (b07)

Related Reports
Backport:
Backport:
Backport:
Relates:

Sub Tasks

Description
There is a known issue in JDK7, JDK-8024218, that may cause crashes if a system running with large pages fails to allocate the large pages and has to fall back to using standard pages. The issue will be fixed in 7u60, but we need to make it easier to debug until then. We should:

1) Fix the error message when failing to allocate large pages. Right now it is:
os::commit_memory(0x00000006b1600000, 352321536, 2097152, 0) failed; 
error='Cannot allocate memory' (errno=12) 

It should be something along the lines of
os::commit_memory(0x00000006b1600000, 352321536, 2097152, 0) failed; 
error='Cannot allocate large pages, falling back to small pages' (errno=12) 

Not sure if small pages is a thing

2) We should add a counter of how many times this has happened, and print it in the hs_err file. This will make it easier for Support and Sustaining to see if a crash may be related to this issue

3) We should document this as a known issue
                                    

Comments
Webrev available at ftp://jrpgftp.se.oracle.com/cce/webrev_8026887/index.html

Still not pushed, there are some questions around where this should go in. The webrev should be enough to get the critical approval though

Critical request motivation:
Since we can't include the fix for the known issue JDK-8024218, we must make it possible to debug if anyone runs into this. The fix should be very safe, it is a change in a warning and an extra variable printed in the hs_err file.
                                     
2013-10-30
No failures in VM nightly with the fix. SQE OK to take it in CPU14_01.
                                     
2013-11-06



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