JDK-8026887 : Make issues due to failed large pages allocations easier to debug
  • Type: Bug
  • Component: hotspot
  • Sub-Component: gc
  • Affected Version: 7u40
  • Priority: P3
  • Status: Closed
  • Resolution: Fixed
  • Submitted: 2013-10-18
  • Updated: 2015-01-26
  • Resolved: 2013-11-06
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JDK 7
7u51 b07Fixed
Related Reports
Relates :  
JDK-8031787 - Remove fix JDK-8026887 from 7u60
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
No failures in VM nightly with the fix. SQE OK to take it in CPU14_01.
06-11-2013
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.
30-10-2013